J-PARC
ANNUALREPORT2 O 2 O
Vol.2: Materials and Life Science
Experimental Facility

MLF
ANNUALREPORTCover photographs
1 : Sample Preparation at BL11 PLANET
2 : Participation at the Japan Analytical & Scientific Instruments
Show 2020 Exhibition
3 : Japanese Sword Neutron Imaging Analysis

1

4 : Dynamic Nuclear Polarization Experiment at BL17 SHARAKU
2

3

5 : Muon D1 Spectrometer
6 : Inside of a Floral Shaped Beam Duct

4

5

6

Materials and Life Science Division
J-PARC Center
https://mlfinfo.jp/en
J-PARC was jointly constructed and is now operated by the High Energy Accelerator
Research Organization (KEK) and the Japan Atomic Energy Agency (JAEA).

Comprehensive Research Organization for Science and Society
https://neutron.cross.or.jp/en

J-PARC 21-02

MLF Annual Report 2020

Preface

PrefaceToshiya Otomo

Division Head of Materials and Life Science Division, MLF
During the COVID-19 pandemic, a state of emergency was officially announced by the Government of Japan on
April 14. J-PARC was forced to limit users visits for 47 days and imposed an unscheduled outage for 13 days in FY2020.
The difficulties with the users visits affected seriously the user program of the MLF. Because domestic travel was limited and no user could visit the MLF from abroad for experiments, mail-in type experiments were performed with the
dedicated support of the MLF staff. We tried to conduct as many experiments as possible in the 2020A period, however, many experiments were carried over to the 2020B period. Consequently, the available beam time to accept new
proposals in the 2020B period decreased. 2020B and 2021A were called simultaneously.
Personnel exchange programs, such as AONSA Young Research Fellowship and SAKURA program with ESS,
were postponed. Also, the annual meeting of industrial application at the MLF and the Neutron-Muon School werecanceled. Meanwhile, Neutron Advisory Committee, Muon Advisory Committee, J-PARC International Advisory
Committee, Quantum Beam Science Festa, which is an annual conference mainly for domestic users of MLF J-PARC
and IMSS KEK, were held on-line.
The proton power ramp up on the neutron target and instrument upgrades were kept in progress under COVID-19.
In fiscal year 2020, the beam operation started with beam power of 500 kW and the beam power was raised to 600 kW
on May 18. At the end of the beam operation before the summer outage, high-power operation was maintained for36.5 hours at 930 kW from June 25 to 27, much longer than the 10.5 hours achieved in 2019. The validity of the systemdesign regarding a stable 1-MW operation was reconfirmed. A new detector module for a time-of-flight Laue singlecrystal diffractometer installed in BL18, SENJU, was developed based on scintillator and wavelength-shifting fiber
technology. The thickness was reduced to 60% of the original detector. Constructions of the muon beam lines, H-line
and S2 area, progressed. Automatic and remote experiment environments of neutron beam lines were implemented
to realize efficient experiments under COVID-19.
The Efforts to make the user program successfully under COVID-19 conditions will be continued by discussions
with users and sharing know-hows with international facilities.
In the annual report, the research highlights and technical developments in 2020 are described in detail.

Materials and Life Science Division, Japan Proton Accelerator Research Complex
https://mlfinfo.jp/enPreface

MLF Annual Report 2020

Preface

Mitsuhiro Shibayama

Director, CROSSThe Comprehensive Research Organization for Science and Society (CROSS), a partner organization of the Materials
and Life Science Experimental Facility (MLF), is honored to release the J-PARC MLF ANNUAL REPORT 2020, which includes sections on Research and Development Highlights, Neutron Source, Neutron Science, Muon Science, and othertopics. CROSS is the registered institution of the specific neutron beam facilities of J-PARC, accredited in 2011 by theGovernment of Japan, it also supports the activities of the MLF. CROSS is involved in operating the user program andrunning a fair and open proposal selection system for the seven Public Beamlines of the MLF: BL01 4SEASONS, BL02
DNA, BL11 PLANET, BL15 TAIKAN, BL17 SHARAKU, BL18 SENJU, and BL22 RADEN. It provides high-quality user support
and promotes facility utilization for both academic and industrial researchers.
In FY2020, the neutron beam at the MLF was stably operated mostly at 500 – 600 kW, which ensured a highly
reliable machine opera-tion. However, the COVID-19 pandemic affected the beam schedule, selection schedule, experiment styles, and so on. The neutron beam was shut down for a month from April to May, which was followed byan increase of the numbers of proxy experiments and carry-over experiments to the next beam cycle. The proposalround had to be changed to 2020B + 2021A by unifying 2020B and 2021A. The total numbers of (short term) neutron
proposals submitted and accepted in the term of 2020B + 2021A were 400 and 215, respectively, and those for the
Public Beamlines were 203 and 98, respectively. Regarding the outcome, 198 scientific papers (excluding proceedings)
were published from the MLF in 2020, 75 of which were papers from the Public Beamlines. The details are included in
the Research and Development Highlights collected in this volume. The numbers of press releases were 11 from the
MLF and 4 from the Public Beamlines. These numbers illustrate the high activities of the Public Beamlines and the MLF,
which have been used by a wide range of users from the academia and various industries. The special program for newusers “New User Promotion (NUP)”, which started in 2016, was also operated in 2020, and 5 NUP neutron users conducted experiments at the MLF. Long-Term Proposals, started in 2017B, continued its successful run in 2020. 24 FTPs
(Fast Track Proposal) were accepted in 2020 and most of them were conducted at the three BLs (BL08, BL11, and BL21),
that system was extended to seven BLs by adding BL16, BL17, BL18, and BL22.
Regarding public relations, I would like to address the release of a J-PARC MLF pamphlet, which introduces theperformance, instru-ment scientists, and highlights of the beamlines, for the convenience of the MLF users. This pamphlet was released in December 2020 and is available through the web (https://mlfinfo.jp/ja/reports/published.html).
I hope this Annual Report would provide useful information about the current status of the MLF operations andrecent scientific achievements, the technical R&D reports, and so on. On behalf of CROSS, I sincerely welcome your visit
to the MLF.

Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society
https://neutron.cross.or.jp/en

Contents
PrefaceOrganization Chart
J-PARC Map
Muon and Neutron Instruments

Research and Development Highlights
Hierarchical Magnetic Excitations in La2–xSrxCuO4···································································································································

2

Spin Dynamics of a Magnetic Weyl Semimetal Sr1−xMn1−ySb2·············································································································

4

Magnetism Induced by Interlayer Electrons in the Quasi-Two-Dimensional Electride Y2C······················································

7

Dynamics of Proteins with Different Structure in Solution Studied by Quasielastic Neutron Scattering···························

9

Disorder in Crystal Structures of Poly(vinyl Alcohol) and Its Iodine Complex as Revealed by Concerted
WAXD/WAND Data Analysis······································································································································································ 12
Neutron Crystallography Reveals Unprecedented Active-site Structure in Copper Amine Oxidase··································· 14
Features of Neutron Resonance Spin Echo Spectrometer using Time of Flight Method·························································· 17
Effect of Annealing on the Crystal Structure of Li2MnO3-type Cathode Material for Lithium-ion Batteries······················ 19
Novel Atomic Imaging Technique for Light Elements: White Neutron Holography on BL10·················································· 21
Experimental Evidence for the Existence of a Second Partially-Ordered Phase of Ice VI·························································· 23
Quantum Spin Liquid State in a Square-Kagome Antiferromagnet································································································· 26
Neutron Scattering Study on Half-Heusler ZrNiSn································································································································· 29
Multiple Magnetic Bilayers and Unconventional Criticality without Frustration in BaCuSi2O6··············································· 31
Freezable and Unfreezable Hydration Water: Distinct Contribution to Protein Dynamics Revealed by Neutron
Scattering········································································································································································································ 34
Morphological Analysis of Sulfonated Polyphenylene Membranes································································································· 37
Magnetoelectric Responses in the Chiral Polar Magnet Ni2InSbO6·································································································· 40
Water Distribution in Nafion® Thin Films on Hydrophilic and Hydrophobic Carbon Substrates··········································· 43
Interfacial Cross-Link Inhomogeneity of a Phenolic Resin on a Silica Surface as Revealed by XRR and
NR Measurements························································································································································································ 46
Garnet-Type High Li-ion Conductivity Single Crystal as Solid Electrolyte for All-solid-state Li Battery······························· 49
In-situ Neutron Diffraction Analysis on Low Temperature Deformation Behavior in Low Alloy Steel································· 52
In-plane Low Thermal Expansion of NiTi Via Controlled Cross Rolling···························································································· 54
Crystal Structural Investigations for Understanding the Hydrogen Storage Properties of YMgNi4-Based Alloys··········· 57
Identifying Water/ice in Simulated Fuel Cell for Vehicle by Pulsed Neutron Imaging······························································· 59
Polarization Analysis for Small-Angle Neutron Scattering with 3He Spin Filter············································································ 62
A Novel Challenge of Nondestructive Analysis for Medical Inheritances: Identification of OGATA Koan’s Sealed
Medicine by Muonic X-ray Analysis······························································································································································ 64
Detection of Metallic Li Deposition on an Anode of a Li-ion Battery Using Muonic X-rays····················································· 66

Neutron Source
Neutron Source Section···················································································································································································· 70
Target Diagnostic System by Sound Measurement································································································································ 72
Experimaital Characterization of High-Energy Neutrons at NOBORU (BL10)··············································································· 74
Proton Beam Transport for High-Intensity Beam···································································································································· 76

Neutron Science
Neutron Science Section·················································································································································································· 80
BL01: 4D-Space Access Neutron Spectrometer 4SEASONS················································································································· 82
Current Status of BL02 DNA in 2020····························································································································································· 84
Current Status of iBIX in 2020········································································································································································· 86
Neutron Filtering System for keV Neutron Capture Cross Section Measurement at BL04: ANNRI········································ 88
Status of Fundamental Physics Beamline BL05 (NOP) in 2020··········································································································· 90
BL06: Commissioning Status of Village of Neutron Resonance Spin Echo Spectrometers (VIN ROSE)······························· 92
BL08: Commissioning of a New Cryofurnace············································································································································ 94
Current Status of BL09 (SPICA)······································································································································································· 96
BL10: NOBORU····································································································································································································· 98
Development of Piston Cylinder Cells for Diffraction, QENS, and SANS at High Pressures······················································ 99
High Resolution Chopper Spectrometer HRC·········································································································································· 101
BL14 AMATERAS·································································································································································································· 103
Upgrading TAIKAN······························································································································································································ 105
Detector Replacement of Neutron Reflectometer at BL16 SOFIA····································································································· 106
Current Status of SHARAKU: Polarized Neutron Reflectometer········································································································· 108
Status of SENJU 2020························································································································································································· 110
Engineering Materials Diffractometer TAKUMI········································································································································ 112
The Current Status of the Versatile Neutron Diffractometer, iMATERIA·························································································· 114
Status of the High Intensity Total Diffractometer (BL21, NOVA)········································································································ 116
Current Status of the Energy-Resolved Neutron Imaging System RADEN····················································································· 118
Polarized Neutron Spectrometer POLANO················································································································································ 120
Sample Environment at MLF··········································································································································································· 123
A New Position-Sensitive Scintillation Neutron Detector for Obliquely Downward Scattering Bank in SENJU··············· 125
Locally Adaptive Kernel Density Estimation on Quasi-Elastic Neutron Scattering Energy Profiles······································· 127

Muon Science
MUSE Facility Overview···················································································································································································· 130
Present Status of the Muon-Beam Source················································································································································· 133
Development of Monitoring System for the Muon Rotating Target Using an Infrared Camera············································ 135
Muon Beamlines and Control System························································································································································· 136
Current Status of the µSR Experiment at D1············································································································································· 139
Development of Sample Environment at the S1 Area··························································································································· 140
S2 Area Construction - Recent Progress······················································································································································ 143
Commissioning of the μSR Spectrometer at U1A··································································································································· 145
Construction of Transmission Muon Microscope at U1B······················································································································ 147
The Progress of the Laser System for Ultralow Muon Generation····································································································· 148
H-Line Construction – Recent Progress······················································································································································· 150

MLF Safety
Research Safety···································································································································································································· 154

MLF Operations in 2020
Beam Operation Status at the MLF······························································································································································· 158
Users at the MLF·································································································································································································· 160
MLF Proposals Summary – FY2020······························································································································································· 161
MLF Division Staff 2020····················································································································································································· 163
CROSS Staff 2020································································································································································································· 166
Ibaraki Neutron Beamline Staff in 2020······················································································································································ 168
Proposals Review System, Committees and Meetings·························································································································· 169
Workshops, Conferences, Seminars and Schools in 2020···················································································································· 173
Award List·············································································································································································································· 175
MLF Publication 2020························································································································································································ 176
Editorial Board - MLF Annual Report 2020················································································································································· 186

Organization Chart

MLF Annual Report 2020

Organization Chart
Organiza on Chart
Organiza on Chart of
J-PARC Center
Director, J-PARC Center
Deputy Director (JAEA, KEK, Safety)
Safety Division

Organiza on Chart of
CROSS

CROSS is “Registered Ins tu on for facility Use
Promo on” for the public-access neutron
beam facili es at J-PARC.

President
CROSS Head Office

Accelerator Division

Research Center for
Science and Society

Materials & Life Science Division

Neutron Science andTechnology Center

Neutron Source Sec on
Neutron Science Sec on
Neutron Instrumenta on
Sec onMuon Science Sec on
Technology Development
Sec onPar cle & Nuclear Physics Division
Nuclear Transmuta on Division
Cryogenics Sec on
Informa on System Sec on
Administra on Division
Users OfficeDirector, Neutron Scienceand Technology Center
Science Coordinators
R&D Division
U liza on Promo on
Division
Industrial Collabora on
Promo on Division
Safety Division
Administra on Division
New Business Crea on
Division

The Role of CROSS

Under the terms of the legisla on that supports
the Public Neutron Beam Facility, CROSS is
entrusted with specific responsibili es. In
prac cal terms, the core func ons of CROSS canbe summarized as follows:Proposal Selecon and Beamme Allocaonon the Public Beamlines
User Support on the Public BeamlinesEstablishment of an Informaon Resource for
Facility Users
Outreach and Facility Ulizaon PromoonContract Beamline Assessment and SeleconMLF Annual Report 2020

J-PARC Map

J-PARC MAP
CROSS(Ibaraki Quantum Beam Research Center)

J-PARC Center Users Oﬃce

R245

(

KEK Tokai Campus

Main Gate
R245
Linac

HENDEL R&D Building

3 GeV Synchrotron

MLF

50 GeV Synchrotron

J-PARC Research Building

J-PARC Map

S1

S2

25 m

1m

As of March 2021

MLF Annual Report 2020

400 ｍmH LineMuon and Neutron Instruments

Research and Development
Highlights

Research and Development Highlights

MLF Annual Report 2020

Hierarchical Magnetic Excitations in La2–xSrxCuO4
1. Introduction
The relationship between spin correlations and superconductivity in Mott insulators remains a fascinating
issue in condensed matter physics. In the hole-doped
La2–xSr xCuO4 (LSCO), a magnetic excitation spectrum
showing a characteristic shape called “hourglass” excitation in energy(ω)-momentum space is commonly observed in the superconducting phase [1, 2]. The waistenergy of hourglass excitations increases with the superconducting transition temperature upon doping,
and the shape of the waist becomes unclear in the overdoped region [3]. Thus, the origin of such characteristics
is important to be clarified in connection with the mechanism of high-Tc superconductivity. There are theoreticalmodels to reproduce the excitation spectra, such as the
stripe model [4], Fermi surface nesting model [5], andthe spiral model [6]. However, since the experimental
resolution and the observed intensity were insufficientin the previous measurement, distinguishing adequate
models was difficult. Using 4SEASONS (BL01), which provides efficient measurements with the multi-Ei method,
we corrected high-quality data with sufficient statistics.
An analysis based on the two-component model was
performed to determine the detailed shape of magnetic
excitations [7].
2. Experimental details
Inelastic neutron scattering (INS) experiments werecarried out on the optimally-doped (OP) LSCO withx = 0.16. We selected the incident neutron energy of
33.7 meV and 71.1 meV with a chopper frequency of
250 Hz, yielding the energy resolution at the elastic position of 0.8 meV and 2.2 meV, respectively. Comparedto the previous measurements, both the signal-to-noise
ratio and statistical accuracy of the intensity are muchhigher in the present measurement [8]. The improvement in the data quality is due to the removal of the
background and increase of the sample volume. The
high-quality data obtained with better experimental
conditions are essential to provide a new aspect in themagnetic excitations.
3. Results and discussion
So far, the low-ω magnetic excitation has beenthought to form a hourglass dispersion as the positionof the incommensurate (IC) peak gradually approaches(0.5, 0.5) reciprocal position with increasing ω and connects to outwardly dispersive high-ω spin-wave-like2

excitations. However, conventional analysis of our highquality data exhibits a discontinuous behavior in incommensurability (δ) against ω in a narrow range around25 meV (see Fig. 1). This abrupt change of δ is difficult
to understand in either the stripe model or the nestingmodel, suggesting that the existence of only the IC component in the low-ω region is insufficient to reproduce
the observed spectra. We, therefore, analyzed the dataassuming the superimposition of the IC component with
fixed δ and the isotropic commensurate (C) component
peaked at (0.5, 0,5). As shown in Fig. 2, this two-component model reproduced the spectral shape very well. It
was clarified that with increasing ω, the spectral weightof the IC component weakens toward the previously reported Ecross for x = 0.16, whereas the C component gains
the intensity at the high-ω regions. The results of theanalysis suggested a new perspective on the hourglass
excitation. That is, the superposition of two components
with a particular intensity balance forms an hourglassshaped excitation, and Ecross corresponds to ω, where the
C component becomes dominant with increasing ω.
Furthermore, we found out that the IC component
disappears at high temperatures. The thermal evolutionof the excitation revealed the persistence of the IC component to the pseudo-gap state [6] in which anisotropic
gaps are formed in the electronic system. Such anisotropic gaps could be the origin of the steeply standing
IC structure along the ω direction. Therefore, it can beinferred that the IC excitation in the low-ω region is attributed to an electron-hole pair excitation that reflects
the topology near the Fermi surface. On the other hand,
the C component, which is a part of spin-wave-like excitations expanding up to 300 meV, remains even at

Figure 1. Incommensurability as a function of ω evaluated byassuming only an IC component.

MLF Annual Report 2020

Research and Development Highlights

Figure 2. (a) The observed spectra for La2-xSrxCuO4 with x = 0.16 at ω = 18 meV. (b) The reproduced spectra based on
the two-component model and the individual spectra for (c) the commensurate and (d) incommensuratecomponent. (e), (f ) Corresponding spectra along the directions shown in (b).

~300 K without changing the intensity. These features
suggest that the C component reflects predominantly
the collective mode of localized spins with a large exchange coupling, which exists in the parent material.
Therefore, the hourglass excitations seen in the superconductor LSCO are composed of two types of magnetic
excitation whose origin is different and has a hierarchical structure against ω. Similar results were obtained
for the underdoped LSCO with x = 0.10, in which Ecrossis ~35 meV.
The itinerant spin nature has been reported from
INS measurements for the gapped low-ω excitations innearly OP single-layer HgBa2CuO4+y (Hg1201) [9] and OP
double-layer YBa2Cu3O6+y [10]. Especially, Hg1201 showsa C structure. The variety of the spectral shape supports
the strong influence of the structure of the Fermi surface on the low-ω magnetic excitations. By contrast, theoutwardly dispersive high-ω excitation is common tocopper oxides. This common feature suggests that the

localized spin correlation, which robustly remains evenafter carrier doping, is the driving force of high-temperature superconductivity.
References[1] J. M. Tranquada et al., Nature 429, 534 (2004).
[2] B. Vignolle et al., Nat. Phys. 3, 163 (2007).
[3] O. Lipscombe et al., Phys. Rev. Lett. 102, 167002(2009).
[4] M. Vojta and T. Ulbricht, Phys. Rev. Lett. 93, 127002(2004).
[5] M. R. Norman, Phys. Rev. B 63, 092509 (2001) .
[6] Y. A. Kharkov and O. P. Sushkov, Phys. Rev. B 100,
224510 (2019).
[7] M. Sato et al., J. Phys. Soc. Jpn. 89, 114703 (2020).
[8] M. Sato et al., JPS. Conf. Proc. 3, 107010 (2014).
[9] D. Reznik et al, Phys. Rev. B 78, 132503 (2008).
[10] M. K. Chan et al., Phys. Rev. Lett. 117, 277002 (2016).

K. Sato1, K. Ikeuchi2, R. Kajimoto3, S. Wakimoto4, M. Arai5, and M. Fujita6
Department of Science, Tohoku University; 2Neutron Science and Technology Center, CROSS; 3Neutron Science Section, Materials and Life
Science Division, J-PARC Center; 4Materials Sciences Research Center, Japan Atomic Energy Agency; 5European Spallation Source; 6Institutefor Materials Research, Tohoku University

1

3Research and Development Highlights

MLF Annual Report 2020

Spin Dynamics of a Magnetic Weyl Semimetal Sr1−xMn1−ySb2
1. Introduction
Dirac semimetals are featured by two doubly degenerate linear bands crossing at the Dirac point [1–3].
The low-energy quasiparticle excitations near the Diracpoint can be described by the 4 × 4 Dirac equation.
Magnetic Dirac semimetals are particularly intriguing as
they not only exhibit fascinating phenomena but alsooffer a platform for investigating the interplay between
Dirac fermions and spin dynamics.
In recent years, Sr1−xMn1−ySb2 has been suggested
to be a prime candidate, where the net ferromagnetic
moment induces the time-reversal-symmetry breaking,lifts the degeneracy of the Dirac points, and leads to themagnetic Weyl semimetal state [4]. However, whether
and how the topological fermions interplay with themagnons in this particular magnetic Dirac semimetals
remains an open question.

conductivity σxx, which was converted from the ρxx andρxy, using σxx = ρxx/(ρ2 xx + ρ2 xy ). By subtracting the background, we obtained the oscillatory component σxx, as
shown in the inset of Fig. 1(b). These strong de Haas vanAlphen (dHvA) and Shubnikov de Hass (SdH) oscillations
at moderate magnetic field suggest the high mobility
and light effective mass of the carriers.
We have fitted the temperature dependence of theamplitude of M, and the results are shown in Fig. 1(c). We
obtained an effective mass of 0.10(3)m0 for the sample
by averaging the results obtained at several fields. We
further analyzed the dHvA data with a two-frequency
Lifshitz-Kosevich (LK) model, and the results are shownin Fig. 1(d). From the LK fit, we obtained the Berry phaseof 0.3π and π corresponding to the bands of 73.2 and57.2 T, respectively. These strongly indicate that theband structure is topologically nontrivial.

2. Topological electronic properties
We first probed the electronic properties ofSr1− xMn1−ySb2 by measuring the resistivity and magnetization under an external magnetic field. As shown in
Fig. 1(a), the magnetization shows very clear oscillations
at moderate fields. In Fig. 1(b), we plotted the in-plane

3. INS spectra
By performing inelastic neutron scattering (INS)measurements on high-quality single crystals ofSr1− xMn1−ySb2 on 4SEASONS of J-PARC [Figs. 2(a) and(b)] and MERLIN of ISIS [Figs. 2(c) and (d)], we obtained
comprehensive spectra that revealed the spin dynamics

Figure 1.	(a) Oscillatory component of the magnetization (∆M) by subtracting the background at various temperatures. (b) Magnetic-field dependence of the in-plane conductivity (σxx). The solid line indicates the smooth background. The inset isthe oscillatory component (∆σxx) by subtracting the smooth background. (c) Temperature dependence of the oscillatory
amplitude, normalized by ∆M at 2K. The solid line through data is the fit. (d) ∆M at 2K plotted as a function of 1/B. The inset
shows the fast Fourier transform spectra of ∆M which show two oscillating frequencies. The solid line is the fit to ∆M witha two-frequency Lifshitz-Kosevich formula.

4

MLF Annual Report 2020of the material.
In Figs. 2(a) and (b), we present magnetic dispersions along two high-symmetry directions of [100] and[110], respectively, measured with an incident energy Ei
of 100.1 meV at 6K. Along the [100] direction, the excitation spectra disperse from the antiferromagnetic ordering wavevector (1, 0, 0) and reach the band top at about
76 meV at (0.5, 0, 0) and (−1.5, 0, 0) [Fig. 2(a)]. Note thatthe (1, 0, 0) peak is structurally forbidden, and only appears below the antiferromagnetic transition temperature TN of 304K, so these excitations are not contributedby phonons but are purely magnetic. The weak spectral
weight for wave vectors Qs ranging from (−0.5, 0, 0) to(0.5, 0, 0) is due to the small magnetic structure factor.
The signal at the point with H = 0 is expected to be
weak due to the antiferromagnetic structure [4]. The
spin waves remain well defined up to about 70 meV.
Along the [110] direction, the band top is reduced toabout 50 meV, as shown in Fig. 2(b), indicating thestrong anisotropy within the a-b plane. The dispersion
shows a local minimum at (−0.5, 0.5, 0). To probe the

Research and Development Highlights

low-energy excitations, we used an Ei of 16 meV, and theobtained dispersion along the [100] direction is shownin Fig. 2(c). The dispersion in the left panel of Fig. 2(c)clearly shows a spin gap of 6 meV. The gap is also evident
from the cut at (100) along the energy axis [right panelof Fig. 2(c)]. In Fig. 2(d), we plot the dispersion along the[001] direction. The out-of-plane dispersion also exhibits a clear spin gap at 6 meV, and the total band widthis about 5 meV, an order of magnitude smaller thanthose in the plane shown in Figs. 2(a) and (b), consistent with the quasi-two-dimensional crystal structure ofthis material. These spin-wave excitations remain welldefined at high energies, distinct from some iron-based
superconductors where the high-energy excitations arestrongly damped and the spin waves decay into a Stonercontinuum
The INS spectra can be well described by a localized
Heisenberg model with SJ1 ~ 28.0 meV, SJ2 ~ 9.3 meV, SJc~ −0.1 meV and SD ~ −0.07 meV, with no effect from the
topological Weyl electrons as revealed by our transport
results.

Figure 2.	Magnetic dispersions of Sr1−xMn1−ySb2 measured at 6K together with the theoretical calculation results. (a, b) Dispersions
along the [100] and [110] directions, respectively, obtained on 4SEASONS with Ei = 100.1 meV. (c, d) Dispersions along the[100] and [001] directions obtained on MERLIN with Ei = 16 meV. Panel (c) focuses on the low-energy part of (a) to show
the spin gap. In panels (a), (b), and (d), solid lines are the calculated dispersions. The calculated dispersions with intensities
are shown on the right-hand side of each panel to be compared with the experimental data on the left-hand side. Datain (a) and (c) were integrated with K = [−0.2, 0.2] rlu, and all available Ls; data in (b) with a thickness of 0.1 rlu about each
momentum along the [−110] direction; data in (d) with H = [0.8, 1.2] rlu, and K = [−0.2, 0.2] rlu. The dashed line in (c) illustrates an energy scan at (100). The scan profile is plotted on the right-hand side with the energy and intensity being the yand x axis, respectively. The arrow indicates the gap value. In (d), the low-energy part below about 4.5 meV is due to theBragg peaks and some spurious signals, and the broad experimental data can be reproduced by spin-wave calculations
convoluting the instrumental resolution.

5

Research and Development Highlights

MLF Annual Report 2020

4. Discussions and conclusions
In Sr1−xMn1−ySb2, the magnetic excitations are resulting from the local moments in the Mn layers, whereas
the itinerant electrons are contributed by the Sb layers,which are separated from the former [4-8]. The material has a quasi-two-dimensional structure with a large
c-axis constant of 23.1359 Å. The large SdH oscillation
amplitude also indicates that the electronic structure
for Sr1−xMn1−ySb2 is two-dimensional like. Furthermore,
the spin-wave spectra indicate that the magnons are
quasi-two-dimensional as well. Our fitting indicates that
SJ1 and SJ2 are 28.0 and 9.27 meV, respectively, while Jc is
only −0.10 meV, two orders of magnitude smaller. Taking
these into account, it is not surprising that we did notobserve the effect of the itinerant electrons on the spin
dynamics.
To conclude, while our electrical transport and magnetization measurements indicate that Sr1−xMn1−ySb2 is a
topological semimetal, our INS data reveal well-defined
spin waves resulting from the Mn local moments, which

1

1

1

1

can be nicely described using a Hamiltonian including
SJ1 ~ 28.0 meV, SJ2 ~ 9.3 meV, SJc ~ −0.1 meV, and SD~ −0.07 meV. Our results suggest that the topologicalfermions do not impact the magnons. We propose thisto be due to the separated layers of the localized spins
and itinerant carriers and the weak interlayer coupling.
References[1] N. P. Armitage et al., Rev. Mod. Phys., 90 015001 (2018).
[2] T. O. Wehing et al., Dirac material, Adv. Phys., 63 1
(2014).
[3] O. Vafek and A. Vishwanath, Annu. Rev. Condens. Matter
Phys., 5 83 (2014).
[4] J. Y. Liu et al., Nat. Mater., 16 905 (2017).
[5] J. Park et al., Phys. Rev. Lett., 107 126402 (2011).
[6] M. C. Rahn et al., Phys. Rev. B, 95 134405 (2017).
[7] J. R. Soh et al., Phys. Rev. B, 100 144431 (2019).
[8] M. A. Farhan et al., J. Phys.: Condes. Matter, 26 042201(2014).

2

1

1

1

1

Zhengwei Cai , Song Bao , Wei Wang , Zhen Ma , Zhao-Yang Dong , Yanyan Shangguan , Jinghui Wang , Kejing Ran , Shichao Li ,
3
4
5
1
1
1
Kazuya Kamazawa , Mitsutaka Nakamura , Devashibhai Adroja , Shun-Li Yu , Jian-Xin Li , and Jinsheng Wen
1
2
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University; Department of Applied Physics,
3
4
Nanjing University of Science and Technology; Neutron Science and Technology Center, CROSS; Technology Development Section,
5
Materials and Life Science Division, J-PARC Center; ISIS Facility, Rutherford Appleton Laboratory

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MLF Annual Report 2020

Research and Development Highlights

Magnetism Induced by Interlayer Electrons in the
Quasi-Two-Dimensional Electride Y2C
1. Introduction
The electride is a special type of ionic crystal inwhich electrons serve as anions. In contrast to the nearly
free electrons in a metal, the anionic electrons in electrides are loosely bound at the interstitial spaces, whichleads to the unique physical properties of electrides. A
low work function in electrides, especially provides a
fertile field of applications, such as electron injection
layers in organic light-emitting diodes and catalysts forammonia synthesis [1].
Y2C is a quasi-two-dimensional electride. As shownin Fig. 1, Y2C exhibits the anti-CdCl2 type structure withthe space group R-3m. The standard valence states of Y
and C are Y3+ and C4−, respectively; therefore, there are
two excess electrons per formula unit to preserve thecharge neutrality. Density functional theory (DFT) calculations [2] and angle-resolved photoemission spectroscopy [3] have established that these excess electronsin Y2C are mostly confined to the interlayers of [Y 2C]2+
as anionic electrons, and that the anionic s-like orbitals
hybridize with the Y 4d orbitals to form ‘electride bands’
at the Fermi level.
Magnetism arising from the anionic electrons has
been a fundamental issue since the discovery of electrides in the 1980s. Among the reported electrides,
Y2C exhibits unusual magnetic features. For example,
although the magnetic susceptibility of Y2C has CurieWeiss-like temperature dependence, the effective magnetic moments are highly sample dependent. Moreover,Figure 1.	Crystal structure of Y2C and schematics of an anionic electron layer [4].

the estimated Weiss temperatures are negative, as is thecase with antiferromagnets, which stands in sharp contrast with the prediction of the DFT calculations thatY2C is a weak itinerant ferromagnet. More importantly,
which one is the magnetic moment carrier, anionic electrons or Y 4d electrons?
In order to investigate the unusual magnetism of
Y2C, we performed inelastic neutron scattering experiments [4].
2. Experiments
A polycrystalline sample of Y2C was synthesized byan arc melting method. A 2.2 g polycrystalline ingot was
clamped to an Al plate and sealed in an Al sample cellwith He gas. The inelastic neutron scattering measurement was performed by the time-of-flight method using
a near-backscattering spectrometer with high energy
resolution, DNA, installed at BL02 in the MLF, J-PARC.
To survey the range of energy transfer (E) up to 1 meV
while maintaining the high energy resolution (ΔE ~3.6 μeV) and high signal-to-noise ratio (ca. 105) of DNA,
five phases of a pulse shaping chopper were employed.
The intensities were normalized to absolute units withincoherent scatterings after background subtraction.
3. Results and discussion
We observed weak but clear magnetic scattering
around Q ~ 0 at both 7 and 120 K, while no magnetic
order was observed down to 7 K. These results indicatethat the observed scattering comes from ferromagnetic spin fluctuations rather than spin waves in the
ferromagnet. Figure 2(a) shows the E dependence ofthe scattering function S(Q, E) for different values of the
momentum transfer Q at 7 K. The observed S(Q, E) are
well fitted by the conventional function to describe theparamagnetic state of itinerant electrons (see Ref. [4] formore details).
In the nearly ferromagnetic metal, where spin fluctuations with small |Q| and E are dominant, an inverse
lifetime of spin fluctuation ΓQ, which is contained in theabove function, is proportional to |Q|(Q2+κ2), where κis the inverse correlation length. On the other hand, inthe case of a localized moment (Heisenberg) system,
ΓQ in the paramagnetic phase is often proportional
to Q2(Q2+κ2). We found that the proportionality of ΓQ
to |Q|(Q2+κ2) (Fig. 2(b)) is more plausible than that of7

(a)MLF Annual Report 2020

|f (Q)|2 (arb. units)

Research and Development Highlights

T=7K

0.006

Q = 0.175 Å-1

Obs.
Fitting

0.004
0.002

S(Q,E ) (meV-1 f.u.-1)

0
0.006

Q = 0.225 Å-1

0.004

0

0.5

1.0

1.5

2.0

Q (Å )
Q = 0.275 Å-1

0.004

Figure 3.	Estimate of the squared magnetic form factor. For
comparison, the magnetization distribution of a 4d
electron in a single Y atom is also shown (orange
curve). A dotted line is a guide for the eyes [4].

0.002
0
0.006

Q = 0.325 Å-1

0.004
0.002

(SCR) theory [5]. In the case where the parameters of
the system do not reach the so-called Stoner condition
for ferromagnetism, the ground state remains paramagnetic. In such a case, being close to the ferromagnetic
ground state, 1/χ(T) in the SCR theory increases almost
linearly with T at high temperature, which appears likethe Curie-Weiss law with a negative value for the apparent Weiss temperature [5]. This theoretical consequenceis in approximate agreement with the reported propertyof Y2C.

0

-0.2

0

0.2
E (meV)

0.4

0.6

(b)
0.6

ΓQ (meV)

Y0

-1

0
0.006

0.4

0.2
7K
120 K

0

0.05 0.1 0.15 0.2 0.25 0.3 0.35

Q(Q2 + κ2) (Å-3)

Figure 2.	(a) E dependence of S(Q, E) at 7 K. The elastic components between E ± 0.05 meV are masked. (b) ΓQ as
a function of Q(Q2+κ2) [4].

Q2(Q2+κ2). Therefore, we concluded that Y2C is a nearlyferromagnetic metal.
Figure 3 shows the estimated Q dependence ofthe squared magnetic form factor, which is determinedfrom the relative magnitude of the magnetic scattering
intensity around the 003 Bragg point (Q ~ 1.05 Å−1). The
magnetic form factor in Y2C decays faster than that of a
4d electron in a single Y atom. This result provides direct
experimental evidence that the magnetism in Y2C does
not originate from Y 4d electrons, but the anionic electrons in the interlayers.
As we have shown, the magnetic moments are carried by anionic electrons with substantial spatial extension (itinerancy); therefore, it is natural to invoke themode-coupling effect of spin fluctuations as the origin,as described by the self-consistent-renormalization
1,*

0.5
0

0.002

0

1.0

1,2

1

1

4. Conclusion
We performed the inelastic neutron scatteringexperiments to investigate the unusual magnetism inpolycrystalline Y2C. Ferromagnetic spin fluctuations
were successfully observed over a wide temperature
range. Our analyses of the dynamical susceptibility andthe magnetic form factor demonstrated that Y2C is anearly ferromagnetic metal, and the magnetism in Y2C
originates from anionic electrons in the interstitial sites,
rather than from Y 4d electrons. The Curie-Weiss-like behavior of the magnetic susceptibility is ascribed to themode coupling effect as described by the SCR theory.
References[1] C. Liu, et al., J. Mater. Chem. C, 8 10551 (2020).
[2] T. Inoshita, et al., Phys. Rev. B, 92 201109(R) (2015).
[3] K. Horiba, et al., Phys. Rev. B, 96 045101 (2017).
[4] H. Tamatsukuri, et al., Phys. Rev. B, 102 224406 (2020).
[5] T. Moriya, Spin Fluctuations in Itinerant Electron
Magnetism (Springer-Verlag, Berlin, 1985).
3

4

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2,5

H. Tamatsukuri , Y. Murakami , Y. Kuramoto , H. Sagayama , M. Matsuura , Y. Kawakita , S. Matsuishi , Y. Washio , T. Inoshita ,62
N. Hamada , and H. Hosono
12
Condenced Matter Research Center and Photon Factory, Institute of Materials Structure Science, KEK; Materials Research Center for
3
4
Element Strategy, Tokyo Institute of Technology; Neutron Science and Technology Center, CROSS; Neutron Science Section, Materials and56Life Science Division, J-PARC Center; National Institute for Materials Science; Faculty of Science and Technology, Tokyo University of*
Science; Present affiliation: Neutron Science Section, Materials and Life Science Division, J-PARC Center

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MLF Annual Report 2020

Research and Development Highlights

Dynamics of Proteins with Different Structure in Solution Studied by Quasielastic Neutron Scattering
1. Introduction
Under physiological condition (solution state), proteins are not fixed to certain configurations. In otherwords, there is protein internal dynamics (internal dynamics) [1], which could be deeply relevant to the development of their own functions. Hence, the clarificationof this internal dynamics is indispensable for unveilingthe mechanism of their functions. It should be notedthat hydrogen (H) atoms are uniformly distributed inprotein; it is possible to determine the internal dynamics from H atoms in it through incoherent quasielastic
neutron scattering (QENS). We then apply QENS to two
proteins with different molecular architecture to study
their internal dynamics. One is globular domain protein(GDP) and the other is intrinsically disordered protein(IDP). Through the characterizations of their internal dynamics, we can elucidate their origin.
2. Experimental
As examples of GDP and IDP, we selected MurD [2]and the intrinsically disordered region of helicase-associated endonuclease for fork-structured DNS (HefIDR) [3]. Both samples were prepared in D2O buffer inorder to suppress the scattering from the buffer. Protein
solutions of MurD and Hef-IDR (52.0 and 8.0 mg/mL,
respectively) were prepared for the present study. The
QENS measurements were performed using an inverted
geometry time-of-flight spectrometer (BL02 DNA) [4] installed at the Materials and Life Science Experimental
Facility (MLF) in J-PARC, Tokai, Japan. The magnitude of
the scattering vector Q (Q = 4πsinθ /λ f, where 2θ and λ f,
= 6.26 Å are the scattering angle and the wavelengthof the analyzed neutron, respectively) ranged from 0.12
to 1.78 Å−1. From the measurement of vanadium, theresolution function was determined and the energy
resolution (δ E) was calculated to be 12 μeV. The measurements were performed at 298 K.
3. Results and discussion
Figure 1 shows the dynamics scattering laws
(S(Q, ω)) from the MurD and Hef-IDR solutions, respectively. Compared to the resolution function, the spectrafrom both samples broadened, meaning that the dynamics within the present temporal and spatial scales
was detected. It was determined that the observed
S(Q, ω) consisted of approximately three representative

dynamics, translational diffusion, rotational diffusion
and internal dynamic. Namely, we took into consideration the contribution of translational diffusion and rotational diffusion to the observed S(Q, ω). For this purpose,
we had to obtain the translational diffusion (Dt) and rotational diffusion (Dr) constants through an appropriate
procedure. Then, we performed small-angle X-ray scattering (SAXS) measurements on both samples to solve
their structures in solution. Thanks to the assistance ofrecent state-of-the art computational approaches [5, 6],
the solution structures of both samples were solved.
Utilizing such solved solution structures, Dt and Dr values
were computed utilizing the software “HYDROPRO” [7].
Following the procedures proposed by Pérez et al. [8],we computed the S(Q, ω) originating from the translational and rotational diffusions, as shown by green lines
in Fig. 1. It is clearly seen that only the contribution of
the translational and rotational diffusions could not reproduce the observed S(Q, ω), meaning the detection

Figure 1. (a) Pink circles show S(Q, ω) of MurD at Q =1.0 Å−1.
Broken orange, solid green and solid blue lines correspond to the resolution function, S(Q, ω) originating from the translational and rotational diffusionand curve fit with model function [9], respectively.
(b) Blue circles show the experimental S(Q, ω) of
Hef-IDR at Q =1.0 Å−1. Broken orange, solid green,and solid red lines correspond to the resolutionfunction, S(Q, ω) originating from the translationaland rotational diffusion and curve match the model function [9], respectively.

9Research and Development Highlights

MLF Annual Report 2020of internal dynamics of both samples. Referring to thework by Sarter et al. [9], we then adopted the model
function, which included the contribution of the translational diffusion, rotational diffusion and internal dynamic in order to reproduce the observed S(Q, ω) fromboth samples. The details of this model function havebeen covered in our paper [10]. The pink and blue lines
in Fig. 1 show how the results matched our model function for MurD and Hef-IDR, respectively, indicating thatboth S(Q, ω)s were correctly described by this function.
From the results of the match with the model function,
two parameters: relaxation rate (Γ ) and elastic incoherent structure factor (A(Q)) were obtained. Figure 2 (a)shows the Q2 dependence of Γ values from both samples. In agreement with our expectations, the Γ -valuesof Hef-IDR were found to be larger than those of MurD.
It means that the internal dynamics of Hef-IDR is much
faster than that of MurD. We also focused on the Q dependence of A(Q) in Fig. 2 (b) and analyzed it using thefollowing equation:
A(Q)=p*exp(-<u2>Q2)+(1-p),where p and <u 2> correspond to the fraction andthe mean square displacement of mobile H atoms,

Figure 2. (a) Q2 dependences of the Γ values of MurD (pinkfilled circle) and Hef-IDR (blue filled circle), respectively. (b) Q dependences of A(Q)s of MurD (pinkfilled circle) and Hef-IDR (blue filled circle), respectively. Solid lines correspond to the matches theequation in the main text for MurD (pink line) and
Hef-IDR (blue line), respectively.

10

respectively. The p and <u2> values were calculated tobe 0.33±0.07 and 2.1±0.4 Å2 for MurD, and 0.85±0.05
and 2.1±0.2 Å2 for Hef-IDR, respectively. Although the<u2> values of both samples coincided within the experimental error, the fraction of mobile H atoms was higher
in Hef-IDR than that in MurD. This fact must be the originof the internal dynamics’ differences between them.
It is considered that the H atoms located at thesolvent’s accessible surface possess a higher mobility than those buried inside the protein [11]. We thencomputed the solvent’s accessible surface areas (SASA)[10] of the constituent amino acid residues of MurD and
Hef-IDR based on the solution structures resolved by
SAXS measurements. The mean SASA values of MurD
and Hef-IDR were calculated to be 44.1 and 117.2 Å2,respectively, meaning that the mean value of SASA of
Hef-IDR was higher than that of MurD. This made us consider the possibility of a correlation between the internal dynamics and SASA. Then, we adopted the idea thatamino acid residues exposed to a solvent could affectthe internal dynamics. The detailed procedures for determining whether or not H atoms in constituent aminoacid residues are located at solvent’s accessible surface,have been covered in our paper [10]. Finally, we definedsuccessfully the appropriate parameter that can satisfy
the results from SAXS and QENS without inconsistency.
Figure 3 shows the schematic view of amino acid residues in both MurD and Hef-IDR located at the solvent’s
accessible surface area. Such amino acid residues werepredominantly segregated on the surface of MurD, on
the other hand, they were homogenously distributedin the whole structure of Hef-IDR. This finding supports
the idea that the amino acid residues at a surface withaccess to a solvent plays a main role for the internal
dynamics of proteins regardless of protein’s moleculararchitectures.

Figure 3. Schematic view of solvent-exposed amino acid residues for (a) MurD (pink sphere) and (b) Hef-IDR (bluesphere). The red line corresponds to the whole structure of MurD.

MLF Annual Report 2020

4. Outlook
Through the application of the QENS technique, we
succeeded in unveiling the origin of internal dynamics
of protein. We will also apply our established analytical
approach to a biologically significant sample in order
to figure out how the dynamics triggers the functionsof that sample.
References[1] J. A. McCammon and S. Harvey, Dynamics of Proteins
and Nucleic Acids (Cambridge UniversityPress,
Cambridge,1987).
[2] T. Saio et al., Sci. Rep. 5,16685 (2015).
[3] S. Ishino, et al., J. Biol. Chem. 289, 21627 (2014).

Research and Development Highlights[4] K. Shibata et al., JPS Conf. Proc. 8,036022 (2015).
[5] S. Grudinin, M. Garkavenko, and A. Kazennov, Acta
Cryst. D 73, 449 (2017).
[6] D. Schneidman-Duhovny, M. Hammel, J. A. Tainer,and A. Sali, Nucleic Acids Res. 44, W424 (2016).
[7] J. Torre, De La. García, M. L. Huertas and B. Carrasco,
Biophys. J. 78, 719 (2000).
[8] J. Pérez, J. M. Zanotti, and D. Durand, Biophys. J. 77,
454–469 (1999).
[9] M. Sarter et al., J. Phys. Chem. B 124, 324 (2020).
[10] R. Inoue et al., Sci. Rep. 10,21678 (2020).
[11] R. Fraczkiewicz and J. Braun, J. Comp. Chem. 19, 319(1998).

R. Inoue1, T. Oda2,3, H. Nakagawa4,5, T. Tominaga6, T. Saio7, Y. Kawakita5, M. Shimizu1, A. Okuda1, K. Morishima1, N. Sato1, R. Urade1,
M. Sato2, and M. Sugiyama1
1
Institute for Integrated Radiation and Nuclear Science, Kyoto University; 2Graduate School of Medical Life Science, Yokohama City
University; 3Rikkyo University; 4Materials Sciences Research Center, JAEA; 5Neutron Science Section, Materials and Life Science Division,
J-PARC Center; 6Neutron Science and Technology Center, CROSS; 7Institute of Advanced Medical Sciences, Tokushima University

11Research and Development Highlights

MLF Annual Report 2020

Disorder in Crystal Structures of Poly(vinyl Alcohol) and
Its Iodine Complex as Revealed by Concerted WAXD/
WAND Data Analysis
1. Introduction
Poly(vinyl alcohol) [PVA, -(-CH2CH(OH)-)n-] was synthesized in Germany in 1924 and industrialized for the
first time in Japan in 1950 by the Kuraray company. Since
then, PVA (commercial name POVAL) has been utilized ina variety of application fields. PVA in its amorphous stateis soluble in hot water because of the presence of many
OH groups. On the other hand, the high-temperatureannealing of PVA increases the water resistance becauseof the increment of crystalline phase population. In thisway, the property of PVA changes sensitively between
the hydrophobicity and hydrophilicity depending on
the relative content of the crystalline region. This meansthat the basic knowledge of the crystalline phase is indispensable for the development of practical usage of
PVA as one of the most typical multipurpose-polymers.
The study of the crystal structure of PVA was started in 1930s or in the earliest stage of polymer science.
The most plausible crystal structure was reported by
Dr. C. W. Bunn of England in 1948 by the quantitative
analysis of X-ray diffraction data [1]. As shown in Fig. 1,
the planar-zigzag chains are packed face to face so thatthe intermolecular hydrogen bonds are formed effectively between these chains. The thus-proposed model
has been utilized without almost any doubt as the mostbasic structural information in the physicochemical research of PVA in the last 70 years.
In general, the crystal structures of synthetic polymers are determined by the quantitative analysis of thewide-angle X-ray diffraction (WAXD) data, but the reliability of the thus-proposed structure is not very high. It
is because of the relatively poor X-ray diffraction data ofab

Figure 1. Crystal structure of PVA proposed by Bunn [1]12a semi-crystalline polymer substance with small crystallites of low regularity. Different from the single crystalsof small molecules giving several thousands of sharp
diffraction spots, the observable X-ray diffraction peaksof the polymer are only several tens in number, broadand diffuse as a whole. The same situation is observedin the present PVA case. It might be difficult to refine
the structure model proposed by Dr. Bunn as long as
only the X-ray diffraction data are focused as the targetof analysis. We have to change our strategy to increase
the reliability of the X-ray analyzed structure from a different point of view.
2. Combination of WAXD and WAND
We had challenges to utilize the wide-angle neutron diffraction (WAND) data. The large difference inthe atomic scattering power (or cross-sectional area)
between the X-ray and neutron scatterings may give
us a chance to judge the quality of the proposed crystal structure from a different viewpoint. However, one
serious problem was encountered at the starting pointof the WAND experiment: we needed to use the fully
deuterated PVA sample, because the deuterium gives
strong coherent elastic neutron scattering comparable
to that of C and O atoms, which is in a strong contrast
with the hydrogen atom giving a substantially highincoherent scattering as a background. The deuterated PVA sample was kindly synthesized by the Kuraraycompany. The 2D-WAND patterns were measured for thehighly-oriented deuterated PVA and its iodine-complex
samples using the BIX-3 diffractometer of JRR-3 and also
the iBIX system of the MLF, J-PARC. The thus-obtained
WAND data were analyzed in various ways to check thereliability of the Bunn’s model. However, the observed
neutron diffraction profile along the equatorial line, forexample, was not reproduced very well, in strong contrast to the good agreement in the WAXD profiles between the observed and calculated ones.
A similar situation was also observed in the PVAiodine complex sample, which was prepared by immersing the oriented PVA film in an iodine aqueous solution.
The PVA-iodine complex is popular as an optical polarizer, which is utilized for liquid-crystal TV screens,sunglasses etc. The crystal structure of the complex isMLF Annual Report 2020

indispensable for the physicochemical study of the polarizer. The crystal structure derived from the X-ray diffraction data analysis could not reproduce the WAND
data at all [Fig. 2 (a) and (b)]. Different from neutron scattering, X-ray scattering power is larger for an atom thathas larger number of electrons. The scattering power ofthe iodine atom is overwhelmingly stronger than thatof C and O atoms (D, H << C ~ O << I ). Therefore, the
X-ray diffraction pattern is governed mostly by the iodine ion positions in the unit cell. The positions of PVA
chains are difficult to determine precisely. On the other
hand, when the neutron diffraction data are used in the
structure analysis, the neutron scattering power is in theorder of D ~ C ~ O >> I. The crystal structure model ofthe PVA-iodine complex must reproduce consistently
the observed data of WAXD and WAND. In other words,
the combination of these two different kinds of diffraction data may allow us to determine the positions of PVA
and iodine ions without any problem.
(a)

(b)

(c)

(d)

Figure 2.	Comparison of WAXD and WAND profiles of PVAiodine complex between the observed and calculated ones [2]. (a)(b): regular model and (c)(d):slipped-domain model.

3.	New structure models of PVA and PVA-Iodine
complex
After many trial-and-error procedures, we cameup with one new idea, i.e., introduction of disorder inthe crystal lattice. The crystal lattice is assumed to consist of the aggregation of domains built up by a finite
number of unit cells with the regular packing structure(Fig. 1). But these domains are mutually slipped alongthe 110 plane as illustrated in Fig. 3. The slipped-domain

Research and Development Highlights

Figure 3. Slipped-domain model of PVA [2]Figure 4. Crystal structure of the PVA-iodine
complex consisting of
the slipped-domains [2]model satisfied quite well and consistently the observed
diffraction profiles for both the WAXD and WAND data.
The slippages are retained even after the formation of
the PVA-iodine complex (Fig. 4). Different from the caseof the regular structure model [Fig. 2 (a)(b)], the slippeddomain model of the PVA-iodine complex reproduced
also both of WAXD and WAND data without any problem[Fig. 2 (c)(d)].
4. Future prospective
As described here, the harmonic combination of
WAXD and WAND may lead us to the consistent determination of the crystal structure models of crystalline
polymers. However, the actual success stories have been
limited to only a few cases: polyethylene, poly(lacticacid), polyoxymethylene, poly(ethylene oxide), PVA, andso on [2, 3]. The determination of the accurate structure
is indispensable for the quantitatively-reliable prediction of physical property of these polymers. Of course,
the simultaneous analysis of vibrational spectral data
combined with WAXD and WAND data is more suitable
for this purpose.
References[1] C. W. Bunn, Nature, 161, 929 (1948).
[2] K. Tashiro et al., Macromolecules, 53, 6656 (2020).
[3] K. Tashiro et al., Kobunshi Ronbunshu, 71, 508 (2014).

Kohji Tashiro1,2 and Katsuhiro Kusaka3
Professor emeritus, Toyota Technological Institute; 2Guest Professor, Ibaraki University; 3Frontier Research Center for Applied Atomic
Sciences, Ibaraki University

1

13Research and Development Highlights

MLF Annual Report 2020

Neutron Crystallography Reveals Unprecedented
Active-site Structure in Copper Amine Oxidase
1. Introduction
Focusing micro structures is one of the major strategies to unveil principles and fundamentals of biologicalphenomena. Starting with microscopic observation ofcells or bacteria, we are now able to see the smallest
atom, hydrogen/proton, in protein structures. Chemical
reactions in solution, including an enzyme-catalyzing
one, show crucial involvement of protons [1]. Redox enzymes facilitate the catalytic reactions by proton transfers with electron movements. Therefore, great attention
has been paid to neutron crystallography because it
can visualize the specific positions of hydrogen/proton
in protein crystal structures [2]. At extremely high resolution over 1 Å, X-ray crystallography can also detect apart of hydrogen atoms, but not all are detected.
A target enzyme of the present work is copper
amine oxidase (CAO) that catalyzes oxidative deamination of primary amines, having various functions, suchas assimilation of primary amines in bacteria and degradation of bioactive primary amines in animals [3]. All
CAOs are the homodimers of a ~70–95-kDa subunit. The
active site in each subunit contains Cu2+ and redox cofactor topaquinone (TPQ) that is generated from a specific Tyr residue through autocatalytic posttranslational
modification only requiring Cu2+ and molecular oxygen.

It is known that TPQ has a flat structure and a visible
absorption band around 480 nm due to its conjugatedsystem. The catalytic reaction is divided into the initial
reductive half-reaction involving 2e− and 2H+ transferfrom amine substrate to the oxidized TPQ (TPQox) andthe subsequent oxidative half-reaction involving the2e− and 2H+ transfer to molecular oxygen for cofactor
reoxidation. According to involvement of protons, thecatalytic reaction is significantly influenced by pH andthe protonation state of dissociative groups in the activesite. For CAO from Arthrobacter globiformis (AGAO), theneutron crystal structure having TPQox was determinedat high resolution to elucidate the catalytic mechanism(Fig. 1A) [4].
2. Unprecedented cofactor structure
The neutron crystal structure of AGAO was determined at 1.72/1.14-Å resolution by joint refinementwith neutron/X-ray diffraction data for an extra-large
crystal after hydrogen-deuterium exchange in deuterated buffer at pD 7.4 (Fig. 1A) [4]. Subunit size of AGAO
(70 kDa/638 residues) is the largest in the neutron crystal structures reported so far, transcending the previous
limitation for molecular size. The crystal structure unambiguously provides protonation state of dissociable

Figure 1. Neutron crystal structure and TPQ equilibrium of copper amine oxidase from
Arthrobacter globiformis (AGAO). A: Homo-dimeric structure of AGAO. The two
active sites are presented by dotted red circles. B: Equilibrium between enolate
and keto forms of TPQ. H-D exchange found in the crystal structure is shown.

14

MLF Annual Report 2020groups and hydrogen-bond networks in the entire
structure.
Electron density (ED) and neutron scattering lengthdensity (SLD) maps revealed striking features in theactive-site cofactor [4] (Fig. 2A). In contrast with theprevious findings, the TPQ ring was apparently bentwith non-planar geometry. Moreover, the positive SLD
expanded beside the ring C3 position in nearly perpendicular direction against the TPQ plane. These facts
suggest that two deuterium atoms derived from solvent
D2O are covalently attached to the C3 atom, and thatthe conjugated system of the TPQ ring is partially broken. It is apparent that the keto form of TPQ is generated
form the enolate form that has been so far believed as
only a chemical structure of TPQox. We finally refined the
TPQ structure as equilibrated mixture of the keto (41%)
and enolate forms (59%) (Fig. 1B). Interestingly, the side
chain of Asn381 most likely has two conformers, proving the enolate/keto equilibrium (Fig. 2A) [4]. The refined
occupancies were 56% and 44% for the conformers aand b of Asn381, respectively, which are related throughflipping around the Cβ-Cγ rotation. Steric hindrance is
induced between the C3 deuterium atom of the ketoform and the amide protons of the conformer a, causing
rotation of the amide group to the conformer b. Thus,

Research and Development Highlights

the occupancy of the alternative conformer b (44%) ofAsn381 was comparable to that of the keto form (41%).
3. Unusual “levitated” proton
Another striking finding is the presence of a residual positive SLD with a spherical shape between TPQ
O5 and a conserved Asp residue (Asp298) (Fig. 2B) [4,5].
The SLD was not assigned as a water molecule due tothe absence of accompanied ED and the short distancesfrom the surrounding atoms. Following a careful examination, we assigned this SLD as a delocalized deuteriumion (deuteron, D+). It is likely that the D+ is “levitated” atunusual position among three O atoms as follows. The
D+ resides nearly coplanar with three oxygen atoms(Oδ1 and Oδ2 of Asp298 side chain, and O5 of TPQ), but
the distance from either Oδ1 (2.0 Å), Oδ2 (1.6 Å), or O5(1.6 Å) far exceeded the length of a typical O-H covalentbond (ca. 0.95 Å) (Fig. 2B), clearly indicating that the D+ion is non-covalently interacted with the surrounding
oxygen atoms. In addition, the distance between O5 of
TPQ and Oδ1 (3.5 Å) or Oδ2 (2.7 Å) of Asp298 is clearly
longer than that of a typical low-barrier hydrogen bond
(2.2−2.5 Å) [6]. Thus, these results suggest that the detected D+ ion (H+ in H2O) is a triply shared deuteron (proton) in hydrogen bonds. While TPQ O2 and O4 are fixed

Figure 2. Three unprecedented structures found in AGAO. A: Bent structure of TPQox and deuterium atoms covalently attached at the C3 position. The enolate and keto forms of TPQox are indicated.
B: Unusual levitated proton. C: Metal-induced deprotonation of His431. His431 is assigned
as an imidazolate anion (full deprotonated form). A red triangle indicates the deprotonatedHis431 Nδ1. In all panels, gray meshes (negative SLD omit maps) and cyan meshes (positive
SLD omit maps) represent the presence of hydrogen and deuterium atoms, respectively.

15

Research and Development Highlights

MLF Annual Report 2020

effect was also found for axially Cu2+-coordinated water(Wax). The positive SLD for one of two deuterium atoms
covalently bound to the oxygen atom of Wax showed asignificantly lower than the other SLD. While the pKa ofbulk water is 14, it is consistent with the fact that pK aof the water molecule coordinating to the Cu2+ ion isestimated to be 7.5 [9], that is close to data collection
pD (= 7.4).

by tight hydrogen bonds with two water molecules andTyr284 phenolic OH, respectively, it is predicted that thethird tight hydrogen-bond interactions via the shared
proton tether the O5 moiety of TPQ toward Asp298, forcing the TPQ ring to bend. We are unable to find anothershared proton in AGAO, suggesting the specific role of
D+ ion on the catalytic mechanism. Interestingly, several
similar shared protons are being identified in the active
site of the other enzymes including HIV protease [7] andcholesterol oxidase [8] by neutron crystallography. Any
common mechanism buried in the enzyme structure
might generate shared protons as an essential chemical species to enhance the catalytic reaction.

5. Conclusions
The present study reveals unprecedented structuralfeatures in the active-site structure of AGAO. These havenot been identified by previous X-ray crystallographic
studies. Especially, protons (bare hydrogen nuclei) are
impossible to detect by X-ray crystallography since the
X-ray reflection depends on the interaction with electrons. In contrast, neutron crystallography can detecteven protons because neutrons interact with atomic nuclei. We expect that there are unprecedented structuresor unique protons within the other reaction intermediates of AGAO or the other proteins. Neutron crystallography at high resolution will be an essential tool toreveal such unique micro structures.

4. Unusual histidine deprotonation
An interesting protonation state was also foundin Cu2+-ligands (His431, His433, His592, and two watermolecules) taking a distorted pyramidal geometry as
shown in the previous structures (Fig. 2C) [9]. Three imidazole side chains coordinate to Cu2+ through the lonepair of deprotonated Nε2 of His431, Nε2 of His433, andNδ1 of His592. The other imidazole nitrogen atoms of
His433 and His592 were identified as a single protonated form. However, SLD was undetected only for Hδ1
of His431. We assigned His431 as an imidazolate anion(full deprotonated form) despite of extreme high pKa(=14) for the second proton dissociation of free imidazole (Fig. 2C) [4]. It is suggested that Cu2+ can attractelectrons of the imidazole ring to significantly lower its
apparent pKa (metal-induced histidine deprotonation).
The apparent pKa for the second proton of His431 isestimated to be significantly lower than 7.4. All otherHis side chains were single- or double-protonated in
the entire AGAO, suggesting specific environments of
His431. The findings with high-resolution SLD map unambiguously provided the first structural evidence forthe metal-induced deprotonation. Similar pKa-lowering

1

2

2

3

References[1] M. Eigen, Angew. Chem. Int. Ed. Engl. 3 1 (1964).
[2] W. B. O’Dell, et al., Arch. Biochem. Biophys., 602 48 (2016).
[3] G. Floris, and B. Mondovi, Copper Amine Oxidases:
Structures, Catalytic Mechanisms and Role in
Pathophysiology, (C.R.C. Press, Inc., Boca Raton, FL, 2009).
[4] T. Murakawa, et al., Proc. Natl. Acad. Sci. U.S.A., 117
10818 (2020).
[5] Y. C. Chiu, et al., Biochemistry 45 4105 (2006).
[6] W. W. Cleland, Arch. Biochem. Biophys., 382 1 (2000).
[7] O. Gerlits, Angew. Chem. Int. Ed., 55 4924 (2016).
[8] E. Golden, et al., Sci. Rep., 7 40517 (2017).
[9] S. Kishishita, et al., J. Am. Chem. Soc., 125 1041 (2003).

2

4

T. Murakawa , K. Kurihara , T. Tamada , K. Kusaka , M. Adachi , and T. Okajima
2
Faculty of Medicine, Osaka Medical and Pharmaceutical University; Institute for Quantum Life Science, National Institutes for Quantum
3
4
Science and Technology; Frontier Research Center for Applied Atomic Sciences, Ibaraki University; SANKEN, Osaka University

1

16

MLF Annual Report 2020

Research and Development Highlights

Features of Neutron Resonance Spin Echo Spectrometerusing Time of Flight Method
1. Introduction
Neutron spin echo (NSE) [1] is a neutron scattering spectroscopy method with a high energy resolution from picoseconds to sub-microseconds in the time
domain. The NSE method, in which the neutron spin is
manipulated by RF fields, is called neutron resonancespin echo (NRSE) [2]. For measurements covering a wide
space-time range and a variety of sample types, two
resonance type spectrometers, named NRSE and MIEZE,
were constructed at the J-PARC MLF BL06 (Village ofneutron resonance spin echo spectrometers; VIN ROSE).
In the MIEZE instruments, the required spin manipulation to obtain an echo signal is done before the sample
position. This feature is especially useful to examine thespin dynamics and MIEZE spectroscopy was employed to
study the spin fluctuations of the magnetic Skyrmion [3].
In the commissioning of the MIEZE instrument at
BL06 (Fig. 1), the features of resonance spin echo spectrometers using the time of flight (TOF) method in
pulsed neutron sources were studied analytically andexperimentally. We demonstrated that the derivative of
the phase of echo signals with respect to TOF was equal
to the frequency shift in off-echo conditions deviatedfrom the spin echo condition, in which neutrons of all
wavelengths are in phase.
We report the features of MIEZE spectroscopy using
the TOF method (TOF-MIEZE), which are interesting andcan be used to perform an accurate measurement.
2. Experimental setup
The experiment was performed in a simple MIEZE
system with two π/2 spin flippers. The frequencies ofthe first (RSF1) and second (RSF2) flippers were set

Figure 1.	The MIEZE-type spin echo spectrometer at BL06 at
J-PARC MLF.

as f1 = 200 kHz and f2 = 400 kHz, respectively, and the
MIEZE frequency was f2 – f1 = 200 kHz. To test a wide
neutron wavelength band available in the spallation
source of the MLF, the second frame mode, in which
the pulse repetition frequency is 12.5 Hz, was used,while the original one at the MLF is 25 Hz. The spin echo
condition of the system is given by �1𝐿12 =(�2–�1)𝐿2d,
where L12 and L2d denote distances between RSF1 andRSF2, and RSF2 to the detector, respectively. The deviation from the echo condition can be represented by a detuning parameter [4]: Ω = [–�1𝐿12 + (�2–�1) 𝐿2d]/𝐿0d. L0d
denotes the total flight path length of the neutrons. To
investigate the phase and frequency of the TOF-MIEZE
signals when the system deviated from the echo condition (Ω = 0), the positions of RSF1, RSF2 and the detector were changed.
3. Results and discussion
Figure 2 shows the observed frequency shifts andTOF (wavelength) dependency of the phase of the TOFMIEZE signals in various Δyd. In the echo condition, (c)Δyd = 0, the phase is nearly constant over all neutron
wavelengths. In off-echo conditions (Δyd ≠ 0), the phasesof the TOF-MIEZE signal change linearly with the TOF.
The slope of phase vs. TOF plot, Δϕ/Δt increases as
the spatial displacement increases. Good quantitative
agreement was found between the slope, Δϕ/Δt and thefrequency shift, Ω with our analytical model.
These understandings of the phase shift of the TOFMIEZE signals are important to realize a phase correctionin the detector plane. The phase of the MIEZE signal depends on the neutron path length and the phase difference becomes larger as the MIEZE frequency andneutron wavelength increases for high resolution measurements. Figures 3 (a) and (b) illustrate the path length
differences of scattered neutrons on the detector plane.
Unless the detector has a perfect spherical surface, thephase of the MIEZE signal has a position dependence on
the detector plane as shown in Fig. 3 (c). This phase difference can be corrected by applying a time shift on thesignal according to the neutron wavelength and MIEZE
frequency: Δ𝑡  =  Δ𝐿 /𝑣. Here, ΔL and v denotes the path
length difference and neutron velocity. After the phasecorrection, the phase becomes much less dependent on
the position, as shown in Fig. 3 (d).
17Research and Development Highlights

MLF Annual Report 2020

Figure 2.	Phase and frequency shift of the TOF-MIEZE signals
in off-echo conditions with Δyd = +10 (a), +4.0 (b),0.0 (c), –4.0 (d), –10 mm (e). The left column shows
the Fourier transforms of the TOF-MIEZE signal. The
right column shows the TOF dependency of thephase (blue closed circles) and contrast (red lines).

4. Summary
Features of the TOF-MIEZE spectroscopy are reported. The detuning parameter Ω can be a useful indicator
for the deviation from the spin echo condition. The findings enable the accurate and precise tuning of a TOFMIEZE instrument and contribute to the data analysis of
the spectroscopy.
Acknowledgements
This study was conducted in collaboration with
M. Hino, Y. Kawabata (Kyoto University), H. Endo, and
H. Seto (KEK). We thank S. Sato, H. Ohshita, T. Seya,and Y. Yasu (KEK) for the valuable technical support.
The neutron scattering experiment was approved by
the Neutron Scattering Program Advisory Committeeof IMSS, KEK (Proposal Nos. 2009S07, 2014S07 andFigure 3.	(a) layout of a scattering experiment. (b) Phase shift
between the actual MIEZE signal (solid line) and thaton the virtual equidistant surface (dashed line). (c, d)Phase maps on the detector plane of MIEZE signal
for neutron wavelength λ = 0.8 nm without/with
the phase correction.

2019S07). Device developments are supported by the
program of the Development of System and Technology
for Advanced Measurement Analysis (SENTAN), JST,the Photon and Quantum Basic Research Coordinated
Development Program, MEXT Japan, and the Neutron
Scattering Program Advisory Committee of IMSS, KEK(Proposal Nos. 2009S07 and 2014S07). This work is partly supported by JSPS KAKENHI Grants No. JP17K14133,
JP19K20601, and JP19H01856.
References[1] F. Mezei, Z. Phys. 255, 146 (1972).
[2] R. Gähler, R. Golub, and T. Keller, Physica B 180, 899(1992).
[3] T. Nakajima, T. Oda, M. Hino, H. Endo, K. Ohishi, K.
Kakurai, A. Kikkawa, Y. Taguchi, Y. Tokura, and T.
Arima, Phys. Rev. Research 2, 043393 (2020).
[4] T. Oda, M. Hino, H. Endo, H. Seto, and Y. Kawabata,Phys. Rev. Applied 14, 054032 (2020).

T. OdaInstitute for Integrated Radiation and Nuclear Science, Kyoto University (Present address: Institute for Solid State Physics, The University ofTokyo)

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MLF Annual Report 2020

Research and Development Highlights

Effect of Annealing on the Crystal Structure of
Li2MnO3-type Cathode Material for Lithium-ion Batteries
1. Introduction
Layered manganese oxides, such as LiMnO2 (monoclinic, C2/m or orthorhombic, Pmmn), Li2MnO3 (monoclinic, C2/m) and Li 2MnO 3-LiMO 2 (M = Co, Mn, Ni;
hexagonal, R3̄m) solid solution, are attractive cathodematerials for lithium-ion batteries because they are safer,cheaper, less toxic, and have a higher operating voltage
than LiCoO2 and LiNiO2. The Li2MnO3-type cathode materials have attracted much attention among the layered
manganese oxides. We have synthesized the Li2MnO3type materials with and without the substitution of Co.
It was found that the charge-discharge capacity did notdegrade even after repeated charge-discharge cycles in
the Co-substituted material [1] and that the charge-discharge capacity increased when the charge-discharge
cycles in the Li2MnO3 material were repeated without
the substitution of Co [2]. Recently, we found that annealing in a controlled oxygen atmosphere improved
the charge-discharge capacity of the Ni-substituted
Li2MnO3 material. The purpose of this study is to analyze
the changes by annealing in the crystal structure of the
Ni-substituted Li2MnO3 material.
2. Experimental
The Ni-substituted Li2MnO3 samples with the composition of Li1.87Mn0.94Ni0.19O3 were synthesized by coprecipitation technique [1] and annealed at 900°C under anoxygen partial pressure of 10−2 torr. Neutron powder diffraction data of the samples before and after annealing
were taken at room temperature on the time-of-flightneutron powder diffractometer SuperHRPD. The diffraction data were analyzed using a Rietveld refinement
program Z-Rietveld (version 1.1.10) [3, 4] on the basis of
the Li2MnO3-type structure model [1, 2]. The coherent

scattering lengths, b, used for Rietveld refinement, were-1.90 fm (Li), -3.75 fm (Mn) and 10.3 fm (Ni).
3. Results and discussion
The Li2MnO3-type structure has two sites (Li1 andLi2) on the Li layer and a periodic arrangement of theLi3 and Mn sites on the MnO2 layer, which makes it different from the LiCoO2-type structure (hexagonal, R3̄m)that simply has alternating layers of Li and CoO2 (Fig. 1).
We have investigated which cation (Li, Mn and Ni) is substituted at each site (Li1, Li2, Li3 and Mn), based on the
structure model of the previous studies [1, 2]. We candetermine whether Mn or Ni is likely to be substituted ateach site by refining the occupancies of Li because theneutron coherent scattering length increases in the order of Mn, Li and Ni. The occupancies were constrained
so that the cation ratio determined from the occupancies was the same as the composition of the samples.
Table 1 shows the R factors, lattice parameters andoccupancies of the cations. Figure. 2 shows the Rietveld
refinement patterns. The fitting is good and the structure model is supported. While there was no substitution of Ni at the Li2 and Li3 sites in the sample before
annealing, the substitution of Ni at the Li2 site was observed in the sample after annealing. The arrangementof Li and Mn on the MnO2 layer also differed between
the samples before and after annealing (Fig. 3). While
37% of Mn was substituted at the Li1 site in the sample
before annealing, the amount of the substitution of Mn
at the Li1 site became 16% and Li was almost eliminatedfrom the Mn site in the sample after annealing. When theoccupancies of the sample after annealing are refined,
the amount of Li determined from the occupancies exceeds the composition due to the larger occupancy of

Figure 1. Crystal structure of Li2MnO3.

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MLF Annual Report 2020

Table 1.	
R factors, lattice parameters and occupancies of
Li1.87Mn0.94Ni0.19O3 before and after annealing.
Sample Before annealing
R factors
S
2.29
5.25%
Rwp
4.20%
Rp
5.83%
RB
11.61%
RF
2.29%
Re
Lattice parametersa/Å
4.9435(2)b/Å8.5516(4)c/Å5.02758(13)109.270(4)β/°Occupancies
Li1
Li: 0.63(4), Mn: 0.37(4)Li2
Li: 1, Ni: 0
Li3
Li: 1, Ni: 0
Mn
Li: 0.054(18),
Mn: 0.756(18), Ni: 0.19

After annealing
2.13
4.46%
3.59%
6.08%
9.56%
2.09%
4.94463(16)8.5593(3)5.03135(10)109.224(3)Li: 0.84, Mn: 0.16
Li: 0.890(5), Ni: 0.110(5)Li: 1, Ni: 0
Li: 0.00, Mn: 0.86, Ni: 0.14

Figure 2.	Rietveld analysis patterns for Li1.87Mn0.94Ni0.19O3(a) before and (b) after annealing.

Figure 3.	Structure of the MnO2 layer of Li1.87Mn0.94Ni0.19O3(a) before and (b) after annealing. The area inside
the circle shows the amount of the substitution ofeach ion.

Li at the Li1 site. The occupancies at the Li1 and Mn sites
were fixed in the sample after annealing. The findings
indicate that the arrangement of Li and Mn in the MnO2
layer is ordered by annealing. Refining the occupanciesof oxygen at the O1 and O2 site showed no significant
deficiency in both samples.
4. Conclusions
The crystal structure of the Li1.87Mn0.94Ni0.19O3 cathode material, whose capacity is improved by annealing,
before and after annealing was analyzed by neutron
powder diffraction. The results show that the annealing
promoted the ordering of Li and Mn on the MnO2 layer
and the substitution of Ni at the Li2 site.

T. Mochiku
National Institute for Materials Science

20

References[1] K. Ozawa, Y. Nakao, T. Mochiku, Z. Cheng, L. Wang, H.
Iwai, Y. Tsuchiya, H. Fujii and N. Igawa, J. Electrochem.
Soc. 159, A304 (2012).
[2] Y. Nakao, K. Ozawa, Y. Menoto, F. Uesugi, H. Fujii and
T. Mochiku, J. Ceram. Soc. Jpn. 123, 589 (2015).
[3] R. Oishi, M. Yonemura, Y. Nishimaki, S. Torii, A.
Hoshikawa, T. Ishigaki, T. Morishima, K. Mori and T.
Kamiyama, Nucl. Instrum. Meth. Phys. Res. A 600,
94–96 (2009).
[4]	R. Oishi-Tomiyasu, M. Yonemura, T. Morishima, A.
Hoshikawa, S. Torii, T. Ishigaki and T. Kamiyama, J.
Appl. Cryst. 45, 299 (2012).

MLF Annual Report 2020

Research and Development Highlights

Novel Atomic Imaging Technique for Light Elements:
White Neutron Holography on BL10
1. Introduction
For most of the functional materials, or strongly
correlated electron systems, the properties can be controlled by doping foreign elements. From the viewpointof structural physics, it is obvious that changes of atomic
structures around dopants (Fig. 1), called local atomic
structures, must play an important role in transforming
their properties. Recently, atomic resolution holography(ARH) has been developing rapidly in Japan as a directprobe of local atomic structures using fluorescent X‐raysand photoelectrons [1]. ARH has the following important advantages:
1: ARH can visualise three dimensional (3D) atomic
structures around particular atoms (dopants), that is,
ARH has element selectivity.
2: ARH can observe atoms up to 20 Å from thedopants.
3: For visualisation, ARH does not need any models because it can record the change of phases. Consequently,
atomic images can be obtained directly by Fouriertransform.
X-ray ﬂuorescence and photoelectron holography
have already provided plenty of results for investigations of novel functional materials, such as dilute magnetic semiconductors, relaxor ferroelectric materials,
topological insulators, and so on.
Neutron holography was firstly proposed by Cser
et al., and realised by Sur et al. in the Chalk River research
reactor [3, 4]. In Japan, the first neutron holography
experiment was conducted by the authors group in
JRR-3 [4]. However, the accuracy of the atomic images
obtained in the reactor facilities were not sufficient

Figure 1. Local atomic structures around a dopant (orange).

because only one wavelength could be used for experiments. In principle, atomic images obtained by data using one wavelength include many artifacts, which lowers
significantly the accuracy. In 2017, the authors groupsucceeded in enhancing the accuracy of atomic images
drastically by using white neutrons on BL10 in the MLF[5]. One can obtain holography data with 130 different
wavelengths at once. The authors group has already succeeded in visualising local atomic structures in typicalscintillator crystal, 2at% Eu doped CaF2 [5], 0.26at% B
doped Si [6], thermoelectric materials, 0.75at% B doped
Mg2Si [7], and so on. The principle and experimental
specifics are reported elsewhere in detail [6].
2. Recent results
In the typical strongly correlated electrons systema
RB6 (R: rare earth), characteristic phonon softening wasobserved, which results from motions of R in the B cageshown in Fig. 2. On the other hand, when Sm is dopedin RB6 (R: Yb, La), Sm becomes divalent in LaB6, and trivalent in YbB6. Since the difference of ion radii of Sm2+ andSm3+ is ten times larger than that of the lattice constants,
the motions of Sm in YbB6 and LaB6 must be different.
To detect the local behaviour of doped Sm, the authors
observed local atomic structures around Sm in 2at% Sm
doped RB6: (R: Yb, La) on BL10.
Figure 3 shows a local atomic structure in 2at% Sm
YbB6 in a (100) plane including Sm. Yb around doped Sm
are clearly visualised up to 14 Å from Sm. From the estimations of widths of R around Sm, we found that Sm in
YbB6 fluctuates with a mean displacement, σ = 0.25(4) Å,while that of LaB6 is at most σ = 0.15 Å; this is due to the

Figure 2.	Crystal structure of RB6 (R: rare earth). Central Yellow
and green spheres are R and B, respectively.

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Research and Development Highlights

MLF Annual Report 2020

difference in the ion radius. On the other hand, we confirmed that the fluctuations of Yb around Sm are negligible. We successfully visualised B images around Sm as well.
Figure 4 indicates the distance dependence of the intensityof atomic images of B. The dashed line is the theoreticalresult. As shown in Fig. 4, the intensity of the second nearest neighbour (NN) and more distant B are consistent
with the theoretical values, while that of the first NN B
is reduced by 28%. This reduction of intensity can be
explained if the first NN B is fluctuated with σ = 0.28 Å.
These results mean that Sm doping causes fluctuation of
only the first NN B, while Yb and the other B are not affected because of strong covalent bonding of the B cages.
This is the first observation of local structures and local behaviour of dopants and atoms around the dopants in rareearth borides.

Figure 3.	Local atomic structures of Yb in 2at% Sm doped
YbB6[8]. The circles and dashed square are expected
positions of Yb, and the unit cell. (Reprinted withpermission)

3. Summary
The authors group has succeeded in realising investigations of local structures/behaviour of light elements
on BL10. Since light elements play important roles infunctional materials, white neutron holography will be
an indispensable probe for materials science. Note thatwhite neutron holography can be realised only in J-PARC
at the moment; thus, the authors believe that this method will provide a new direction to J-PARC.
References[1] K. Hayashi and P. Korecki, J. Phys. Soc. Jpn., 87,
061003(2018).
[2] L. Cser, et al., Europhys. Lett. 54,747 (2001).
[3] B. Sur, et al., Nature, 414, 525(2001).
[4] K. Hayashi et al., Jpn. J. Appl. Phys. 47, 2291(2008).
[5] K. Hayashi et al., Sci. Adv. 3, e1700294(2017).
[6] K. Ohoyama and K. Hayashi, Phys. Status Solidi B, 255,
1800143 (2018).
[7] K. Hayashi et al., AIP Advances 10, 035115 (2020).
[8] S. Uechi et al., Phys. Rev. B, 102, 054104 (2020).

Figure 4.	Distance dependence of atomic images of B in Sm
doped RB6 (R: Yb, La) [8]. (Reprinted with permission)

K. Ohoyama1 and K. Hayashi2
1
Graduate school of Science and Engineering, Ibaraki University; 2Graduate School of Engineering, Nagoya Institute of Technology

22

MLF Annual Report 2020

Research and Development Highlights

Experimental Evidence for the Existence of a Second
Partially-Ordered Phase of Ice VI
1. Introduction
To date, more than 20 crystalline and amorphous
phases of ice have been reported [1]. This extraordinary
polymorphism makes ice unique with its universality
and has inspired many studies within broad disciplines
of sciences. The structural variety of ice arises from thegeometric flexibility of hydrogen bonds and hydrogenorder-disorder phase transition [2]. A prominent unsolved question [3] concerning the structural diversity
induced by hydrogen ordering is whether a hydrogendisordered phase of ice transforms into only one hydrogen-ordered phase. Since hydrogen-ordering causes
significant changes in the physical property of ice, suchas electric conductivity and dielectricity, the hitherto
undiscovered variety of ice polymorphism would be a
key point to find or control the functionality of ice. We
reported recently a second hydrogen-ordered phase for
ice VI, ice XIX, unambiguously demonstrated by in-situ
dielectric and neutron diffraction measurements underhigh pressure [4]. Although theoretical studies report a
possibility of existence of multiple hydrogen ordering
for ice VI, no experimental studies have found evidenceof multiplicity mainly due to technical difficulties of detecting hydrogen ordering of ice VI under high pressure.

2. Experiments
Comprehensive observation of hydrogen orderingof ice VI was first conducted by dielectric experiments
in a stable pressure range of ice VI, 0.88–2.2 GPa. Ice VI
was initially obtained at room temperature and its dielectric properties were determined in both coolingand heating runs in the temperature range 100–150K,
using a newly developed pressure cell (Fig.1a). Basedon a phase diagram of ice VI and its hydrogen-orderedphases clarified by the dielectric measurement, neutron
diffraction experiments were conducted in a pressure
range, where ice XIX appears, using a pressure-temperature controlling ‘Mito system’ ([5], Fig.1b). Both coolingand heating runs were conducted at each pressure in
the temperature range 80–150K. The neutron diffraction
experiments were conducted at beamline PLANET in the
MLF of J-PARC.
3. Results and discussion
Phase transitions from ice VI to its hydrogenordered phases were observed at around 120–130K,
along with sudden weakening/slowing down of thedielectric response of ice VI with decreasing temperature (Fig. 2a). Based on the slope of the obtained phaseboundary (Fig. 2b), i.e. dT/dP, between ice VI and its

Figure 1.	(a) Schematic drawings of hybrid high pressure cell for dielectric measurement using piston cylinder.
(b) Pressure and temperature controlling system (‘Mito system’) for neutron scattering measurement.

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Research and Development Highlights

MLF Annual Report 2020

Figure 2.	(a) Temperature dependence of dielectric constant and loss of ice VI and ice XIX obtained at 1.9 GPa (left). Pressure changesof temperature dependence of relaxation time of ice VI and ice XIX (right). (b) Phase diagram of ice obtained in this study.

Figure 3.	(a) Temperature changes of neutron diffraction patterns of ice VI and ice XIX obtained at 1.6 GPa.
The blue and black ticks represent all the peak positions expected from the unit cells of ice XIX
and ice XV, respectively. Blue triangles indicate new peaks at 2.20 Å and 2.26 Å, which do notappear from the unit cell of ice XV. (b) Structure models of ice XIX based on the Pcc2 model.

hydrogen-ordered phases changes from negative topositive at 1.5−1.6 GPa with increasing pressure. From
the Clausius–Clapeyron relationship, this sign change
for dT/dP strongly indicates that ice VI has two differenthydrogen-ordered phases with opposite signs for ∆V.
Since the currently known hydrogen ordering from ice VI
to ice XV shows a positive volume change (observed at
the lower pressure, 0.4 GPa, [6]), the hydrogen-ordered24phase in the higher-pressure region is the new phase. A
transition from ice VI to ice XIX was also confirmed in theneutron diffraction experiments at 1.6 and 2.2 GPa, as
the appearance of new peaks due to symmetry lowering(Fig. 3a). Some of the new peaks, e.g. those at 2.20 Å and2.26 Å (indicated by blue triangles in Fig. 3a), cannot be
assigned to the unit cell of ice XV; instead, they can be
assigned to an expanded × × 1 cell with respect toMLF Annual Report 2020

the unit cell of ice VI (the unit cell of ice XV has a 1×1×1
cell with respect to that of ice VI). This is unambiguous
evidence that ice XIX is a new hydrogen-ordered phaseof ice VI. The Rietveld method was applied for structure
analysis of ice XIX considering the group–subgroup relationship between ice VI and XIX and reflection conditions obtained in the neutron experiments. As a result,− and Pcc2 structural models are the most plausible for
P4
the space group of ice XIX. Considering the suggested
space group of ice XV, P −1 [7] or Pmmn [6], centrosymmetry of hydrogen configurations is the most significant
difference in hydrogen configuration between ice XIX
and ice XV. In particular, Pcc2 suggests that a pyroelectric structure, as well as ice XI and its polar direction, isalong the c axis. In addition, the P −4 and Pcc2 structuralmodels include deuterium (hydrogen) atoms whose site
occupancy is 50%; in other words, the models show that
ice XIX is partially ordered state as the Pmmn structure
model by Komatsu et al [6] suggested for ice XV. The− and Pcc2) indicate a possibility of thespace groups (P4existence of another fully hydrogen-ordered phase of
ice VI instead of the partially hydrogen-ordered ice XIX
considering the third law of thermodynamics.

Research and Development Highlights

4. Future plans
We plan to verify the existence of the fully hydrogen-ordered phase of ice VI by applying high pressure and high electric field (HP-HE) neutron diffraction
technique [8]. An electric field may induce the fully hydrogen-ordered phase considering the non-centrosymmety of ice XIX. The HP-HE neutron diffraction technique
has recently been developed by our group to observe
unique structure changes of materials induced in thefrontier region. We hope that the newly discovered diversity of ice polymorphism would spread further in the
P-E phase diagram with intriguing physical properties.
References[1] M. Millot et al., Nature, 569 251 (2019).
[2] E. Whalley, D. W. Davidson and J. Heath, Chem. Phys.,
45 3976 (1966).
[3] C. G. Salzmann, J. Chem. Phys., 150 60901 (2019).
[4] R. Yamane et al., Nat. Commun., 12 1129 (2021).
[5] K. Komatsu et al., High Press. Res., 33 208 (2013).
[6] K. Komatsu et al., Sci. Rep., 6 28920 (2016).
[7] C. G. Salzmann, P. G. Radaelli, E. Mayer and J. L.
Finney, Phys. Rev. Lett., 103 105701 (2009).
[8] R. Yamane et al., Phys. Rev. B, 99 174201 (2019).

R. Yamane1, #, K. Komatsu1, J. Gouchi2, Y. Uwatoko2, S. Machida3, T. Hattori4, H. Ito1, and H. Kagi1
Geochemical Research Center, Graduate School of Science, The University of Tokyo; 2The Institute for Solid State Physics, The Universityof Tokyo; 3Neutron Science and Technology Center, CROSS; 4Neutron Science Section, Materials and Life Science Division, J-PARC Center;#
Present affiliation: Institute for Materials Research, Tohoku University

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MLF Annual Report 2020

Quantum Spin Liquid State in a Square-Kagome
Antiferromagnet
1. Introduction
New insight into the spin behavior in an exotic stateof matter puts us closer to the next-generation spintronic devices. The quantum spin liquid (QSL) state is
an exotic state of a magnet where the spin of electrons,
which generally exhibits order at low temperatures, remains disordered. Observation of a QSL state is one of
the most important goals in condensed-matter physics.
However, the QSL state in two-dimensional (2D) systems
has not been clearly observed in real materials owing to
the presence of site-mixing disorder or deviations from
ideal models. The lack of a suitable model material exhibiting the QSL hinders observations of the QSL statein the 2D spin-1/2 systems.
Square-kagome lattice (SKL) (see Fig. 1(a)) magnet is known as the highly frustrated 2D system. Thereis a possibility that the QSL ground states are realized
in the antiferromagnetic S = 1/2 Heisenberg model on
SKL [1]. However, the lack of a model compound for the
SKL system has obstructed a deeper understanding of
its spin state. Motivated by the present status on the
study of the SKL system, we searched for compoundswith the SKL containing Cu2+ spins and synthesized successfully the first compound of a SKL antiferromagnet,
KCu6AlBiO4(SO4)5Cl [2].

2. Experimental details
Single phase polycrystalline KCu6AlBiO4(SO4)5Cl was
synthesized by the solid-state reaction in which highpurity KAl(SO4)2, CuCl2, CuSO4, CuO, and Bi2O3 powders
were mixed in a molar ratio of 2 : 1 : 6 : 5 : 1, followed byheating at 600°C for three days and slow cooling in air.
The μSR experiments were performed using the spinpolarized pulsed surface-muon (μ +) beam at the D1
beamline of the Materials and Life Science Experimental
Facility (MLF) of the Japan Proton Accelerator ResearchComplex (J-PARC). The spectra were collected in thetemperature range from 58 mK to 300 K using a dilution refrigerator and 4He cryostat. The high-energy INS
experiment was performed on the HRC, installed at
the BL12 beamline in the MLF at J-PARC [3]. A GM-typeclosed cycle cryostat was used to achieve 5 K. The energy
of incident neutrons was Ei = 45.95 meV, which yieldedan energy resolution of Ei = 1 meV at the elastic position. The data collected by HRC were analyzed using thesoftware suite HANA [4]. The INS spectrum in a wide momentum-energy range were measured using the coldneutron disk chopper spectrometer AMATERAS installedin the MLF at J-PARC [5]. The sample was cooled to 0.3 K
using a 3He refrigerator. The scattering data were collected with a set of incident neutron energies, Ei = 1.69,
3.14 and 15.16 meV. The data collected by AMATERAS

Figure 1.	(a) Crystal structure of KCu6AlBiO4(SO4)5Cl. Square- kagome lattice consisting of the Cu2+ions with nearest- neighbor exchange couplings J1, J2, J3 and next-nearest- neighborexchange coupling JX. (b) Crystal structure of KCu6AlBiO4(SO4)5Cl featuring a large interlayer spacing.

26

MLF Annual Report 2020

were analyzed using the software suite UTSUSEMI [6].
3. Results and discussion
The synthesis of KCu6AlBiO4(SO4)5Cl was conceived
following the identification of the naturally occurring
mineral atlasovite KCu6FeBiO4(SO4)5Cl [7]. As shown Fig.
1(a), the SKL in the crystal structure of KCu6AlBiO4(SO4)5Cl
comprises the Cu2+ ions. In each SK unit, the square is
enclosed by four scalene triangles. From this crystal
structure, it is recognized that KCu6AlBiO4(SO4)5Cl has
three types of first neighbor interactions, J1, J2 and J3,
as shown in Fig. 1(a). One prominent and importantfeature of the present structure is the occupancy ofnonmagnetic atoms in the interlayer space of the unit
cell (Fig. 1(b)), which elongate the inter-layer spacing.
Furthermore, the Cu2+ ions and nonmagnetic ions havedifferent valence numbers in KCu6AlBiO4(SO4)5C, avoiding site mixing. Therefore, the crystal perfectness andhigh two-dimensionality of KCu6AlBiO4(SO4)5Cl are ideal
for studying the intrinsic magnetism on frustrated 2D
magnets.

Figure 2.	(a) LF-μSR spectra at representative temperatures.
(b) LF-μSR spectra measured at 58 mK under several
fields. The thick lines behind the data points are thefitted curve

Research and Development Highlights

To determine the magnetic parameters of
KCu6AlBiO4(SO4)5Cl, we calculated the magnetic susceptibility, the magnetization curve at zero temperature. We
succeeded in reproducing the magnetic susceptibility
and magnetization curve of KCu6AlBiO4(SO4)5Cl with the
J1-J2-J3 SKL model with J1 = 135 K, J2 = 162 K, J3 = 115 K
and g = 2.11 (for detail see [2]).
To confirm the absence of spin ordering caused byquantum fluctuations, we performed muon spin relaxation (μSR) experiments using the spin-polarized pulsed
surface-muon (μ +) beam at the D1 beamline of the
J-PARC MLF. Figure 2(a) shows the weak longitudinalfield (LF) (= 50 G) μSR spectra at various temperatures.
The weak LF was applied to quench the depolarization
due to random local fields from nuclear magnetic moments. The spectra are well fitted by the exponentialfunctiona(t) = a1e−λt + aBG
where a1 (= 0.133) is an intrinsic initial asymmetry,aBG (= 0.047) is a constant background, λ is the muon
spin relaxation rate. The weak LF signals at the lowest
temperature (58 mK) decrease continuously without
oscillations up to 15 μs, as shown in Fig. 2(a). The relaxation rates λ at 58 mK is 0.759 μs−1. If this spectrum is due
to static magnetism, the internal field can be estimatedas λ/γ μ (γ μ is the muon gyromagnetic ratio), and thus itshould be less than 10 G. However, as shown in Fig. 2(b),the relaxation is clearly observed, even in the LF at 3950
G, which is evidence for the quantum fluctuation of Cu2+electron spins without spin ordering/freezing.
To grasp the whole picture of the spin excitation,
we performed inelastic neutron scattering (INS) experiments using the high-resolution chopper spectrometer(HRC) and cold-neutron disk chopper spectrometer(AMATERAS) installed in the MLF at J-PARC. As shownin Fig. 3(a), flat signals at around E = 10 and 7 meV wereobserved at 5K. The signal due to magnetic excitationis generally enhanced at low-Q values, whereas phonon
excitation is dominant at high-Q. The signals at around10 and 7 meV increase with decreasing the Q, indicating that it comes from magnetic excitation. As shownin Fig. 3(b), streak-like excitation at Q = 0.8, 1.25, and1.58 Å−1 is clearly visible down to the elastic line, andits intensity increases continuously without signature ofenergy gap at least within the instrumental resolution.
These INS data are consistent with a gapless continuumof spinon excitations. Judging from the findings above,
the flat signals at 10 and 7 meV probably indicate a van
Hove singularity of spinon continuum edges at this energy level.
27

Research and Development Highlights

MLF Annual Report 2020

4. Future plans
Our experimental results strongly suggest the formation of a gapless QSL in KCu6AlBiO4(SO4)5Cl at very
low temperature close to the ground state; however,they are inconsistent with the theoretical studies basedon the J1-J2-J3 SKL Heisenberg model. We calculated the
dynamical spin structure factor S(q, ω) in the SKL modelwith various values of the parameters, but we could not
reproduce the INS experimental results. In the inelastic
neutron-scattering experiment, in the low-energy region, the strongest intensity was registered at aroundQ = 0.8 Å−1 as shown Fig. 3(a), while in the dynamical
DMRG method, it was around Q = 1.3 Å−1 [2]. Therefore,
in order to realize the QSL state in the SKL, we must
impose an additional condition, such as longer-range
exchange interactions. Further experimental and theoretical studies would reveal the conditions, inducing the
QSL state in SKL antiferromagnets.
References[1] K. Morita et al., J. Phys. Soc. Jpn. 87, 043704 (2018).
[2] M. Fujihala et al., Nat. Commun. 11, 3429 (2020).
[3] S. Itoh et al., Nucl. Instr. Meth. Phys. Res. A 631, 90(2011).
[4] D. Kawana et al., J. Phys.: Conf. Ser. 1021, 012014(2018).
[5] K. Nakajima et al., J. Phys. Soc. Jpn. 80, SB028 (2011).
[6] Y. Inamura et al., J. Phys. Soc. Jpn. 82, SA031 (2013).
[7] V. Popova et al., Zap. Vses. Mineral. Obshch. 116, 358(1987).

Figure 3.	(a) INS spectra at 5 K observed using HRC with anincident neutron energy of 45.95 meV. (b) INS spectra at 0.3 K observed using AMATERAS with incident
neutron energy of 3.14 meV.

M. Fujihala1, K. Morita2, R. Mole3, S. Mitsuda1, T. Tohyama2, S. Yano4, D. Yu3, S. Sota5, T. Kuwai6, A. Koda7,8, H. Okabe7,8, H. Lee7,8,S. Itoh9,10, T. Hawai9,10, T. Masuda10,11, H. Sagayama10, A. Matsuo11, K. Kindo11, S. Ohira-Kawamura12, and K. Nakajima121
Department of Physics, Tokyo University of Science; 2Department of Applied Physics, Tokyo University of Science; 3Australian Nuclear
Science and Technology Organisation; 4National Synchrotron Radiation Research Center; 5Computational Materials Science Research Team,RIKEN Center for Computational Science; 6Graduate School of Science and Engineering, University of Toyama; 7Muon Science Section,
Materials and Life Science Division, J-PARC Center; 8Institute of Materials Structure Science, KEK; 9Neutron Science Section, Materials andLife Science Division, J-PARC Center; 10Institute of Materials Structure Science, KEK; 11The Institute for Solid State Physics, The Universityof Tokyo; 12Neutron Science Section, Materials and Life Science Division, J-PARC Center28

MLF Annual Report 2020

Research and Development Highlights

Neutron Scattering Study on Half-Heusler ZrNiSn
1. Introduction
As a typical energy material, the thermoelectric (TE)material can be used to generate electricity based on the
Seebeck effect when a thermal gradient exists or to transfer heat against temperature gradient based on the Peltier
effect when an electric current is applied. The energy conversion efficiency for thermoelectric materials is limitedby the Carnot’s theorem and depends heavily on thematerials’ performance. Practical application of thermoelectric techniques requires to improve further the
performance of thermoelectric materials, which is quantified by the thermoelectric figure of merit, zT = α2σT/(κele + κlat), where α, σ, T, κele and κlat are the Seebeckcoefficient, the electric conductivity, the absolute temperature, the electronic thermal conductivity and thelattice thermal conductivity, respectively. Hence, good
TE materials should be ‘Phonon Glass Electron Crystal’,
which means good electrical transport properties (assessed by the power factor, α2σ) and a low thermal conductivity. However, the relationship between the carrier
concentration and mobility is still a mystery in this area.
2. Experiments
In FY2020, we applied superHRPD and HRC to measure the temperature- and composition-dependence of
ZrNiSn1–xSbx, respectively. Two series of compounds had
been synthesized with/without hot pressed.
3. Study the lattice and phonons by neutron scattering
Half-Heusler (HH) material is a typical TE system
to study both carrier concentration and mobility effects with the formula of ABX (A and B: transition metalelements, X: sp-valent elements such as Sn, Sb ect.).
Figures 1(a) and 1(b) present the crystal lattice and themobility versus concentration of ZrNiSn-based HH TE
compounds at room temperature, respectively [1, 2].
Our recent work demonstrated a comprehensive understanding of both electronic and thermal transport
properties in the ZrNiSn-based HH TE compounds. By
combinations of inelastic neutron scattering, neutron
diffraction, bulk measurements and first-principles calculations, we studied both polycrystalline and singlecrystalline Sb-doped ZrNiSn and revealed that theelectron-phonon interaction was beyond the expected
acoustic phonon scattering, Figs. 2(a)–(d). Specifically,
the ionized impurity, the grain boundary, and the polar optical phonon scatterings were shown to contribute significantly to controlling the electronic transport,
Fig. 2(e). On the other side, those three scatterings could
be well screened by mobile electron gas and the screening effect caused a non-monotonous dependence of themobility on carrier concentration. Finally, we establisheda carrier scattering ‘phase diagram’ in the space of temperature and carrier concentration for the ZrNiSn-based
compounds, Fig. 2(f ), which could not only serve as a
guide for optimizing the thermoelectric performanceof HH thermoelectric materials, but also refresh themethod of designing a new TE system [3]. Furthermore,
the different effects of grain boundary scattering onelectronic and thermal transport properties in lightly
and heavily doped NbFe1–xTixSb compounds provide apractical example for the applicability of the ‘carrier scattering’ phase diagram.

Figure 1.	(a) Schematic of the layered crystal structure of ZrNiSn. (b) Room temperature carrier mobility
versus carrier concentration n/p of several half-Heusler TE compounds [1].

29Research and Development Highlights

MLF Annual Report 2020

Figure 2.	(a) The temperature-dependence of ZrNiSn0.88Sb0.12 by neutron diffraction (superHRPD); (b) S(Q,E) of ZrNiSn byinelastic neutron scattering; (c) Carrier concentration dependence of phonon density-of-state; (d) the simulated
phonon dispersions of ZrNiSn by first-principles calculations; (e) Phonon density-of-state vs LO-TO splitting; (f ) The
phase diagram with single- and poly-crystalline data as function of the carrier concentration at 300 K.

4. Future plans
For the neutron diffraction measurement, we foundthat the atomic ratio of ZrNiSn is not 1 : 1 : 1, and there
are more Ni at different atomic site in the system to scatter phonons and conduct electrons, which is regulatedby the Sb-doping effect. We will analyze the diffraction
data in detail and discuss the extra-Ni effect on the thermoelectricity of Half-Heusler ZrNiSn compound.

References[1] C. Fu et al., Energy Environ. Sci. 8, 216-220 (2015).
[2] Qiu Q et al., Adv. Energy Mater. 9, 1803447 (2019).
[3] Q. Ren et al., Nat. Commun. 11, 3142. (2020).

Q. Ren1, C. Fu2, Q. Qiu3, S. Dai4, Z. Liu1, T. Masuda5, M. Hagihara6,7, S. Lee8, S. Torri6,7, T. Kamiyama6,7, L. He9,10, X. Tong10,11, C. Felser2,
D. Singh12, T. Zhu3, J. Yang4, and J. Ma1
1Shanghai Jiao Tong University; 2Max Planck Institute for Chemical Physics of Solids; 3Zhejiang University; 4Shanghai University; 5Neutron
Science Laboratory, Institute for Solid State Physics, University of Tokyo; 6Neutron Science Section, Materials and Life Science Division,
J-PARC Center; 7Institute of Materials Structure Science, KEK; 8Sokendai (The Graduate University for Advanced Studies); 9Institute ofPhysics, Chinese Academy of Sciences; 10Spallation Neutron Source Science Center, China; 11Institute of High Energy Physics, Chinese
Academy of Sciences; 12University of Missouri-Columbia

30

MLF Annual Report 2020

Research and Development Highlights

Multiple Magnetic Bilayers and Unconventional
Criticality without Frustration in BaCuSi2O6
1. Introduction
A foundation stone of statistical physics is the theory of classical and quantum criticality, which states thatall physical properties around a quantum phase transition (QPT) obey universal scaling laws dependent only
on the dimension of space, d, and the dynamical exponent, z. The idea that perfectly frustrated competinginteractions could lead to an effective reduction of d has
been both proposed [1–2] and contested [3–4] to explain the physics of BaCuSi2O6.
This S = 1/2 material, known as Han Purple from its
use as a pigment in ancient China, presents a three-dimensional (3D) stack of Cu2+ bilayers [Fig. 1] with dominant antiferromagnetic (AF) dimerization, significant
intra-bilayer interactions, and a geometrically exact offset between adjacent bilayers, but was reported to show
2D scaling exponents around the field-induced QPT [1].
The discovery of inequivalent bilayers in BaCuSi2O6 [5, 6]
raised the question of whether geometric frustrationof the inter-bilayer interactions or structural modulation, or both, would be required to explain the apparent dimensional reduction [1]. Intensive investigation[2–4, 6, 7], has not yet resolved this issue, which in fact
has far-reaching implications for any layered material.
A recent ab initio analysis [8] suggested effectively
ferromagnetic (FM) intra-bilayer interactions, which

would preclude the aforementioned frustration. Thus anexperimental determination of the sign of these interactions is crucial for the understanding of this material.
2. Experimental
We have performed high-resolution inelastic neutron scattering (INS) measurements at 0.3 K on the
direct-geometry time-of-flight (TOF) spectrometer
AMATERAS in MLF at J-PARC using a single crystal of
BaCuSi2O6, of weight 1.01 g, aligned with (h 0 l) in the
scattering plane. The data were pre-processed and converted to energy-momentum space using the software
Utsusemi [9]. Figures 2 (a)–2 (d) collect the TOF intensity
data measured on AMATERAS (for incidents neutrons ofenergy Ei = 9 meV) along four high-symmetry directions→
in Q space as functions of energy transfer. Additional
data were collected on EIGER at PSI up to larger values→
in |Q|.
3. Results and discussion
Our results show clearly the presence of three distinct excitations in large regions of the Brillouin zone
[Figs. 2(a), 2(b) and 2(d)]. These must result from threedifferent types of bilayer, and so we label them A, B, andC in ascending order of energy.
We draw attention to the three qualitative features

Figure 1.	Schematic representation of one unit cell of the minimal magnetic model for BaCuSi2O6 ; {Jσ , J’σ , J’’} are Heisenberg interactions. The three distinct bilayer types are labelled A, B, and C. The effective inter-dimer interaction parameters within eachbilayer ( Jσ’ , edges of colored squares) result from four pairwise ionic interactions (inset).

31

Research and Development Highlights

MLF Annual Report 2020of our data, which all lie beyond the results of Ref. [5].
(i) The minima of strongly dispersive modes in
Figs. 2(a) and 2(b), give an unambiguous statement about
the intra-bilayer interactions. (ii) Although the inter-bilayer interaction is very weak, making the bands in Fig. 2(c)almost flat, it can be determined from the variation of
the intensity with Ql . (iii) Where this band dispersion becomes Ql -independent [Fig. 2(d)], the data can be used
to establish the relative intensities of the three separate
bilayer contributions [inset, Fig. 2(h)], from which we deduce a bilayer ratio of A:B:C = 3:2:1 [10].
Figures 3(a)–3(d) show mode energies and intensities→
as a function of Q along two high-symmetry directions,which were extracted by Gaussian fits to energy transfer cuts obtained from the AMATERAS data [Figs. 2(a)and 2(c)] and energy scans measured on EIGER. The
modes A, B, and C could not be resolved individually due
to the lower energy resolution on EIGER. Because thedouble peak structure in intensity of mode A along (0 0Ql ) [Fig. 3(d)] is sensitive to the value of the inter-bilayerinteraction parameter J’’, the mode intensities of A and
B+C are ideal to determine this interaction parameter.
A quantitative fit of the complete mode energy andintensity data [Figs. 3(a)–3(d)] using the model shownin Fig. 1, yields the intra-dimer interaction parameters
J A = 4.275(5), J B = 4.72(1), and J C = 4.95(2) meV, effective→

intra-bilayer interactions J ’A = –0.480(3), J ’B = –0.497(8),and J ’C = –0.57(1) meV, and the inter-bilayer interaction
J ’’= –0.04(1) meV, where J > 0 refers to AF interactions
and J < 0 to FM [10]. These optimal values were used
to model the spectra shown in Figs. 2(e)–2(h), which
are in excellent agreement with the measured spectra [Figs. 2(a)–2(d)]. In addition, these interactions wereused to calculate the mode energies and intensities
shown as solid lines in Figs. 3(a)–3(d). The signs and sizesof these interaction parameters are fully consistent withthe ab initio analysis presented in Ref. [8]. Thus we haveconfirmed experimentally that the intra-bilayer interactions are effectively FM, which makes frustration of theinter-bilayer interactions impossible.
4. Quantum Monte Carlo (QMC) Simulations
These zero-field parameters have immediate consequences for the field-temperature phase diagram
and the field-induced QPT. Figures 3(e)–3(g) show theresults of QMC simulations of the six-bilayer (ABABAC)
model [Fig. 1] using the interaction parameters wedetermined by INS [10]. The critical properties can be
determined from the field-induced triplet densities(ρ A , ρ B , and ρ C ), shown in Fig. 3(f ) for T = 100 mK, whose
behavior agrees with nuclear magnetic resonance measurements [6]. From these we deduce that the effective

Figure 2.	(a)–(d) Intensity, I( Q , ω) measured on AMATERAS for selected high-symmetry directions. (e)–(h) Corresponding spectra
calculated with the fitted interaction parameters. The inset in panel (h) shows the intensity, I (ω) , obtained by integrating→–over the Q ranges [0.95, 105] in Q h , [–0.05, 0.05] in Q k , and [4, 8] in Q l , (denoted by Q l ).

32

MLF Annual Report 2020

triplet tunneling between the bilayers remains finite at
H = H C1 and the dispersion is strongly anisotropic but 3Dwith a critical exponent φ = z /d = 2/3 of a fully 3D QPT.
However, the structural modulation introduces a newenergy scale (J ’’)2/(J B – J A ) [7]. Temperatures above thisenergy scale (approximately 0.04 K) may act to decouple
the A bilayers, leading to an anomalous effective exponent φ (H – H C 1 ) ≳ 0.72 [Fig. 3(g)].

5. Conclusion
The appearance of dimensional reduction near
the QPT [1] is a consequence not of frustration [4] but
only of the inequivalent bilayer units, which causes
an anomalous and non-universal scaling regime. With
rapidly improving technological capabilities for building atomically layered magnetic materials, this type ofknowledge concerning emergent behavior due to layer
modulation will be essential to the design of their physical properties.

Research and Development Highlights

References[1] S. E. Sebastian et al., Nature 441, 617 (2006).
[2] J. Schmalian and C. D. Batista, Phys. Rev. B 77,
094406 (2008).
[3] M. Maltseva and P. Coleman, Phys. Rev. B 72, 174415(2005).
[4] O. Rösch and M. Vojta, Phys. Rev. B 76, 180401(R);ibid. 224408 (2007).
[5] C. Rüegg et al., Phys. Rev. Lett. 98, 017202 (2007).
[6] S. Krämer et al., Phys. Rev. B 76, 100406(R) (2007);
ibid. 87, 180405(R) (2013).
[7] N. Laflorencie and F. Mila, Phys. Rev. Lett. 102,
060602 (2009); ibid. 107, 037203 (2011).
[8] V. V. Mazurenko et al., Phys. Rev. Lett. 112, 107202(2014).
[9] Y. Inamura et al., J. Phys. Soc. Jpn. 82, SA031 (2013).
[10] S. Allenspach et al., Phys. Rev. Lett 124, 177205(2020).
[11] M. Jaime et al., Phys. Rev. Lett. 93, 087203 (2004).

Figure 3.	(a-d) Mode energies and intensities. Lines show calculated results; in (a) and (b) the solid blue line represents themode energy of bilayer B, whereas in (c) and (d) it represents the mode intensity of B+C. The dashed green line
denotes the mode energy of bilayer C calculated in the range where it was not distinguishable in the experiment.
(e-g) QMC results for the ABABAC model [Fig. 1]. (e) (H, T ) phase diagram of the field-induced ordered regime,
compared with experimental data from Refs. [1, 6, 11]. (Inset) Power-law scaling obtained for ABABAC and AB models and compared with the scaling forms of pure 2D (ϕ = 1) and 3D (ϕ = 2/3) criticality. (f ) Triplet populations in thethree types of bilayer shown as functions of field at T = 100 mK. (Inset) Population ratios. (g) Effective exponent,
ϕ , extracted from power-law fits of the QMC data [inset (e)] to a window of width hwindow.

S. Allenspach1,2, A. Biffin3, U. Stuhr3, G. S. Tucker3,4, S. Ohira-Kawamura5, M. Kofu5, D. J. Voneshen6, M. Boehm7, B. Normand1,
N. Laflorencie8, F. Mila4, and C. Rüegg1,2
1
Neutrons and Muons Research Division, Paul Scherrer Institute; 2Department of Quantum Matter Physics, University of Geneva; 3Laboratory
for Neutron Scattering and Imaging, Paul Scherrer Institute; 4Institute of Physics, École Polytechnique Fédérale de Lau-sanne; 5Neutron
Science Section, Materials and Life Science Division, J-PARC Center; 6ISIS Facility, Rutherford Appleton Laboratory; 7Institut Laue Langevin;
8
Laboratoire de Physique Théorique, CNRS and Université de Toulouse33

Research and Development Highlights

MLF Annual Report 2020

Freezable and Unfreezable Hydration Water: Distinct Contribution to Protein Dynamics Revealed by Neutron Scattering
1. Introduction
Water is an indispensable solvent for protein torealize its functions. Especially, water molecules surrounding a protein, i.e. hydration water, play a crucialrole for protein dynamics and functioning [1]. Neutron
scattering is one of the powerful tools to study the effect of hydration on the protein dynamics, because it
can directly monitor the latter by hydrating proteins
with D2O instead of H2O. It is well known that protein
dynamics is activated at ~220 K only when the protein
is hydrated, which has been referred to as the protein
dynamical transition [2]. This activation occurs after the
dynamical coupling between protein and hydration water. However, the details of the coupling have not been
fully understood.
A calorimetric study has determined that there arefreezable and unfreezable types of hydration water existing on the protein surface [3, 4]. Recently, Yamamoto
et al. observed some hydration water freezes when thehydration degree is high [5, 6]. Based on the observation, in this study, we tried to figure out how thesefreezable and unfreezable types of hydration water
contribute to the activation of protein dynamics by using neutron scattering [7]. Freezing was monitored by
q-dependent coherent scattering of ice, whereas protein dynamics were evaluated using energy-dependent
incoherent scattering.
2. Experimental procedure
In this study, we used hen egg lysozyme with a controlled amount of hydration. To exchange solvent H2O or
exchangeable proton of protein by D2O or deuterium,
the protein powder was dissolved in D2O, incubated for
12 h, followed by lyophilization. The procedure was repeated three times. This lyophilized sample was definedas the dehydrated state. Then the dehydrated powder
was hydrated by D2O. To change the amount of freezable hydration water, we prepared three different hydrated samples whose h values were 0.30, 0.37, and 0.48,
respectively, where the h value indicates the mass ratioof water to protein. Above h ~ 0.30, freezable hydrationwater starts to accumulate on the protein surface [3].
The neutron scattering experiment was conducted using BL14, AMATERAS [8]. Data analyses were performed
with the software suite Utsusemi [9].
343. Results
Figure 1 shows q-dependence of elastic scatteringof the hydrated sample, where the data in the range of0 ± 0.05 meV were integrated. The spectra were normalized using integrated values in the range of 0.5 ≤ q ≤1.5 Å−1 at 83 K so that spectra among different hydration levels could be compared per the same amountof protein molecules. At h = 0.37 and 0.48, diffraction
peaks characteristic to ice Ih of D2O were clearly observed at around q = 1.62, 1.72, and 1.82 Å−1 in the lowtemperature regions, which are fairly identical to those
calculated by simulation based on the structure of D2O
ice Ih [10] (indicated by bottom black lines in Fig. 1 in
h = 0.48). On the other hand, no such diffraction patterns were observed in the sample at h = 0.30 or in thedehydrated one at 83 K (Fig. 1(a), gray line shown in h
= 0.30). These results demonstrate that unfreezable hydration water only exists at h = 0.30, whereas freezable
water emerges at the higher hydration levels (h = 0.37
and 0.48), which is consistent with the previous reportin calorimetry where they were termed as uncrystallized
and crystallized types of hydration water [3].
We found that the diffraction peaks possess temperature-hysteresis phenomena in the higher hydrationlevels. The intensity at q = 1.62 Ǻ−1 is plotted in Fig. 1(b)as a representative of the diffraction peaks to confirm
the hysteresis phenomenon. At h = 0.48, the diffraction
peaks disappear at 273 K during heating from 83 K and
re-appear at 243 K during cooling from 293 K. Similar
trend was also observed at h = 0.37, whereas no such
hysteresis occurred at h = 0.30. These data demonstratethat freezable hydration water and not unfreezable hydration water do contribute to the hysteresis phenomenon. This phenomenon is caused by supercooling, as
mentioned in the calorimetry study [3, 4]. This is the firsttime to observe the diffraction of freezable hydrationwater and its temperature hysteresis phenomenon in
neutron scattering.
Because the timescale of translational or rotational
dynamics drastically changes upon freezing or melting,the protein dynamics would also possess a temperaturehysteresis phenomenon if they conjugate with freezing
and melting of hydration water. To monitor how protein
dynamics are affected with the temperature-hysteresis
phenomenon, quasi-elastic scattering from protein
was monitored. The energy resolution (full width at half

MLF Annual Report 2020

Research and Development Highlights

maximum) was 0.1 meV, which corresponded to the resolution time of ~2 × 10−11 s. This means that dynamics fasterthan 2 × 10−11 s can be detected at this setup. Figure 2(a)and (b) shows the intensity plots of the incoherent-scattering spectra in the elastic (E = 0 ± 0.05 meV) and quasielastic (E = 0.2 ± 0.05 meV) regions, respectively, where
the spectra were normalized using integrated values in
the range of 0.5 ≤ q ≤ 1.5 Ǻ−1 at 83 K. In the hydrated
states, apparent kinks were observed at around 220 K
in comparison with the dehydrated state, both in theelastic and quasi-elastic components. This indicates thatthe activation of protein dynamics is induced upon hydration, similar to the protein dynamical transition [11].
However, no temperature hysteresis was observedon the elastic and quasi-elastic scattering components
at h = 0.37 or 0.48, where apparent temperature hysteresis in the formation of ice is observed (shown in the insets of Fig. 2(a) and (b)). This result clearly demonstrates

Figure 1.	(a) q-dependence of the elastic neutron scattering of a hydrated lysozyme integrated at E = 0± 0.05 meV. The left and right panels show scattering profiles obtained in heating and cooling,respectively. The measurement cycle initiated byraising the temperature from 83 to 293 K, followed
by decreasing to 233 K. The spectrum of the dehydrated sample (h = 0.12) at 83 K is also shownin the top of the left panel. The black curves in thebottom of both panels indicate a simulated diffraction pattern of D2O ice Ih based on the crystal
structure. (b) Comparison of temperature dependences of the scattering intensities at 1.62 Å−1 inthe heating and cooling processes, respectively.
Offset values are added on data at h = 0.37 and0.48 for guiding the eyes.

Figure 2.	Elastic (a) and quasi-elastic (b) components of theenergy-dependent spectra, which were normalized by an integrated value at 0.5 ≤ q ≤ 1.5 Å−1 at
83 K. The insets show comparison of the results
obtained in the heating and cooling processes
where offset values are added on data at h = 0.37
and 0.48 for guiding eyes.

35Research and Development Highlights

MLF Annual Report 2020

that the protein dynamics are seldom affected by thehysteresis phenomenon. This indicates that freezable
hydration water does not affect the protein dynamics,
and only unfreezable hydration water contributes to theactivation of protein dynamics. We note here that thedefinition of freezable and unfreezable hydration wateris valid as long as their exchanging rate is slower than
the time scale of protein dynamics, including the temperature range we studied.
The degree of departure from the dehydrated statein the scattering components at h = 0.37 and 0.48 islarger than at h = 0.30, which is due to an increase in thenumber of unfreezable hydration water even after freezable hydration water starts to appear [3, 4]. A slightly
higher activation of protein dynamics at h = 0.48 than
0.37 would be due to a rearrangement of unfreezable
hydration water or its slight increase on the protein surface [2, 12].
4. Discussion
Unfreezable hydration water molecules are thosestrongly perturbed by protein, and thus they are supposed to directly interact with the protein surface via
hydrogen bonds and electrostatic interactions. On theother hand, as our experimental result and previous experiments imply, hydration of freezable water starts tooccur once the number of unfreezable hydration water
is about to reach a plateau [3, 4]. Therefore, the freezable
hydration water molecules could be those interactingwith unfreezable hydration water, and not the protein
surface. In this case, the dynamics of unfreezable hydration water couple with those of protein due to theirstrong interaction, so that the unfreezable hydration water and protein behave as if they were one integrated
structure. Due to their strong interaction, the freezable
hydration water would rather be independent from theunfreezable hydration water or protein, and thus the interaction of freezable hydration water with unfreezable

hydration water would be much weaker. In this situation, the dynamics of the freezable hydration water decouple from those of the unfreezable hydration water,which could thus cause the dynamical decoupling offreezable hydration water from protein.
5. Future Plans
Using a different neutron spectrometer, such as BL02,
DNA, it would be quite interesting to see if the dynamic
decoupling observed in this study is still valid in a slower
time scale, such as nanosecond or microsecond, in which
proteins would realistically be functioning. Moreover, theoretical studies will help to reach a deeper understanding of the phenomenon.
References[1] J. A. Rupley and G. Careri, Adv. Protein. Chem. 41,
37-172 (1991).
[2] J. H. Roh, et al., Biophys. J., 91, 2573-2588 (2006).
[3] A. Panagopoulou, et al., Food Biophys., 6, 199-209(2011).
[4] A. Panagopoulou, et al., BBA-Proteins Proteom.,
1814, 1984-1996 (2011).
[5] N. Yamamoto, et al., J. Phys. Chem. B, 122, 1367-1377(2018).
[6] N. Yamamoto, et al., J. Phys. Chem. B, 120, 4743-4755(2016).
[7] N. Yamamoto, et al., J. Phys. Chem. Lett., 12, 21722176 (2021).
[8] K. Nakajima, et al., J. Phys. Soc. Jpn., 80, SB028(2011).
[9] Y. Inamura, et al., J. Phys. Soc. Jpn., 82, SA031 (2013).
[10] S. W. Peterson and H. A. Levy, Acta Cryst., 10, 70-76(1957).
[11] S. Magazu, et al., J. Phys. Chem. B, 115, 7736-7743(2011).
[12] H. Nakagawa and M. Kataoka, J. Phys. Soc. Jpn., 79,083801 (2010).

N. Yamamoto1, M. Kofu2, K. Nakajima2, H. Nakagawa2,3, and N. Shibayama1
School of Medicine, Jichi Medical University; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center; 3Materials
Sciences Research Center, JAEA

1

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MLF Annual Report 2020

Research and Development Highlights

Morphological Analysis of Sulfonated Polyphenylene
Membranes
1. Introduction
Proton conductive or proton exchange membranes(PEMs) have attracted considerable attention in applications to energy devices, such as fuel cells, batteries, andwater electrolyzers. Perfluorosulfonic acid (PFSA) ionomer membranes have been used mostly as state-of-theart PEMs because of their high proton conductivity, thinmembrane flexibility, and dimensional and chemical stabilities [1, 2]. Sulfonated hydrocarbon PEMs which do
not contain fluorine atoms are regarded as promising alternatives to PFSA ionomer membranes because of theirpotential cost effectiveness, wide variety of molecular
structures, and environmental compatibility.
In the present study, we have examined the structure of sulfonated polyphenylene (SPP) membranes as
emerging hydrocarbon PEMs [3–5]. In particular, theeffect of meta- and para-phenylene sequence on themorphology and properties of the SPP membranes wasinvestigated via NMR, TEM and SANS technique undercontrolled temperature and humidity conditions.
2. NMR analyses
Three kinds of sulfonated polyphenylenes, SPP-MP,-BP, and -QP (Fig. 1a), were synthesized from dichlorobenzenes, dichlorobiphenyls, and dichloroquinquephenylene, respectively, as hydrophobic comonomers.
Figure. 1b shows 1H NMR spectra obtained for the SPPMP, -BP, and -QP (intensity was normalized by the largest
aromatic peak of 1). Because of the similar composition(unsubstituted meta-phenylene / unsubstituted paraphenylene / sulfonated para-phenylene ratio), the 1H
NMR spectra were very similar. One of the noticeable

differences was observed at ca. 7.9 ppm, assignable
to the protons 4 in the unsubstituted para-phenylene
connected with the unsubstituted meta-phenylene. The
signal intensity at ca. 7.9 ppm was in the order SPP-QP> -MP > BP, suggesting this sequence (i.e., the unsubstituted para-phenylene - the unsubstituted meta-phenylene) was most contained in the SPP-QP. The result isreasonable considering the fact that the unsubstituted
para-phenylene in SPP-QP is connected solely with theunsubstituted meta-phenylene, while all components(unsubstituted meta-phenylene, unsubstituted paraphenylene, and sulfonated para-phenylene) can be connected with each other for SPP-BP and -MP.
Another significant difference was observed in the
integral ratio of the three signals at ca. 8.0–8.5 ppm
correlated with the protons a in the sulfonated paraphenylene (SP). We assigned the three peaks of protons
a, as “unsubstituted phenylene - SP (a1) - unsubstituted
phenylene”, “SP - SP (a2) - unsubstituted phenylene”, and“SP - SP (a3) - SP” (Fig. 1c), and defined the integral ratio of (a1/a1+a2+a3) as the randomness of the SP unitor the isolated hydrophilic component (SP) ratio in the
backbone for SPP-QP prepared with different polymerization promoters (please note that peaks a3 and 2 wereoverlapping). The ratio of a3 was calculated using thefollowing equation:

3 =

−

− 2

−

1 −

2

(1)

where I is the total and a1, a2 and a3 are the integral values estimated from the 1H NMR spectra, N is the numberof protons in the hydrophobic components, and X andY are the compositions of hydrophilic and hydrophobic

Figure 1.	(a) Chemical structures and (b) 1H NMR spectra of SPP-MP, SPP-BP, and SPP-QP.
(c) Possible sequences of the sulfophenylene (SP) units.

37

Research and Development Highlights

MLF Annual Report 2020

segments calculated from the titrated ion exchange capacity (IEC) values. The randomness of the SP unit wascalculated using the titrated IEC values and was in theorder, SPP-MP (51%) > -BP (32%) > -QP (19%), indicating that the hydrophobic components dominated thesequence of the hydrophilic component.
3. TEM images
Transmission electron microscopic (TEM) images
were obtained to examine the effect of the sequence(or randomness) of the hydrophilic components on themembrane morphology under dry conditions. Figure 2
shows the cross-sectional TEM images of the SPP-MP,-BP, and -QP membranes stained with Pb2+ ions, in which
the dark areas represent the hydrophilic clusters composed of lead-stained sulfonic acid groups and bright areas represent the hydrophobic clusters. The membranes
showed typical phase-separated morphology based on
the hydrophilic/hydrophobic differences in the components, although the interfaces of the domains were notvery distinct due to the rigid polyphenylene structure.
The size of the clusters was in the order, SPP-MP (ca. 1.8± 0.4 nm) = -BP (ca. 1.8 ± 0.3 nm) < -QP (ca. 2.8 ± 0.2 nm)
for hydrophilic, and SPP-MP (ca. 1.9 ± 0.4 nm) = ‑BP (ca.
2.0 ± 0.5 nm) < -QP (ca. 2.7 ± 0.8 nm) for hydrophobic,

respectively. The result is reasonable, because the higher
randomness should lead to a smaller sequence of thehydrophilic component. As the randomness increased,
more isolated SP units must have been included, suppressing the self-aggregation of the components.
4. SANS analyses
To investigate the morphology of the SPP membranes and the structure of the absorbed water molecules, SANS measurements were carried out at 80°C
under controlled humidity. Deuterium has a large positive coherent scattering length, while hydrogen has anegative scattering length, and thus, hydrophilic clusters adsorbing D2O have large contrast in comparison
to the hydrophobic clusters. Figure 3 shows SANS patterns of SPP-MP, -BP, and -QP membranes humidified
with D2O. Weak peaks were observed for SPP-BP and -QP
membranes, while no peaks were observed for SPP-MP
membrane under dry conditions (0% RH). As the humidity increased, the scattering intensity increased inall samples. SANS patterns were more related with thestructure of water filling in the membranes. The development of the peak (ca. q = 0.7 nm−1) with humidity wasmost pronounced for the SPP-QP membrane. From thebackground-subtracted profiles, the slopes in the Porod

Figure 2.	TEM images of (a) SPP-MP, (b) SPP-BP, and (c) SPP-QP membranes.

Figure 3.	SAXS patterns of (a) SPP-MP, (b) SPP-BP, and (c) SPP-QP membranes humidified with D2O.

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MLF Annual Report 2020

region were roughly estimated to be ca. -1 for SPP-MP, -2
for -BP, and -3 for -QP membranes at 80% RH, suggestingthat water clusters were rod-like for -MP, thin disk-like for-BP and more spherical for -QP membranes. At 80% RH,
the d values were 3.1 nm, 10.4 nm, and 9.0 nm for SPPMP, -BP, and -QP membranes, respectively, suggestingthat lower randomness of the hydrophilic component
led to the formation of more uniform, larger water clusters. Then, the sum of the power law and Teubner - Strey(TS) model was applied to the curves for more quantitative analysis. The curve fitting was performed using thefollowing equation,

( )=

+

[16 4

(

2 2 ( −2

4 )
2)

4( 2

2 )]

+

(2)

where A, B and C are constants of each component.
The ξ and D terms are the domain size and interdomain
distance, respectively. Figures 4a and b show the humidity dependence of the ξ and D values. It is noted thatboth ξ and D values showed only minor dependence
on the humidity. The ξ value of SPP-QP (ca. 2.45 nm at
80% RH) was much larger than those of SPP-BP (ca. 0.88
nm at 80% RH) and SPP-MP (ca. 0.67 nm at 80% RH). This
result is reasonable, because the smaller randomness of
the SP unit must have led to larger water-containinghydrophilic clusters. The D value was not correlated
well with the randomness and was higher for SPP-BP
and -QP (ca. 7.9 nm) than for SPP-MP (ca. 3.8 nm). In
Figure 4c ξ/D is plotted: it represents the connectivity of
the water clusters as a function of the humidity. The ξ/Dvalues were in the order SPP-QP > -MP > -BP, suggestingthat the hydrophilic clusters were more interconnected

Research and Development Highlights

for the SPP-QP membrane, while those in the SPP-BP
membrane were rather isolated. The connectivity was
not dependent on the humidity but was nearly constantin the humidity range from 30 to 80% RH. Although theexistence of dead-end channels has not been well-supported by the SANS analyses, relatively small ξ/D values
are indicative of dead-end and/or isolated channels.
5. Conclusions
In the SPP membranes, the sequence of the hydrophilic component (or randomness) had a great impact
on the morphology. SPP-QP, with smaller randomnessof the sulfophenylene units, contained more uniform,
larger water clusters with higher interconnectivity.
Increasing the humidity led to an increase in the number of water clusters but did not change their size,interdomain distance, or interconnectivity. The interconnectivity was highly correlated with some important membrane properties (proton conductivity andmechanical properties), which are not included in thisreport but have been covered in detail in our previous
publication [5].
References[1] M. A. Hickner et al., Chem. Rev., 104 4587 (2004).
[2] M. M. Whistna et al., Proc. Natl. Acad. Sci. USA, 116
4899 (2019).
[3] J. Miyake et al., Sci. Adv., 3 eaao0476 (2017).
[4] K. Shiino et al., Chem. Commun., 55 7073 (2019).
[5] K. Shiino et al., ACS Appl. Polym. Mater., 2 5558
(2020).

Figure 4.	Humidity dependence of (a) domain size (ξ), (b) interdomain distance (D), and (c) ξ/D values of SPP-MP, SPP-BP and
SPP-QP membranes calculated from the SANS patterns in Figure 3.

K. Miyatake1,2,3, K. Shiino1, J. Miyake1, T. Otomo4,5, T. Yamada6, H. Arima6, K. Hiroi4, and S. Takata4
Clean Energy Research Center, University of Yamanashi; 2Fuel Cell Nanomaterials Center, University of Yamanashi; 3Department of Applied
Chemistry, Waseda University; 4Neutron Science Section, Materials and Life Science Division, J-PARC Center; 5Institute of Materials Structure
Science, KEK; 6Neutron Science and Technology Center, CROSS

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MLF Annual Report 2020

Magnetoelectric Responses in the Chiral Polar Magnet
Ni2InSbO6
1. Introduction
The space-inversion breaking in magnetic matter
gives rise to the antisymmetric exchange interaction
between neighboring magnetic moments. The antisymmetric interaction may compete with the conventional
exchange, which often results in noncollinear magnetic
structures. Such a noncollinear magnetic structure may
induce the magneto-electric coupling in insulating magnets and the anomalous transport in itinerant magnets.
Corundum-type sesquioxide compounds are one of
the most common mineral family on earth. While thecorundum structure is centrosymmetric, the cation sites
are not on the inversion center or on the reflection mirror. Therefore, some cation order may break the space
inversion and/or mirror reflection. The cation-ordered
corundum oxide compounds have hence been considered as a good playground for exploring a large magneto-electric coupling. Ni3TeO6 was reported to exhibit alarge change in electric polarization (~3 mC/m2) acrossthe magnetic transition temperature [1].
Ni2InSbO6 was first synthesized and confirmed to be
isostructural with Ni3TeO6 by S. A. Ivanov et al. [2]. Ni,
In, and Sb atoms are ordered in the corundum-based
structure, as shown in Fig. 1. A half of the magnetic
Ni ions and the same number of In ions are arranged
to form a little buckled Ni-In sheets of ordered honeycomb (like hexagonal boron nitride) perpendicular tothe c axis (in this report, we use the hexagonal setting).
The Ni-In sheets alternate with Ni-Sb sheets of a similarordered honeycomb. Each Ni ion occupies a distorted

octahedron site formed by six oxygen atoms. The NiO6octahedron is connected with other six NiO6 octahedra on neighboring sheets by sharing corners and withthree InO6 or SbO6 octahedra in the same sheet by sharing edges. A theoretical study on Ni3TeO6 proposed
dominant antiferromagnetic exchange interaction between neighboring Ni layers, which should stabilize thelayered antiferromagnetic order [3]. On the other hand,the chiral polar crystal structure may favor noncollinear
magnetic order. The previous powder neutron diffraction study proposed helimagnetic order of screw or cycloid type with a 15-nm modulation along the b axis [2].
The long-wavelength modulation is attributable to theantisymmetric exchange interaction originating fromthe inversion breaking [4].
Here we carry out a neutron diffraction study by using single crystals to pin down the magnetic structure
and to reveal the magnetic-field effect. We also measure
the magnetization and magnetoelectric effect.
2. Methods
Single crystals of Ni 2InSbO 6 were grown by thechemical vapor transport method [5]. The crystals hada large c plane. Low-field magnetization was measured
as a function of magnetic field and temperature by using a commercial magnetometer (MPMS-XL, Quantum
Design). Electric polarization along the c axis was measured on a homochiral domain with an area of 0.74 mm2
by integrating the displacement current, measured byusing an electrometer (6517A, Keithley). The dielectric

Figure 1. Crystal structure of Ni2InSbO6. Oxygen atoms are omitted.in the right panel.

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MLF Annual Report 2020

constant along the c axis was measured on a thin crystal
using an LCR meter (E4980A, Agilent). Pulsed-magneticfield measurements of the magnetization and electric
polarization were performed at the Institute for Solid
State Physics, the University of Tokyo.
A neutron scattering measurement was performedby using the time-of-flight diffractometer TAIKAN on
BL15 [6]. A single crystal of Ni2InSbO6 was mounted in arefrigerator equipped with a superconducting magnet.
3. Results and discussions
Temperature dependence of magnetization at
0.1 T shows the presence of a magnetic transition at
77 K. Electric permittivity also shows a peak at the magnetic transition temperature, implying some coupling
between the magnetism and electricity in this compound. Electric polarization gradually changes by about
2 mC/m2 across the transition.
Figure 2 shows neutron diffraction patterns in thereciprocal (h k 3) plane around a fundamental Bragg
peak (003). Ring-like satellite is observed in the pattern(top panel) collected at 60K after zero-field cooling. The
radius of the ring agrees with the previously reported
magnetic modulation period [2]. On the other hand,
the ring implies that the modulation axis would not

Research and Development Highlights

be clamped to the b* or equivalent axis but can varyin the c plane. It is here noteworthy that a hexagonalunit cell contains three pairs of Ni-In and Ni-Sb sheets.
The magnetic satellite peaks strongly suggest that theNi moments on each sheet are gradually modulated in
the sheet and that the sheets are antiferromagneticallystacked along the c axis.
We also measured the diffraction pattern after cooling the crystal in a magnetic field of 6 T applied along
the a* axis. The ring was merged into two broad spots
along the magnetic field. This result may be explainedby assuming the screw-type magnetic order.
Figure 3 shows the magnetization and electric polarization at various temperatures measured by using
a pulsed magnet. When the magnetic field is appliedalong the sheet in the helimagnetic phase, a clear metamagnetic transition is observed. The magnetization
curve is convex below the metamagnetic transition andalmost linear in the high-field phase. The typical screw
magnetic order is changed to a conical structure andthe cone axis is reduced to zero with the increase of themagnetic field parallel to the screw axis. The observed
magnetization is not consistent with the scenario. The
linear magnetization curve with a non-zero magnetization extrapolated to zero field is explained by assuming

Figure 2.	Neutron diffraction patterns in the reciprocal (h k 3) planearound a fundamental Bragg peak (003). (a) Pattern in theabsence of the magnetic field after zero-field cooling. (b) Pattern in a magnetic field of 6 T applied along the a* axis after
cooling the crystal in the field. (c) Pattern at 0 T and 80K.

41

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MLF Annual Report 2020

Figure 3.	Magnetic field dependence of magnetization and electric polarization at various
temperatures. The electric polarization is measured parallel to the c axis. Pulsed magnetic field is applied (a, b) perpendicular to the c axis and (c, d) parallel to the c axis.
Low-field parts of polarization measurements are affected by the noise of starting
pulsed magnetic field.

the existence of canted layered antiferromagnetic structure in the high-field phase.
A magnetic field along the c axis induces a firstorder metamagnetic transition accompanied by a clear
hysteresis. The magnetic structure remains unrevealedyet.
4. Conclusion
Neutron diffraction of Ni2InSbO6 indicates the screw
type helimagnetic structure based on the layered antiferromagnetism. The application of a magnetic field
induces a magnetic transition accompanied by a fairly
large magnetoelectric effect.

1

1

1

1

1

2

References[1] Y. S. Oh, S. Artyukhin, J. J. Yang, V. Zapf, J. W. Kim, D.
Vanderbilt, and S.-W. Cheong, Nat. Commun., 5 1 (2014).
[2] S. A. Ivanov, R. Mathieu, P. Nordblad, R. Tellgren, C. Ritter,
E. Politova, G. Kaleva, A. Mosunov, S. Stefanovich, and
M. Weil, Chem. Mater., 25 935 (2013).
[3] F. Wu, E. Kan, C. Tian, and M.-H. Whangbo, Inorganic
Chem., 49 7545 (2010).
[4] I. E. Dzyaloshinskii, Sov. Phys. JETP, 19 960 (1964).
[5] Y. Araki, T. Sato, Y. Fujima, N. Abe, M. Tokunaga, S.
Kimura, D. Morikawa, V. Ukleev, Y. Yamasaki, C. Tabata,
H. Nakao, Y. Murakami, H. Sagayama, K. Ohishi, Y.
Tokunaga, and T. Arima, Phys. Rev. B, 102 054409(2020).
[6] https://mlfinfo.jp/ja/bl15/

3

4

1

T. Arima , Y. Araki , T. Sato , Y. Fujima , N. Abe , H. Sagayama , M. Tokunaga , K. Ohishi , and Y. Tokunaga
2
3
Department of Advanced Materials Science, University of Tokyo; Institute of Materials Structure Science, KEK; Institute for Solid State
4
Physics, University of Tokyo; Neutron Science and Technology Center, CROSS

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MLF Annual Report 2020

Research and Development Highlights

Water Distribution in Nafion® Thin Films on Hydrophilicand Hydrophobic Carbon Substrates
1. Introduction
Polymer electrolyte membrane fuel cells (PEMFCs)
have attracted considerable attention during the past
two decades as clean and sustainable energy conversion devices. Hydrogen fuel cells emit only water andnot carbon dioxide, which can cause global warming at
the point of operation. Traditionally, a critical part of a
PEMFC is the catalyst layer (CL), which is composed of Pt
nanoparticles on carbon supports (Pt/C) and perfluorosulfonic acid ionomers, such as Nafion. Since protons
and oxygen must be transferred through the Nafion, thetransport properties limit the power generation performance. During normal operation, a polymer electrolyte
membrane (PEM) experiences a range of humidity conditions. These conditions can influence both the watercontent and the connectivity of the hydrophilic clustersof the PEM, which control the proton conductivity [1].
In this study, we performed H2O and D2O double
contrast neutron reflectivity (NR) measurements to investigate the water uptake properties of Nafion thinfilms in CLs, focusing on the effects of hydrophilicity on
the carbon surface as well as the humidity conditions.
For this purpose, we prepared hydrophobic and hydrophilic carbon surfaces using ultraviolet (UV) irradiation.
In the NR experiments conducted on these films, 80%
relative humidity (RH) water vapor and bulk water wereused to determine the effects of the humidity conditions. Based on the double contrast NR data, we evaluated the volume occupancies of water and Nafion in thethin films as functions of the distance from the substrate.

2. Experimental
We prepared ~25-nm-thick Nafion films by spin
coating Nafion solutions on the hydrophobic and hydrophilic carbon films. The Naﬁon solution (D2020) underwent further dilution to a concentration of 1.0 wt%
using 1-propanol. Finally, we annealed the obtained
films for 2 h at 140°C in a vacuum oven to mimic PEMFCs
formed by hot-pressing more closely.
We performed the NR measurements using the
SOFIA reflectometer at the Materials and Life Science
Experimental Facility (MLF) at J-PARC, Japan. The obtained
reﬂectivity data were analyzed using the Motoﬁt macro
package of Igor Pro. Notably, the NR experiments were
performed with two scattering contrasts on the same
system using H2O and D2O (double contrast measurements). This method enabled quantitative evaluation of
the amount of water penetrating the Nafion thin films.
3. Results and discussion
Figures 1(a) shows the NR curves and the fitting results for Nafion thin films on the hydrophobic carbon
in 80% RH H2O and D2O vapor. The fit between the calculated and observed NR curves is good for both the
H2O and D2O contrasts. Then, we evaluated the corresponding SLDs based on the fitting results, as shownin Fig. 1(b). To examine the distribution of water in the
Nafion thin films quantitatively, we directly evaluatedthe amount of water in the films in both water vaporand bulk water. Then, we evaluated the distributions ofwater and Nafion in the thin film along the depth direction from the SLD profiles in Fig. 2.

Figure 1.	(a) NR curves and fitting results (solid curves) for the Nafion thin film on hydrophobic carbon in dry nitrogen (black), 80%
RH H2O vapor (blue), and 80% RH D2O vapor (red). (b) SLD profiles of the Nafion thin films on hydrophobic carbon in dry
nitrogen (black), 80% RH H2O vapor (blue), and 80% RH D2O vapor (red). Adapted with permission from [7]. Copyright 2020
American Chemical Society.

43Research and Development Highlights

MLF Annual Report 2020

Figures 2 present the volume occupancy evaluated for water and Nafion in the Nafion thin films onhydrophobic(a) and hydrophilic(b) carbon in 80% RH
water vapor. Figures 2 show that the Nafion density ishigher at the air than in the middle of the thin films onhydrophobic and hydrophilic carbon. This tendency
must be due to the crystallization of Nafion near thesurface. This may be because heterogeneous nucleation more easily occurs in material interface than inbulk. On the other hand, the Nafion density is higher at
the carbon interface than in the middle only on hydrophilic carbon. This characteristic likely occurs because of
the charged side chains in Nafion accumulated near thehydrophilic carbon surface due to the hydrophilic nature ofcarbon. In addition, a water-rich layer exists near the hydrophilic carbon surface, closer than the dense Nafion layer.
Using the H2O and D2O double contrast, we evaluated the depth profiles of water and Nafion in the thinfilms quantitatively. However, these measurements indicated other problems. Summing the volume occupancies of Nafion and water in Figures 2(a) and 2(b) yielded
less consistency in the thin films, and ~0.80 was obtained in a case in which the occupancy was particularly
small when calculated using the bulk values of densityfrom the literature [2]. We considered two feasible physical scenarios. One is the existence of excess free volume
or voids in the Nafion thin film. Another possibility is asfollows. Exposure of a Nafion thin film to water vapor
or immersion in bulk water means that an exchange ofwater occurs between the inside and outside. However,this scenario assumes the existence of water in the filmthat cannot be exchanged with outside water. The former and latter are referred to as exchanged water (EW)
and residual water (RW), respectively. Further, we assumed that the introduction of RW occurred in the film
during the spin-coating process or the first immersion

into water. As mentioned in the experimental part, theNafion thin films were thermally annealed. Then, we
expected that voids or the residual water could be removed, but they were not. One of the possible reasonsis that the paths to the voids from the outside were collapsed during the thermal annealing, resulting in theisolated voids or the residual water region. To evaluate
the distributions of RW and EW, we applied the volumeconservation law in this experiment.
Figure 3 presents the volume occupancies of Nafion,
RW, and EW, for the thin films on hydrophobic carbon
in (a) 80% RH water vapor as functions of the distancefrom the carbon surface. This figure elucidates the distributions of RW in the thin films. It is clear that the RW
filled the open volume, according to volume conservation. The amounts of RW in the films in water vapor andbulk water is less than that in the dry film. This observation indicates that some of the RW was exchanged withthe water molecules from outside. The RW near the airinterface was exchanged more than that near the carbon interface and was more enhanced in bulk water.
As mentioned before, we considered that the residual
water was isolated due to the collapse of the paths tothe outside, and the present observation suggested thatthe collapse occurred more frequently near the carbon
surface than near the air surface.
Figure 3(b) presents the results of the same analyses for the Nafion thin films on hydrophilic carbon filmin 80% RH water. The RW distribution is mainly in thecentral part of the Nafion film for hydrophilic carbon,
whereas the EW is evenly distributed across the film andshows higher volume occupancy near the hydrophiliccarbon interface. This distribution is due to the hydrophilic nature of the carbon surface. In any case, the EW
distribution is essentially the same as in the first analysis
without considering the RW; hence, the discussions of

Figure 2.	Volume occupancies of Nafion and water in films on hydrophobic (a) and hydrophilic (b) carbon in 80% RH water vapor asfunctions of the distance from the carbon surface. Adapted with permission from [7]. Copyright 2020 American Chemical
Society.

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MLF Annual Report 2020

the water and Nafion distributions in regard to Figs. 2
remain valid.
The first and second physical scenarios suggest thatsome voids were present and there was RW, which was
not exchanged with outside water. Both possibilities
imply the existence of areas (voids or RW areas) isolated
from the outside water, which probably indicates thatsuch isolated areas have no paths connecting to theoutside. On the other hand, EW, which is mainly locatednear charged side chains as a cluster [3], can move in
the Nafion thin film. In this case, the RW in the Nafion
film cannot contribute to proton transfer in the PEMFC
operation. In other words, the wetting ratio (ratio of thewater fraction to the Nafion fraction) is not directly related to the proton transfer. This point is crucial to noteregarding the efficiency improvement of PEMFC.
Finally, Figures 4 schematically illustrate the conceptof voids or RW in Nafion thin films. The key point is thepresence of some isolated regions (voids or RW areas)

Research and Development Highlights

and portions that are connected to the outside (EW areas) in the Nafion film. The Nafion and water distributions
along the depth direction are also involved.
This is the first report on the depth profile of the water distribution in Nafion thin films on hydrophobic andhydrophilic carbon in water vapor and bulk water. This
depth profile information is crucial for the developmentof properties in PEMFCs such as proton conductivity [4],flooding [5], and discharge of water [6].
References[1] B. R. Frieberg et al., ACS Appl. Mater. Interfaces 8,33240 (2016).
[2] A. Kusoglu et al., Chem. Rev. 117, 987 (2017).
[3] T. Mashio et al., J. Phys. Chem. C 114, 13739 (2010).
[4] M. Bass et al., Macromolecules 44, 2893 (2011).
[5] D. K. Paul et al., Macromolecules 46, 3461 (2013).
[6] R. P. Dowd et al., J. Electrochem. Soc. 164, F138 (2017).
[7] K. Ito et al., Langmuir 36, 12830 (2020).

Figure 3.	Volume occupancies of Nafion, EW, and RW in the Nafion thin films on hydrophobic (a) and hydrophilic (b) carbon as functions of the distance from the carbon surface in 80% RH water vapor. Adapted with permission from [7]. Copyright 2020
American Chemical Society.

Figure 4.	Schematic illustrations of inner structures of Nafion thin films on hydrophobic and hydrophilic carbon in 80% RH water
vapor. Nafion crystals or dense region (green lines), residual water (or voids) isolated from the outside (gray circles), and exchanged water penetrating from outside (blue circles). The blue lines show the connecting paths between the exchanged
water clusters. Adapted with permission from [7]. Copyright 2020 American Chemical Society.
K. Ito1, M. Harada2, N. L. Yamada1,3, K. Kudo2, H. Aoki1,3, and T. Kanaya1,3
1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Toyota Central R&D Labs., Inc.; 3Institute of Materials
Structure Science, KEK

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MLF Annual Report 2020

Interfacial Cross-Link Inhomogeneity of a Phenolic
Resin on a Silica Surface as Revealed by XRR and
NR Measurements
1. Introduction
Transportation vehicles, such as automobiles, aircrafts, and trains, are required to further reduce fuelconsumption because of global warming gas emission
regulations. One of the most effective ways to reduce
fuel consumption is to reduce vehicle weight via replacement of metals with resins. A glass fiber-reinforced
phenolic resin has been widely used as a metal replacement material, especially in mechanical parts, such as
in transmissions, pulleys, and pump impellers, whereparticularly excellent strength and rigidity are required.
However, a decrease in the interfacial adhesion between
the resin and glass fiber causes undesirable interfacialdelamination that causes cracks in the glass fiber-reinforced resin. Therefore, understanding the interfacial
resin structure on the silica surface at a nanometer levelis important for improving the adhesion and for achieving long-term reliability of the glass fiber reinforcement.
In this study, to determine the interfacial structureof a phenolic resin on a glass surface, the structure ofhexamethylenetetramine (HMTA)-cured phenolic resin
nanofilms prepared on a silicon wafer with a native silica
layer on its surface was investigated by complementary
X-ray and neutron reflectometry (XRR and NR, respectively) analyses [1]. As a contrast-variation technique,the structural analyses were performed in the dry andwater-absorbed wet states. The water absorption canchange structural contrast in terms of mass density via
swelling. Additionally, using deuterated water with thecoherent neutron scattering length density (SLD) of
6.36 × 10−4 nm−2 can increase the SLD of the resin via
the D2O absorption and can allow H-to-D exchange reactions of hydroxyl groups on phenolic rings to proceed,
which considerably changes the structural contrast in
the NR analyses.
2. Experimental
Phenolic resin nanofilms were prepared via spin
coating using 1.5, 1.2, and 0.9 wt% ethanol solutions of
a 1.0/0.12 (wt/wt) mixture of novolac resin and HMTA.
The ethanol solution was deposited onto an ethanolcleaned wafer with a diameter and thickness of 50 and
2 mm, respectively, and then spun at 2000 rpm for 15 s.
The spin-coated wafer was heated at 100°C for 2 min on46

a hotplate to remove the remaining solvent and thencured at 180°C for 8 h in an oven under atmosphericconditions. The water-absorbed wet samples were prepared by immersing the dry samples in water at room
temperature for 3 h after the reflectivity measurements
in which H2O and D2O were used for the XRR and NR
analyses, respectively. Samples PR-1.5, PR-1.2, and PR0.9 were prepared from 1.5, 1.2, and 0.9 wt% solutions,
respectively.
XRR measurements were performed on an Ultima IV
X-ray diffractometer (Rigaku Corporation) using X-rays
with a wavelength (λ) of 0.154 nm from a CuKα spectralline excited at 40 kV and 40 mA.
NR measurements were performed on a time-offlight neutron reflectometer, SHARAKU, installed at theBL17 beamline at the MLF, J-PARC, using a 25-Hz pulsed
neutron beam at an accelerator operating power of 0.5
MW. The reflected neutrons with a λ band of 0.22–0.88
nm were measured using a 3He gas tube neutron detector at three reflection angles of 0.3, 0.7, and 1.6°.
The measurements of the dry and wet samples were
performed under low and high humidity conditions, respectively, to avoid structural changes during the measurements due to moisture absorption or drying of theresin: XRR and NR measurements were conducted at 21–
25°C and 21–28% RH under atmospheric conditions forthe dry samples and at 28–30°C and 81–85% RH for thewet samples. The NR measurement was conducted under a D2O vapor-containing nitrogen atmosphere using
a beamline-specific humidity-controlled sample cell [2].
3. Results and discussion
Figure. 1 shows the XRR profiles of PR-1.5. The reflection profiles exhibited a clear interference pattern over awide q range, which is called Kiessig fringes, indicatingthat the specimen exhibited a flat and smooth surface.
Both XRR profiles of dry and wet samples were successfully reproduced by a structural model with a single-resin layer on the native silica. The water absorption of thephenolic resin layer resulted in an increase in t from 41.6
to 44.0 nm and a decrease in ρm from 1.40 to 1.39 g cm−3,
thereby indicating that the amount of absorbed water
was 5.0 wt% based on the dry resin.
Figure. 2 shows the NR profiles of PR-1.5. Both theMLF Annual Report 2020

Research and Development Highlights

Figure 1.	XRR profiles of PR-1.5 in dry and wet states. The profile in the dry state is vertically shifted by a factorof 10 for clarity. The solid lines represent the fitting
curves. (Inset) Mass density profiles of PR-1.5 in thedry and wet states. Reprinted (adapted) with permission from [1]. Copyright 2020, American Chemical Society.

Figure 2.	NR profiles of PR-1.5 in dry and wet states. The profile in the dry state is vertically shifted by a factorof 10 for clarity. The solid lines represent the fitting
curves. (Inset) SLD profiles of PR-1.5 in the dry andwet states. Reprinted (adapted) with permission
from [1]. Copyright 2020, American Chemical Society.

interference fringes of the XRR and NR profiles decayedwith increasing q, whereas the NR profiles have a feature in which the logarithmic-scale fringe amplitude
recovered at q > 0.12 nm−1. The NR profile analysis was
performed in the observed q range of 0.075–1.5 nm−1, in
which structural parameters of the silicon and silica layers were fixed to those obtained from the XRR analysis
as a constraint for the fitting procedure. The structuralmodel with a single-resin layer on the native silica that
was applied in the XRR analysis was first investigated;
however, the fitting analysis failed and the aforementioned feature of interference fringes of the NR profile
was not reproduced with the model. However, a structural model containing a low-SLD resin layer with athickness of 1–2 nm between the bulk phenolic resin
and native silica produced good fitting results both fordry and wet samples as shown in Fig. 3. This result indicates that there was an interfacial layer between thebulk phenolic resin and native silica in terms of SLD, andthe interfacial layer had the same mass density and alower SLD compared with the bulk resin layer. According
to the theoretical SLD values [1], the bulk layer of thedry sample with the SLD of 2.68 × 10−4 nm−2 was wellcharacterized as a HMTA-cured phenolic resin, where
the theoretical SLD was 2.65 × 10−4 nm−2, and the increase in the SLD to 3.54 × 10−4 nm−2 by D2O absorption
can be explained by ≈5 wt% D2O absorption and theprogress of the H-to-D exchange of hydroxyl groups. Theinterfacial layer on the native silica exhibited an SLD of
2.31 × 10−4 nm−2 and t of 1.6 nm in the dry state. The SLD
value suggests that the interfacial layer had a structure
similar to the novolac resin, where the theoretical SLD
was 2.34 × 10−4 nm−2. Thus, an increase in the SLD to
3.20 × 10−4 nm−2 by D2O absorption can be similarly explained as for the bulk resin layer. The thickness of theinterfacial layer corresponds to a few repeating units of
the novolac resin. These results suggest that the lowSLD interfacial layer was regarded as a novolac resin
adsorption layer on the native silica.
The formation of the adsorption layer could be driven by a strong hydrogen-bonding interaction between
the novolac resin and the silica surface [40]. The presence of a low-SLD interfacial layer on the silica surface
indicates that the novolac resin adsorption layer was
first formed before curing via the strong hydrogenbonding interaction between the resin and silica surface. The preferential formation of the novolac resin
adsorption layer caused a low HMTA concentration in
the layer compared with that in the bulk resin layer,
which resulted in the presence of the low-SLD layer after
curing. There was no distinct difference in mass densities between the novolac and HMTA-cured resins, which
resulted in the absence of the interfacial structure in the
XRR profiles.
When the low-SLD interfacial layer owing to the novolac resin adsorption onto the silica surface is a general47

Research and Development Highlights

MLF Annual Report 2020

Figure 3.	Interfacial structure of a HMTA-cured phenolic resin
on silica surface. Reprinted (adapted) with permission from [1]. Copyright 2020, American Chemical
Society.

structural feature of the HMTA-cured phenolic resin,
the thickness of the interfacial layer, 1–2 nm, will not besignificantly affected by the thickness of the bulk resin
layer as illustrated in Fig. 3. This conjecture was verified
by additional dry-state NR analyses with PR-1.2 andPR-0.9, in which their bulk-layer thicknesses were 30 and
20 nm, respectively, and interfacial-layer thicknesses
were both 1.3 nm.
4. Summary
The interfacial structure of a HMTA-cured phenolic
resin on silica surface was investigated by complementary use of XRR and NR. The contrast-variation technique

was applied using D2O for the NR analysis in which the
SLD largely changed because of D2O absorption of thedry phenolic resin and H-to-D exchange of phenolic hydroxyl groups. The XRR profile indicated no clear interfacial structure in terms of the mass density, whereas the
NR profile indicated the presence of an interfacial nanolayer on the native silica surface in terms of the SLD.
The thickness of the interfacial layer was 1–2 nm, which
was independent of the thickness of the bulk resin layer.
The formation of the interfacial layer on the silica surface could be driven by preferential adsorption of thenovolac resin on the silica surface via strong hydrogenbonding between phenolic units in the novolac resinand silanol and silyl ether groups on the silica surface,which resulted in interfacial cross-link inhomogeneity ofthe phenolic resin on the silica surface in the thickness
direction.
5. Future plans
This interfacial structure may correspond to a “weakboundary layer (WBL)” for phenolic resin–silica composites in which the WBL considerably affects the interfacialadhesive strength [3]. Further elucidation of the adsorption nanolayer via XRR and NR analyses and characterization of the interfacial structure–property relation ofphenolic resin–silica composites are our future tasks.
References[1] A. Izumi et al., Macromolecules, 53 4082 (2020).
[2] S. Ohira-Kawamura et al., Neutron News, 30 11(2019).
[3] J. J. Bikerman, Ind. Eng. Chem., 59 40 (1967).

A. Izumi1, Y. Shudo1, M. Shibayama2, T. Yoshida2, N. Miayata2, T. Miyazaki2, and H. Aoki3,4
Corporate Engineering Center, Sumitomo Bakelite Co., Ltd.; 2Neutron Science and Technology Center, CROSS; 3Neutron Science Section,
Materials and Life Science Division, J-PARC Center; 4Neutron Science Section, Materials and Life Science Division, J-PARC Center Instituteof Materials Structure Science, KEK

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Research and Development Highlights

Garnet-Type High Li-ion Conductivity Single Crystal as
Solid Electrolyte for All-solid-state Li Battery
1. Introduction
The all-solid-state lithium battery, which is one of
the next-generation secondary batteries, is expected to
be a secondary battery that has both high safety andhigh energy density because it does not use an organic
electrolyte. To this realization, research and development is currently being carried out at research institutes
and companies around the world. The all-solid-state Li
battery includes an oxide-based all-solid-state Li battery
that uses an oxide as a solid electrolyte and a sulfidebased all-solid-state Li battery that uses a sulfide. It has
been reported that sulfide-based solid electrolytes havehigh ionic conductivity and high moldability, and it iseasy to make an all-solid-state lithium battery, but hydrogen sulfide becomes toxic when it reacts with water.
Therefore, there is a drawback in safety. On the other
hand, oxide-based solid electrolytes provide excellent
safety, but their lithium-ion conductivity is about anorder of magnitude lower, and there is a problem withmoldability, making it difficult to improve the relative
density of the sintered body. Therefore, our researchteam started to grow a large single crystal in order toproduce a solid electrolyte with a relative density of100%. The target substance is a garnet-type solid electrolyte that has a relatively high lithium-ion conductivity
among oxide-based solid electrolytes. If a large single
crystal is successfully grown, accurate bulk lithium-ion
conductivity can be measured, making it more attractive
as a member. In addition, detailed crystal structure analysis using single crystal neutron diffraction, which has
not been performed so far, can be performed [1, 2]. In
this report, we report on the lager single crystal growthof garnet-type solid electrolyte and crystal structure
analysis using single crystal X-ray and neutron diffraction data.

2.	Single crystal growth of garnet-type solid
electrolyte by melting method
Our team had previously used the flux method togrow garnet-type solid electrolytes. However, the flux
method did not make the size usable as a member,and because of repeated studies, we tried to grow agarnet-type solid electrolyte single crystal by the floating zone method (FZ method) in an optical image
furnace (Crystal system, Inc., Japan) equipped withfour 1 kW halogen lamps. The FZ method is one of themelting methods. There are two reasons for choosing
the FZ method. One is a single crystal growing method that does not use a crucible, so that impurities can
be avoided. Another point is that the volatile component (lithium) can be controlled because the molten
part is local. In single crystal growth, considering thevolatilization of lithium, lithium carbonate was charged
1.2 times in molar ratio, and single crystals of garnettype solid electrolytes Li6.5La3Zr1.5Nb0.5O12 (LLZNb05) andLi6.5La3Zr1.5Ta0.5O12 (LLZTa05) were grown. As a typicalsingle crystal, Figure. 1 shows a photograph of the single
crystal of LLZNb05. A single crystal with a diameter ofabout 8 mm and a length of about 40 mm was grown by
the FZ method. The orientations of the as-grown single
crystals were measured using monochromatized Cu Kα1
radiation (40 kV, 30 mA) at 295K on a two-axis X-ray diffractometer (Rigaku SmartLab, Japan) equipped with acharge-coupled device detector and a Johansson’s Ge(111) curved crystal. The X-ray diffraction pattern of the
LLZNb05 single-crystal plate collected with a biaxial
diffractometer indicated that crystal growth occurredin the <332> direction.

Figure 1. As-grown LLZNb05 single crystal rod by the FZ method.

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MLF Annual Report 2020

3.	Crystal structure analysis by X-ray and neutron
diffraction using single crystal
In order to analyze their crystal structures, smalltransparent crystals were processed into 0.2 mm (ϕ)
spheres for single-crystal X-ray diffraction (XRD) and
0.5 mm (ϕ) spheres for single-crystal neutron diffraction measurements. For structural refinement, the XRD
intensities of the LLZNb05 and LLZTa05 single crystals
were recorded on a 2D diffractometer (Rigaku R-AXIS
RAPID-II, Japan) equipped with an imaging plate detector, a graphite monochromator, and a Mo Kα radiation
source (50 kV, 30 mA) at 295K. The neutron diffraction
intensities of the LLZNb05 and LLZTa05 single crystals were measured using a time-of-flight neutron
diffractometer equipped with a 2D detector (BL18SENJU; J-PARC, Japan, proposal No. 2015A0147 and2016A0235) [3] using a poisoned decoupled hydrogenmoderator (100 kW) at 295K. Structural refinement was
performed using the Jana2006 program [4].
The structure in LLZNb05 and LLZTa05 comprisedof LaO8 and (Zr, Nb, or Ta)O6 polyhedra was refined using the single-crystal XRD data and the reported garnettype atomic coordinates. The Li sites in LLZNb05 LLZTa05
were determined from the single-crystal XRD and neutron diffraction data using a differential Fourier synthesis map. The reliability values of the single-crystal XRD
data obtained from LLZNb05 were R = 4.25% and wR =5.82%. R and wR of the single-crystal neutron diffraction

were 7.09% and 7.94%, respectively. The R and wR valuesof the single-crystal XRD data from LLZTa05 were 3.32%
and 4.45%, respectively. The reliability values of the single-crystal neutron diffraction data were R = 8.82% andwR = 7.45%. Even when the XRD and neutron diffraction
data were used complementarily for refinement, it wasdifficult to determine the occupancy ratios of Zr and Nb
or Ta. We, therefore, refined the crystal structure using
fixed values obtained from the ICP-AES analysis. The
LLZNb05 and LLZTa05 crystal lattice parameter (a) was
refined by the least-squares method using the singlecrystal XRD data. In LLZNb05, a = 12.9130(8) Å, whereas
a = 12.9455(6) Å in LLZTa05. Figure 2 shows the refined
crystal structure of LLZNb05. A similar crystal structure
was constructed for LLZTa05. Based on these structuralrefinements, we determined the chemical composition of LLZTa05 to be Li6.32La3Zr1.5Ta0.5O12. The chemicalcomposition of LLZNb05 was Li6.49La3Zr1.5Nb0.5O12. Liions occupied two interstitial sites in the framework
structure. Li1 and Li2 ions were located in distorted
tetrahedral and octahedral 96h sites, respectively. In
the (La3Zr1.5Ta0.5O12)6.5− and (La3Zr1.5Nb0.5O12)6.5− garnet
solid electrolyte framework structures, Li+ occupied
the A-sites formed by (Zr, Nb, or Ta)O6 and the C-sites
formed by LaO8. The 96h sites were split from the 24dsites, where Li ions formed tetrahedrons. However,other 96h sites were split from the 48g sites, where
Li ions formed octahedrons. The conductivity of Li-ion

Figure 2.	Crystal structure of LLZNb05 (LLZTa05) by X-ray and neutron diffraction
data refinement using a single crystal.

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MLF Annual Report 2020

seems to have been improved by splitting because
the distance between Li sites was shortened. Our results suggested that the arrangement of Li ions in thegarnet structure differed from the previously reported
arrangement. In previous studies, Li ions in a crystal
structure within the Ia3̄d space group were reported
to occupy the tetrahedral 24d and distorted octahedral
96h sites [5, 6]. Thus, the Li­-Li distances in our structures
were shorter than those reported previously. A short Li-­Li distance, disordering of Li sites, and partial occupation
by Li atoms are thought to be key for Li-ion diffusionin the garnet structure. Accordingly, we speculated that
Li ions might have diffused more rapidly in our single
crystals than they did in the reported polycrystalline
samples [5, 7, 8].
4. Future plans
We will continue to explore the growth of garnettype solid electrolyte single crystals with higher lithiumion conductivity. Furthermore, we aim to elucidate theLi-ion conduction phenomenon in solids by combining
garnet-type solid electrolyte single crystals and single

Research and Development Highlights

crystal neutron diffraction. In addition, we will conduct
research and development to realize an all-solid-statelithium battery that uses a garnet-type solid electrolyte
single crystal as a member.
References[1] K. Kataoka, H. Nagata and J. Akimoto, Sci. Rep., 89965 (2018).
[2] K. Kataoka and J. Akimoto, ChemElectroChem, 52551 (2018).
[3] T. Ohhara et al., J. Appl. Crystallogr., 49 120 (2016).
[4] V. Petricek, M. Dusek, L. Z. Palatinus, Kristallografiya,
229 345 (2014).
[5] N. Hamao, K. Kataoka, N. Kijima, J. Akimoto, J. Ceram.
Soc. Jpn., 124, 678 (2016).
[6] J. Awaka, A. Takashima, K. Kataoka, N. Kijima, Y.
Idemoto, J. Akimoto, Chem. Lett., 40 60 (2011).
[7] H. Yamada, T. Ito, R. H. Basappa, Electrochim. Acta,
220 648 (2016).
[8] K. Hayamizu, Y. Matsuda, M. Matsui, N. Imanishi,
Solid State Nucl. Mag., 70 21 (2015).

K. Kataoka
Energy Conversion and Storage Material Team, Advanced Coating Technology Research Center, National Institute of Advanced Industrial
Science and Technology (AIST)

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In-situ Neutron Diffraction Analysis on Low Temperature
Deformation Behavior in Low Alloy Steel
1. Introduction
Transformation-induced plasticity (TRIP) resultsin improvement of strength and ductility in low alloysteel due to the transformation of metastable retained
austenite (γ) to martensite (α’) (deformation induced
martensitic transformation: DIMT) [1]. The behavior of
TRIP strongly depends on the mechanical stability of γ.
Sugimoto et al. [2] reported that a low alloy steel containing metastable γ showed excellent total elongation
at 423 K as the γ was in a suitable stable condition. On
the other hand, there are few reports on the stabilityof γ and the DIMT at low temperatures. In our previous
study [3], we investigated the tensile properties andchanges of the phase fraction of γ in a low alloy steel
at low temperatures using the electron back scattereddiffraction (EBSD) method. The tensile strength of thesteel increased without decreasing the total elongation as the deformation temperature decreased from
293 K to 193 K, which was accompanied by a high workhardening rate in the initial stage of deformation. Then,
we suggested that γ with the DIMT contributed to thehigh work-hardening rate, but there was no direct proof
showing evolution of the stresses of γ and α’ during deformation. In addition, a reason why the steel showed
the excellent elongation at low temperature was also
not clear yet because the counting loss of γ with a small
grain size occurred in the EBSD measurement. Hence, anaccurate observation of the DIMT behavior of γ at low
temperatures is necessary.
In-situ neutron diffraction during tensile deformation represents an effective method for the simultaneous evaluation of the deformation and DIMT behavior.
In this study, the changes of phase fractions and phasestresses of constituent phases (bainitic ferrite matrix, γ,and α’) in a low alloy steel during tensile loading below
room temperature were evaluated using in-situ neutron
diffraction, and the role of γ in the deformation and
DIMT is discussed.
2. Experimental procedure
Fe-0.31C-1.74Si-1.49Mn (in mass%) was used in
the present study. The steel consists of bainitic ferrite(α matrix) and γ. Plate type specimens with a thicknessof 2.5 mm were prepared. In-situ neutron diffraction
measurement during a tensile test at low temperature
was carried out at TAKUMI. The test temperatures were52

293 K, 233 K, 193 K, and 134 K, which were controlled
by liquid nitrogen cooling system equipment. The tensile test was done by a step-increasing load control with
300 s holding time in the elastic region and by a continuous crosshead speed control with the initial strain
rate of 1.3 × 10−5 s−1 in the plastic region. The measurements were performed up to the ultimate tensile
strengths. Peak separation between α and α’ was conducted by assuming that the c/a ratio of α’ was constantduring the whole deformation and could be simplified
by a single-broad BCC peak [4]. The phase fractions of γ
were obtained by Rietveld refinement using a software
called Z-Rietveld. The lattice constants were obtained
by Pawley refinement using the same software. Since
α’ was not found in the specimen before loading, thestress-free lattice constant of α’ (a α’ ,0) was evaluated byusing a stress equilibrium approach. That is, the sum ofphase stresses -weighted by their phase fractions must
be equal to the applied true stress in a loaded state.
The a α’ ,0 value for each test temperature was determined independently.
3. Results and discussion
Figure 1(a) shows the nominal stress-nominal strain
curves at various test temperatures. The steel exhibited
good balance of tensile strength and homogeneous
elongation at 233 K, 193 K, and 134 K. The changes ofthe phase fraction of γ during tensile deformation at various test temperature are shown in Fig. 1(b). The phasefraction of γ before deformation at low temperaturesslightly decreased (~1%) during cooling. The martensitic
transformation occurred mostly after macroscopic yielding at each test temperature. At 293 K, the phase fractionof γ decreased linearly with the increase in the applied
true strain, and this trend was kept until the end of deformation. The phase fraction of γ decreased at a higher
rate by lowering the test temperature, in which the rate
became smaller at the latter part of deformation.
The phase strains for all constituent phases were
evaluated and converted to the phase stresses. By
weighting the phase stress with the phase fraction ofeach constituent phase, a contributed stress to thestrength (contributed stress) of each constituent phasecan be evaluated. Figure 2 shows the contributed
stresses of α matrix, γ, and α’ as a function of the applied true strain during a tensile test at 293 K and 134 K.

MLF Annual Report 2020

Research and Development Highlights

phase fraction. The contributed stress of α’ is enhancedwith deformation and becomes much higher than thecontributed stress of α, due to the increase in the phasefraction and the work hardening of α’. The contributed
stresses of α matrix and α’ are enhanced also by decreasing the test temperature. The contributed stressof γ, however, decreases by progressing of deformation,
particularly at low temperature. The main reason may be
due to the decrease of the phase fraction of γ as a resultof continuous DIMT with the progress of deformation.
We conclude that the role of γ in the low alloy steel
used in this study at low temperature deformation, does
not contribute directly to the stress but it improves theelongation through the TRIP effect and increases thework hardening rate by promoting the DIMT.

Figure 1.	(a) Nominal stress – nominal strain curves and(b) phase fraction of retained austenite as a function of the true strain at various test temperatures.
Adapted from Ref. [5].

The contributed stress of the α matrix is higher than theother phases at the early stage of deformation due to its
large phase fraction. It increases with deformation due
to its work hardening. The contributed stress of α’ is very
low at the early stage of deformation due to its small

Acknowledgement
This study was financially supported by JSPS
KAKENHI Grant Number 15H05767 and 19K15279. The
neutron diffraction measurements were performed in
the MLF of J-PARC with the proposal of 2016P0200.
References[1] I. Tamura, Metal Sci., 16 245 (1982).
[2] K. Sugimoto et al., Metall. Mater. Trans. A, 23 3085
(1992).
[3] T. Yamashita et al., ISIJ Int., 58 1155 (2018).
[4] S. Harjo et al., Sci. Rep., 7 15149 (2017).
[5] T. Yamashita et al., Scripta Mater. 177 6 (2020).

Figure 2.	The changes of fraction weighted phase stresses of each consisting phases during the tensile
test at (a) 293 K and (b) 134 K. Adapted from Ref. [5].
1

2

2

2

3

4

T. Yamashita , S. Morooka , S. Harjo , T. Kawasaki , N. Koga , and O. Umezawa
2
Joining and Welding Research Institute, Osaka University; Neutron Science Section, Materials and Life Science Division, J-PARC Center;
3
4
Faculty of Mechanical Engineering, Kanazawa University; Faculty of Engineering, Yokohama National University

153Research and Development Highlights

MLF Annual Report 2020

In-plane Low Thermal Expansion of NiTi Via Controlled
Cross Rolling
1. Introduction
Recently, efforts were devoted to develop polycrystalline shape memory alloys (SMAs) with macroscopic
low thermal expansion (TE) along a certain direction tofurther enhance the functionality of the materials [1–5].
Among the different routes reported, microstructure
control via uniaxial rolling has attracted the attention.
Without altering the intrinsic TEs of the constituent crystals, such route aims to achieve low TE of polycrystalline
SMAs via tuning the microstructural parameters such as
grain size, phase compositions and textures [2, 3, 5]. One
limitation of unidirectionally rolled SMAs is that the TE
is highly anisotropic in the rolling plane and the low TE
is only achieved along a specific direction, while large
positive and negative TEs still exist along other directions, which dramatically limits real applications. It is desirable to reduce such TE anisotropy and even to achieve
in-plane low TE of SMAs.
Here, we find that via controlled cross rolling, thein-plane coefficients of thermal expansion (CTE) of a NiTi
SMA sheet can be lowered to near-zero within a very
narrow range over a large temperature window of 223 K.
The mechanism for the achieved in-plane low TE is identified via neutron diffraction and theoretical calculation.
2. Results and Discussions
We processed a solution-treated NiTi sheet throughcross rolling with 30% total thickness reduction and athree-step rolling path (RD-15%, TD-10% and RD-5%).
The in-plane TE behaviors of the sample (hereafter called(a)CroR-15%-10%-5% NiTi) are presented in Fig. 1(a), showing in-plane CTEs within the range of –2.7 × 10–6 K–1 to+3.0 × 110–6 K–1 over the temperature range of 77 K to300 K. Such in-plane CTEs are smaller than the valuesof the reported SMAs and are comparable to that of
the commercial FeNi Invar alloy (Fig. 1(b)). the strain vstemperature curves of all the samples are nonlinear andexhibit a small hysteresis loop over a large temperature
span, indicating that a continuous and reversible formation of B19’ martensite takes place in cooling and contributes to the observed macroscopic TE.
We observed the microstructure of the CroR-15%10%-5% sample using TEM at room temperature. As
shown in Fig. 2(a), the microstructure is characterized
by triple-cross bands of 100 ~ 200 nm wide and several
microns long (Fig. 2(a1)). Inside the bands, we observed
nanocrystals of 10 ~ 100 nm in size (Fig. 2(a3)). The electron diffraction patterns in Fig. 2(a2) show the presenseof the B19’ phase at room temperature, which reaches
50% of volume fraction as quantified by neutron diffraction. Such rolling-induced residual B19’ phase indicatesthe existence of large residual stress in the nanostructure, which can reach 400 MPa as estimated from thecritical stress for B2 → B19’ phase transformation [6, 7].
We performed in-situ neutron diffraction using
iMATERIA on the CroR-15%-10%-5% NiTi at temperatures from 2.3 K to 300 K (Fig. 2(b)). The results show thatupon the cooling and heating over a large temperature
span, a small fraction (12 vol%) of reversible B2 ↔ B19’transformation takes place (Fig. 2(b1)). Such overall(b)Figure 1. (a) Measured in-plane TE of the CroR-15%-10%-5% NiTi sheet. (b) Comparison of the CTEs of the CroR-15%-10%-5% NiTi
with those of other reported SMAs and commercial FeNi Invar alloy.

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MLF Annual Report 2020

continuous phase transformation is caused by the nanoscale grain size inhomogeneity and the presence ofthe residual stress [6, 8–10]. At 300 K, the B19’ phase has{102}〈UVW〉 fiber texture (Fig. 2(b2)), indicating its nearly
random orientation in the rolling plane. During cooling,
the orientation densities on the entire fiber increasehomogeneously, meaning that the thermally induced
B19’ variants also have {102}〈UVW〉 fiber texture. Such inplane randomly oriented variant formation is probably
due to the weak direction sensitivity of residual stress.
During heating and cooling, both the TEs of the
textured B2 and B19’ aggregates and the reversible
B2 ↔ B19’ transformation will contribute to the macroscopic overall TE. To identify the governing mechanism for the overall in-plane low TE, we quantified eachcontribution using a theoretical model based on Reuss
approximation [11] together with the data measured
by neutron diffraction (including lattice-level TEs, temperature-dependent volume fractions and textures of
the B2 and B19’ phases). The calculated TE behaviors arecompared with the measured ones in Fig. 3. Overall, themodel calculations agree fairly well with the measurements (Fig. 3(d)). Moreover, the calculation reveals thatthe B2 ↔ B19’ phase transformation produces negative
TE along both the RD and TD through the reversible(a)Research and Development Highlights

formation-vanishing of the {102}〈UVW〉 fiber-textured
B19’ variants (Fig. 3(a)). Such in-plane negative TE compensates the positive TEs of the B2 aggregate (Fig. 3(c))
and B19’ aggregate (Fig. 3(b)), leading to the overall inplane low TE.
3. Conclusions
In summary, we show that via three-step crossrolling with 30% total thickness reduction and the 15%10% -5% rolling path, the in-plane CTEs of the NiTi are
reduced down to a very narrow range of −2.7 × 10−6 K−1
to +3.0 × 10−6 K−1 over the temperature range from77 K to 300 K. Such in-plane CTEs are not only significantly smaller than those of other reported SMAs but
also close to the value of commercial FeNi Invar alloy(+2.0 × 10−6 K−1). In situ neutron diffraction and a rule-ofmixture calculation show that in the cross-rolled nanostructured NiTi, the in-plane positive TEs of textured B2and B19’ aggregates are compensated by the in-plane
negative TE caused by the reversible continuous formation (vanishing) of {102}〈UVW〉 fiber-textured B19’ variants in cooling (heating), thereby leading to the overall
in-plane low TE. Such unusual property represents animportant and big step forward to the commercialization of the low thermal expansion SMAs.

(b)

Figure 2.	(a) Nanostructure of the CroR-15%-10%-5% NiTi. (b) Thermally-induced nanoscale phase transformation of the
CroR-15%-10%-5% NiTi characterized using iMATERIA at temperatures from 2.3 K to 300 K.

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MLF Annual Report 2020

(a)

(b)

(c)

(d)

Figure 3. Comparison between the calculated and measured macroscopic TE of the CroR-15%-10%-5% NiTi: (a) Calculated
TE from B2 ↔ B19’ phase transformation; (b) Calculated TE of the B19’ aggregate; (c) Calculated TE of the B2 aggregate; (d) calculated and measured overall TE of the sample.

References[1] T. Saito et al., Science 300(5618) (2003) 464-467.
[2] H. Y. Kim et al., Acta Materialia 61(13) (2013)4874-4886.
[3] L.S. Wei et al., Acta Materialia 100 (2015) 313-322.
[4] J. A. Monroe et al., Acta Materialia 102 (2016)
333-341.
[5] A. Ahadi et al., Acta Materialia 124 (2017) 79-92.

1

1

3

[6] A. Ahadi et al., Acta Materialia 76 (2014) 186-197.
[7] P. Hua et al., Acta Materialia 185 (2020) 507-517.
[8] T. Waitz et al., Acta Materialia 52(1) (2004) 137-147.
[9] T. Waitz et al., Materials Science and Technology
24(8) (2013) 934-940.
[10] A. Ahadi et al., Applied Physics Letters 103(2) (2013)
021902.
[11] Q. Li, et al., Acta Materialia 204 (2021) 116506.

1, 2

Qiao Li , Zhongzheng Deng , Yusuke Onuki , and Qingping Sun
1
Department of Engineering Mechanics, Wuhan University, Wuhan, China; 2Department of Mechanical and Aerospace Engineering, The
Hong Kong University of Science and Technology, Hong Kong, China; 3Frontier Research Center for Applied Atomic Sciences, Ibaraki
University, Shirakata, Tokai, Ibaraki, Japan

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Research and Development Highlights

Crystal Structural Investigations for Understanding theHydrogen Storage Properties of YMgNi4-Based Alloys
1. Introduction
Efficient hydrogen storage methods have been
considered as key issues for establishing of a hydrogen-based society. At present, gaseous hydrogen,liquid hydrogen and hydrogen storage alloys (metal
hydrides) are candidate methods. In particular, the hydrogen storage alloys, in which hydrogen is stored as
atomic state, can reach higher volumetric hydrogendensities than gaseous or liquid hydrogen stored as hydrogen molecules [1]. Although Mg or Mg containing
intermetallic compounds are promising candidates inhydrogen storage alloys, most of them are thermodynamically stable, which indicates to heat materials up
for hydrogen absorption and desorption reactions [2].
By contrast, REMgNi4 based alloys (RE: rare-earth metals)
exhibit reversible hydrogen absorption and desorption
reactions at room temperature through formation ofα-, β-, γ-phase hydrides [3-8]. The γ-phase hydride has
the highest hydrogen storage capacities formed at thehighest hydrogen pressure. Though Y as RE elements
was expected to acquire higher gravimetric hydrogendensities due to the lightest element in the RE elements, the hydrogen absorption reaction of YMgNi4 ishalted during the formation of the β-phase hydride [3].
In our recent studies of hydrogen storage propertiesin Y(2-x) MgxNi4 (0 < x < 2), the hydrogen absorption anddesorption reaction pressure decreased and hydrogenstorage capacities increased with the decrease of the Mg
amounts [9]. In the study, Y1.06Mg0.94Ni4.00 had the highesthydrogen storage capacities in Y(2-x)MgxNi4.
Hence, we attempted neutron diffraction experiments under D2 pressure combined with synchrotron
X-ray diffraction experiments to understand the hydrogen absorption reaction of Y1.06Mg0.94Ni4.00 viewed fromthe atomic arrangements.
2. ExperimentY1.06Mg0.94Ni4 were prepared from powder mixtures
of YNi2 and MgNi2 at molar ratios of 1.2 : 0.8 [9].
Crystal structures of as-synthesized and hydrogen(deuterium) absorbed samples were investigated bysynchrotron radiation powder X-ray diffraction (SRPXD) and powder neutron diffraction (PND) performedon the BL-8A at the PF, and the NOVA at the J–PARC, respectively. For the SR-PXD, the samples were placed ina Lindemann glass capillary with an outside diameterof 0.3 mm and thickness of 0.01 mm. The measurement
was conducted in an Ar atmosphere, and the data werecollected at room temperature. For the PND, the samples were placed in a V sample container with an outside diameter of 10.80 mm and thickness of 1.5 mm. The
samples were heat-treated at 423 K in a vacuum for 3 h
to initiate the hydrogen absorption reaction. Following
heat treatment, the PND data were collected at 323K under vacuum and deuterium gas pressure.
3. Results
Figure 1 shows Rietveld refinement fits of the PND
patterns of Y1.06Mg0.94Ni4.00 under vacuum, D2 pressureof 3 MPa and vacuum at 323 K. The Bragg peaks undervacuum and D2 pressure of 3 MPa were indexed by
an FCC unit cell and an orthorhombic unit cell, whichwere finally refined to become a = 7.04108(08) Å and
Z = 4 in F-43 m (No. 216), and a = 5.0407(1) Å, b =5.4162(2) Å, c = 7.3035(2) Å and Z = 2 in Pmn21 (No. 31) inY1.06Mg0.94Ni4.00D3.86, respectively. The deuterided phasecorresponds to the β-phase hydride.
Crystal structures and atomic arrangements aroundD atoms during the absorption reaction of Y1.06Mg0.94Ni4.00
are illustrated in Fig. 1. The D atoms were located in four
crystallographically different sites, D1, D2, D3, and D4.
The D1 and D2 atoms were located inside the triangular bipyramids and coordinated by two Y, one Mg, andtwo Ni atoms. The D3 atoms were positioned inside of
the tetrahedron and coordinated by one Y and three Ni
atoms. Although the positions of D1, D2, and D3 wereanalogous to those previously reported for the β-phasehydrides of REMgNi4, small amounts of D4 atoms, whichwere located inside the tetrahedron and coordinated by
one Y and three Ni atoms, were identified in our crystal
structural investigations.
The crystal structure model of Y1.06Mg0.94Ni4.00D3.86
containing the D4 atoms exhibited better reproducibility of the experimentally observed PND pattern
than the crystal structure model without the D4 atoms.
Although the better Rietveld refinement fits of the
PND for Y1.06Mg0.94Ni4.00D3.86 with D4 atoms were obtained, the interatomic distances between the D4 andthe D2 (1.62 Å) or the D3 (1.87 Å) atoms were shorter
than a criterion reported by Switendick [10] in which
the minimum interatomic D–D distance were described
to be 2.1 Å. Shorter interatomic D–D distances than the57Research and Development Highlights

MLF Annual Report 2020

Figure 1.	The Rietveld refinement fits of (left) Y1.06Mg0.94Ni4.00 (under vacuum) and Y1.06Mg0.94Ni4.00D3.86 (under D2
pressure of 3MPa), and (right) their crystal structures. The Y, Mg, Ni and D atoms are represented by thegrey, orange, green and blue circles, respectively. In the atomic arrangements around D atoms, the Datomic sites in the triangular bipyramid and tetrahedra are represented by pink (D1), yellow (D2), cyan(D3) and green (D4) polyhedra. Parentheses indicate occupancies at each D atomic site.

criterion have been often reported for intermetallic
compounds [11]. Recently, the shortest H–H interatomic
distances with 1.5–1.6 Å in ZrV2 (ZrV2H3.7), were reported
by Borgschulte et al. who investigated the H atomic positions in ZrV2H3.7 by inelastic neutron scattering combined with theoretical calculations [12]. In this study,
Y1.06Mg0.94Ni4.00 adopted similar arrangements with ZrV2.
Notably, the local atomic arrangements of the D4 atoms
in Y1.06Mg0.94Ni4.00D3.86 corresponded to some D atomic
positions in the γ-phase hydride, which are obtained inhigher H2 pressure than β-phase hydrides. Consideringon similarities to ZrV2H3.7 and the γ-phase hydride of
REMgNi4 and better Rietveld fits with D4 atoms, we propose the presence of the D4 atoms in the crystal structure of the β-phase hydride, Y1.06Mg0.94Ni4.00D3.86.
4. Future plans
We will study hydrogen vibrational properties during the hydrogen absorption reactions using inelastic
neutron scattering for further understanding of hydrogen in YMgNi4-based alloys. Based on the results, we willpropose room temperature operated hydrogen storage
materials, which have higher gravimetric and volumetrichydrogen densities than applicably used hydrogen storage alloy LaNi5-based AB5 alloys.
Acknowledgements
This research was supported by JST SICORP(JPMJSC 1802) and MEXT/JSPS KAKENHI (JP18H05513,
JP18H05518, 19K05051).
References[1] A. Züttel, Mater. Today, 6 24 (2003).
[2] J. -C. Crivello et al., Appl. Phys. A, 122 97 (2016).
[3] K. Aono et al., J. Alloys Compd. 309 L1 (2000).
[4] L. Guénée et al., J. Alloys Compd. 348 129 (2003).
[5] N. Terashita and E. Akiba, Mater. Trans. 47 1890
(2006).
[6] K. Sakaki et al., J. Phys. Chem. C 116 19156 (2012).
[7] K. Sakaki et al., Inorg. Chem. 52 7010 (2013).
[8] V. V. Shtender et al., J. Alloys Compd. 603 7 (2014).
[9] T. Sato et al., ACS Omega 5 31192 (2020).
[10] A. C. Switendick, Z. Phys. Chem. 117 89 (1979).
[11] V. A. Yartys et al., J. Alloys Compd. 330-332 132 (2002).
[12] A. Borgschulte et al., Proc. Natl. Acad. Sci. USA 117
4021 (2020).

T. Sato1, T. Mochizuki2, K. Ikeda3, T. Honda3, T. Otomo3, H. Sagayama3, H. Yang4, 5, W. Luo4, 5, L. Lombardo4, 5, A. Züttel4, 5, S. Takagi2,
T. Kono2, and S. Orimo2, 6
1
Shibaura Institute of Technology; 2Institute for Materials Research, Tohoku University; 3Institute of Materials Structure Science, KEK;
4
Institute of Chemical Sciences and Engineering, Basic Science Faculty, EPFL Valais/Wallis; 5Empa Materials Science and Technology;
6
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University

58

MLF Annual Report 2020

Research and Development Highlights

Identifying Water/ice in Simulated Fuel Cell for Vehicle
by Pulsed Neutron Imaging
1. Introduction
Polymer electrolyte fuel cells (PEFCs) are electrochemical devices that convert the chemical energy
stored within hydrogen into electricity, with water as the
only by-product. PEFCs are expected to be an efficientand clean powertrain for automobiles. Toyota launched
the world’s first mass-produced fuel cell electric vehicle(FCEV), the MIRAI, in 2014 [1].
FCEVs have to be operated under various environmental conditions, including sub-zero start-up operations. If produced water in the FC stack freezes, ice
formation in the cell could prevent the transfer of thehydrogen and oxygen gases [2–7]. Therefore, the liquid water and/or ice distribution in the FC is important.
Energy-resolved neutron radiography has been a vitallyeffective methodology to identify liquid water and ice[8–10]. In the latest research, water and/or ice in gas diffusion layers and flow channels of PEFC were measured
using this method [10].
In this work, energy-resolved neutron imaging withlarge view area was employed to visualize the distribution of liquid water and ice in a simulated environment of an automotive FC at the RADEN beamline,
which is the dedicated instrument for energy-resolved
neutron imaging [11–14] in the Materials and Life
Science Experimental Facility (MLF) of the Japan Proton

Figure 1.	
Setup of the experiment. (a) thermal insulationchamber, highlighted by the red dashed line, with
Al windows. (b) cooling pads sandwiching the Al
sample case, and Fluorinert is flowed inside [15].

Accelerator Research Complex (J-PARC).
2. Experimental and data processing
The experimental setup and the sample are shownin Fig. 1 and Fig. 2 [15]. A CCD camera system [16] wasemployed, and energy-selected images using the wavelength-definition chopper were recorded. The field ofview of the CCD camera was 300 mm × 300 mm. Theenergy ranges were 20 – 100 meV (first energy range,
E1, in which the neutron cross section of liquid water isalmost equal to that of ice.) and 0.9 – 2.0 meV (second
energy range, E2, in which neutron cross section of liquidwater is larger than that of ice).
The sample size was 4 mm × 96 mm × 256 mm tosimulate the flow channels of automotive FC. Glass andstainless-steel capillaries, both water-filled and empty,
were mounted in the case made from Al alloy (A2017).
Titanium (Ti) plate sealed in an Al foil bag with water was
also mounted. Thermocouples were installed around theAl case. The sample case was sandwiched by two cooling pads, in which Fluorinert© (FC-770) flowed as therefrigerant. The sample with cooling pads was placed ina polycarbonate chamber with Al windows, and dried air
was continually flowed through the chamber to avoid
condensation of water vapor.
Time-lapse observations were performed while

Figure 2.	Sample contents in the Al alloy case. The samples
consist of (a) long stainless-steel and glass capillaries (inner diameter of 2.0 mm), (b) short glass
capillaries (inner diameter of 1.15 mm), and (c) an
additively manufactured Ti plate with the raisedlogo of Toyota Central R&D Labs., Inc. (TOYOTACHUKEN). The plate thickness ranges from 0.9 to
1.9 mm [15].

59Research and Development Highlights

MLF Annual Report 2020

alternately changing the neutron energy range (E1 andE2). Measuring temperature was, at first, –30°C, and thenwas gradually heated up to 17°C. Since the MIRAI guarantees its operation at –30°C, the evaluation of FCs under such a cold environment is necessary.
Two parameters were used in data processing. The
one concerns the amount and the phase recognition of
H2O, and is calculated from the neutron transmission at
the higher neutron energy range (above a few tens meV,which is E1 in this report) as follows:ln[ 1⁄

2( , , )] = ( , ) ( , ) ′ ( , , )(1)

where 2 ( , , ) is the transmission for neutron energy E at the position ( , ) , ( , ) is the molecularnumber density, ( , ) is the projected number of molecules. 2 ( , , ) is calculated from the radiograph ofthe sample as a numerator and the blank image as thedenominator. ′ ( , , ) is the cross section including
possible contributions due to scattered neutrons fromthe neighboring capillary. Eq.1 depends only on theamount of H2O, irrespective of its state. The other parameter for the phase recognition is obtained by consideration of the neutron cross section at the lower neutronenergy range below a few meV, which is E2. Here we define another new parameter, α , which is the normalized
cross section calculated from two transmission images
taken at different energies, cancelling the uncertainty ofσ and d , as follows:( 2, , )]( 1, , )]2( , )=′( 2 , , ) ln[=′( 1 , , ) ln[( , )=( , ) − ( , )ice
( , )water − ( , )ice

2(2)

For the following visualizations, we normalized theparameter α ( E ) as β . The value was between 0 and 1,
corresponding to ice and water states, respectively.
(3)

We also introduced the additional parameters αʹ and β ʹ ,defined below, which are used as alternatives to α and β
when blank images are not available.
′=′=ln[ sample ( 2 ) ]ln[ sample ( 1 ) ]′ − ′ice′water − ′ice

(4)
(5)

3. Results and discussion
Figure 3 show a neutron radiograph of the sample
and images of βʹ during the thawing process for water/ice
identification. Note that the base value, αʹ ice and αʹ water,used for the calculation of β ʹ , were taken at –12°C and
17°C, respectively. The hues of these images changed incorrespondence with the volume change of H2O in thecapillaries arising from the phase transition from ice to60

Figure 3.	(a) Transmission image at −30°C and (b) water/ice
identification images during the thawing process
are shown. The temperatures show the average ofthe measured values by the thermocouples aroundthe sample case [15].

MLF Annual Report 2020

liquid. The β ʹ images showed that that the thawing of
ice in the capillaries did not happen simultaneously at
the temperature close to 0°C. Additionally, inhomogeneous thawing seemed to had happened in this setup.
Thus, visualization of ice and liquid water distributions with a large field of view was confirmed according
to the analysis method introduced in this experiment,
and recognition of the state of water in the large size
system (full-scale of automotive FC) was successfully
performed.
By utilizing the difference of the energy-dependentneutron cross section of ice and water states, we wereable to distinguish with a large field of view the phaseof H2O in a metal-cell. However, it did not cancel correctly the contribution of objects other than H 2O, because blank images are not available. In the case of an
actual FC, it is possible to measure and extract the water
information free from the interference of the surroundings, since FCs in a dry condition can be easily measured.
We expect to be able to clarify the freezing-thawing behavior of H2O in-side the automotive FC by using theidentification by the energy-dependent imaging withpulsed neutrons.
List of symbols and units
T
TH O
2

T sampleσσʹ

Transmission.
Transmission of only H2O.

–3

number density of H2O molecule [m ].

dThickness of H2O [m].

α
β

βʹ

References[1] N. Konno, S. Mizun et al., SAE Int. J. Alt. Power., 2015,
4, 123–129.
[2] G. S. Hwang et al., Electrochim. Acta, 2013, 95, 29–37.
[3] S. Kim, et al., J. Power Sources, 2008, 179, 140–146.
[4] Y. Ishikawa et al., J. Power Sources, 2008, 179,
547–552.
[5] Y. Tabe et al., J. Power Sources, 2012, 208, 366–373.
[6] I. Mayrhuber et al., Chem. Electro. Chem, 2015, 2,1551–1559.
[7] L. Li, S. Wang et al., Int. J. Hydrogen Energy, 2019, 44,12033–12042.
[8] J. Biesdorf et al., Phys. Rev. Lett., 2014, 112, 248301.
[9] M. Siegwart et al., Rev. Sci. Instrum., 2019, 90,
103705.
[10] M. Siegwart et al., J. Electrochem. Soc., 2020, 167,
064510.
[11] K. Mochiki et al., J. Instrum., 2018, 13, C01038.
[12] Y. Kiyanagi et al., Phys. Procedia, 2013, 43, 92–99.
[13] T. Shinohara et al., J. Phys.: Conf. Ser., 2016, 746,
012007.
[14] T. Shinohara et al., J. RADEN, Rev. Sci. Instrum., 2020,
91, 043302.
[15] Y. Higuchi et al., Phys. Chem. Chem. Phys., 2021, 23,1062–1071.
[16] Y. Matsumoto et al., Phys. Procedia, 2017, 88,
162–166.

Transmission of sample.
2
neutron cross section [m ].
2
Value equivalent to neutron cross section [m ].

ραʹResearch and Development Highlights

Identification term.

α including background.
Identification term.

β including background.

Y. Higuchi1, D. Setoyama1, K. Isegawa2, Y. Tsuchikawa2, Y. Matsumoto3, J. D. Parker3, T. Shinohara2, and Y. Nagai1
Materials Analysis & Evaluation Research-Domain, Toyota Central R&D Labs., Inc.; 2Neutron Science Section, Materials and Life Science
Division, J-PARC Center; 3 Neutron Science and Technology Center, CROSS.

1

61

Research and Development Highlights

MLF Annual Report 2020

Polarization Analysis for Small-Angle Neutron Scatteringwith 3He Spin Filter
1. Introduction
Small-angle neutron scattering (SANS) is a powerful
technique to study microscopic structures of soft matters such as polymers, collides, biomolecules and so on.
In the SANS experiment, incoherent scattering, which
does not contain structural information, is a main sourceof background to determine structures of a sample. If
the size of the scatterers containing hydrogen atoms,
which has very large incoherent scattering cross section, is less than several nanometers, the coherent andincoherent scattering intensities tend to compete in a
Q region of typically Q > 0.1 Å. Therefore, accurate separation of the coherent scattering from the incoherent
scattering is necessary in such cases. Since a neutron
spin polarity flips with a probability of 2/3 in the incoherent scattering but not in the coherent scattering, thecoherent and incoherent scattering intensities can beseparated by the polarization analysis with a polarized
neutron beam.
3
He spin filter is a neutron polarization device inwhich polarized 3He gas is encapsulated into a special
glass cell. It can polarize a neutron beam in a broad
energy range with a large solid angle, and therefore, it
is suitable as a polarization analysis apparatus of BL15TAIKAN, which is a small- and wide-angle neutron scattering instrument at MLF [1].
This paper reports on our new experimental setup
for the polarization analyzed SANS using 3He spin filter
at TAIKAN and its first result of the demonstration study.
2. Development of polarization analysis system
The 3He spin filter based on a spin exchange optical method has been developed in J-PARC for various
neutron scattering experiments [2]. We fabricated a 3He

spin filter with a diameter of 60 mm and thickness of
40 mm for the SANS experiment using a gas filling station at J-PARC. The 3He gas pressure was 1.5 atm, which
is optimized to neutrons around 3 Å. The 3He spin filter
was polarized by a fiber laser system with a power of
110 W and then transported to the neutron beam line.
Since the 3He polarization decays by an inhomogeneous
magnetic field at the beamline, a Helmholtz coil with adiameter of 60 cm was developed to apply a homogenic
magnetic field to the 3He spin filter (Fig. 1). It equips a
motorized sample changer on which six samples can bemounted simultaneously. The 3He spin filter was placed
10 mm behind the sample to cover a wide solid angle,
which corresponds to a scattering angle of 0–24°. Notethat the scattering angles covered by middle-angle (MA)and small-angle (SA) detector banks at TAIKAN were
11.5–25.0° and 0.20–12.5°, respectively.
3. Experiment and results
Some types of colloidal particle dispersion samples
were measured in this study. The incident neutron beam
was polarized by magnetic supper mirrors installed at
the upstream-optics section of TAIKAN. A measurement
time of 2 hours was required for each sample. The 3He
spin polarity was fixed, and the neutron spin polarity
was flipped every hour using a spin flipper placed justbehind the polarizer. Since the 3He polarization varies
due to a polarization relaxation, it was periodically determined during the experiment by measuring the neutrontransmission of the 3He spin filter measured without the
sample. The 3He polarization at the start time of the experiment and the relaxation time were 71% and 170 h,
respectively. They are sufficient for continuous use forapproximately 2 days, thus reaching the typical duration

Helmholtz coilSampleeutronzed nPolari

3He spin ﬁlter

beam

X stage

Figure 1.	The polarization analysis system with the 3He spin filter for the SANS experiment.

62

MLF Annual Report 2020

required for a complete set of SANS experiments.
In the experiment, we measured scattering intensities when polarized neutron spins and that of 3He areparallel and anti-parallel for each sample. By correcting
these scattering intensities with the 3He polarization
degree, transmission of 3He cell and the sample, thespin-flip and spin-non-flip intensities I sf, I nsf were obtained. The coherent and incoherent scattering intensities I coh, I inc are given as(1)
I nsf = (1 – p) I inc + I coh(2)
I sf = p I inc.
Since the spin flip probability of the incoherent scattering p is deviated from 2/3 depending on a composition of the sample because of the multiplicity of neutron
scattering event in the sample, the value of p was estimated using a Monte-Carlo simulation by considering
the elemental composition of the sample. The experimental results are shown in Fig 2. We can see that the
scattering intensity was accurately separated to thecoherent and incoherent components. The incoherent
component from the SA detector bank is almost constant with Q as expected, whereas that from the MA detector bank is Q-dependent and is not consistent withthat of SA even at the same Q. However, the coherent
components show good agreement with the SA and MA
detector banks in the overlapping Q region. Note thatthe difference in the inelastic scattering component,
which is contained in the incoherent component in the
SA and MA detector banks, is likely to contribute to the

Research and Development Highlights

discrepancy in the scattering intensity, which is known
as the Placzek effect [3]. This result shows that a contribution of the inelastic scattering can be isolated as wellas the incoherent component from the coherent component by using the polarization analysis method. We
successfully demonstrated the polarization analysis withthe 3He spin filter at the SANS experiment, and these results provided substantial progress in SANS data analysis
at TAIKAN. The details of the experimental setup, corrections, and results are described in Ref. [4].
4. Future plans
The polarization analysis in the higher Q region is
also worth studying because the influence of inelastic scattering event becomes more pronounced at thehigher Q region. We are planning to perform a polarization analysis experiment with a high-angle and backward detector banks at TAIKAN in the near future. The
polarization analysis method reported in this work is
anticipated to be used frequently, not only in SANS experiments but also throughout neutron scattering experiments at J-PARC.
References[1] S. Takata et al., JPS Conf. Proc., 8 036020 (2015).
[2] T. Okudaira et al., Nucl. Inst. and Meth. Phys. Res. A,
977 164301 (2020).
[3] G. Placzek, Phys. Rev., 86 377–388 (1952).
[4] T. Okudaira et al., J. Appl. Cryst., 54 548–556 (2021).

Figure 2.	SANS profiles obtained for the colloidal particle
dispersions of PtCl6(BEHU·H)2 complexes. Coherent scattering intensity (red close and open circles) and incoherent scattering component (blueclose and open circles) are plotted as a result of
the polarization analysis. SANS profiles obtainedusing an unpolarized incident neutron beam areindicated by black closed and open circles. The
abbreviations SA and MA denote the small-angle
and middle-angle detector banks, respectively.
T. Okudaira1,2, Y. Ueda3,4, K. Hiroi5, R. Motokawa2, Y. Inamura5, S. Takata5, T. Oku2,6, J. Suzuki7, H. Endo5,8, and H. Iwase7
Department of Physics, Nagoya University; 2Technology Development Section, Materials and Life Science Division, J-PARC Center;
3
Materials Sciences Research Center, Japan Atomic Energy Agency; 4Advanced Science Research Center, Japan Atomic Energy Agency;
5
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 6Graduate School of Science and Engineering, Ibaraki
University; 7Neutron Science and Technology Center, CROSS; 8Institute of Materials Structure Science, KEK
1

63

Research and Development Highlights

MLF Annual Report 2020

A Novel Challenge of Nondestructive Analysis for
Medical Inheritances: Identification of OGATA Koan’s
Sealed Medicine by Muonic X-ray Analysis
1. Introduction
OGATA Koan (1810–1863) was a physician and the
director of Tekijuku, and he contributed to Western
medicine in the late Edo period. Two of his medicine
chests are preserved at Osaka University. The medicine chest which was used in his last years (the second
chest) contained 22 glass bottles and 6 wooden cylinders. These bottles and cylinders contained formulated
medicines; however, about half of them were sealed
tightly and could not be opened after having been kept
in storage for a long time. It is necessary to reveal thephysical properties of both the containers and their contents for their proper preservation. However, destructive
analysis is not allowed, because they are historically precious inheritances. To analyze these medicines sealed in
the glass bottles, we focused on muonic X-ray analysis,
which has high transmittance that would realize theanalysis of contents through the glass. We applied thisgroundbreaking method on medical inheritances forthe first time and tried to analyze the chemical components of both the containers and their contents.
Before the analysis of Koan’s inheritance, we performed a preliminary experiment to examine the analytical method using the historical medicinal specimen
preserved at the Osaka University. Second, we appliedthat method on the bottles stored in the second chest(Fig. 1) [1].
2. Experimental
First, we applied X-ray fluorescence (XRF) to identify

Figure 1. OGATA Koan’s second medicine chest.

64

the component of the glass of the bottles stored in thesecond chest. Thereafter, we moved on to the muonic
X-ray analysis.
The muonic X-ray analysis was conducted at the D2
area in the Material and Life Science Facility, J-PARC. We
constructed the muonic X-ray analysis setup according
to the previous method [2, 3]. The muon beam was collimated to a diameter of 30 mm. Muonic X-rays emitted from the sample were recorded by two high-purity
germanium semiconductor detectors (ORTEC, GMX20).
Before the long-time analysis, muon irradiations withincident muon momenta of 40–60 MeV/c were conducted, and an optimum incident muon momentum
was determined to stop the muon in the medication of
the bottle efficiently. The durations of muon irradiations
with optimum incident muon condition were 7 h for the
preliminary study and 12 h for Koan’s inheritance. The elemental composition at the muon stopping position foreach measurement was determined from the intensities
of muonic X-rays for constituent elements by correcting
the detection efficiencies of the germanium detectors.
3. Results and discussion
For the preliminary study, we selected the sealed
glass bottle with tablets containing mercuric chloride(HgCl2) from the specimen stored at Osaka University. By
the muonic X-ray analysis, the peaks of Hg and Cl weredetected at the 55 MeV/c incident muon condition andthose muons were estimated to stop at the tablets. This
result showed that the muonic X-ray measurement cananalyze the medicinal inheritances sealed in a glass
bottle.
Then we chose the sealed glass bottle with the label“甘” from the second chest for muonic X-ray analysis. Its
height was 62.5 mm and the base was a rectangle witheach side of 19.0 mm × 18.0 mm, then a white powder
was left in the bottle at a depth of about 13 mm. By thehistorical investigation and the appearance of the content of the bottle, the sign “甘” was inferred to represent “甘汞” which means calomel or mercurous chloride(Hg2Cl2).
Muonic X-ray analysis was performed for the bottle, and we attained the spectrum shown in Fig. 2. The
peaks of Hg, Cl, Pb, Si, and O were detected at 55 MeV/c

MLF Annual Report 2020

a）
（(a)

Research and Development Highlightsb） 400 muonic Hg P and muonic O K X-ray
（(b)
α

α

muonic Hg NαX-ray

Counts300

muonic Hg
OαX-rayannihilation gamma ray
muonic Cl Kα X-ray
muonic Hg Mα X-ray

200

100
muonic Si Kα X-ray

0

muonic Pb NαX-ray

200

400

600

Energy /keV

800

1000

Figure 2.	OGATA Koan’s glass bottle used for the analysis (a) and muonic X-ray spectrum from its measurement (b). Muonic X-rays from Hg and Cl were originated from the contents of the bottle. Small muonic X-ray peaks from Pb, Si andO came from the muon stop in the bottle.

incident muon momentum condition. The significant
peaks, Hg and Cl were assigned as the main components of the medication. The rest of the smaller peaks,
Pb, Si, and O seemed to originate from the bottle. In thisstudy, the beam diameter was larger than the bottle andthe muons should have also stopped in the glass. These
detected elements correspond with the result of XRF,
which have suggested the glass to be lead potash glass.
The intensity ratio of muonic Hg to Cl X-rays was
about three times higher than that from the analysis
by the sample of the preliminary study. We concluded
that the content of the glass bottled specimen “甘” isnot HgCl2 but Hg2Cl2. The result from the muonic X-ray
analysis was consistent with the historical and pharmacognostical investigation. Through these studies, wedemonstrated that the muonic X-ray can be used for anovel nondestructive analysis of medical inheritances.
4. Future plans
In this study, we applied the muonic X-ray analysis
on the medical inheritances and succeeded in analyzing
the content sealed in a glass bottle. This would be an epoch-making method for cultural properties which would
allow the nondestructive analysis of both container andcontents even if it is completely sealed. Presently, mostof the targets of the muonic X-ray analysis are inorganic
materials. On the other hand, it has been revealed thatthe muon capture processes are different with structures of muon capturing molecules [4]. This suggests
the possibility for application of muonic X-ray analysis
on organic materials, and such advances will expand its
further application on cultural properties.
Acknowledgments
The muon experiment at the Materials and Life
Science Experimental Facility of the J-PARC was performed under a user program (Proposal No. 2019B0314
and 2014MS01). This work was supported by Grant-inAid for Scientific Research (A) (No. 17H00832) and Grantin-Aid for Scientific Research (C) (No. 18K01102) from theJapan Society for the Promotion of Science.
References[1] K. Shimada-Takaura et al., J. Nat. Med., 75 532 (2021).
[2] K. Ninomiya et al., Bull. Chem. Soc. Jpn., 85 228 (2012).
[3] K. Ninomiya, Hamon, 25 13 (2015).
[4] K. Ninomiya et al., J. Radioanal. Nucl. Chem., 319 767(2019).

Kyoko Takahashi1,2, Kayoko Shimada-Takaura1, Kazuhiko Ninomiya3, Akira Sato3, Naomi Ueda4, Motonobu Tampo5, Soshi Takeshita5,
Izumi Umegaki 6, and Yasuhiro Miyake5
1
The Museum of Osaka University; 2Tekijuku Commemoration Center; 3Graduate School of Science, Osaka University; 4Gangoji Institute for
Research of Cultural Property; 5High Energy Accelerator Research Organization; 6Toyota Central Research & Development Laboratories., Inc.

65

Research and Development Highlights

MLF Annual Report 2020

Detection of Metallic Li Deposition on an Anode ofa Li-ion Battery Using Muonic X-rays
1. Introduction
In recent years, the applications of the lithium (Li)ion batteries have expanded making them an indispensable part of our lives. Recently, the reuse of used Li-ion
batteries is being considered, and in order to reuse themsafely and efficiently, it is necessary to observe the insideof Li-ion batteries in a non-destructive manner. In a usedbattery, Li is sometimes reduced and deposited as metal
on its electrode, depending on the operating conditionsof the battery. The metallic Li is known to lead to shortcircuits between electrodes, thermal reactions with theelectrolyte, and reduced capacity. Once deposited, metallic Li does not easily return to ions, so it is importantto evaluate the amount of the metallic Li deposition before reusing Li-ion batteries.
In the elemental analysis with fluorescent x-rays, ingeneral, Li can be detected only at the surface of a sample because their energy for Li is below 0.5 eV. There aresome non-destructive analysis techniques to detect Li:
Auger Electron Spectroscopy, Rutherford Backscattering
Spectroscopy and Electron Probe Micro Analyzer(EPMA). However, the applications of these techniques
are also limited to the surface of a sample.
On the other hand, elemental analysis with muonic
x-ray is a candidate for a non-destructive analytical technique. This is because a muon can penetrate a sample
deeply depending on its momentum. The energy of muonic x-rays, which is generated when a negative muon
is captured by a nuclear to form a muonic atom in thesample, is about 200 times higher than that of fluorescent x-rays. In the case of Li, it is 18.7 keV. Since the energy is intrinsic to an element, the latter is determinedby detecting muonic x-rays. Then, the muonic x-rays of
Li can pass through the housing of a Li-ion battery to be
detected by a Ge semiconductor detector.
2. Experimental
A highly sensitive detection system for muonic
x-rays of Li in Li-ion batteries has been developed at
MUSE, MLF, J-PARC. In addition, a low-momentum, highintensity negative muon beam is required to measuresamples with a layered structure of several tens of μm
thick electrodes, such as Li-ion batteries.
We prepared two samples, which were composed ofa fully charged (C6Li) graphite anode and metallic Li deposition. They were wrapped in a laminated sheet. The
location of the deposition was set at 45 μm (Sample A)
and at 135 μm (Sample B) from the surface of the samples [Fig. 1(b)].
3. Results and consideration
We obtained energy spectra including some peaks
corresponding to the elements of main components
for Sample A, that is, C and Li. The peak at 18.7 keV was
assigned as Kα signal for Li. Figure 1 shows the depth
dependence of the intensity of the peak (ICLi). The intensity of the muonic x-rays of Li is normalized by that of
the C-Kα signal represented as ICLi, because the signal of

Figure 1.	The depth dependence of ICLi for samples with metallic Li deposition located at 45 (Sample A) and 135 μm (Sample B) in thedepth from the surface.

66

MLF Annual Report 2020

Li-Kα cannot be distinguished from the one of C-Lβ withthe resolution of Ge semiconductor detectors. Assuming
the ratio of signals between C-Kα and C-Lβ is constant,any deviation of the ratio represents the existence of Li.
As the depth increases, ICLi increases up to 0.17 anddecreases down to 0.115 at 70 μm. Above 70 μm, thecomposition is C6Li and ICLi is 0.115. This broad increment
is considered to be corresponding to the existence of
Li at 45 μm [Fig.1(b)], since the distribution of muons
is rather wide at several tens of μm. It was the first time
to apply successfully nondestructive detection of metallic Li deposited on a graphite anode. We concluded
that detection of metallic Li can be achieved due to thehigh contrast between metallic Li and Li in an anode(Fig. 2). Such high contrast between metallic Li and C6Li
comes from the fact that the capture rate of negative
muons differs between metallic Li and Li ions in C 6Li,
and the detection sensitivity per Li atom for both differs
by about 50 : 1.
Furthermore, we obtained the depth dependenceof ICLi for Sample B, in which metallic Li was depositedat 135 μm in the depth [Fig.1(a)]. The increase of ICLi

Research and Development Highlights

between 105 to 180 μm, represented the existence of
metallic Li deposition. Since the location of metallic Li
deposition in a Li-ion battery will be similar to this situation, this result implies the possibility to detect metallic
Li deposition in a Li-ion battery.
It is noted that, in this study, the electrode withmetallic Li deposition was obtained and wrapped ina laminated sheet for this experiment, while batteriescommercially available also possess containers andelectrolytes inside. Although it is necessary to consider
the change in the stopping range due to the electrolyte,
this effect is not significant. In addition, since a 0.5 mmthick aluminum housing allows muonic x-rays to passthrough, this technique can be applied to a Li-ion battery with an aluminum housing as well as a laminatedLi-ion battery. It is hoped that this research will lead tofurther improvements in the safety of Li-ion batteries,
which will promote eco-friendly reuse of Li-ion batteriesin near future.
Further information can be obtained from [1].
4. Future plans
Future enhancement of muon intensity and improvement of the detectors may enable in-situ analysis.
It is also desirable to obtain an image of the metallic Li
deposition on the electrode in a non-destructive way inorder to control the metallic Li deposition. We will expand this technique to an imaging technique providing
elemental mapping for Li in a non-destructive way.
Reference[1] I. Umegaki, Y. Higuchi, Y. Kondo, K. Ninomiya, S.
Takeshita, M. Tampo, H. Nakano, H. Oka, J. Sugiyama,
M. K. Kubo, and Y. Miyake, Analytical Chemistry, 92
12, 8194-8200 (2020).

Figure 2. The relationship between ICLi and the charge capacity.

I. Umegaki1,2, M. Tampo1,2, S. Takeshita1,2, Y. Miyake1,2, and K. Shimomura1,2
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK

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MLF Annual Report 2020

Neutron Source Section
1. Overview of the beam operation
In fiscal year 2020, the neutron source section started the beam operation with beam power of 500 kW, but
it was forced to stop it from April 20 to May 15 due to thecoronavirus pandemic. After the beam operation was resumed, the beam power was raised to 600 kW on May
18 and the stable operation continued. Thus, for the firsttime, an operation with over 600 kW for the long-term
user program was achieved. At the end of the beam operation before the summer outage, a high-power operation was maintained for 36.5 hours at 930 kW from June
25 to 27, much longer than the 10.5 hours achieved in
2019. This made it possible to obtain significant operation data, which normally would require long time toreach a stable value. Also, the validity of the system design with regard to the ultimate power goal was reconfirmed. After the summer outage, the beam operation
for the user program started on December 1 after three
weeks delay from the original schedule. The neutron
source continued its stable operation at 600 kW after
the summer outage period and the average operational
efficiency in fiscal year 2020 reached 91%.
2. Mercury target system
A notable achievement was the successful operation of the new-type target vessel, target #11, in which
the coupling-free structure between the inner mercury
and the surrounding outer water shroud removes the
structural cause of generating high thermal stress on thetarget. This was one of the major milestones to achieve
stable and long-term operation at 1 MW.
There was also an important outcome in the pitting damage mitigation technology of the target vesselto achieve a stable 1 MW operation. As shown in the
middle of Fig. 1, injection of micro-bubbles of helium
gas into the mercury flow in the target vessel was used
to reduce the intensity of the pressure waves whichcaused pitting damages. In addition to that, the narrow
channel has been made by adding an inner wall at theforefront wall of the target vessel to mitigate the pitting
damage by a steep velocity gradient of rapid mercury
flow. Specimens were cut out from the forefront wall oftarget vessel #11 with a hole-saw drilling machine. The
bottom picture in Fig. 1 shows that the pitting damages
on both the narrow channel side and the bulk side of
the inner wall specimen are very small, even after thelong run of the 600 kW operation. These results demonstrated the excellent effect of the present technology for
70

Figure 1.	Cutting machine (top) and structure of the target
vessel (middle) and the surfaces of an inner wall
specimen (bottom)

pitting damage mitigation and are promising for further
power ramp-up.
Target vessel #11 was replaced with a new target
vessel but misalignment of the coolant pipe position
led again to a target replacement with another sparetarget, which caused a delay in the maintenance schedule. To prevent a recurrence of this failure, the fabrication and inspection procedure for the target vessel was
improved.
3. Cryogenic hydrogen system
The cryogenic hydrogen system, which supplies liquid hydrogen to three moderators, was designed to suppress the temperature rise of liquid hydrogen, causedby the nuclear heating at the moderators, to be below
3 K at a 1 MW beam operation. The dependency of thetemperature rise on the flow rate of liquid hydrogen,which corresponds to the rotation speed of the hydrogen circulation pumps, were measured during the 1 MW
beam test, and it was shown that the temperature riseat the coupled moderator was 2.7 K with the flow rate of
82 g/s at 915 kW beam power. This result demonstrated

MLF Annual Report 2020

Neutron Source

the 3 NBT control LAN were replaced with next generation models. In addition, operation tests on the personal
protection system were carried out successfully basedon the periodical inspection that is conducted once
every 5 years by the Nuclear Safety Technology Center.

Figure 2.	Temperature rise of liquid hydrogen at each moderator at 915 kW beam operation.

the capability of the cryogenic hydrogen system toachieve the design goal, but the rotation speed of thehydrogen circulation pumps had to be increased fromthe rated value of 40,000 rpm to 47,000 rpm to achieve
the result. It is necessary to verify the stability of the hydrogen circulation pump at high revolutions for a longterm operation.
4.	Replacement of a proton beam window and maintenance of the general control system
During the summer outage, replacement of the
proton beam window was carried out after a 3 year
operation since the last replacement in 2017. Because
the used proton beam window is a highly radioactive
component irradiated within a relatively short period oftime, in a situation similar to that of the used target vessel, it will be transported to the RAM (Radio ActivatedMaterials) building in near future.
The general control system (GCS) of the MLF has
been modified according to the annual upgrade of thetarget systems, user apparatuses, etc. and instrumentsof subsystems comprised in GCS have been replaced
based on their sustainable maintenance plans. In 2020,
modification of GCS was carried out to increase user apparatuses of muon S2 and H1 lines, and instruments of

5. Fabrication of a decoupler for a spare moderator
The lifetime of the moderators and the reflector is 6
years under the 1 MW beam operation and fabricationof spares for those components is going on. The neutron
absorber, made of Au-In-Cd alloy and called decoupler,is the important part mounted in the moderators andthe reflector for realizing high neutronic performanceof the neutron source and is manufactured in-house.
In 2020, we introduced a small NC milling machine toform the precise shape of the decoupler parts. Since
cadmium is a toxic material, the milling machine wasinstalled in a fume hood and special care had to betaken to secure the chemical safety. The finished decoupler was sent to the vendor and mounted in the newmoderator.

Figure 3.	NC milling machine (Left) and upper part of the decoupler (Right).

6. International collaboration
As one of the international collaborations, technicalworkshop with SNS (Spallation Neutron Source) of Oak
Ridge National Laboratory was held in March 2021 andsubstantial amounts of information were exchanged,
including R&D for the pitting damage mitigation technology, material fatigue experiments, and the cryogenic
moderator system operation.

K. Haga
Neutron Source Section, Materials and Life Science Division, J-PARC Center71

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MLF Annual Report 2020

Target Diagnostic System by Sound Measurement
1. Introduction
In the mercury target for the J-PARC pulsed neutron
source, cavitation erosion caused by the proton beaminduced-pressure waves degrades the structural integrity of the target vessel. So far, the cavitation erosion isthe dominant factor to determine the lifetime of the vessel, since the thickness of the beam window is designed
to be 3 mm to reduce the thermal stress. To reduce thecavitation erosion, a technique of gas microbubble injection into the flowing mercury, which mitigates thepressure waves that induce cavitation, was developed,
and applied to the target system [1].
The radiation resistance of the sensors is required toremotely diagnose the operational status of the target
vessel, including the effect of the gas microbubble injection on pressure wave mitigation in the high-radiationdose environment. At the J-PARC, the target diagnostic
system consists of a laser Doppler vibrometer (LDV),
which has been installed to enable non-contact andremote-control measurements [2]. A microphone has
also been installed as a backup of the LDV system for
unexpected troubles [3]. The recent troubles affecting
the LDV system were the drop of a retro-reflective mirror for target No. 9, and misalignment of the optical axis
for target No. 11.
Here, the applicability of the sound measurementof the alternative method of the LDV diagnostic system
for the target vessel was evaluated through investigating correlation between the operational conditions (theproton beam power and the gas flow rate for injecting
gas microbubbles) and the sound signals.

Figure 1.	Schematic view of the target diagnostic system installed in the helium vessel.

72

2. Target diagnostic system
Figure 1 shows a schematic view of the helium vessel installed at the J-PARC. The front end of the target
vessel is inserted into the helium vessel during the operation. The helium gas microbubbles are injected into
the mercury through a microbubble generator that was
installed in the target vessel [1].
A laser head of the LDV system was placed on aniron shield in the helium vessel approximately 3 m fromthe target vessel. A He-Ne laser was irradiated to theretro-reflective mirror on the target vessel by a paththrough the narrow gap between the iron shield and thepiping of the poisoned moderator using a mirror assembly. The microphone was also placed on the iron shieldin the helium vessel aiming to detect the sound propagated from the gap between the shield and the pipingof the decoupled moderator as shown in the upper leftof Fig. 1. Dynamic microphone with flat frequency response from 150 Hz to 1 kHz was used for the soundmeasurement since the back-electret microphone commonly used for the sound measurement is drasticallydamaged by the radiation environment.
3. Sound measurement
Sound signal was recorded with the sampling rateof 100 kHz. Figure 2 shows the time responses of thesound signals with and without gas microbubble injection for a single-shot beam injection at equivalent beam
power of 300 kW . The ratio of the injected gas flow rate
to the mercury, known as the void fraction, was approximately 10−3. It should be noted that the time 0 denotes
the timing of the proton beam injection in mercury,and the sound signal was arbitrarily unit-normalized at
the peak value of the averaged signal due to the lack of
calibration.

Figure 2.	Time histories of a sound signal with and without
gas microbubble injection at 300 kW/pulse.

MLF Annual Report 2020

The attenuation time of the sound was longer than
40 ms regardless of conditions. Therefore, echo of thesound signal was superimposed under the 25-Hz operation. The difference between those recorded with andwithout injection of gas microbubbles before approximately 15 ms, was hardly noticeable. In contrast, after
15 ms, it was confirmed that the sound amplitude wasclearly reduced by injecting gas microbubbles. The peak
amplitude of sound with injection of gas microbubble
was approximately 0.4 of that without injection of gas
microbubbles. It is thought that the sound source before
15 ms originated from the water shroud.
The relationship between the peak amplitude of
the sound signal and the proton beam power with andwithout gas microbubble injection under the conditionof a 25-Hz operation is summarized in Fig. 3. It can beseen that the peak amplitude is well correlated with thebeam power and is clearly reduced by gas microbubble injection regardless of the beam power even at a25-Hz operation. Details are not shown here, the soundamplitude changes depending on the gas flow rate forthe microbubble injection [3]. To understand the effectof gas microbubbles on pressure wave mitigation during operation, we defined the bubble effect as a ratio of
the equivalent beam power under gas injection to theactual operational beam power. Equivalent beam power
denotes the beam power whose peak sound amplitudewith gas microbubble injection corresponds to the one
without gas microbubbles as shown in Fig. 3.

Neutron Source

bubble effect is almost constant regardless of the beam
power, although the individual bubble effect varies
widely due to the unstable gas flow rate for the microbubble injection. In contrast, for target No. 10, the variation of the bubble effect is clearly lower than that of
No. 11, and the overall bubble effect (0.30) is lower thanthat of No. 11 (0.43). It is because the indirect path toeliminate the gas flow fluctuation in the target trolley
was applied. Due to the low variance for the bubble effect by adopting an indirect path, we understood thatthe bubble effect changes depending on the gas andmercury temperature immediately after the recovery of
the beam operation from the beam trip.

Figure 4.	Time histories of the bubble effect and beam power for targets Nos. 11 and 10 during the 25-Hz operation.

4. Summary
It was revealed that the sound measurement
has the potential to diagnose both the beam power
dependency and the status of the gas microbubble
injection. Sound measurement is applicable to the alternative method of the LDV diagnostic system for the
mercury target vessel installed in the high-radiationdose environment.

Figure 3.	Relationship between the peak amplitude of thesound signal and the proton beam power with andwithout injection of gas microbubbles.

References[1] H. Kogawa et al., J. Nucl. Sci. Technol., 54 773 (2017).
[2] M. Teshigawara et al., J. Nucl. Mater., 398 238 (2010).
[3] T. Naoe et al., Nucl. Inst. and Meth. Phys. Res. A, 982
164566 (2020).

Figure 4 shows the time histories of the beam power
and the bubble effect for target vessels Nos. 11 (fabrication number) and 10. For target No. 11, an averaged
T. Naoe, H. Kogawa, T. Wakui, M. Teshigawara, and K. Haga
Neutron Source Section, Materials and Life Science Division, J-PARC Center73

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MLF Annual Report 2020

Experimaital Characterization of High-Energy Neutrons
at NOBORU (BL10)
1. Introduction
In the spallation neutron source at J-PARC, neutrons
with high energy ranging up to 3 GeV are generated byspallation reactions in a mercury target with a 3 GeV proton incident. Although the source is primarily designed
to provide slow neutrons and to shield high-energy
neutrons from the mercury target, it could be possible
to extract high-energy neutrons through beam holes in
the primary shield structure. We have already provided
a neutron spectrum of each beam line obtained by calculation of a model based on the engineering design ofthe source. The problems associated with high-energy
neutrons above 1 MeV are identified as follows:(1) High-energy neutrons could potentially become
background elements in the experiment data because they have stronger penetration capability
compared to low-energy neutrons. Simulation
results of the early stage show that the high-energy neutron intensity for neutron energies above
1 MeV ranges from 105 to 106 n/cm2/s at the sample position in BL10 (14 m).
(2) As high-energy neutrons ranging from 1 MeV
to a few hundred MeV are requested for irradiation tests to detect the soft-error and hard-error
resistance of semiconductor devices with respect
to cosmic rays, obtaining precise neutron spectral
intensity is imperative.
(3) It is necessary to construct a complex model forthe simulation of high-energy neutrons extracted
through the beam lines. Additionally, calculating
neutron spectral intensity is time consuming. It isbasically required to experimentally validate thesimulated neutron spectral intensity used in thedesign, which was provided to the users.

Therefore, this research aims to measure the highenergy neutron spectrum at NOBORU (BL10), particularly above 1 MeV along the extracted neutron beam at the
J-PARC pulsed neutron source. The foil activation method is selected with different threshold energies ranging
from 0.3 MeV to 80 MeV [1]. The foil activation method
is the conventional technique to make it possible todetermine the absolute neutron flux value. The result iscompared with the simulation using the PHITS code [2],the JENDL-3.2 nuclear data [3, 4], and the JENDL dosimetry file [1]. In this manuscript, the measurement results
with/without a filter and a slit, and a comparison withcalculations were mentioned. The details have alreadybeen reported in Ref [5].
2. Experiment2.1. Foil irradiation for activation
Table 1 shows a list of threshold reactions appliedin this experiment. Threshold energies of activation
reactions ranged from 0.3 MeV to 63.1 MeV, whichcorresponded to those of the 115In(n, n’)115𝑚In and the209
Bi(n, 8n)202Bi reactions, respectively. A sample foil wason an aluminum plate of 0.1 mm in thickness and positioned at 13.4 m from the moderator surface along theneutron beam axis and was irradiated for the required
time. The sizes of the foils were 20 mm × 20 mm × 2 mm
for Al, 15 mm × 15 mm × 1 mm for In, 20 mm × 20 mm
× 1 mm for Nb and 20 mm × 20 mm × 3 mm for Bi. The
opening and closing times of the neutron beam shutter
corresponded to the start and stop time of irradiation.
Irradiation times for the cases were about 8 hours forabout 500 kW operation.
2.2. Radioactivity measurement
The γ -rays from the radioactive materials produced

Table 1. Reactions with high-energy neutrons and theirthreshold energies.
Reaction
115

In(n, n’)27

Threshold energy (MeV)

115 𝑚

In

24

Al(n, α ) Na

93

3.2

92 𝑚

Nb(n, 2n)

Nb

8.9

209

206

22.6

209

204

38.0

209

202

63.1

Bi(n, 4n) Bi
Bi(n, 6n) Bi
Bi(n, 8n) Bi

74

0.3

MLF Annual Report 2020

Neutron Source

were measured using a high-purity germanium detector(GEM20P4-70, ORTEC®). The detector efficiency for the
full-energy peak of γ -ray was calibrated using standard
γ -ray sources Europium-152 (152Eu).
3.	Calculation and experiment results of the effect of
the boron carbide slit and lead filter
The B4C slit of NOBORU, which consists of couplesof plates of 5 mm in thickness sintered B4C, are normallyused to form incident thermal and cold neutron neutrons. The B4C slit, by full closing, also eliminated thermal and cold neutrons extracted from the moderator
and reduced unnecessary radioactivity associated withthe reactions of the slow neutrons in the sample. In thisstudy, the B4C slit was used as a filter by full closing. The
purpose of the Pb filter was to attenuate γ -rays from themoderator. Three irradiations were performed with andwithout the slit and the filter to examine the effect onneutron spectral intensity at the sample position. The
irradiation cases were (1) No filter case, (2) B4C slit (thickness: 10 mm) case, and (3) B4C slit (thickness: 10 mm)
and Pb filter (thickness: 25 mm) case.
Figure 1 shows the calculation results with/without the B4C slit and the Pb filter at 13.4 m in NOBORU.
Figure 2 shows the comparison of the calculations withthe measurements. Although there were materials of
the slit and the filter reducing neutrons slightly, the reaction rates of Case 2 and Case 3 were nearly identicalto those of Case 1 because of the transparency of highenergy neutrons for media such as B4C and Pb.
4. Summary
This is the first study to experimentally confirm theadequacy of calculation results of the high-energy neutron flux spectrum using the foil activation method at
the J-PARC spallation neutron source facility. Reaction
rates for the threshold reaction tended to decrease with
the increase in reaction threshold energy in the rangeof 0.9 – 1.3.
Acknowledgments
We would like to thank Y. Kasugai for his guidanceand R. Kikuchi for his support in the experiment. The
neutron experiment at the Materials and Life Science
Experimental Facility of J-PARC was performed underuser programs (Proposal No. 2015P0801, 2016I0010,
2017I0010 and 2018I0010).

Figure 1. Calculated neutron spectral intensity at BL10.

Figure 2.	Calculation/Experiment ratio as a function of thethreshold energy.

References[1] F. Maekawa, et al., in: Proc. ISRD-10, American
Society for Testing and Materials, 2001, p. 417.
[2] T. Sato, et al., J. Nucl. Sci. Technol. 55 (2018) 684.
[3] T. Nakagawa, et al., J. Nucl. Sci. Technol. 32 (1995) 1259.
[4] K. Shibata, et al., J. Nucl. Sci. Technol. 34 (1997) 1171.
[5] M. Harada, et al., Nucl. Instr. Meth. A 1000 (2021)
165252.

M. Harada1, M. Teshigawara1, M. Ooi1, K. Oikawa2, H. Takada1, and Y. Ikeda3
Neutron Source Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science Section, Materials and Life Science Division,
J-PARC Center; 3J-PARC Center

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MLF Annual Report 2020

Proton Beam Transport for High-Intensity Beam
1. Introduction
Cavitation erosion of the target-vessel material is asignificant concern in the high-power operation at the
MLF and is a life-limiting factor of the mercury target
vessel. After operating the beam at high power without
the helium bubbler to mitigate the cavity erosion, significant pitting erosion of the mercury target caused bypressure waves was observed in a spent target vessel at
the MLF and the SNS in Oakridge National Laboratory(ORNL). To minimize the damage on the target vessel,
reducing the peak beam current density on the target
is crucial. Beam scanning is commonly used to decrease
the time-averaged peak current density at many facilities. To obtain a flat beam profile, beam scanning withpulse magnets to create a flat time-averaged profile
is generally employed. In the case of a short-duration
beam impinging on a liquid-metal target, scanning thebeam with a deflecting magnetic field does not mitigate
the pitting damage caused by the beam because thisdamage is proportional to about the fourth power ofthe peak density.
Using linear optics (i.e., quadrupole magnets) for
beam transport, the peak current density can be reduced by expanding the beam at the target. However,beam expansion increases heat near the target, where
the shielding is located. Therefore, the peak current density is limited by the heat induced near the target, theallowable limit of which is possibly lower than 1 W/cc. At
the MLF, the minimum peak current density is expected
to be 9 μA/cm2, resulting in a thermal-energy densityof 14 J/cc/pulse at the target. Owing to the low repetition rate of 25 Hz at the MLF, which is 60 Hz in the caseof SNS, the beam power of one shot and the peak heatdensity in mercury at the MLF for a 1 MW beam is about
twice as high as that in the present 1.4 MW SNS beam.
Therefore, to mitigate the pitting erosion, a beam-flattening system for peak-density reduction is urgently
required at the MLF.
2. Study on nonlinear optics using octupole magnet
The octupole magnet has a cubic function of themagnetic field along the transverse direction, which
introduces nonlinearity in the beam optics. By the cubic function, the particles located at the beam periphery are deflected toward its center, which flattens thebeam distribution. To obtain a flat distribution in boththe horizontal and vertical directions, two octupole
magnets are required. Using a simplified model dealing
76

with the beam as a simple filament distribution in thephase, called filament model, the required parameters
were known to obtain flat beam distribution at thetarget. However, the filament model was found not topredict the beam shape and the beam loss correctly by
the exact solution of the beam transport equation. We
proceeded with a detailed study on the nonlinear optics
and found that the beam shape can be characterized byonly two parameters [1], which are the octupole magnetic field of K ∗8 related to the beam width at the octupole magnet and the cotangent of the phase advance of
φ between the octupole magnet and the target.
With the nonlinear focusing, the shape of the beam
can be manipulated to fit the aperture at the target aswell. Due to the reduction of the intensity at the tail, it ispossible to reduce the peak current density by an expansion of the beamwidth. As a typical case, we discussed
a target with an aperture of 2.5 times beamwidth of 1σ
by linear optics. Figure 1 shows the integral intensity ofthe beam located outside of ±2.5 σ in a single plane forvarious K ∗8 and cot Φ. Due to the nonlinear optics, theintegral intensity can be reduced about 7 magnitudes
lower than linear optics with K ∗8 = 1.5 and cot φ = 8, respectively. Note that the integral beam intensity for thesame area with the linear optics is 1.2 × 10−2. The integral
intensity located outside of 2.5 σ becomes smaller forthe case of K ∗8 ≥ 0.5 and cot φ ≥ 3 due to nonlinear convergence. The solid black line shown in Fig. 1 indicatesa guide curve to achieve the lowest intensity under theminimization of K ∗8. For the same K ∗8 compared to the filament model result shown in the solid red line, a slightly
larger cot φ was found to be optimal. The solid black line
in Fig. 1 can sustain beam convergence with minimized
beam loss downstream of the octupole magnet. On the

Figure 1.	Beam intensity using the nonlinear optics with an
octupole magnet at the outside of the beamwidthfor 2.5 σ given by linear optics.

MLF Annual Report 2020

contrary, at the phase advance of cot φ = −1, the beam
shape is spread as an increase of the octupole magnetic
field K ∗8. This spread shape is a side effect of nonlinear
optics, introducing beam loss. To suppress the beam loss
to less than the allowable value (1 W/m) while obtaining
a reasonable flatness, the optimal parameter was chosen as cot φ = 3 and K ∗8 = 1, which was applied in theactual beam operation.
3. Nonlinear beam optics using octupole magnets at
the MLF
Based on the optics design, two pieces of the octupole magnet shown in Fig. 2 were fabricated for horizontal and vertical nonlinear focus on the target. We
designed the octupole magnets with OPERA-3D code.
The designed magnetic field gradient is ∼900  T/m3, andthe magnet has a bore diameter of 0.3 m and a length of
0.6 m in the direction of the pole. To obtain a significant
degree of freedom for beam turning, the octupole magnet was powered using bipolar power supplies.
At J-PARC, a 3 GeV proton beam with a beam powerof 1 MW and a repetition rate of 25 Hz is extracted fromthe RCS. The 3 GeV proton beam is delivered via a beamtransport channel called 3NBT in J-PARC. The 3 GeV proton beam extracted from the RCS is well described bya simple Gaussian. With linear beam optics, the beam
shape remains Gaussian. Two octupole magnets wereplaced upstream of the muon production target to obtain a flat beam shape at the target.

Figure 2. Fabricated octupole magnet placed at 3NBT.

Neutron Source

4. Beam profile at the target
The beam profile for the 1-MW beam was observed
at 1.8 m upstream of the target using linear and nonlinear optics (i.e., without and with excitation by theoctupole magnet), respectively. The results of the beamprofile of the experiment and the calculation are compared in Fig. 3. The calculation shows a good agreementwith the experiment, which proves that the beam can becontrolled as intended. During beam operation with 1
MW, the beam loss was confirmed to be enough smaller
than the allowable one along the beam transport line.

Figure 3.	Comparison of the experiment and the calculationof the beam profile at 1.8 m upstream of mercury
target. The left and right panels show a conventional technique based on linear optics, and the right
one presents a technique based on nonlinear optics, respectively.

5. SummaryThanks to the present beam flattening system,a beam for neutron and muon production with thepower of 600 kW had been steadily delivered by 3NBT in
Japanese Fiscal Year (JFY) 2020. At the end of June 2020,
we successfully delivered a proton beam of 920 kW for
3 days. The present work is expected to contribute tostable beam operation of future high-intensity accelerator facilities, such as the ADS. Among other works
related to beam transport, a technical award was received from the Japanese Society for Neutron Sciencein September 2020.
Reference[1] S. Meigo, et al., M. Ooi, and H. Fujimori, Phys. Rev.
Accel. Beam 23, 02802 (2020).

S. Meigo1, Y. Yamaguchi1, M. Ooi1, and H. Fujimori2
Neutron Source Section, Materials and Life Science Division, J-PARC Center, JAEA; 2Muon Science Section, Materials and Life Science
Division, J-PARC Center, Institute of Materials Structure Science, KEK

177

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MLF Annual Report 2020

Neutron Science Section
1. Introduction
The Neutron Science Section (NSS) has worked
hard to expand the neutron scientific and experimental
activities on neutrons in the Materials and Life Science
Experimental Facility (MLF). In 2020, the COVID-19 pandemic prevented researchers from travel, which affected
the user facilities, such as J-PARC. Most of the users fromabroad had to cancel their scheduled MLF experiments.
The situation was more serious for students who wereabout to earn their degrees. The NSS took notice of the
difficult situation and proceeded to deal with it. Someof the experiments were carried out by the instrumentgroup as a representative, as mentioned below.
We renewed the NSS. The Leader and Sub-Leadersof the Neutron Science Section were replaced in April
2020: K. Nakajima by Y. Kawakita as the section leader.
S. Itoh and Y. Kawakita by T. Yokoo and M. Nakamura as
the sub-leaders, respectively. The new NSS started witha new management under the COVID situation.
2. Proposal round in 2020
A state of emergency was officially announced by
the Government of Japan on April 14, which caused thecancelation of the MLF beam operation from April 20
to May 14. After the accessibility to the MLF resumed
on May 15, it was gradually extended from in-house
use and mail-in experiments to all users’ access on June
19. Since it was expected that the available beamtime

would be significantly decreased in the period of 2020B
due to the existence of many experiments carried overfrom 2020A, 2020B and 2021A were jointly called.
Among 384 neutron general proposals, 200 were approved to be conducted by July 2021. The beamlines
available for the Fast-Track Proposal (FTP) were timely
added in the fall, so that 7 beamlines - BL08, BL11, BL16,
BL17, BL18, BL21 and BL22, are available for FTP. The
long-term proposal (LTP) was not called for the 2021
round, because all approved LTPs showed certain delay in the experimental plan and therefore a half-year
elongation of the approved term was accepted. A new
category, “one-year proposal”, was introduced to BL11
PLANET aiming at promotion of research projects that
include technology development in collaboration with
the instrument group.
Under the pandemic situation, many of the user experiments were carried out by the instrument group, asshown in Fig. 1, instead of the users, because the latter
were unable to travel. For some of the beamlines popular among foreign researchers, this rate exceeded 50%of the conducted experiments. Developments of remote
access and automation of the instrument were closed
up in priority. The government also supported our activities by an additional budget (PRISM) of 55 million JY
prompting collaboration among industry, government
and academia.

Figure 1.	Rate of the remote experiments among the conducted experiments.

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3. Instrumentation up to date
The new beamline instrument, POLANO (BL23)
started as a part of the user program in 2019. POLANO
is a polarization inelastic spectrometer, currently operating in an unpolarized-mode only for the user program.
Unfortunately, all proposed experiments were canceled
because of COVID-19. For the future polarization experiment, spin exchange optical pumping (SEOP) polarizer
system, and several magnets for the guide field were almost ready to start commissioning. Vin Rose (BL06) is aneutron spin echo (NSE) spectrometer consisting of two
different types of NSE instruments, namely, a modulated
intensity by zero effort (MIEZE) type instrument and aneutron resonance spin echo (NRSE) type instrument.
The user program was served by MIEZE with a 4 Kelvin
GM cryostat and an electromagnet generating a field of
up to 0.6 Tesla.
4. Award
SuperHRPD (BL08) group (S. Torii, K. Oikawa, M.
Hagihala, C. Kwanghee, T. Kamiyama) received theTechnical Award by the 20th Annual Meeting of theJapanese Society for Neutron Science for the achievement of “Development of the World’s Highest Resolution
TOF Type Powder Neutron Diffractometer, SuperHRPD”.

Figure 2.	Contribution to the strength of each constituent
phase at maximum and minimum macroscopicstrains.

5. Scientific outcome
The research activities in neutron science at the MLF
resulted in more than 190 papers and 12 press releases.
Representative papers are listed in the references [1–9].
Neutron Diffraction study using TAKUMI revealed themechanism for strengthening cast iron (see Fig. 2),
which is widely used in the casing of hydraulic equipment for construction machinery and various parts ofautomobiles [2]. The developed research method in thisstudy will be applied to elucidate the excellent deformation mechanism of advanced metal materials.

References[1] V. Sonnenschein et al., Rev. Sci. Instrum., 91 033318(2020).
[2] S. Harjo et al., Acta Mater., 196 584 (2020).
[3] N. L. Yamada et al., J. Appl. Crystallogr., 53 1462
(2020).
[4] T. Yamamoto et al., Nat. Commun., 11 5923 (2020).
[5] K. Hirota et al., Prog. Theor. Exp. Phys., 2020 123C02(2020).
[6] M. Yashima et al., Nat. Commun., 12 556 (2021).
[7] R. Yamane et al., Nat. Commun., 12 1129 (2021).
[8] Y. Kosugi et al., Adv. Funct. Mater., 31 2009476 (2021).
[9] L. Kong et al., Adv. Funct. Mater., 31 2009131 (2021).

Y. Kawakita1, T. Yokoo1,2, and M. Nakamura1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK

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MLF Annual Report 2020

BL01: 4D-Space Access Neutron Spectrometer 4SEASONS

82

1. Use trends
4SEASONS is a direct-geometry time-of-flight neutron spectrometer for thermal neutrons, and one of
the Public Beamlines in the MLF [1]. The momentumenergy region for this spectrometer occupies the middle of the momentum-energy space covered by all the
MLF spectrometers [2]. In 2020, 21 General Use (shortterm) proposals and 1 Instrument Group Use proposal
were approved for 4SEASONS. Due to the COVID-19
pandemic, some of the proposals in 2019 were carriedout in 2020, and a part of the proposals in 2020 were
postponed for 2021. Conversely, 5 reserved (short-term)
proposals were given beam-time to compensate for thevacancy. The user group of 4SEASONS includes a large
number of international users, and 77% of the General
Use proposals were submitted by the latter. Some of theusers’ experiments, for which the research group had difficulties to visit the MLF due to the pandemic, were carried out by the instrument group instead of the researchgroup. 66% of the submitted proposals were in the fieldof magnetism, while the rest of them targeted phonons
and other atomic vibrations. As for the outcomes fromusing the instrument, 11 peer-reviewed papers were
published in 2020. 10 were papers about material science, while 1 paper was related to the instrumentation.

aging of an O-ring seal. Then, we developed a new lowtemperature sample stick to replace the old one (Fig. 1).
In addition, we developed a new high-temperature sample stick with Si diode sensors, which can warm up thesample up to 500 K. It is under commissioning and will
be available next year.
Beam optics: 4SEASONS has a 45 × 45 mm2 rectangular beam collimator just upstream of the sample todefine the beam size in combination with a four-quadrant beam slit. In 2020, we replaced this collimator witha rotary optics switching device. This device developedby the Technology Development Section of the MLF canhold four optical devices at maximum and switch themby rotation (Fig. 2). Now it holds a simple rectangularcollimator of the same dimension as before, but we plan
to add other optics, such as Soller-type beam collimatorand converging beam guide.
Detector: 4SEASONS increased the 3He detectors
gradually and completed the installation in 2019. The
pulse height distribution of the detected signal depends
on the circuit parameter of the preamplifier, and it candiffer between detectors due to the difference in thecircuit parameters. We recently found that preamplifiers after a certain period of time display largely different
circuit parameters from the older preamplifiers, which

2. Instrument upgrade
Vacuum system: The vacuum system for the sample scattering chamber of 4SEASONS consists of ascrew pump (Leybold SP630), a turbo-molecular pump
(Leybold MAG W2200), and a cryopump (Polycold PFC1100HC). The combination of these pumps evacuates
the chamber to reach enough high vacuum for operating the cryostats (typically 10 −3–10−4 Pa). However,these pumps have been used since the first day of theoperation of the instrument and have become unstableor were at the end of their designed lifetime. To solve
the problems with aging, in 2020, we replaced the screw
pump with a new one (Kashiyama SDE603X), switched
the turbo-molecular-pump to the spare one, and overhauled the cryopump.
Sample environment: We have been using a lowtemperature sample stick with Si diode sensors for
low-temperature experiments below room temperature and a high-temperature sample stick with Rh-Fe
sensors for experiments below 600 K in combination
with a top-loading closed-cycle refrigerator. However,the low-temperature stick caused vacuum leak due to

Figure 1.	The old (left) and new (right) low-temperature sample sticks.

MLF Annual Report 2020

Neutron Science

this new chopper, and the chopper was operated locallyon the controller. In 2020, the Technology Development
Section developed a device driver for the device control
software framework IROHA2 [3]. By installing this driver,
we now operate the T0 chopper remotely on the web
similarly to the other neutron devices at 4SEASONS.

Figure 2.	The rotary optics switching device being installedin the vacuum scattering chamber of 4SEASONS.

caused significant difference in the pulse height distribution. In 2020, we repaired the electric circuits of the
problematic preamplifiers to mitigate this pulse heightproblem.
Chopper: As reported in the 2019 annual report,
4SEASONS has been operating with a renovated T0
chopper since 2019, which can now run at 100 Hz at
maximum. However, there was no control software for

Acknowledgements
We thank K. Inoue and W. Kambara for their support and advice. The instrumentation works describedhere were supported by the engineers of the Neutron
Science Section and the Technology Development
Section of the MLF.
References[1] R. Kajimoto et al., J. Phys. Soc. Jpn. 80, SB025 (2011).
[2] H. Seto et al., Biochim. Biophys. Acta, Gen. Subj.
1861, 3651 (2017); K. Nakajima et al., Quantum
Beam Sci. 1, 9 (2017); R. Kajimoto et al., Physica
B 562, 148 (2019).
[3] T. Nakatani et al., JPS Conf. Proc. 8, 036013 (2015).

R. Kajimoto1, M. Nakamura1, K. Kamazawa2, Y. Inamura1, K. Iida2, K. Ikeuchi2, and M. Ishikado2
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS

1

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MLF Annual Report 2020

Current Status of BL02 DNA in 2020
1. Introduction
DNA is a TOF backscattering spectrometer designed
to elucidate atomic and molecular dynamics [1]. DNA
can provide micro-eV energy resolution measurements
over a broad energy range of -500 μeV < E < 1500 μeV,
thanks to the near-backscattering geometry of the instrument and its pulse-shaping options. DNA has two
types of analyzers Si111 and Si311 which allow to access momentum transfer range from 0.08 to 1.86 Å−1,
and from 1.79 to 3.39 Å−1, respectively.
The hot topic for 2020 is the participation of Dr.
Tamatsukuri in the BL02 team (Fig. 1). His current research interest is in the field of low-energy dynamics ofconducting ions or spins in recently-developed functional materials, such as hydride conductors and anionicelectron systems (electrides).
The number of peer-reviewed papers from DNA was
8 in 2020, almost at the average yearly amount since2017. BL02 was also used for one master thesis and one
doctoral thesis.
2.	User Program in the periods 2020A and 2020B-2021A
In 2020, 20 (2020A) and 33 (2020B-2021A) General
Proposals (GP) were submitted to BL02. 5 GPs, and
13 GPs (including 1 New User Promotion (NUP)) were approved for 2020A and 2020B, respectively. The portionof approved beamtime from all requested beamtime
was 25% for 2020A and 38% for 2020B. The competition rate was high: 5.0 and 2.75 for 2020A and 2020B,
respectively. Additionally, 3 and 2 reserved proposals
were conducted in 2020A and 2020B.
Due to the pandemic situation, users, especiallyfrom foreign countries, could not come to J-PARC. Threeexperiments with simple setup were conducted by theBL02 staff without the users. Unfortunately, one experiment requiring careful sample handling was canceled.
One project conducted as a Long Term Proposal(hereafter LTP) in the General Proposal Program has
been accomplished in 2020A. Instead, one LTP adopted
from 2020B. In total, 4 LTP’s ran at BL02.
3. Beamline activities
Additional Si311 analyzer mirrors were installed atscattering angle (2θ) of −90° < 2θ < −54°. Now, Si311
analyzers cover momentum transfer from 1.79 to 3.39
Å−1, which overlaps Q-region of Si111 0.08 < Q < 1.98 Å−1.
However, some spurious peaks from the aluminum wallof the BL02 cryostat exist for Si311 analyzers. We plan tosuppress those scatterings by oscillatory radial collimators, which will be installed during the beam shutdown
in 2021.
The impact of COVID-19 is accelerating the developments for remote or smart experiments. In BL02, weare promoting the Internet of Things (IoT) of the equipment involved in BL02. The equipment in BL02 can be
categorized as follows: (a) sample environment devices,(b) devices, such as a vacuum pump, which need to work
properly under the BL02 operation, and (c) utilities (electricity, water, gas, and compressed air). As (a) and (b) areoften electrically controlled, they are potentially easy tointroduce IoT, but (c) is often not.
For (a), we have developed a device for the automatic control of the atmosphere in the inner vacuum
chamber (IVC), naming DNA IVC control equipment(DICE) [2]. DICE facilitates the control of the amount ofgas in the IVC by sequentially operating solenoid-valves

Figure 1.	A photograph of the BL02 regular meeting held by Zoom. Clockwise from top left: Y. Kawakita,
M. Matsuura, H. Nakagawa, T. Tominaga, T. Yamada, and H. Tamatsukuri.

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Figure 2.	A photograph of the single crystal sapphire cell within the Al cell.

and a gate-valve, to flash the IVC, to set the helium gas
pressure and to set the high vacuum continuously. An
automatic sample changer (PEACE), which elevates up
and down in the IVC [2], has now extended the controlled sample temperature range of 10–320K. We arealso developing an automatic sample changer capableof loading 20 cells.
For (b), we have developed a remote-turbomolecular pump (rTMP), which enables remotely the start/stopof the TMP operation and the monitoring of the vacuum gauge. A pressure regulator with a digital pressuregauge was developed to monitor the residual pressureof the helium gas cylinder introduced to the IVC.
The developed IoT devices are linked to the operating system of neutron scattering measurements by the
IROHA2 software [3], which can integrate the devices
status. With these smart devices, we automated successfully various operations and management that havebeen done manually or visually.
To maintain the stability of the beam monitor, wedeveloped a gas replacement system and freshened
the converter gas. The intensity of the monitors was restored by the refreshment. In addition, we found that
the TOF spectrum was shifted when the beam monitor
was measured at the sample position. We speculate thatthe shift consists of the inaccurate position of the beam
monitor and the neutron wavelength dependent TOFoffset. To overcome this issue, we also plan to develop a
new monitor, which can be used at the sample position.
Since 2019, we have been developing a special
sample stick which can apply electric field at 300°C
with the help of Dr. Kazuhiro Mori in Kyoto University.
To see the dynamics of Li ions under an electric field,
we measured the electric field dependence of QENS in a
Li7P3S11 metastable crystal. We successfully observed theenhancement of QENS in a wide energy range, indicating the activation of the Li Ion movement.
In addition, we have developed a single crystal sapphire cell (Fig. 2) which is utilized for aqueous samples,such as biological solution samples, as an alternate option to avoid unfavorable corrosion of the Al cell.
Almost all these beamline activities were publishedin JPS Conf. Proc. Vol.33 in March 2021 [4].
SoftwareAdvanced Computing Environment (ACE) managed
by the MLF computing team was installed to replace thedata storage system. The instrument control software,
IROHA2 [3], was updated to improve the stability. The
data reduction software, Utsusemi, was also updated tobe compatible with Python 3.
4. Future plans
We will proceed with the further installation of
Si311 analyzer mirrors and replacement of damaged
Si111 analyzer mirrors. We are developing a compact
furnace that can heat up to 1000°C Radial collimators
will be installed in 2021 to reduce the scattering fromsample environments, such as the BL02 GM-cryostat andthe compact furnace.
References[1] Kaoru SHIBATA et. al., JPS Conference Proceedings,
8 (2015), 036022.
[2] T. Tominaga et al., JPS Conf. Proc. 33, 11095 (2021).
[3] T. Nakatani et al., Proceedings of NOBUGS 2016, P1719 (2016).
[4] The proceedings of J-PARC Symposium 2019,https://journals.jps.jp/doi/book/10.7566/J-PARC2019

Y. Kawakita1, M. Matsuura2, T. Yamada2, T. Tominaga2, H. Tamatsukuri1, and H. Nakagawa1,3
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS; 3Materials
Sciences Research Center, JAEA

1

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MLF Annual Report 2020

Current Status of iBIX in 2020
1. Introduction
The complementary use of both neutron diffraction data and X-ray diffraction data is one of the powerful methods to obtain the structure information of
all atoms in the protein samples because the neutron
diffraction data include more information about hydrogen (deuterium) atoms, and the X-ray diffraction data
include more information about non-hydrogen atoms(such as C, O, N, and S). This is particularly important,because understanding the enzyme chemistry of proteins at the atomic level requires the visualization of hydrogen atoms on active sites and water molecules. The
IBARAKI biological crystal diffractometer called iBIX is ahigh-performance time-of-flight single crystal neutron
diffractometer to elucidate the hydrogen, protonationand hydration structures of organic compound and biological macromolecules in various life processes [1, 2].
In 2019, the iBIX diffractometer, equipped with 34 detectors, was available for user experiments on organic
compound, biological macromolecules and polymer
samples, supported by the Frontier Research Center ofApplied Atomic Sciences, Ibaraki University. The specifications of iBIX are shown in Table 1.
2. Current status
In 2020, J-PARC was operated regularly at an accelerator power of 600 kW. We were able to collect afull data set of biological macromolecules for neutron
Table 1. Specifications of iBIX.
Moderator
Range of wavelength ofincident neutron (Å)
Neutron intensity(n/s/mm2) (@1 MW)

0.7 ~ 4.0 (1st frame)
4.0 ~ 8.0 (2nd frame)
0.7 × 106

L1 (m)40

L2 (mm)Solid angle of detectors(% for 4π str)

491

Detector covered region(deg.)
Detector size (mm2)
Detector’s pixel size
(mm2)
No. of detectors
Sample environment

86

Coupled22.0
15.5 ~168.5
133 × 133
0.52 × 0.52
34
Gas flow type cooling system by N2 gas (~100K)
Heating system for polymer
sample (~600K)
Tensile loading system forpolymer sample (~200 N,~90 mm, 1~1000 mm/sec)

structure analysis with around 2.0 Å resolution in about
7 days by using iBIX at the accelerator power of 600 kW.
The maximum unit cell size was 135 × 135 × 135 Å3. The
typical crystal volume of the sample measured by iBIX
was around 1.0 mm3. If the accelerator power reaches
1 MW, the total measurement time will be reduced tonearly half of the previously necessary time, or the sample size can be reduced to nearly half size with the samemeasurement time.
In 2020, 12 test measurements for a proposal of
an innovative research project of the Ibaraki Neutron
Beamline (2020A: 4, 2020B: 8), 1 test measurement fora proposal of the MLF general use, and 5 test measurements for a proposal of a leading research project of the
Ibaraki Neutron Beamline (2020A: 2, 2020B: 3) were performed using iBIX. Also, 8 proposals involving full datacollection for neutron structure analysis moved forward.
Due to the effects of COVID-19 and a trouble withthe accelerator, the total amount of beam time for user
experiments was reduced in both 2020A and B. If theaccidents did not happen, 1 or 2 more protein samples
could have been provided for full data collection.
3. Development
The current data acquisition (DAQ) system was installed in FY2013. The maintenance contract of all components of DAQ system expired in the end of FY2019.
The DAQ system should have a faster data reading andwriting function and a higher capacity storage than theprevious one because iBIX will need to collect the diffraction data in the 1 MW operation of the accelerator
in the near future. A part of the DAQ system (storage,
KVM drawer, uninterruptible power supply and network
switch) was updated at the end of FY2019 and the largescale parallel access storage of the MLF advanced computational environment (MLF-ACE) was connected tothe iBIX DAQ system as the main data storage for diffraction experiments by iBIX. In FY2020, 4 DAQ computerswere replaced with new ones and connected to the iBIXDAQ system and the large-scale parallel access storageof MLF-ACE (Fig. 1). By the end of December 2020, we
completed their installation and at the same time, thesystem became available for user experiments.
4. Future plans
It has been over 10 years since the iBIX instrument
was installed on the beam line, so some components
already need replacement due to age deterioration. One

MLF Annual Report 2020

Replaced DAQ CPU

Figure 1. New data acquisition system for iBIX.

Neutron Scienceof them is the temperature control system of the experimental hatch. Temperature control of the experimental
hatch is important to constantly maintain the detector sensitivity because the photomultiplier tube of our
scintillator detectors is very sensitive to temperaturechanges. Next year, we will replace the water-cooledtype air-conditioning package of the temperature control system.
In the near future, the accelerator power of J-PARC
will increase to about 1 MW. iBIX should be available
regularly for full data-set measurement of samples witha volume of less than 1 mm3. We will continue to develop the data reduction software and the beam line
instruments to improve the measurement efficiency
and the accuracy of intensity data obtained from small
samples.
References[1] I. Tanaka, K. Kusaka, T. Hosoya, N. Niimura, T. Ohhara,
K. Kurihara, T. Yamada, Y. Ohnishi, K. Tomoyori and T.
Yokoyama, Acta Cryst., D66 1194 (2010).
[2] K. Kusaka, T. Hosoya, T. Yamada, K. Tomoyori, T.
Ohhara, M. Katagiri, K. Kurihara, I. Tanaka and N.
Niimura, J. Synchrotron Rad., 20 994 (2013).

K. Kusaka, T. Yamada, N. Yano, T. Hosoya, and I. Tanaka
Frontier Research Center for Applied Atomic Sciences, Ibaraki University

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MLF Annual Report 2020

Neutron Filtering System for keV Neutron Capture Cross
Section Measurement at BL04: ANNRI
1. Introduction
Ever since the J-PARC accelerator was switched to
double-bunch mode, neutron capture cross section
measurements using keV neutrons have become impractical. In the keV region, the 0.6 µs time difference
between neutron generating events, i.e., spallation reactions, is not negligible as it is within the same orderof magnitude compared to the neutron time-of-flight(TOF), which is lower than 30 µs for En > 5 keV neutrons.
Thus, the double-bunch mode introduces serious ambiguities for keV-neutron induced reactions due to thedichotomy between the two neutron-generating events
since it is not possible to separate the contribution fromeach proton pulse. As an example of the difference inenergy, neutron events detected with a TOF of 6.4 µs
have a nominal value of 100 keV but can also have thevalue of 120 keV if they were induced by neutrons generated by the delayed proton shot.
The neutron filtering technique was applied to theBL04 of the MLF to bypass the double-bunch structure of the neutron beam. The incident neutron flux
was tailored into sharp quasi-monoenergetic peaksby means of using filter material with the attribute of

Figure 1.	Neutron total cross section of natFe and natSi fromJENDL-4.0.

a sharp minimum in the neutron total cross section.
Neutrons with the energy of the minimum are able topass through the filter materials whereas the remaining majority of neutrons with different energies are
stopped. natFe and natSi were employed in order to moldthe incident neutron flux into sharp peaks with averageenergy of 24 keV for natFe and 54 and 144 keV for natSi as
shown in Fig 1.
2. Experiment and simulation
The filter materials were introduced into the rotarycollimator of the BL04 before the experimental areas
with filter configurations consisting of 20 cm of natFe and20 cm of natSi. The exact position of the neutron filter isdisplayed in the schematic of the BL04 in Fig. 2.
The performance of the neutron filtering system
was tested through neutron capture experiments employing the NaI(Tl) spectrometer in the BL04. The time
distribution of the filtered neutron flux was determinedfrom the −10B(n, αγ)7Li reaction using a 90.4% enrichedboron sample, because this reaction solely emits one
γ-ray with the energy of 478 keV and, hence, it is rather
easy to identify this reaction from the detected events.
At the same time, simulations using the Monte-Carlocode PHITS [1] were performed to derive the neutronenergy distribution within the filtered neutron peaks. In
TOF neutron capture cross section experiments, the neutron energy distribution is directly derived from the experimentally measured time distribution, however, due
to the double-bunch structure, the energy distribution
cannot be reliably determined for keV neutrons fromexperimental analysis. Simulations with the PHITS code
are able to accurately reproduce the time distribution of
the incident filtered neutron beam as presented in Fig. 3.
Thus, since the PHITS code is able to simultaneously calculate the time and energy distribution for the present

Figure 2.	Schematic of the BL04 of the MLF. The neutron filter material, namely natFe and natSi, was introduced in the rotary collimator.

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experimental setup, the neutron energy distribution canbe precisely derived from the PHITS simulations basedon the good agreement of the time distribution results.
The neutron energy distribution at each of the three filtered peaks was derived by gating the events from 5.4
to 6.4 µs and from 8.6 to 9.8 µs for the Si filter and from
12.6 to 15.0 µs for the Fe filter. The centroid energy ateach filtered peak as well as the standard deviation isshown in Table 1. The averaged value for the highest
energy filtered peak for Si was determined as 127.7 keV,much lower than the expected value around 144 keV.
The reason for this is the amount of 27Al included in theBL04 which has a large neutron scattering cross section
at around 145 keV and shifts the filtered peak to a lower
averaged neutron energy.

Figure 3.	
Experimental TOF spectrum measured with the
NaI(Tl) spectrometer (black) compared with PHITS
results (red) for the filter array consisting of 20 cm of
Fe (up) and 20 cm of Si (down).

Neutron Science

the prowess of the neutron filtering system involving
the use of natFe and natSi was evaluated by determining
the 197Au(n, γ) 198Au at the averaged neutron energies of
the three filtered peaks of 23.5 keV for Fe; and 51.5 and127.7 keV for Si. As shown in Fig. 4, the present results
agree within uncertainties with the evaluated data fromboth JENDL-4.0 [2] and the IAEA Standard [3] libraries.
4. Conclusions
A neutron filtering system has been instituted in
the BL04 of the MLF in order to circumvent the double-bunch structure of the neutron beam. Sharp welldefined quasi-monoenergetic peaks are tailored by theneutron filtering system through the use of natFe andnat
Si as filter materials with averaged neutron energiesof 23.5 keV for natFe; and 51.5 and 127.7 keV for natSi. The
performance of the neutron filtering system in neutron
capture cross section measurements was analyzed bymeans of the standard 197Au(n, γ) 198Au reaction. The
present results using the neutron filtering system provide agreement within uncertainties with both the
JENDL-4.0 and the IAEA Standard evaluated nuclear
data libraries. Thus, proving to be a suitable solution forneutron capture cross section measurements in the keV
region. Further information about the neutron filteringsystem can be found in Ref. [4].

Table 1.	Summary of the averaged neutron energy for thethree neutron filtered peaks.
Filter Material TOF gate [µs] Av. energy [keV] Std. dev. [keV]Fe
12.6–15.0
23.5
1.4
8.6–9.8
51.5
3.9
Si
5.4–6.4
127.7
12.5

3. Performance in neutron capture cross section
measurements
The effectiveness of the neutron filtering technique
was evaluated by means of neutron capture cross section measurements of the cross section standard 197Au.
An extensive amount of experimental data is available
for the 197Au(n, γ) 198Au reaction and, hence, it is commonly used as standard value in order to evaluate thecapabilities of detection systems. In the present study,

Figure 4.	Averaged neutron capture cross section results for
197
Au using the filter arrangements of 20 cm of Si(51.5 and 127.7 keV) and 20 cm of Fe (23.5 keV)compared with the evaluated data from JENDL-4.0
and the IAEA standard data library. The standard deviation is represented as the x-axis bars.

References[1] T. Sato et al., J. Nucl. Sci. Technol., 55 684 (2018).
[2] K. Shibata et al., J. Nucl. Sci. Technol., 48 1 (2011).
[3] A. D. Carlson et al., Nucl. Data Sheets, 148 143 (2018).
[4] G. Rovira et al., Nucl. Inst. Meth. A, 1003 165318 (2021).

G, Rovira1, A. Kimura1, S. Nakamura1, S. Endo1, O. Iwamoto1, N. Iwamoto1, T. Katabuchi2, Y. Kodama2, H. Nakano2, J-I. Hori3,
Y. Shibahara3, and K. Terada3
1
Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency.; 2Laboratory for Zero Carbon Energy, Tokyo Institute ofTechnology.; 3Institute for Integrated Radiation and Nuclear Science, Kyoto University

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Status of Fundamental Physics Beamline BL05 (NOP) in 2020
1. Introduction“Neutron Optics and Physics (NOP/ BL05)” at the
MLF in J-PARC is a beamline for studies in the field offundamental physics. The beamline is divided at the
upstream into three branches, the so-called Polarized,
Unpolarized, and Low-Divergence branches, used in different experiments in a parallel way [1–2].
A neutron lifetime measurement is conducted at
the Polarized beam branch with a spin flip chopper.
Pulsed ultra-cold neutrons (UCNs) by a Doppler shifter
are available at the Unpolarized beam branch. At the
Low-Divergence beam branch, the search for an unknown intermediate force is performed by measuring
neutron scattering with rare gases. The beamline is usedalso for R&D of optical elements and detectors.

We published our first result of the neutron lifetime as
τn = 898 ± 10 (stat.) +15–18 (sys.) s [4] (Fig. 1).
Upgrades are in progress. Currently, data corresponding to a statistical uncertainty of 4 s for theneutron lifetime have been obtained. The goal of theexperiment is 1 s. In 2020, a spin-flip chopper (SFC) was
enlarged, and the intensity was increased by 3.2 times.
This will enable us to reach the accuracy of 1 s in about
60 days.
3. Multilayer-type Neutron Interferometer
Neutron interferometry can observe the interactionof the neutron waves with high sensitivity. The sensitivity of multilayer-type neutron interferometers can be
improved by using neutrons with longer wavelength
and/or making the flight path longer. By using a pulsed
neutron beam and the time-of-flight (TOF) method, thenumber of neutrons available can be greatly increased.
Furthermore, the time-dependent systematic uncertainty can be suppressed because the interference fringes
are repeated on the TOF of the pulse repetition.
A multilayer-type neutron interferometer wasdemonstrated with pulsed neutron at J-PARC MLF BL05
(NOP). The geometrical optics of the Jamin interferometer was constructed using a “beam splitting etalon” [5, 6],
which is a high-precision assembly of multilayer neutron
mirrors on a quartz substrate. The anti-correlated moderations between the forward (O) beam and deviatedNeutron lifetime[s]2. Measurement of the neutron lifetime
A neutron decays into a proton, an electron, andan antineutrino. The decay lifetime is an important parameter for the unitarity of the CKM matrix and also forthe primordial big bang nucleosynthesis [3]. However,recently reported values for the neutron lifetime deviate significantly from the systematic uncertainties. An
experiment to measure the neutron lifetime with apulsed beam is ongoing at BL05 (NOP). The lifetime ismeasured as a ratio of the electron events of the neutron decay to the 3He(n, p)3H events caused by 3He gas
precisely doped in a time projection chamber (TPC).

920
915
910

J-PARC BL05

905
900
895

Beam method: 888.0 ± 2.0 s

890
885
880
875
1990

Storage method: 879.4 ± 0.6 s
1995

2000

2005

2010

2015

2020
Year

Figure 1.	(Left) The results of the neutron lifetime obtained from previous experiments by the bottle (blue)
methods, the beam (red), and by the present experiment [4]. The new SFC installed at the Polarization branch of BL05.

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Neutron Science

H beam

O beamFigure 2.	(Left) The setup of the multilayer-type neutron interferometer. A neutron wave function is divided into thetwo paths at the first half-mirror and recombined at the second half-mirror. (Right) TOF spectrum of the H
beam and O beam at the detector position. The anti-correlated moderations between the two were clearlyobserved [7].

(H) beam on the TOF were clearly observed (Fig. 2) [7].
In the future, we plan to expand the available wavelength range and improve the experimental environment to develop an interferometer for high-precisionexperiments. We aim to apply the high-precision measurement of scattering length of various nuclei as basic
data to basic physics experiments, such as the search forunknown interactions.

References[1] K. Mishima et al., “Design of neutron beamline
for fundamental physics at J-PARC BL05”, Nucl.
Instruments Methods Phys. Res. Sect. A, vol. 600, no.

1 (2009) 342–345.
[2] K. Mishima, “J-PARC Neutron fundamental physics
beamline (BL05/NOP),” Hamon Neutron Netw. news,
vol. 25, no. 2 (2015) 156–160.
[3] P.A. Zyla et al. (Particle Data Group), Prog. Theor. Exp.
Phys. 2020, 083C01 (2020) and 2021 update.
[4] K. Hirota et al., “Neutron lifetime measurement withpulsed cold neutrons”, Prog. Theor. Exp. Phys. (2020)
123C02.
[5] M. Kitaguchi, et al., Phys, Rev. A 67, 033609 (2003).
[6] Y. Seki, et al., J. Phys. Soc. Jpn. 79, 124201 (2010).
[7] M. Kitaguchi et al., “Multilayer-type neutroninterferometer”, The 20th Annual Meeting of theJapan Society for Neutron Science (2020).

K. Mishima1,2 on behalf of NOP collaboration
1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK91

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MLF Annual Report 2020

BL06: Commissioning Status of Village of Neutron
Resonance Spin Echo Spectrometers (VIN ROSE)
1. Introduction
NSE is a variety of inelastic and quasi-elastic neutron scattering methods with fine energy resolution [1].
Because the energy resolution of the energy transfer
measurement is not limited by the energy spectrum of
the incoming neutrons in the NSE technique, a moderately (10–15% FWHM) mono-chromatic neutron beam
can be acceptable. In addition, the intermediate scattering function can be directly derived by NSE, so thatthe method is suitable for investigating slow relaxation
dynamics in condensed matter, and high-intensity andhigh-energy-resolution NSE spectrometers have beendeveloped and realized [2].
At BL06, two types of resonance neutron spin echo(NSE) spectrometers, which are a modulated intensity
by zero effort (MIEZE) instrument and a neutron resonance spin echo (NRSE) instrument, have been underconstruction in collaboration between Kyoto University
and The High Energy Accelerator Research Organization(KEK) since 2011.
The NSE spectrometers are equipped with neutron
resonance spin flippers (RSFs), which enable us to replace large magnetic precession fields with low guidefields, therefore downsizing and adjacence of the two
spectrometers have become possible [3].
In this report, the status of the MIEZE and NRSE
spectrometers at BL06 in FY2020 is summarized.
2. Commissioning status at BL06 in FY2020
The user program has started partially with the
MIEZE spectrometer since the 2017B proposal round. At
the NRSE spectrometer, used for fine-energy resolution,commissioning of devices, such as two-dimensional ellipsoidal neutron-focusing mirrors [2], is still necessaryand has been intensively conducted.
The main scientific highlights of BL06 achieved in
FY2020 are (i) The quantitative understandings of timeof-flight (TOF) MIEZE [3] and (ii) slow dynamics of magnetic skyrmions in MgSi studied by MIEZE [4], which aredescribed in the following sections in detail.
3. The characteristics of TOF MIEZE
In this study, the features of MIEZE by using pulsed
beams, which are based on the quantum-state manipulation of the neutron spin and energy, were comprehensively examined. A formulation of the MIEZE combined92with the TOF method (TOF MIEZE) was established byconsidering the characteristics of the pulsed neutron
beams. Moreover, a parameter, namely, the detuning
parameter, was introduced as a measure of the magnitude of detuning from the optimized instrumental state,
known as the spin-echo condition. The phase and frequency shifts of the neutron intensity signals resulting
from the TOF MIEZE under various configurations were
investigated systematically, and the detuning parameter
was found to be equal to the derivative of phase withrespect to the TOF, whose zero-point corresponds tothe spin-echo condition. The theoretical predictions onphase and frequency shifts by the established formulation were well validated by the experiments at BL06. The
further detailed description of this result is given in [3]and another article in this annual report.
4.	Dynamics of crystallization of magnetic skyrmions in MgSi
The dynamics of crystallization of magnetic skyrmions were investigated by means of the MIEZE method.
The magnetic skyrmions are nanometric vortexlike spin
objects, which can be regarded as topological defects ina ferromagnetic spin arrangement, and thus behave likeparticles [5]. It was found that the skyrmions aggregate
into small skyrmion-lattice (SkL) domains with orientational disorder on the transition from the paramagnetic
phase to the SkL phase. These domains are nearly static
dynamically and coexist with chiral spin fluctuations
with a characteristic relaxation time of 10−9 [s] near thetransition temperature. As the temperature is further decreased, the SkL domains merge into the long-rangeordered SkL, see the ref. [4].
This experiment could be made possible by the
MIEZE method, as rather strong magnetic field (~0.2 T)parallel to the beam direction at the sample positionis necessary to realize the skyrmion phase, while sucha strong magnetic field is typically impossible for NSE
with the conventional Mezei type spectrometers. The
maximum 0.6 T electromagnet and 4 K GM cryostat havebeen available as sample environments of BL06 since
FY2021, see Fig. 1.
5. Summary
In this report, the current status of BL06 VINROSE in FY2020 was summarized. The two scientificMLF Annual Report 2020

Neutron Science

Figure 1.	Pictures of the 4 K GM cryostat and the max. 0.6 T electromagnet for the MIEZE spectrometer. Left: the overall view at
the sample position. Right: the side view of the magnet and the cryostat.

achievements were introduced, i.e., the characteristics
of TOF MIEZE were elucidated both theoretically and experimentally, which was only possible with BL06. Then,the achievement was immediately fed into the study ofthe dynamics of crystallization of magnetic skyrmions
to evaluate the spin echo data very quantitatively. Bothresults have been already published in refs. [3] and [4].

References[1] F. Mezei ed., Neutron Spin Echo, Lecture Notes inPhysics, (Springer, Berlin) 128, (1982).
[2] T. Hosobata, M. Hino, H. Yoshinaga, T. Kawai, H. Endo,
Y. Yamagata, N. L. Yamada, S. Takeda, JPS Conf. Proc.
22, 011010 (2018).
[3] T. Oda, M. Hino, H. Endo, H. Seto, Y. Kawabata, Phys.
Rev. Appl. 14, 054032 (2020).
[4] T. Nakajima, T. Oda, M. Hino, H. Endo, K. Ohishi, K.
Kakurai, A. Kikkawa, Y. Taguchi, Y. Tokura, T. Arima,
Phys. Rev. Res. 2, 043393 (2020).
[5] S. Mühlbauer, B. Binz, F. Jonietz, C. Pfleiderer, A.
Rosch, A. Neubauer, R. Georgii, and P. Böni, Science
323, 915 (2009).

H. Endo1,2, M. Hino3, T. Oda4, N. L. Yamada1,2, H. Seto1,2, and Y. Kawabata3
Neutron Science Division, Institute of Materials Structure Science, KEK; 2Neutron Science Section, Materials and Life Science Division,
J-PARC Center; 3Institute for Integrated Radiation and Nuclear Science, Kyoto University; 4The Institute for Solid State Physics, The Universityof Tokyo1

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MLF Annual Report 2020

BL08: Commissioning of a New Cryofurnace

2. Specification of the cryofurnace
The design specifications of our cryofurnace areshown in Table 1.
Figure 1 shows the drawing and external view of
the cryofurnace. The Gifford-McMahon cryocooler andcompressor used in this cryofurnace are RDE-418D4 andF-50L manufactured by Sumitomo Heavy Industries,
Ltd [3]. Silicon diodes and platinum resistance thermometers are used for the temperature sensor, and Model

336 manufactured by Lake Shore Cryotronics, Inc [4] isused for the temperature control. Figure 2 shows the offbeam cooling test data. The temperature of the sample
sensor was below 4.2 K in 5 hours as per the specification, and the lowest temperature reached was ~3.5 K.
Table 1. Specifications of the cryofurnace
Minimum temperature

4.2 K

Maximum temperature

800 K

Time to reach minimum
temperature from RT~5 hours

Temperature rise time
4 K to 300 K~2 hours

300 K to 800 K~2 hours

300
temperature / K

1. Introduction
The Super High Resolution Powder Diffractometer(SuperHRPD [1, 2]) is a TOF-type neutron diffractometerwith the highest resolution in the world. It is one of the
J-PARC MLF beamlines that has been open for General
Use Proposals since the end of 2008 and has been in
operation for more than 10 years. The sample environments of SuperHRPD includes an auto sample changer
for room temperature measurements, a 4 K-cryostat, a
top-loading cryostat, a 1 K-cryostat, a vanadium hightemperature furnace and a 14 T magnet. Of these, theauto sample changer and the top-loading cryostat had
been used at the KENS facility of KEK for more than
20 years and needed to be upgraded to improve theefficiency of the measurements. In addition, there wasa growing demand from users for a consistent measurement environment from low to high temperatures
across room temperature, but we had to replace thesample environment above and below room temperature. Therefore, we decided to introduce a cryofurnace that can measure consistently from low to hightemperatures.

control temp.
sample temp.

250
200
150
100

3.45K

50
0
0

1

2

5

6

Figure 2.	Off-beam cooling test data. The control temp.
and sample temp. are the temperatures of thesensors located at the sample chamber and thesample mounting attachment of the sample stick,respectively. The tempera-ture reached ~3.5 K after
5 hours of cooling.

Figure 1. Drawings and external view of the cryofurnace.

94

3
4
time / hour

MLF Annual Report 2020

3. On-beam commissioning
In this cryofurnace, the sensor located at the sample
mounting attachment of sample stick is used to record
the temperature near the sample, but the actual sample
temperature is expected to be somewhat different due
to the distance from this sensor. In order to verify this difference, we first performed the on-beam commissioning
using a sample with a structural phase transition at low
temperature. Figure 3 shows the temperature dependence of the magnetic peak intensity of Co2(OD)3Br. The
magnetic transition was reported to occur at TN1 = 6.2 K
and TN2 = 4.8 K [5], and this sample was suitable for verification near the lowest temperature. For reference, thedata of the existing 4 K cryostat are also shown. For the
low temperature measurement, the data were almost
the same as the magnetic peak appearance temperature of the 4 K cryostat. By adjusting the pressure of theexchange gas, it is expected that the difference between
the sample temperature and the sensor near the sample
can be reduced.
The measurements at high temperatures were validated using the structural phase transition of Na2CO3 [6].
Figure 4 shows the temperature dependence of thecrystal structure parameters. Since the transition temperature of the reference material is ~750 K, we founda temperature difference of about 2%. In the high temperature measurement, there is a concern about the

The temperature dependence of the magnetic
Figure 3.	
peak intensity of Co2(OD)3Br. The data of a bottomloading 4 K cryostat is also plotted for reference.
The temperature at which the magnetic peak occurs was found to be comparable to that of theexisting cryostat. In the case of "moderate", thesample chamber was filled with He gas at 0.01 MPaat room temperature. For "excess gas", the gas wasfilled at 0.05 MPa.

Neutron Sciencetemperature gradient of the sample because it is heatedin a vacuum atmosphere. Currently, we are installing an
additional sensor closer to the sample to improve thetemperature accuracy, including the optimum value of
PID control for the high temperature side.
4. Summary
As one of the new sample environments forSuperHRPD, a cryofurnace has been introduced.
Commissioning of the first stage has been completed
and it is being used for user experiments. We are planning to improve the temperature accuracy further bycontinuing the detailed commissioning.
References[1] S. Torii et. al., J. Phys. Soc. Jpn. SB020 SB020-1-4(2011).
[2] S. Torii et al., J. Phys.: Conf. Ser. 502 012052 (2014).
[3] https://www.shi.co.jp/products/precision/cold/
index.html[4] https://www.lakeshore.com/products/categories/
temperature-products/cryogenic-temperaturecontrollers[5] M. Hagihala et. al., Phys. Rev. B, 82, 214424 (2010).
[6] I. P. Swainson et al., J. Phys.: Condens. Matter, 7, 4395
(1995).

Figure 4.	The temperature dependence of the crystal structure parameters of Na2CO3.

S. Torii1,2, M. Hagihala1,2, K. Cho2, and T. Kamiyama1,2
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK

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MLF Annual Report 2020

Current Status of BL09 (SPICA)
1. Introduction
Special Environment Powder Diffractometer (SPICA)
installed at BL09 is a time-of-flight neutron powder diffractometer [1]. It has been designed and dedicatedto studies for the next generation rechargeable battery [2- 6]. Now it is also open for General Use Proposals,and 5 proposals (including 2 Long-Term Proposals) were
accepted in the 2020A and 2020B+2021A terms.
The rechargeable battery is a key component of mobile devices and electric vehicles, and there are strong
demands for developing such batteries with higher performance. Observation of the electrochemical reactionsin operating batteries, as well as basic structural studiesof each of the component materials are essential in thedevelopment of the next generation rechargeable battery. BL09 is equipped with 3He detector banks for TOF
neutron powder diffraction and nGEM/μPIC detector instruments for neutron imaging experiments. Together
with its off-line electrochemical evaluation instruments
and chemistry laboratory, BL09 provides an ideal environment for the study of batteries using neutrons.
2. Cryostat and cryofurnace
In FY2020, the temperature control of both the cryostat and cryofurnace was automated. A new IROHA2
device server software was developed to enable automatic temperature dependent measurements. Users canrun programmed measurements, including stepwise
temperature control and/or constant-rate temperaturescanning. This reduced significantly the manpower required for temperature dependent measurements using
these instruments.
Sample exchange procedures in a top-loading cryostat or cryofurnace are easier than those in bottom

loading ones. Still, there are series of operations forexchanging samples, which require time and carefulattention. In FY2020, the software was modified to enable the automation of valve operations for the cryostat
and cryofurnace. Further steps will be taken to partly
automate the sample exchange procedures, which will
reduce the time for sample exchange procedures forthese instruments.
The maximum temperature at the sample position
for the top-loading cryofurnace at BL09 was about 600 K.
There are, however, growing demands for experiments
at higher temperatures at BL09. Therefore, a sample rod
was newly designed and manufactured to increase themaximum sample temperature, as shown in Fig. 1. The
temperature at the sample position was calibrated, andthe maximum sample temperature is now 700 K, which
is about 100 K higher than that for the previous one.
Modification of the sample rod is underway to increase
further the maximum sample temperature.
3. Vanadium furnace
A vanadium furnace is being developed to enablemeasurements at temperatures up to 1000 K. The furnace is designed to perform neutron powder diffraction
measurements from room temperature up to 1000 K,
under vacuum for gas flow. Samples will be heated by
the radiant heat from the surrounding vanadium heater.
In FY2020, we designed and manufactured the sample
rod for the vanadium furnace.
4. General-purpose sample stage
Operando diffraction measurements of commercially available 18650-type lithium-ion batteries canbe done at BL09 by using the sample stage specificallyFigure 1.	New sample rod for the top-loading cryofurnace in
BL09. The inset shows the radiation shields installedaround the sample and the heater.

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MLF Annual Report 2020

designed for such type of battery. For other kinds of battery samples, a 5-axis goniometer is available, although
it requires a crane operation for sample exchange.
Therefore, it is desirable to develop a sample stage suitable for various kinds of battery samples, that does not
require a crane operation for sample exchange. Such asample stage can also be useful for samples with shape
not suitable for an automatic sample changer. In FS2020,
we manufactured a general-purpose sample stage formeasurements at room temperature, which consists ofa sample rod connected to a JIS 200A flange, as shownin Fig. 2. Further modifications will be made to enable operando measurements for rechargeable battery
samples.

Neutron Science

5. Future plans
We will continue to work on the partial automationof the sample exchange procedures for the cryostat andcryofurnace, and on the increase of the maximum sample temperature of the cryofurnace. The development of
the vanadium furnace will also be continued, as well as
the modification of the general-purpose sample stage.
6. Acknowledgements
We would like to thank Mr. Shioya, Mr. Namba, Mr.
Nanjo and Mr. Tanino for the technical support in operating SPICA. This work was supported by the Researchand Development Initiative for Scientific Innovationof New Generation Batteries 2 (RISING2) project of the
New Energy and Industrial Technology Development
Organization (NEDO).
References[1] M. Yonemura, et. al., J. Phys. Conf. Ser., 502(1) Article#
012053 (2014).
[2] S. Shiotani, et. al., J. Power Sources., 325, 404-409(2016).
[3] S. Taminato, et. al., Scientific Reports., 6, Article#
28843 (2016).
[4] T. Matsunaga, et. al., Chem. Mater., 28(12), 4143-4150(2016).
[5] K. Kino, et. al., Solid State Ionics., 288, 257-261 (2016).
[6] T. Matsunaga, et. al., J. Phys. Chem. Lett., 7, 2063-2067(2016).

Figure 2.	General-purpose sample stage in BL09.

1,2,3

1,2,3

T. Saito
and T. Kamiyama
23Institute of Materials Structure Science, KEK; Neutron Science Section, Materials and Life Science Division, J-PARC Center; Departmentof Materials Structure Science, School of High Energy Accelerator Science, The Graduate University for Advanced Studies, SOKENDAI

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MLF Annual Report 2020

BL10: NOBORU
1. Introduction
In FY 2020, fifteen general-use proposals and threeproject-use proposals were carried out at NOBORU.
Three general-use proposals and one long-term proposal were postponed due to an entry restriction forforeigners because of the COVID-19 status.
This year, several experiments were proposed toscan a large sample in two dimensions using prompt
γ-ray activation analysis (PGAA). For this purpose, we
introduced an electrically cooled high-purity germanium (HPGe) detector and its DAQ system to work in the
IROHA2 environment. This system enables automatic
measurement of prompt γ-rays that require more than aweek of continuous scanning. In the following sections,
we briefly describe the measurement system.
2. Development of scanning PGAA system
Figure 1 shows a schematic diagram of the constructed prompt γ-ray automatic measurement system.
An electrically cooled HPGe detector manufactured by
CANBERRA has been used. The signals from the HPGe
detector and a timing signal of 3NBT-CT trigger areconnected to the measurement module, APV8008,
manufactured by TechnoAP. The event data generated by the APV module is recorded on the measurement PC by a DAQ-Middleware component called
GathererAPV. The large sample is mounted on an XY
stage manufactured by KOHZU or SIGMAKOKI. The X
and Y stages are controlled by Tsuji Electronics’ stepper motor controller (PM16C-04XDL), which is widelyused in DAQ-Middleware of the MLF, and its drive control is automated by the IROHA2 facade. The obtained
event data are converted to a photon energy spectra or
photon-energy vs. TOF map by using Python-based CLI

program or GUI program “Utsusemi for APV”.
3. Experiment
Figure 2 shows an example of experimental setting
for the scanning PGAA system at NOBORU. The aperture of the incident beam collimator is made of boron
polyethylene and/or stainless steel, and the diameteris selected from 2 to 10 mm depending on the target
gauge volume. For a PGAA measurement at NOBORU,
a number of lead blocks need to be assembled on theexperimental table to shield the γ-rays from the environmental background. To reduce this time and effort,
we fabricated a mounting frame for the HPGe detector,
which can be uniquely positioned using the screw holes
in the experimental table, thus greatly reducing the setup time, and improving the experimental reproducibility. In addition, a pinhole in the front of the lead shieldof the detector, through which only the target part ofthe sample is restricted to be visible, enables easy andaccurate alignment of the sample at the intersection of
the beam axis and the detector axis.
For the two-dimensional PGAA measurement of asample, a total of 17 × 57 auto-controlled mesh measurements were performed over an area of 27 mm ×
87 mm, and the boron distribution was obtained witha spatial resolution of about 3 mm. The scanning system of the stage also functioned as a sample changer.
About 30 coin-sized boride samples were measured for
1 to 2 hours each to perform automated experiments of
PGAA, and the results were reported [1].

Figure 2.	Experimental setting for the scanning PGAA system.

Figure 1. Schematic of the PGAA measurement system.

Reference[1] Y. Tsuchikawa et al., Nucl. Inst. and Meth. Phys. Res.
A, 991 164964 (2021).

Y. Tsuchikawa, T. Kai, and K. Oikawa
Neutron Science Section, Materials and Life Science Division, J-PARC Center98

MLF Annual Report 2020

Neutron Science

Development of Piston Cylinder Cells for Diffraction,
QENS, and SANS at High Pressures
1. Introduction
Piston cylinder cells have been widely used in insitu and ex-situ high-pressure experiments due to theirsimple structure, compactness, and extraordinarily large
sample volume (~cm3). The last characteristic satisfies
the requirements for neutron scattering experiments inwhich the sample signal is generally weak; thus, many
piston cylinder cells have been developed and applied
to various neutron scattering studies. The compactness
also makes it possible to attach the cells to a cryostat,which enables experiments under multi-extreme conditions. In the last few years, we have been developing
piston cylinder cells for various types of neutron scattering, such as diffraction, INS, QENS, SANS. In this report,
we summarize the recent developments.
2. Piston cylinders and their performance
We used five piston cylinder cells made of different materials or with different diameter, which were invented by Uwatoko [1] and our group [2] (Table 1). Theirperformance in high-pressure generation and neutrontransparency was evaluated at PLANET prior to the application to various types of neutron scattering.
Figure 1 shows the pressure generation performance. A Pb chunk was put in the sample container
made of Al or Teflon, together with water or Fluorinert(3M, FC72), and compressed with a hydraulic press(Riken CDM-10PA). Pressure was determined by thelattice parameter of Pb on the basis of the equation ofstate. The results showed that the maximum availablepressure increased in the order from NA700 monobloc,
SCNM439–NA700 hybrid, CuBe monobloc, and NiCrAl–
CuBe hybrid cells. The pressure generation efficiency
compared to the ideal one without friction was 63–83%
and 87–88% for cells with outer / inner diameter of
30 mm / 8 mm and 25 mm / 6 mm, respectively.

Figure 1.	Pressure-generation performance of various cells.
The ideal performance without friction is also
shown by black lines.

Figure 2 shows the wavelength-dependent neutron transparency. The transmission increases in the order from CuBe (30/8), NiCrAl–CuBe (25/6), CuBe (25/6),
SNCM439–NA700 (30/8) and NA700 (30/8). The CuBematerial was found to have strong attenuation. The
transmission of the SNCM439–NA700 (30/8) hybrid cylinder at 5.10 Å (3.14 meV in energy), which is the wavelength of the incident beam employed in the QENS
experiment shown later, was four times larger than thatfor the CuBe cells, indicating that the hybrid cylinder isefficient in the experiments where the intensity at large
wavelength is important, such as QENS, SANS.

Table 1. Various cells tested and their nomenclature.

Cells*
Outer /Inner diameter
NA700 monobloc (30/8)
30 mm / 8mm
SNCM439–NA700 hybrid (30/8) 30 mm / 8mm
CuBe monobloc (30/8)
30 mm / 8mm
CuBe monobloc (25/6)
25 mm / 6mm
NiCrAl–CuBe hybrid (25/6)
25 mm / 6mm*Numbers in the parenthesis represents outer and inner diameters of the cylinder.

Figure 2.	Neutron transmission of various cells.

3. Application to diffraction at low temperatures
In the PLANET, the lowest temperature at which
neutron diffraction experiments were possible was limited to 77 K. To extend it toward a lower temperature region, the CuBe monobloc cell (30/8) was attached to the
4 K-GM refrigerator (Iwatani, Cryo Mini HE-01). Figure 3
99

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MLF Annual Report 2020shows the temperature dependence of the diffraction
pattern of Ho2Fe17 at 0.85–0.95 GPa. Upon decreasing
the temperature, the magnetic peaks significantly shifted while maintaining the positions of nuclear peaks. The
data quality was not degraded even with the NiCrAl–
CuBe hybrid cell; thus, the experiments at pressuresof up to 2 GPa and temperatures down to 7 K became
possible.

Figure 3.	Temperature dependence of the diffraction patterns of Ho2Fe17 at 0.85–0.95 GPa (courtesy of Yili).

4. Application to QENS at AMATERAS
The incoherent scattering from water was measured
at 0.8 GPa and 300 K with the SNCM439–NA700 hybrid(30/8) cell at AMATERAS. An Al rod slightly thinner than
the inner diameter of the Al container was inserted into
the container, and Milli-Q water was introduced into the
gap to avoid multiple scattering of water. This assembly
was compressed and clamped at the target load, andthen attached to a top loading stick. The S (Q,E) map
with an incident energy of 3.14 meV (Fig. 4) showed themarked incoherent scattering from water, which was
almost the same as that taken without cells [3]. By employing the hybrid cylinder, the investigation of waterover a whole pressure region where water is stable (upto 1 GPa at 300 K) became possible. However, additional
details revealed that the hybrid cell generated an unwanted scattering near (Q,E) = (0,0) due to the magnetic
scattering. Therefore, the combination of nonmagnetic
materials would be preferable in a study in which theintensity near (Q,E) = (0,0) is important.
5. Application to SANS at TAIKAN
Scattering from CrNb3S6 was measured at 1.2 GPaand 3–150 K with a CuBe monobloc (30/8) cell at
TAIKAN. 16 single crystals were glued on both sides ofa thin Al plate in the same crystal orientation. It was inserted into a sample container filled with Fluorinert andcompressed to the target load. The piston cylinder cell
was attached to a 4K-GM refrigerator. Figure 5 shows theI(QX,QY ) map obtained at 3 K. The magnetic peaks wereclearly observed at both sides of the direct beam. On
the other hand, these peaks were not observed due toa high background from the cell when the NiCrAl–CuBehybrid cell was used.

Figure 5.	I(QX,QY) map of single crystal CrNb3S6 obtained at
1.2 GPa and 3 K.

Figure 4.	S(Q,E) map of water at 0.8 GPa taken with SNCM439–
NA700 hybrid cells at high pressures.

References[1] Y. Uwatoko et al., J. Phys. Condens. Matter, 14 11291(2002).
[2] T. Hattori et al., (submitted).
[3] T. Kikuchi et al., Phys. Rev. E, 87 062314 (2013).

T. Hattori1, J. Abe2, S. Kawamura-Ohira1, K. Ohishi2, and Y. Kousaka3
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS; 3Departmentof Physics and Electronics, Osaka Prefecture University

1

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Neutron Science

High Resolution Chopper Spectrometer HRC
1. Introduction
The High Resolution Chopper Spectrometer (HRC)
is being operated at BL12 in the MLF under the S typeproject of IMSS, KEK and the IRT project of ISSP, theUniversity of Tokyo, in order to study the dynamics incondensed matter, especially in a wide range of correlated electron systems. Activities of the HRC in FY2020
are summarized in this report.
2. Web application for INS experiments
We developed a simulation program in the formof Web application using JavaScript for inelastic neutron scattering (INS) experiments using a single crystal
sample on the HRC [1, 2]. The users can simulate INS
experiments on the Web browser without installing
any special software on their personal computers. This
program consists of Neutron Laue diffraction pattern
simulator, Flux/resolution simulator and Accessible Q-E
range simulator, and is useful for planning experiments
and educating students.
In the first step of INS experiments using a single
crystal sample, the crystal orientation is found by observing the Laue spots using a white neutron beam. In
the Laue diffraction pattern simulator, the Laue spots
on the detector map of the HRC are simulated from thecrystal structure with the lattice constants and displayed.
The observed Laue pattern, which is generated on thedata visualization program HANA, is transferred to thesimulator and is compared with the simulation. Figure 1
shows the comparison between the observation andthe simulation of the Laue pattern of Ba2MnGe2O7 withtetragonal crystal structure. The simulation agrees wellwith the observation, and the crystal orientation can be
defined on the coordinate system of the spectrometer.
The crystal axis ω is defined as an angle between theprincipal crystal axis and the incident beam direction.
Then, the INS experiments started with operating
the Fermi chopper. In order to observe the excitations
on the desired 4-dimensional Q-E space limited by thedetector configuration of the HRC, the incident neutronenergy Ei and the crystal angle ω should be selected. In
many cases for 3-dimensional systems, the ω rotation isrequired to observe enough Q-E space. Figure 2 showsan accessible reciprocal lattice space with Ei = 40 meV
and with a certain range of ω, where a* = b* = 1.5 Å−1, in
the Accessible Q-E range simulator. By moving the slide
bar in the upper part of the figure, accessible Q spacecan be found as a function of the energy transfer.
The multi-Ei method can be performed on the HRC,
similarly to the other chopper spectrometers at the MLF.
To realize the multi-Ei method, it is important to know
the neutron flux, the resolution, and the accessible
Q-E space for the Ei’s. These pieces of information canbe consistently obtained by the combined use of theFlux/resolution simulator and the Accessible Q-E range
simulator.

Figure 1.	Typical Laue pattern of a single crystal sample measured on HRC and a comparison with a simulation.

Figure 2.	Accessible Q-E range for Ei = 40 meV. Shaded area
and gray dots show the accessible area and the reciprocal lattice points, respectively.

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3. Other instrumentations
As we reported last year, we performed a maintenance work for T0#2 (the second machine of the T0
chopper). T0#1 was operated until June 2020, then, we
replaced it with the restored T0#2. At the same time, theoptical fibers, which transfer the rotational signal of theT0 chopper, were renewed.
In January 2019, some failures occurred in the startup of the HRC. Due to a lower voltage of the battery in
the PLC (programmable logic controller) of the Fermi
chopper controller, the Fermi chopper became out ofcontrol and a touch-down occurred in the magnetic levitation system of the rotor. Therefore, this Fermi chopper
was replaced with a spare one. This year, to repair thedamaged Fermi chopper, the damaged touch-downbearing was replaced with a new one. However, a stable rotation was not realized due to rotor balance loss.
Further work is required.
In the vacuum system of the scattering chamber,
2 sets of the dry pumps with the mechanical booster
pumps are used for the rough exhaust and the dryer isused for generating dry air for breaking the vacuum. We
performed regular maintenance for these systems. Also,
we performed maintenance for the backing pump (drypump) of the turbo molecular pump for the Fermi choppers, because there was a strange noise.
The neutron choppers are provided by two companies: companies A and B are responsible for the mechanical engineering and the electrical control, respectively.
In company B, the organization was changed and thedevelopment work for the electrical control was terminated. Company B provided KEK with a complete set of
the information of the control system of the neutron
choppers. Company A tried to establish a way to develop the electrical control system based on the information, and successfully manufactured a circuit board for

the Fermi chopper control.
The 1 K refrigerator on the HRC is a 3He gas circulation type one, where the lowest temperature was
0.6 K in the best case. Recently, the lowest temperature
unstably reached 2 K, and the volume of the 3He gas
decreased. We added 3He gas, but the situation did not
improve. An overhaul is required.
4. Scientific results
Several publications came up as results from thegeneral user program: magnetic correlation in YBaCo4O7
with kagome and triangular lattices [3], establishing thecarrier scattering phase diagram for ZrNiSn-based halfHeusler thermoelectric materials [4], gapless spin liquid
in a square-kagome lattice antiferromagnet [5], noncoplanar ferrimagnetism and local crystalline-electric-fieldanisotropy in the quasicrystal approximant Au70Si17Tb13[6], and spin-waves in 2D honeycomb lattice XXZ-type
van der Waals antiferromagnet CoPS 3 [7]. A crystal
growth technique contributing to the experimentson the HRC has been reported: floating zone furnace
equipped with a high-power laser of 1 kW composed offive smart beams [8].
References[1] https://sites.google.com/view/hrc-web-tools/[2] T. Nakajima and D. Kawana, Hamon 31 128 (2021).
[3] M. Soda et al., Phys. Rev. B 101 214444 (2020).
[4] Q. Ren et al., Nat. Commun. 11 3142 (2020).
[5] M. Fujihala et al., Nat. Commun. 11 3429 (2020).
[6] T. Hiroto et al., J. Phys.: Condens. Matter 32 415802(2020).
[7] C. Kim et al., Phys. Rev. B 102 184429 (2020).
[8]	Y. Kaneko and Y. Tokura J. Crystal Growth 533
125435 (2020).

S. Itoh1,2, T. Masuda3,2, T. Yokoo1,2, T. Nakajima3, S. Asai3, H. Saito3, D. Ueta1,2, D. Kawana3, R. Sugiura3, T. Asami3, Y. Ihata4, and H. Tanino1,2
1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3The Institutefor Solid State Physics, The University of Tokyo; 4Technology Development Section, Materials and Life Science Division, J-PARC Center102

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Neutron Science

BL14 AMATERAS
1. Introduction
AMATERAS is a cold-neutron disk-chopper spectrometer for studies of the dynamical properties inatomic, molecular and magnetic systems from cold to
sub-thermal energy range with high efficiency and flexible resolution [1, 2]. In FY2020, due to the global spreadof the coronavirus infection, travels from foreign countries have been restricted all year long. Because of that,
we experienced an unusual situation when many users’
experiments were remotely carried out by the beamline
staff or postponed to FY2021. During a short break of
the beam operation, we upgraded the evacuation system for the vacuum scattering chamber.
2. User program, outreach activities and outcomes
The numbers of general proposals (short-term)
submitted to the 2020A and 2020B+2021A periods
were 25 (accepted: 8, reserved: 16, not approved: 1)
and 35 (accepted: 7, reserved: 27, not approved: 1), respectively. Note that more than 70% of the approved
proposals were from foreign users. In FY2020, the users
and beamline staff members were seriously affected by
the spread of the coronavirus infection. The foreign users could not visit the MLF for their experiments all year
long, and even the domestic users could not enter theexperimental hall in April and May. As a result, many users’ experiments were postponed to FY2021 or carriedout remotely by the beamline staff members in the absence of the users. Experiments of 16 general proposals
and two JAEA project research proposals were carriedout, and 10 of them were done remotely. As of the research fields of the 15 approved general proposals, one
involved liquid and non-crystalline systems, one - theenergy materials, and the other 13 dealt with magnetism and strongly correlated electron systems, which was
the same trend as in the previous periods.
In FY2020, 13 refereed papers related to works at
AMATERAS were published, and two students received
their degrees. Dr. Kazuki Iida (CROSS) won the JSNS
Young Researcher Prize for the study of magnetic fluctuations in novel superconductors by using a pulsed
neutron source, which included works at AMATERAS [3].
Moreover, an article written by Dr. Nobuyuki Kurita andProf. Hidekazu Tanaka (Tokyo Institute of Technology) to“Hamon”, related to the study of magnetism in the frustrated quantum spin system conducted at AMATERAS,

was selected as a JSNS President Choice [4].
AMATERAS was supposed to accept a guest researcher from the AONSA Young Research Fellowship
organized by Asia-Oceania Neutron Scattering
Association. However, his stay has been postponeddue to the COVID-19 pandemic and presently, there isno concrete plan about his visit.
3. Instrument-related upgrades
In FY2020, we upgraded the evacuation systemof the vacuum scattering chamber of AMATERAS during a short break of the beam operation from the endof December 2020 to the beginning of January 2021.
The vacuum scattering chamber originally accommodated a cryopump, which consists of three sets of the
coldhead and compressor, to achieve high vacuum.
However, in recent years, we had often encounteredsome troubles with this cryopump. Therefore, last fiscal
year, we purchased a new cryopump and a gate valve
to achieve a more effective operation of the system. The
new gate valve, a huge elbow and the new cryopump(ULVAC) were fitted to the bottom of the vacuum scattering chamber as shown in Fig. 1. Its control system
was also partly modified and then we carried out a test
operation. Although the cooling power of the new cryopump is lower than the original one, we could achievea vacuum level high enough to perform practical experiments. The cooling time to the lowest temperature
was reduced by half an hour than before. Furthermore,
the newly introduced gate valve enabled us to change
the sample environment without warming up the cryopump. Consequently, we are now able to reduce thetime for changing the samples by more than five hours
in the maximum case. The upgrade of the evacuation
system is expected to bring about an effective beamtime operation. We are planning to modify the vent port
and then automate the system next year.
We have also slightly improved the design of ourbottom-loading closed-cycle refrigerator: we made theradiation shield thinner and added a room-temperatureshield made of aluminum foil. With these modifications,the cooling speed was effectively improved and now ittakes two hours to reach the lowest temperature (~3 K).
Gradual warming in the long-time operation at the lowest temperature was successfully prevented by the newroom-temperature shield.

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References[1] K. Nakajima et al., J. Phys. Soc. Jpn. 80, SB028 (2011).
[2] K. Nakajima, RADIOISOTOPES 66, 101 (2017).
[3] K. Iida et al., J. Phys. Soc. Jpn. 89, 053702 (2020).
[4] N. Kurita and H. Tanaka, Hamon. 30, 130 (2020).

Figure 1.	(a) Gate valve, (b) elbow and cryopump newly introduced to the vacuum scattering chamber of AMATERAS. (c) The new components fitted on the bottomof the vacuum scattering chamber.

S. Ohira-Kawamura1, M. Kofu1, N. Murai1, Y. Inamura1, D. Wakai2, and K. Nakajima3
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2NAT Corporation; 3Materials and Life Science Division,
J-PARC Center (Present: Material Science Research Center)1

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Neutron Science

Upgrading TAIKAN
1. Introduction
The small and wide angle neutron scattering instrument TAIKAN (BL15) has been developed and upgraded at J-PARC to analyze precisely and efficiently the
microstructures or hierarchical structures of substances
in various scientific fields with a 1 MW spallation neutron source [1]. In FY2020, it was upgraded further toperform efficient wide-q measurement and tensile test
measurement.
2. Upgrading for efficient wide-q measurement
The detector system of TAIKAN is composed of
5 detector banks: small-, middle-, high-, ultra-small-angle, and backward detector banks. On the high-angle
detector bank, 80 3He PSD tubes were additionally installed. The measurement efficiency of the high-angle
detector bank increased by 25%. The number of 3He
tubes then increased to 912, 720, 400, and 80 for thesmall-, middle-, high-angle, and backward detectorbanks, respectively, and reached 2,112 in total. The installation ratios of the 3He tubes became 100, 100, 76,
and 100% for the small-, middle-, high-angle, and backward detector banks, respectively, and became 94% as an
overall average. Figure 1 shows the lower section of thehigh-angle detector bank after installing the 3He tubes.
Furthermore, for more efficient measurement, thedetector with a gas pressure of 6 atm was replaced with
one with a gas pressure of 20 atm. Also, 32 detectors
in the center of the small-angle detector bank and 80
detectors in the backward detector bank were replaced.

Figure 1. The lower section of the high-angle detector bank.

3. Upgrading for tensile test measurement
A tensile testing machine with a load cell was developed for the study of soft matter (Fig. 2). A sample
is mounted in a gas chamber. The standard size of thesample is 65 mm long and 40 mm wide. The maximum
stroke is 500 mm. The maximum tensile force is 500 N.
The head speed is 0.01 to 50 mm/min. The temperatureof the sample can be controlled between RT and 80oC.
This machine can be combined with a humidity control
system, and the sample atmosphere can be any mixtureof light and heavy water vapor.
4. Future prospects
The installation of high-angle detectors and thereplacement of low gas pressure detectors with highgas pressure detectors further improved the efficiencyof the wide-q measurement. The development of thetensile testing machine has provided an experimental environment for advancing the study of nanoscale
mechanical deformation behavior of soft matter. Suchupgrades are expected to contribute to the nanoscale
study of non-equilibrium states, a need that emerged
recently.
Reference[1] S. Takata, J. Suzuki, T. Shinohara, T. Oku, T. Tominaga,
K. Ohishi, H. Iwase, T. Nakatani, Y. Inamura, T. Ito, K.
Suzuya, K. Aizawa, M. Arai, T. Otomo and M. Sugiyama,
JPS Conf. Proc., 8 036020 (2015).

Figure 2.	The tensile testing machine with a load cell for the
study of soft matter.

J. Suzuki1, S. Takata2, K. Ohishi1, H. Iwase1, Y. Kawamura1, K. Hiroi2, T. Morikawa1, and M. Sahara1
Neutron Science and Technology Center, CROSS; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center

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Detector Replacement of Neutron Reflectometer at BL16
SOFIA
1. Introduction
Neutron reflectometry (NR) is very useful for investigations of structures of surfaces and buried interfaces
composed of soft materials. SOFIA is a horizontal-type
neutron reflectometer constructed at Beamline 16 (BL16)of the Materials and Life Science Experimental Facility(MLF) of the Japan Proton Accelerator Research Complex(J-PARC) [1, 2]. Due to the high-flux beam of J-PARC, lessthan one hour is needed for taking a full Q-range dataand only a few seconds for a limited Q-range data in thecase of a sample with 3 inches (76 mm) in diameter; eventhough the beam power is still one-third of the planned
value, 1 MW. However, several hours are still needed fora small sample, such as 10 mm × 10 mm, which is a typical size of a sample for X-ray reflectometry.
For further upgrade of the SOFIA reflectometer, wehave developed an elliptical focusing mirror to illuminate a sample with a neutron beam with a large beam
divergence. So far, we developed focusing super-mirrors[3, 4, 5]. The latest mirror is capable of focusing neutrons
with a width of 0.13 mm in full width at half maximum(FWHM). This mirror has already been installed in the
SOFIA and opened for users as reported last year.
Furthermore, we have a plan to realize a multiincident neutron reflectometry (MI-NR) at the SOFIA
by applying focusing mirrors, in which neutrons aretransported by two different paths and converged at asample position with different incident angles. As thedifference in the incident angle is 2.3° and the distancefrom the sample to detector is 2 m, the beam positionsof the two paths are 81 mm apart from each other at thedetector position. This difference is, however, too large
to detect with the detector called RPMT (resistance division photomultiplier tube; Hamamatsu Photonics
K. K.) [6] used in the SOFIA, whose detection area is approximately 80 mm in diameter. In addition, the RPMT
detector was discontinued. Hence, we have evaluateda new detector utilizing a flat-panel multi-anode-type
photomultiplier tube (FRP) with the detection area of48 × 48 mm2 as a replacement for RPMT [7] and replaced
the old RPMT detector with the new FRP detector.
2. Assembly
The FRP system consists of a multi-anode-type
photomultiplier tube, H12700 (Hamamatsu Photonics
K. K.), a resister array E14340 (Hamamatsu Photonics
106

K. K.) installed behind the PMT, and a ZnS (Ag)/ 6LiF scintillator (Scintacor, Ltd.) fixed on the H12700 with a gapof 4 mm. The thickness of the scintillator was 0.45 mm,
which is more than that used with the old RPMT detector, 0.3 mm (OHYO KOKEN KOGYO Co., Ltd.). The highvoltage of -920 V was applied and output analog signals
through an amplifier were processed by the NeuNET as
the RPMT detector.
3. Evaluations
The position of a neutron event converted to photons by the scintillator is detected by a charge division
method. Generally, the detection position shows a good
linearity at the center but is gradually distorted at theedge. Hence, distortion correction is required to use theneutron signals at the edge of the detector. To correlate
the read beam position and the actual position on thedetector, the neutrons with the beam size of 0.1 × 2 mm2
were illuminated on the detector with a checkerboard
pattern at a distance of 2 mm, by moving a sample position. Figure 1 shows the result of the mesh scan. As mentioned before, the signals around the center presented
a good linearity with 22 channel/mm (the full scale was1000 channels), whereas the change in the channel

Figure 1.	Result of the mesh scan for distortion correction.
Symbols indicate the detection positions of a collimated beam with changing the detector positionand lines indicate the contour lines of the 2D-fitting
result with a 10th degree polynomial function every
2 mm.

MLF Annual Report 2020

becomes smaller at the edge. The position dependence
was two dimensionally fitted with a 10th degree polynomial function. This result was used for to make a correction map to convert the detection position to theactual position. With the map, the spatial resolution of
the detector was evaluated to be approximately 0.6 mm
around the center.
Next, the counting efficiency of neutrons wasevaluated. Figure 2 shows the comparison of counting
rates taken with old and new detectors depending on
the neutron wavelength with the same slit condition.
Because of the use of a thicker scintillator, the counting
rate doubles for the thermal neutrons (approximately
20% to 40% in comparison with 3He tube detector).
This indicates that the accumulation time can be cut
in half when taking the data with the same statistics.
Though the gain through the thicker scintillator is lessfor neutrons with a longer wavelength, this doesn’t matter because the counting rate of the reflection neutrons
is higher for longer wavelength owing to the higher
reflectivity.
Finally, the homogeneity of the efficiency of theneutrons was evaluated. Figure 3 presents an image ofincoherent scattering by a polyethylene block. The block
was illuminated with an incident angle of 4°, and thedetector was placed 2 m apart from the block with adeflection angle of 10°. The uniform incoherent scattering by the hydrogens in the block can reveal the homogeneity of the detection efficiency depending on the

Figure 2.	Comparison of the counting rates taken with theold (RPMT) and new (FRP) detectors depending on
neutron wavelength with the same slit condition.

Neutron Science

Figure 3.	Image of incoherent scattering by a polyethylene
block for homogeneity check.

detection position. As shown in the figure, the homogeneity was not bad, but there was a periodic change
in the efficiency. This comes from the pitch of the multiplier tube: the FRP consists of the 8 × 8 tubes with thesize of 6 × 6 mm2. According to frequency analysis, thestandard deviation of the inhomogeneity was 18%.
4. Conclusion
As shown above, the new FRP detector performs
better than the old RPMT detector. The spatial resolution of the new detector is approximately 0.6 mm at thecenter, whereas for the old one it is approximately 1 mm.
In addition, the counting efficiency of the new detector
is approximately 40% to 3He tube, whereas it was 20%
for the old one. Because of these good features, we havealready replaced the detector before the upgrade for the
MI-NR.
References[1] N. L. Yamada et. al., Euro. Phys. J. Plus, 44 9424
(2011).
[2] K. Mitamura et. al., Polymer J., 45 100 (2013).
[3] S. Takeda et. al., Opt. Express, 24 12478 (2016).
[4] T. Hosobata et. al., Opt. Express, 25 20012 (2017).
[5] T. Hosobata et. al., Opt. Express, 27 26807 (2019).
[6] K. Hirota et. al., Phys. Chem. Chem. Phys. 7 1836
(2005).
[7] S. Satoh, Plasma Fusion Res. 13 3 (2018).

Norifumi L. Yamada1,2, Fumiya Nemoto3, and Setsuo Satoh1,2
1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3National
Defense Academy

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Current Status of SHARAKU: Polarized Neutron
Reflectometer
1. Introduction
SHARAKU is a neutron reflectometer with horizontal
scattering plane equipped with a polarization neutron
option installed at BL17 at Materials and Life Science
Facility of J-PARC. It has been used for the structure analysis of the surface and interfaces in thin film samples in
research fields such as polymer and magnetic materials.
To expand the application of the neutron reflectometry
to various research, novel reflectometry techniques [1–3]and sample environments [4, 5] have been developed.
In this fiscal year, we developed temperature-controlledwater cell system, as an example, for the neutron reflectometry experiment to enable to estimate the structureand dynamics of layer structure of thin film samples.
2. Temperature-controlled water cell system
The temperature-controlled water cell system is oneof the sample environment devices that can change thetemperature of the sample and liquid from room temperature to 90°C. It consists of two major parts: a cellhousing, where the sample is mounted, and a temperature controller.
An overview of the cell housing is shown in Fig. 1.
The recommended sample is a silicon wafer with a diameter of 2 inches and a thickness of 3 mm. The liquid
reservoir is made of aluminum alloy and has a capacityof about 5 cc. An O-ring (Kalrez 4079) is used to seal thereservoir to the sample. At the top of the reservoir, there
are two small holes, one for solution injection and theother for air venting, and the solution is sealed with silicon packing. The housing with the sample and solution
is fixed to a copper heater plate.
Neutrons are injected from the side of the substrate,

Figure 1.	A n overview cell housing of the temperaturecontrolled water cell system.

108

which is visible on the side of the housing, and are reflected at the solid-liquid interface between the liquid
reservoir and the substrate. It is then exited from the
opposite side of the substrate. During the actual reflectivity measurement, the housing and the heater plate
are covered with a cover to prevent the spread of contamination by solvent vapor in case of boiling.
An overview of the temperature controller is shownin Fig. 2. This controller was developed mainly to control
the temperature of the housing described above, and isintended for experiments at BL17. However, it can also
be used for other sample environment instruments andbeamlines. The temperature control is mainly done by
UT-55A made by Yokogawa Electric Corporation. Twothermocouples are installed for temperature control. By
monitoring these two K-type thermocouples, an interlock mechanism is provided to prevent abnormal operations due to disconnection of the thermocouples orheater wires.
The interlock mechanism can be triggered not onlyby the functions of the UT-55A as described above, butalso by an emergency button installed in the main bodyof the temperature controller or an emergency button
that can be installed outside the experimental hatchwith an extension cable. The interlock alarm can also
be connected to a patrol light installed in the beamline,
making it possible to notify the surroundings of the occurrence of an abnormality.
This temperature controller can be operated by itself, but it can also be controlled externally via ethernet
communication. For the external control, we have developed a driver for the IROHA2 system, which is the MLF
device control protocol (Fig. 3). This allows the control of

Figure 2. Photograph of the temperature controller.

MLF Annual Report 2020

Figure 3.	I ROHA2 web inter face for the temperature
controller.

the temperature controller to be incorporated into theconventional reflectivity measurement sequence, andthe temperature, sample, and measurement order canbe freely changed by external control from the control
cabin. This improves greatly the efficiency of the experiment. In addition, the developed driver for IROHA2 canbe easily ported to other MLF devices that use IROHA2,
which makes a clear contribution to the common use ofsample environment equipment.
3. Commissioning and future plans
The system was commissioned in the experimental
preparation room at CROSS using water as the solvent,and was confirmed to work reliably in the range from

Neutron Scienceroom temperature to 90°C with an appropriate waitingtime. Based on these results, the temperature controller
passed the MLF safety examination and is now used bymany users.
The developed temperature controller is not only
for this cell but can also be used for general temperature
control experiments. We are planning to apply the controller to a sample environment apparatus that can beheated up to about 200°C in a vacuum atmosphere, andto develop a multi-channel controller that can control
multiple temperature controllers simultaneously.
References[1] K. Sakurai, J. Jiang, M. Mizusawa, T. Ito, K. Akutsu, N.
Miyata, Sci. Rep. 9 571 (2019).
[2] H. Aoki, H. Ogawa, M. Takenaka, Langmuir, 37, 196(2021).
[3] T. Kumada, K. Akutsu, K. Ohishi, T. Morikawa, Y.
Kawamura, M. Sahara, J. Suzuki, N. Torikai, J. Appl.
Crystall. 52 1054-1060 (2019).
[4] S. Ohira-Kawamura, T. Hattori, S. Harjo, K. Ikeda,
N. Miyata, T. Miyazaki, H. Aoki, M. Watanabe, Y.
Sakaguchi, T. Oku, Neutron News, 30, 11 (2019).
[5] H. Arima-Osonoi, N. Miyata, T. Yoshida, S. Kasai,
K. Ohuchi, S. Zhang, T. Miyazaki, H. Aoki, Rev. Sci.
Instrum., 91, 104103 (2020).

N. Miyata1, H. Kira1, S. Kasai1, H. Arima-Osonoi1, T. Miyazaki1, H. Aoki2,3, K.Soyama4, D. Yamazaki5, K. Akutsu1, and T. Hanashima1
Neutron Science and Technology Center, CROSS; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center; 3Instituteof Materials Structure Science, KEK; 4Materials and Life Science Division, J-PARC Center; 5Neutron Instrumentation Section, Materials andLife Science Division, J-PARC Center

1

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Status of SENJU 2020
1. Introduction
SENJU is a TOF single-crystal neutron diffractometer designed for precise crystal and magnetic structure
analyses under multiple extreme environments, suchas low-temperature, high-pressure, and magnetic-field,
as well as for taking diffraction intensities of small single crystals with a volume of less than 1.0 mm3 down
to 0.1 mm3 [1]. Since the operation of SENJU started in2012, our instrument group has carried out continuous
commissioning and upgrades.
In 2020, we installed a top-loading cryostat with aϕ-axis sample stick for rapid sample exchange and stable ω- and ϕ-axes rotation. We also installed an auto He
gas loading system in the vacuum sample chamber toshorten the sample heating time after low-temperature
measurement. In addition, we also report on the purposes of the instrument beam-time for SENJU.
2. Development of a top-loading 2-axes cryostat
The bottom-loading type cryostat is the most frequently used sample environment device in SENJU.
SENJU has two bottom-loading 4 K cryostats; one is a
GM-type cryostat, and another is a pulse-tube-type

cryostat. Both cryostats are equipped with piezo-rotating devices to rotate a sample crystal with two axes, ωand ϕ, under vacuumed and low-temperature conditions. However, the movement of the piezo-rotator is
unstable at low temperature, and the low-temperature
measurement uses the bottom-loading cryostat stacks
often during the automatic sequential measurement. To
overcome this problem and perform users experiments
stably, we developed a top-loading type 4 K cryostat system with ω- and ϕ-axes.
The cryostat system is composed of a main body withthe ω-axis and a sample stick with the ϕ-axis. Figure 1
shows photos of the ϕ-axis sample stick. A pulse motor for the ϕ-axis rotation is attached under the vacuum
flange, where the temperature is kept at room level. The
sample stick has three rotational shafts and two universal joints to transfer the rotation of the motor to the
ϕ-axis at the end of the stick.
In a preliminary cooling test, the bottom temperature of the stick end was 4 K, almost the same as thebottom-loading cryostats. The rotation of the ω- andϕ-axes was stable even at the bottom temperature.

Figure 1.	Photos of the φ-axis sample stick for the two-axes
top-loading cryostat system.

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3.	Development of automatic He gas loading system
for the vacuum sample chamber
In the low-temperature diffraction measurement
at SENJU, a sample crystal is attached at the end of acryostat and set in a vacuum sample chamber. In thesample heating process, following the low-temperature
measurement, a user had to switch off the compressorof the cryostat and vacuum pump and wait for about
five hours to heat the sample. The waiting time madethe sample changing and user switching period very
long. In addition, the compressor/vacuum pump control
was not automated. So, when one SENJU user ended themeasurement and switched to the following user in themorning, the former user had to come to the SENJU site
in the early morning or sometimes at midnight to switch
off the compressor and the vacuum pump. However,in the mail-in and alternate measurements during the
COVID-19 pandemic, the on-site vacuum control becomes a heavy load for the instrument scientists. To
shorten the sample changing and user switching time
and to relieve the load of instrument scientists and users, we developed an automatic He gas loading andvacuum control system for the vacuum sample chamber of SENJU.
Figure 2 shows the schematic view of the He gas

Figure 2. Schematic view of the He gas loading system.

Neutron Scienceloading system. There are two magnetic valves between the vacuum sample chamber and a gas canister.
The IROHA2 system automatically controls the valves.
By opening/closing the two valves sequentially, a small
amount of He gas between the valves is loaded in thechamber, and the He gas pressure in the chamber rises
to about 1 Pa. The He gas in the chamber acts as a heatmedium to heat the sample and the cryostat. The heating time from 4 K to room temperature with the He gas
is about three hours. In addition, we developed and installed an automatic switch on/off system for the compressor and the vacuum pump. The IROHA2 controls thissystem as well.
The use of the automatic He gas loading systemand the switch on/off system for the compressor andvacuum pump shortens the sample changing and user
switching time. In addition, users/instrument scientists
do not need to go to the SENJU site at midnight, evenwhen the following user’s experiment starts the nextmorning.
4. Use of the instrument beam time
In 2020, the instrument beam time was used mainly
for measurements of standard samples, and a vanadium-nickel alloy for calibration of the detector efficiency.

Reference[1] T. Ohhara et al., J. Appl. Cryst., 49 120 (2016).

T.Ohhara1, R. Kiyanagi1, A. Nakao2, K. Munakata2, Y. Ishikawa2, K. Moriyama2, I. Tamura1, and K. Kaneko1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS

1

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Engineering Materials Diffractometer TAKUMI
1. Introduction
TAKUMI is a pulsed neutron diffractometer dedicated for research in engineering materials sciences,installed at beamline 19 in the MLF of J-PARC. TAKUMI
employs careful analysis of the Bragg peaks in a neutron diffraction pattern to reveal important structuraldetails of sample material, such as internal stresses,
phase conditions, dislocations, texture, etc. As expressedin the name of instrument (Engineering Materials
Diffractometer), TAKUMI covers not only residual stressmapping in engineering components, but also microstructural evolutions during deformations of structuralor functional materials at various temperatures, microstructural evolutions during manufacturing (thermomechanical) processes, as well as texture analyses ofengineering materials.
2. Activities in 2020
The following upgrades were performed in FY2020:(1) Development of a new sample chamber for lowtemperature deformation test to reduce the time for the
sample change and the temperature control. The workon the necessary hardware was completed but the commissioning needs to be continued.
(2) Large tilting stage for strain mapping allowing alignment of large samples (< 150 kg) has been built.
(3) The real-time monitoring software allowing to see
the newest diffraction patterns (not summed for thewhole exposure time) was completed, and the device
control software was upgraded.

Due to the COVID-19 pandemic restrictions, call
proposals for the 2020B term were not handled separately, but were processed in the joined term of 2020B+ 2021A. Therefore, it was difficult to separate the proposals assigned only to FY2020. Here, we counted the
proposals until July 2021 (including the 2021A term).
The percentages of the approved general proposals
and reserved ones with beamtime allocation were 78%
for 2020A and 73% for 2020B + 2021A. 30 general use
proposals, 2 long-term proposals and 2 project use proposals were successfully conducted on TAKUMI. Amongthem, about 40% of general proposals were conductedwithout the attendance of principal investigators or thecollaborators, i.e., they were on-behalf experiments, due
to the travel limitations caused by COVID-19. The onbehalf experiment is not a customary type of support
provided by J-PARC, but the instrument scientists wereencouraged not to stop the scientific research activities.
However, 2 general proposals were cancelled, due to difficulties in the handling of samples and devices brought
by users.
The statistics on the experimental types and thesample materials of conducted experiments during
FY2020 are summarized in Fig. 1. More than half of the
beamtime was occupied by in situ measurement during loading test, as it happened every year. In particular, the demand for low temperature loading has been
increasing in the past few years due to the expanding
research on the deformation properties of high entropy
alloys. Meanwhile, for high temperature conditions, theIron & Steel, 38.4%

HT Loading, 13%
RT Loading, 26%
Light Metals, 13.1%

Other, 4%
LT Loading, 33%

Rock & Ceramics, 11.1%

HT & LT, 3%
Instrumental Use, 3%

Composites, 5.1%
Metals & Alloys, 32.3%

Strain Mapping, 20%

(a)

(b)

Figure 1.	The statistics of the kinds of experiments conducted at TAKUMI (a) and the kinds of materials used inthese experiments (b) in FY2020. The percentages show the beamtime use.

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requirements for in situ measurements during thermomechanical controlled processes, which include rapid
heating, cooling and deformation, are increasing. The
instrument called “thermec-mastor” and the newly developed loading machine equipped with an induction
heating system were used for these kinds of experiments. The percentage of beamtime for strain mapping
experiments (internal stress analysis of mechanicalparts) increased slightly in comparison to the last year
statistics (14%). Most of this kind of experiments were
proposed by industrial users. Iron- or aluminum-based
objects were measured in these experiments. Reflecting
the importance of iron and steel as structural materials,
the percentage of these materials in all the samples increased slightly to 38%. The percentage of light metals
slightly decreased, while that of metals and alloys (Nibased superalloy, high entropy alloys and other alloys,
32%) was almost unchanged.
3. Achievements
Thanks to the users and the collaborators, 22 reviewed papers and 2 proceedings papers using the datameasured at TAKUMI have been published in 2020. In
addition, the data were also used in 2 doctoral or master theses. Based on the papers, 2 press releases werelaunched, and 3 awards were achieved. Some of thehighlighted papers are described below:(a) “Role of retained austenite in low alloy steel at
low temperature monitored by neutron diffraction”, by T. Yamashita et al. [1]. In situ neutron diffraction measurements during tensile tests at low
temperatures of a low alloy steel containing retained austenite (γ) have been performed to analyze
and discuss the role of γ in the steel during deformation at low temperatures.
(b) “Extremely high dislocation density and deformation pathway of CrMnFeCoNi high entropy
alloy at ultralow temperature”, by M. Naeem etal. [2]. The deformation behavior of CrMnFeCoNi
high-entropy alloy was investigated by in situ neutron diffraction at an ultralow temperature of 15 K,
to elucidate the extraordinary strength–ductility
combination at ultralow temperature.

Neutron Science(c) “Neutron diffraction monitoring of ductile castiron under cyclic tension–compression”, by
S. Harjo et al. [3]. To understand work hardening
behavior during low-cycle loading, ductile cast ironcontaining 10.1 vol% spheroidal graphite, 19.6 vol%pearlite, and ferrite matrix was investigated in an insitu neutron diffraction study of up to four cycles oftensile–compressive loading with applied strains of±0.01.
(d) “Mechanism of improved ductility of 1500 MPaclass ultra-high strength cold-rolled steel sheet
produced by rolling and partitioning method”, byY. Hosoya et al. [4]. In situ neutron diffraction during
tensile loading was conducted to elucidate the deformation behavior of a newly developed 1500 MPa
class stainless steel sheet having an excellent yieldstrength and total elongation balance.
(e) “Microstructural features and ductile-brittle
transition behavior in hot-rolled lean duplex
stainless steels”, by O. Takahashi et al. [5]. The
characteristics of the texture and microstructureof lean duplex stainless steels with low Ni content
produced through hot rolling followed by annealing
were investigated locally with electron backscatter
diffraction and globally with neutron diffraction, toelucidate the ductile–brittle transition behavior.
4. Future Plans
In order to enhance the convenience of TAKUMI,
several upgrades on the sample environment devices
and the software have been scheduled as follows:(1) Commissioning of a new sample chamber for lowtemperature deformation test.
(2) Upgrades of the data reduction software to make it
more user-friendly.
References[1] T. Yamashita et al., Scripta Mater. 177, 6-10 (2020).
[2] M. Naeem et al., Scripta Mater. 188, 21-25 (2020).
[3] S. Harjo et al., Acta Mater. 196, 584-594 (2020).
[4] Y. Hosoya et al., ISIJ Int. 60, 2097-2106 (2020).
[5] O. Takahashi et al., Quantum Beam Sci. 4, 16 (2020).

S. Harjo1, T. Kawasaki1, W. Gong1, S. Morooka1,2, and K. Aizawa3
1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Materials Sciences Research Center, JAEA; 3Materials andLife Science Division, J-PARC Center

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The Current Status of the Versatile Neutron
Diffractometer, iMATERIA
1. Introduction
Ibaraki Prefecture, local government of Japan’s area
where the J-PARC sites are located, has decided to build
a versatile neutron diffractometer (IBARAKI Materials
Design Diffractometer, iMATERIA [1]) (Fig. 1) to promoteindustrial applications for the neutron beam in J-PARC.
iMATERIA is planned to be a high-throughput diffractometer that could be used by materials engineers andscientists in their materials development work, including chemical analytical instruments.
The applications of neutron diffraction in materials
science are (1) to do structural analyses of newly developed materials, (2) to clarify the correlation between
structures and properties (functions), and (3) to clarify
the relation between structural changes and improvements of functions, especially for practical materials. A
diffractometer with super high resolution is not required
to achieve those goals. The match of features like intermediate resolution around Δd/d = 0.15%, high intensity
and wide d coverage is more important.
This diffractometer is designed to look at a decoupled-poisoned liquid hydrogen moderator (36 mm, offcentered) (BL20), and it has an incident flight path (L1)of 26.5 m, with three wavelength selection disk-choppers and straight neutron guides with a total lengthof 14.0 m. The instrumental parameters are listed inTable 1. There are four detector banks, including a lowangle and small-angle scattering detector bank. The
angular coverage of each detector bank is also shownin Table 1. The rotation speeds for the disk-choppers
are the same, with a pulse repetition rate of 25 Hz forthe most applications (SF mode). In this case, the diffractometer covers 0.18 < d (Å) < 2.5 with Δd/d = 0.16%
and covers 2.5 < d (Å) < 800 at three detector banksof 90-degree, low-angle and small-angle with gradually changing resolution. When the speed of the wavelength selection disk-choppers is reduced to 12.5 Hz (DFmode), we can access a wider d-range, 0.18 < d (Å) < 5
with Δd/d = 0.16%, and 5 < d (Å) < 800 with graduallychanging resolution with doubled measurement timecompared to the SF mode.
2. Current status
All of the four banks, high-resolution bank (BSbank), special environment bank (90-degree bank),
low-angle bank and small-angle bank, are operational. It
takes about 5 minutes (in DF mode) to obtain ‘Rietveldquality’ data in the BS bank at 700 kW beam power for
about 1 g of standard oxide samples.
Figure 2 shows a typical Rietveld refinement pattern

Table 1.	
Instrumental parameters of iMATERIA. L2 is thescattered flight path. The d-range (q-range) for eachbank is the maximum value for 2-measurement
mode.
L1		
26.5 mGuide length		
Position of Disk choppers		
			
			
High
2θ
Resolution
L2
Bankd-rangeSpecial2θEnvironment
L2Bankd-range
Low
2θ
Angle
L2
Bank
d-range
Small
2θ
Angle
L2
Bank
q-range

114

Total 14 m (3section)
7.5 m (double)
11.25 m (single)
18.75 m (single)
150˚ ≤ 2θ ≤ 175
2.0 – 2.3 m
0.09 ≤ d (A˚) ≤ 5.0˚
80˚ ≤ 2θ ≤ 100˚
1.5 m
0.127 ≤ d (A˚) ≤ 7.2
10˚ ≤ 2θ ≤ 40˚
1.2 – 4.5 m
0.37 ≤ d (A˚) ≤ 58
0.7˚ ≤ 2θ ≤ 5˚
4.5 m
–1
0.007 ≤ q (A˚ ) ≤ 0.6

Figure 1.	IBARAKI Materials Design Diffractometer, iMATERIA
without detector for each bank and instrument
shielding. The BS bank, 90-degree bank, and lowangle bank, can be seen from right to left. The
small-angle detector bank, which is not shown in
the picture, is situated in the low-angle vacuum
chamber (left-hand side of the picture).

MLF Annual Report 2020

Figure 2.	Rietveld refinement pattern for LiCoO2 at the BS
bank of iMATERIA.

Neutron Science

The in-operando charge and discharge measurement system for LIB with a sample changer is available
in cylindrical, coin and laminated types of batteries.
Figure 3 shows a typical in-operando time-dependent
diffraction pattern for laminated type LIB under charging process. The changes in the negative electrodeactive material can be observed around 3.5 Å, and thechanges in the positive electrode active material NMC
can be observed around 4.8 Å.

for LiCoO2 sample, cathode material for lithium-ion battery (LIB), at the BS bank by the multi-bank analysis
function of Z-Rietveld software [2]. It takes 20 min in
DF mode to collect the available Rietveld data, due tothe high neutron absorption cross section for natural Li(σsNat =70 barn).
3. Sample environments
The automatic sample changer is the most important sample environment for high-throughput experiments. Our automatic sample changer [3] consists of asample storage, elevating system of two lines, two setsof pre-vacuum chambers and a sample sorting system.
We can handle more than 600 samples continuously atroom temperature (RT) without breaking the vacuum of
the sample chamber.
The vanadium-furnace (~900°C), the gas flow furnace (~1000°C), and the 4K and 1K cryostats are readyfor experiments.
The rapid heating/quenching furnace with automatic sample changer (RT – 1273 K with heating speed
10 K/s and cooling speed >20 K/s) [4] and the universal
deformation testing machine (max loading 50 kN with
RT – 1273 K) [5] are available for texture measurements.

Figure 3.	The in-operando time-dependent neutron diffraction patterns for laminated type LIB under charging
process at the BS bank. It shows the time divisionchanges of the diffraction patterns for 1 minute every 10 minutes.

References[1]	T. Ishigaki, et al., Nucl. Instr. Meth. Phys. Res. A600
(2009) 189-191.
[2] R. Oishi, et. al., Nucl. Instr. Meth. Phys. Res. A600
(2009) 94-96.
[3] A. Hoshikawa, et al., J. Phys.: Conf. Ser. 251 (2010)
012083.
[4] Y. Onuki, et. al., Metall. Mat. Trans. A. 50 (2019)4977-4986.
[5] Y. Onuki, et. al., Quantum Beam Sci., 4 (2020) 31.

T. Ishigaki, A. Hoshikawa, T. Matsukawa, and Y. Onuki
Frontier Research Center for Applied Nuclear Sciences, Ibaraki University

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Status of the High Intensity Total Diffractometer (BL21, NOVA)
1. Introduction
Total scattering is a powerful technique to analyze disordered structure in materials with atomic Pair
Distribution Function (PDF). NOVA was designed to perform total scattering and is the most intense powder diffractometer with reasonable resolution (Δd/d ~ 0.5%) in
J-PARC. It is easy to adapt NOVA to a very wide area offields: liquids, glasses, local disordered crystalline materials, magnetic structures, and so on.
2. Polarized Neutron Scattering Experiment
A neutron polarizer with polarized 3He gas, referred
to as a 3He spin filter, based on the Spin Exchange
Optical Pumping (SEOP) was equipped to perform polarized neutron scattering experiments at NOVA [1]. The
polarizer was installed at the upstream of the beamline,
and the neutron polarization was held by the magnetic
field produced with a guide coil to the sample. The scattered neutrons by the sample were analyzed with two
3
He cells located at 20 mm from the sample position ina vacuum chamber. The diffraction patterns of the NaH
powder were measured with incident beam of non-spinflip (++) and spin-flip (–+) scattering (Fig. 1). Bragg peaksof 111 (lattice spacing, d = 2.82 Å), 311 (d = 1.47 Å) and331 (d = 1.12 Å) were clearly detected only in the caseof (++), which showed that the spin flippers work properly [2]. (Peaks of d = 4.8 Å and 5.0 Å are unexpectedbackground.) Difference for baseline corresponds to significant incoherent scattering cross section, including
inelastic scattering of hydrogen, which is evaluated to
extract coherent scattering term.

3. Reverse Monte Carlo (RMC) modelling
Vanadium hydride is of interest as a possible hydrogen storage material owing to its reversible hydrogen
absorption/desorption reactions at room temperature
between mono-hydride (hydrogen-to-metal ratio;
H/V ~ 1) and di-hydride (H/V ~ 2). Because cyclic hydrogen storage reaction introduces distortion to the metallattice, the local structure around hydrogen is important.
Neutron structure factors of VD0.7 and VD2 were measured on NOVA and their pair distribution functions wereanalyzed using Reverse Monte Carlo (RMC) modelling
method [3]. Partial radial distribution functions (D-D,
D-V, V-V) of VD0.7 and VD2 are shown in Fig. 2. The firstpeak in the D-D partial is in both cases just above 2 Åin compliance with the Switendick criterion [4]. Atomic
arrangements of 1×1×1 were derived from projection
after modelling by 8×8×8 of VD0.7 and VD2, respectively.
Deuterium occupies 8c site of Fm-3m in VD2 with little displacement, but the occupation around 12d siteof Im-3m in VD0.7 is dispersed. In the alloy system, therelationship between the hydrogen-metal pair and thehydrogen storage properties would be investigated.
4. Future plans
We will continue with the development of the polarized neutron scattering experiment system to analyze
the static structure of aqueous solution and hydrides,
and the magnetic structure of strongly correlated electron system. The Reverse Monte Carlo (RMC) modelling
will be expanded to local structure analysis of other disordered crystalline materials.

Figure 1.	Diffraction patterns of the NaH powder with incident beam of non-spin-flip (++) (black) and spinflip (–+) (blue) scattering.

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VD0.71

cicjbibj(g(r)ij-1)

0.0

-0.1
0

cicjbibj(g(r)ij-1)

D-D
D-V
V-V
result

0.1

VD2

0.4

RMC

RMC
D-D
D-V
V-V
result

0.2

0.0

-0.2
2

4

6

8

10

12

r/Å

0

2

4

6

8

10

12

r/Å

Figure 2.	Reverse Monte Carlo (RMC) modelling results of VD0.7 and VD2. Atomic arrangements of 1×1×1
were derived from a projection after modelling by 8×8×8.

Acknowledgements
The polarized neutron scattering experiment system was developed with Dr. Okudaira and Dr. Oku. We
would like to thank Mr. Maya for his technical support
in operating NOVA. The operation and developmentsof NOVA was performed under the S1-type program(2019S06) approved by the Neutron Scattering Program
Advisory Committee of IMSS, KEK.

References[1] T. Okudaira et al., Nucl. Instrum. Methods Phys. Res.
A, 977 164301 (2020).
[2] R.M. Moon et al., Phys. Rev., 181 920 (1969).
[3] M.G. Tucker et al., J. Phys. Condens. Matter, 19335218 (2007).
[4] B. Rao and P. Jena, Phys. Rev. B, 31 6726 (1985).

K. Ikeda1,2,3, T. Honda1,2,3, T. Otomo1,2,3,4, H. Ohshita1,2, S. Sashida3, and M. Tsunoda4
Institute of Materials Structure Science, KEK; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center; 3Department
Materials Structure Science, The Graduate University for Advanced Studies; 4Graduate School of Science and Engineering, Ibaraki University

1

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MLF Annual Report 2020

Current Status of the Energy-Resolved Neutron Imaging
System RADEN
1. Introduction
The Energy-resolved neutron imaging system“RADEN”, installed at beam line BL22 in the MLF of
J-PARC, is a dedicated instrument for wavelength/energy-dependent neutron imaging experiments, which
utilizes fully the short-pulsed neutron’s nature [1]. A
variety of imaging experiments have been conducted
at RADEN, such as Bragg-edge imaging, neutron resonance absorption imaging, and polarized pulsed neutron imaging, in addition to the conventional neutron
imaging. After the start of the user programs, RADEN
has been accepting about 40 user programs every year.
In 2020, because of the spread of the COVID-19 virus,
many users could not visit J-PARC for the experiments
and some of the programs have been conducted by the
instrument group members on behalf of them. In addition, RADEN started accepting the Fast Track Proposals
for the feasibility check before the regular full proposal.
In this report, the results of the technical development
conducted at RADEN are described.
2. High-resolution imaging
We introduced a high-spatial resolution imaging
system, which is utilized for the high-resolution X-ray
imaging, and consists of a scintillator screen, a mirror, optical lenses and an sCMOS camera. This system
uses two lenses behind the mirror so as to magnify theobject image on the image sensor plane. Three scintillator screens, 10 µm-thick P43, 10 and 100 µm-thick
Gd3Al2Ga3O12:Ce (GAGG) were tested with this system,
and achieved spatial resolution of 10.5 µm by using the
100 µm-thick GAGG scintillator (Fig. 1) [2]. This is a remarkable improvement compared to the former spatial

resolution at RADEN, which was 30 µm. Furthermore,
the result that a fine spatial resolution could be realized even though the scintillator thickness was 10 times
larger than the achievable resolution is thought to originate in the small light scattering inside the scintillator
because GAGG is a single crystal. We will continue thedevelopment of high-spatial resolution imaging systemusing a single crystal scintillator screen.
3. Development and deployment of the BµNID
The µNID (µPIC-based Neutron Imaging Detector)[3] is currently one of the main energy-resolved neutron imaging detectors at RADEN. The µNID utilizes atime-projection-chamber with a 400 µm pitch, and a
two-dimensional µPIC (Micro-Pixel Chamber) micropattern strip readout. Using 3He for neutron conversion, afine spatial resolution (0.1 mm) is achieved via threedimensional tracking of the resulting proton and triton.
The µNID also features a 26% detection efficiency forthermal neutrons and an effective global neutron countrate of 1 Mcps.
To improve the rate performance, we developed avariant of the µNID, the BµNID, which replaces the 3He
gas converter with a 10B thin film (~1.2 µm thick) deposited on the drift cathode. Compared to 3He, the n-10B
reaction produces heavier charged secondaries, namely
an alpha particle or Li nucleus, leading to reduced event
sizes and better event separation for improved rate performance up to 10 Mcps. The increased rate comes witha trade-off in both spatial resolution (0.3 mm) and detection efficiency (5%) compared to the µNID; however,there are many use-cases requiring only moderate spatial resolution, which benefit greatly from the increased

Figure 1.	High-resolution image of test pattern using a new imaging equipment [1].
The Siemens star pattern was used to confirm the spatial resolution. The
smallest line width of 10 µm could be well recognized in the right image.

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MLF Annual Report 2020

Neutron Science

Table 1. Performance characteristics of the standard µNID
and BµNID.
BµNID
µNID
10 cm x 10 cm

Area

3

CF4:iC4H10
CF4:iC4H10: He(45:5:50), 2 atm (90:10), 1.6 atm

Filling gas
Spatial resolution

0.1 mm

0.3 mmTime resolution

0.25 µs

10 ns

Efficiency@25.3 meV

26%

5%

Effective count rate

1 Mcps10 Mcps

Figure 2.	Comparison of image quality for µNID and BµNID.
An image of a gadolinium test chart taken withthe µNID (left) and BµNID (right) shows the goodoverall image quality of both detectors, while the
BµNID displays a slightly reduced spatial resolution(0.3 mm) compared to the standard µNID (0.1 mm).

count rate. The performance characteristics of the µNID
and BµNID are listed in Table 1.
Following a successful proof-of-principle study using a prototype detector [4], a dedicated BµNID detector
was prepared, and its commissioning was completed in
December 2020, with the first user experiments startingin January 2021.
4. Application of energy-selective imaging
A neutron imaging equipment consisting of a highspeed gated image intensifier unit and an sCMOS camera has been employed to the energy selective neutron
imaging. With this equipment, it is possible to obtain animage of a given neutron energy because the image intensifier amplifies the light from the scintillator screen ina very short instant synchronizing the pulsed neutron’stime-of-flight by its gate function. The gate timing canbe easily controlled with an electric gate signal generated by using a delay generator. Hence, this system issuitable for experiments, which require a fine spatial
resolution, a short exposure time and a coarse energy
resolution. For example, the ice/water identification in

1

1

1

1

1

a fuel cell for an automobile will be a good applicationof this imaging [5].
5. Summary and future plans
RADEN is used in various fields, not only scientific
but also industrial, and the application spreads widely
now. In addition to the user programs, the RADEN group
continues to improve the instrument and develops
imaging techniques, so as to provide state of the art
neutron imaging environment to users and to perform
application studies with it.
References[1] T. Shinohoara et al., Rev. Sci. Instrum., 91, 043302(2020).
[2] K. Isegawa et al., J. Imaging, 7, 232 (2021).
[3] J. D. Parker et al., Nucl. Inst. and Meth. Phys. Res. A,
726 155 (2013).
[4] J. D. Parker et al., JPS Conf. Proc., 22, 011022 (2018).
[5] Y. Higuchi et al., Phys. Chem. Chem. Phys., 23, 1062
(2021).

1

2

3

3

3

T. Shinohara , T. Kai , K. Oikawa , Y. Tsuchikawa , K. Isegawa , K. Hiroi , Y. Su , H. Hayashida , J. D. Parker , Y. Matsumoto ,4
and Y. Kiyanagi
1
2
Neutron Science Section, Materials and Life Science Division, J-PARC Center; Technology Development Section, Materials and Life
3
4
Science Division, J-PARC Center; Neutron Science and Technology Center, CROSS; Hokkaido University

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Polarized Neutron Spectrometer POLANO
1. Introduction
POLANO is a direct geometry chopper spectrometer with middle energy and spatial resolution. For the
purpose of highly efficient polarization experiments
using the inelastic scattering technique, the POLANO
was optimized for high transfer energy (HTE) polarization analysis [1–3]. The POLANO has been opened to apart of the user program since 2019 with only unpolarized neutron experiments. In order to realize the HTE
polarization, we have made serious efforts to develop
new devices with new ideas and concepts. The HTE polarization can be realized by combining a SEOP 3He gas
spin filter and a 5.5 Qc bending mirror analyzer, as described in the following section. However, even with thistechnique the utilized neutron energy is restricted up toaround Ef = 45 meV for out-going analyzed neutron energy (final neutron energy) by the reflecting capabilityof mirrors. But our final goal for HTE is 100 meV beyond
the reactor-based neutron polarization energy.
By 2019, some of the world’s neutron facilities realized and planned time-of-flight (tof ) polarization spectrometers, but all of them are focusing on polarization
analysis with a low-energy region of the transfer energy
up to several tens of meV. However, this energy rangeof polarization analysis had so far been done with reactor-based neutrons. In the research of the dynamical
properties of atoms, spins, charges, orbitals, and so on,
their energy scale could be over 100 meV. The POLANO
was designed to realize polarization analysis with muchhigher energy by combining a SEOP 3He spin filter andan analyzer mirror, as mentioned above. This enables us

to reach higher transfer energy (Ef ~ 42 meV). As thesecond step, we plan to use a wide-angle SEOP/MEOP
system as an analyzer. In this second step, we are targeting polarization analysis with neutron energy of up
to 100 meV, covering absolutely wide momentum andenergy region in the reciprocal space.
2. Polarization and other devices
1) Safety assessment:
To be approved for use in MLF, any newly installed
device, especially when it is high-risk, must be assessedby a safety group or specific committee in J-PARC prior to use. The laser system used in the SEOP system is
one of those devices. In addition to the laser, we alsoneed to go through the facility safety assessment for a
Helmholtz-coil system and comply with the generalsafety requirements for the system. All examinations
for those safety issues were completed before the endof this year.
2) SEOP polarizer:
The SEOP system used as a polarizer in POLANO has
been under development for a long time. We have beenworking consistently to realize a high-performance device for high-energy neutrons. The glass cell containing 3He and other gases was originally made in-houseusing GE180 glass material and it reached 80% of 3He
spin polarization. Finally, the system has been installedon the beam line for practical use. Figure 1 shows thesystem on the POLANO beam line. A black box containing optical and laser devices addition to 3He cell is themain component of the polarizer, as shown in Fig. 2. The

Figure 1.	Newly installed setup of the SEOP system. The neutron
beam goes directly through the black box (SEOP box),
where the glass cell for the 3He gas filter is positioned.

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dimension of the SEOP box is about 60 cm square, which
is a rather compact design. However, the beam line issignificantly limited in space, as shown in Fig. 1. With lessspace on the beam line, it is especially hard to handle
the beam line devices.
3) Magnetic system:
The spin polarization of the polarized neutron spinsmust be maintained all the way to the analyzer in orderto know if the scattering processes are either in spin flip(SF) or non-spin flip (NSF). Also, the spin direction can becontrolled to measure different spin direction scattering processes. The POLANO report last year introduced
our new asymmetric Helmholtz magnet, which is able toapply magnetic field to any direction in the horizontal
plane, and also a vertical field to the scattering plane.
With this magnetic coil system, it is possible to control
the quantization axis around the sample position.
4) Spin flipper:
In order to measure four spin states (uu, ud, du,dd) before and after the sample, the spin flipper is anindispensable device to flip the direction of neutron
spins. The SEOP has a capability of spin flipping with
NMR technique before the sample. We need anotherflipper after the sample. The flipper should be able tocover very wide scattering angle, almost 180˚, and a limited radial space. In the POLANO case, since there is avacuum chamber in the flight path after the sample, thespace for the flipper is quite limited. Currently, we areconsidering the use of Dabbs-foil (current sheet) typespin flipper. But still, many difficulties need to be overcome. We will continue to develop the device for futurepolarization analysis.
5) Data handling:
Once the set of scattering data is collected, someNeutron Science

numerical treatments as data handling between thefour spin configurations, background subtraction, datanormalization, data correction and so on, are required.
Also, the data visualization is crucial to deduce scientific results from the obtained data. New algorithm foranalyzing the polarization data set should be prepared.
In this year, we improved the data handling software
HANA modifying the current version of HANA, designed
for unpolarized data, to treat polarization data.
6) Analyzer:
As an analyzer of neutron spins, a neutron mirror
is used in POLANO. A 5.5 Qc FeSi bending mirror cananalyze the neutron energy up to about 42 meV, which
can realize the highest energy polarization experiment
ever. The problem is that the coverage of the installed
mirror range is just 20˚ of the scattering angle. Several
sets of scans (experiments) are necessary to see a wide
Q and E area by scanning the analyzer mirror aroundthe scattering angle. The 5.5 Qc mirror is currently thehighest critical angle of neutron polarizing mirror thatenables higher energy polarization. The cost, however,is also extremely high and the neutron energy is still notenough. The 3He gas filter analyzer with a wide angle is
now in the process of development for the future higher
energy experiments.
3. Magnetic devices
We have several magnetic devices in order to keep
the spin polarization, to control the spin direction,and to apply the magnetic field to the sample. One ofthese devices is what we call a fan-shaped magnet. The
magnet has a very unique design, as shown in Fig. 3.
The magnetic field is provided by a set of permanent
magnets of NdFeB and it will be 60 Gauss at maximum

guide coillaser and op�cs

solenoid coils
low-noise ampliﬁer
for NMR

Figure 2.	The suite of magnets, including the SEOP 3He polarizer,
Helmholtz coils, analyzer mirror, and guide fields.

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incoming neutron
sampleNdFeB magnets

NdFeB magnets

Figure 3. Newly designed fan-shaped magnet.

and 30 Gauss at minimum on the neutron path in wide
scattering angle. In order not to obstruct the scatteredneutron beam, the device is tapered to the beam direction. With this new concept, optimized for the wide-angle distribution measurement, homogeneous magnetic
field can be applied.
4. In summary
Now the POLANO is almost ready to launch polarization experiments via an on-beam test at the MLF
beamline BL23. In addition to beam commissioning,developments and updating devices and methods areindispensable to realize spherical polarimetry with thepulse neutron beam. In particular, we are working on
the R&D of new devices, such as a spin flipper after the
sample, high polarization 3He filter, and large solid angle
SEOP analyzer for the future HTE polarization.
References[1] T. Yokoo, et al., EPJ Web of Conferences, 83 03018(2015).
[2] T. Yokoo, et al., AIP conference proceedings, 1969050001 (2018).
[3] MDPI Books, Quantum Beam Science 162 (2019).

T. Yokoo1,2, N. Kaneko1,2, S. Itoh1,2, K. Hayashi1, T. Ino1,2, and M. Fujita3
Institute of Materials Structure Science, KEK; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center; 3Institute forMaterials Research, Tohoku University

1

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Neutron Science

Sample Environment at MLF
1. Introduction
The MLF sample environment (SE) team provides
the sample environment equipment commonly usedamong several beamlines and is also responsible for
upgrading that equipment. The MLF SE team develops“cutting-edge” equipment that can function even under
extreme sample conditions and also fulfills the growing
users’ needs. Our activities in JFY2020 are described
below.

3. High temperature and light irradiation
We have two furnaces as BL-common equipment:a niobium furnace and another furnace that is dedicatedto small-angle neutron scattering (SANS) measurements. In JFY2020, the niobium furnace was used for
two users’ experiments on BL18. In addition, there was arequest from BL21 to use the furnace. It was necessary tomodify it to be able to use on BL21, because dimensionsof the flange of the vacuum chamber are different fromthose of other BLs previously used. In this fiscal year, wefinished this modification and are actually checking its
installation on BL21. It will be used for users’ experiment
on BL21 in JFY2021. We also installed a remote monitoring system with IROHA2 to the furnace, as shown in
Fig. 1. Until now, according to the regulations of the MLF,
one user had to be near the furnace at all times to monitor the status whenever its heater was on. However,with this installation, we have received approval fromthe equipment safety team to operate the furnace under remote monitoring. This is expected to significantly
reduce user’s labor during their experiments.
Using the SANS furnace, we performed the lightirradiation experiment at high temperatures up to
200oC on TAIKAN (BL15) as shown in Fig. 2 (Proposal
No. 2020P0503). Ultraviolet light from a mercury lamp
illuminated the sample in the furnace through the focusing lens system and the quartz glass window of thefurnace on the incidence neutron side. Changes of theneutron scattering at the small-angle and middle-angle
detector banks by the light illumination were successfully observed in the experiment.

Figure 1. Remote monitoring system for the Nb furnace.

Figure 2. Light irradiation experiment at high temperatures on
TAIKAN (BL15).

2. Cryogenics and magnets
We have supported users’ experiments using theBL-common equipment. In JFY2020, the superconducting magnet was operated for 11 experiments, the 4He
cryostat for 8 experiments, the 3He cryostat for 6 experiments, the dilution refrigerator insert for 3 experiments
and the Gifford-McMahon (GM) cryofurnace for 1 experiment, including instrument proposals.
Recently, we purchased another 3He cryostat as BLcommon equipment. This is because the frequency ofuse is increasing and there is no alternative in case of
failure. We are currently preparing a rotary stage anda control box for it. The new 3He cryostat will be introduced to users’ experiments in JFY2021.

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4. A pulsed magnet system
In JFY2020, neutron scattering experiments using
a developed pulsed magnet system, which consists of asolenoid coil within the insert and a cryostat and a GM
refrigerator to cool samples down to less than 4K, were
performed at NOBORU (BL10). The samples we studied
were LiFePO4, which is generally employed as battery,and multiferroics TbMnO3. Pulsed magnetic fields up to
approximately 30 T were applied to the samples. A small
solenoidal coil in the pulsed magnet system was immersed in liquid nitrogen to remove the heat generated
by the magnetic field. So far, liquid nitrogen has been
manually replenished every two hours during the experiment. A new device, automatic liquid nitrogen supply system, has been introduced this fiscal year. Figure 3
shows a photograph of the automatic liquid nitrogen
supply system used in the BL10 for the neutron scattering experiments. As a result of using the new system, it
was possible to reduce the time to supply it up to about
6 hours per day in maximum, compared to supplying it
manually.
5. Humidity
The humidity experimental environment is being
developed in cooperation with several beamline groups[1]. The two-way gas-flow method can generate up to
85% relative humidity within a temperature range of
5°C–85°C. To date, humidity experiments have been carried out in reflectivity, SANS, and quasi-elastic neutron
scattering instruments.
In JFY2020, we started to develop a mixed humidity
gas generator. The first goal is to develop an automatic
system to generate mixed humidity gas of heavy andlight water. This system will enable us to conduct automatic contrast variation humidity experiments.

Figure 3. Automatic liquid nitrogen supply system.

Reference[1] H. Arima-Osonoi, N. Miyata, T. Yoshida, S. Kasai,
K. Ohuchi, S. Zhang, T. Miyazaki, H. Aoki, Rev. Sci.
Instrum., 91, 104103 (2020).

M. Watanabe1, R. Takahashi1, M. Ishikado2, Y. Yamauchi3, S. Ohira-Kawamura1,4, M. Nakamura3, H. Arima2, S. Takata1,4, Y. Su1,
S. Zhang2, T. Morikawa2, K. Ohuchi2, Y. Sakaguchi2, and T. Oku1
1
Technology Development Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS;
3
NAT Corporation; 4Neutron Science Section, Materials and Life Science Division, J-PARC Center

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Neutron Science

A New Position-Sensitive Scintillation Neutron Detector
for Obliquely Downward Scattering Bank in SENJU
1. Introduction
SENJU is a time-of-flight Laue single-crystal diffractometer installed in the BL18 of the J-PARC MLF [1]. This
neutron instrument is equipped with 37 two-dimensional scintillation neutron detectors, and has been inservice since 2012 [2]. One of the recent SENJU upgrades
includes additional four new detector modules, which
are placed in the obliquely downward scattering direction to increase the total angle coverage.
The purpose of this paper is to introduce our new
detector module that has been developed to meet therequired specifications for this specific bank. The thickness of the detector modules should be reduced to fit in
the tight space constraint while maintaining the similar
neutron-sensitive area and pixel size. Moreover, somedetector components are developed and renewed to
improve the count uniformity and detector efficiency.
The detector specifications and experimental results ofthe prototype detector are presented.
2. A prototype detector
Figure 1 shows a photograph of the prototype
detector module. The detector module is made basedon 6Li:ZnS scintillator and wavelength-shifting fiber
technology, where each detector module maintains aneutron-sensitive area of 256 × 256 mm with a pixel
size of 4 × 4 mm. To shorten the depth of the detector
configuration of the optical fibers, multianode PMTs andelectronic cards in the detector has been rearranged.
The clear fibers are bent tightly with a smaller bending radius than the original one while keeping the light
loss acceptably low. The depth of the detector has beensuccessfully decreased to 170 mm, which is 60% of theoriginal detector. Moreover, the scintillator screens, WLS
fibers, and comparator electronics are also modified.

To increase the light-collection yield, the scintillator
screen and WLS fibers are selected; 6Li:ZnS scintillator
screen purchased from SINTACOR, UK and Y11 fiberfrom KURARAY, Japan. The thicknesses of the two scintillator screens are 0.25 and 0.45 mm for upstream anddownstream of the WLS fibers arrays, respectively. New
discriminator electronics cards are implemented to thisdetector [3]. The new discriminator circuit has a frequency bandwidth of ~500 MHz, which is 1.8-fold wider thanthe original one. These cards can pick up signals that aresmaller in height and narrower in time than the original
cards. Table 1 summarizes the detector specifications.
Table 1. Detector specifications.
Pixel size
Neutron-sensitive area
Physical size
WeightDetection efficiency
Gamma-ray sensitivity
Count uniformity
Pulse pair resolution: 4 × 4 mm
: 256 × 256 mm: 320 × 320 × 170 d mm
: 16 kg: 50 - 55% (@2 Å ): 1 × 10−5 (60 Co): 3-5%: 5 μs

3. Experimental results
The developed new discriminator cards help improve both high voltage characteristics and countuniformity. Figure 2 shows a comparison of the highvoltage characteristics for the detector equipped withnew or original discriminator cards. The count plateau
has not been measured clearly in the original detector due to the insufficient frequency bandwidth of theoriginal discriminator cards even when the multianode
PMT voltage is applied at 96% of its maximum rating
20000
New discriminator card
Original discriminator card

Count (a.u.)

16000

12000

8000

4000

0
700

750

800

850

900

950

1000

PMT voltage (V, negative)

Figure 1. A photograph of the prototype detector.

Figure 2. High voltage characteristics of the detector.

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value. On the other hand, the detector with the new discriminator cards acknowledges neutrons at the applied
voltage 100 V less compared with the original discriminator cards. These cards give an extra margin for adjustment to the PMT voltage. The count uniformities of thedetector equipped with new or original discriminatorcards are compared in Fig. 3. In both cases the detector
components, except the discriminator cards, maintained
the same in both detectors. The PMT voltages were set
at -900 and -960 V for the new and original discriminator cards, respectively. With the new discriminator cards
the count uniformity improved to 4.3% from 6.0%. This
is attributed to the new discriminator cards picking up
signals more efficiently than the original ones.

(a)

(a)

(b)

14000
12000
10000

σ/N = 6.0%30Counts

40

The separate experiments revealed the 60Co gamma-ray
sensitivities are ~1 × 10−5 and background rate ~ 0.1 cps/hr,
which are acceptable for use in the beam line.

8000
6000

20
4000
2000

10

x-projy-proj

0
0

0
7

8

9

(b)

40

10
11
3
x10

12

13

14

σ/N = 4.3%

30

10

20

30

40

50

60

70

ChannelFigure 4.	(a) Count distribution, and (b) projection of the x
and y projection of the data of the det-4 (one of the
produced detector modules) with a flood neutron
irradiation [4].

20

10

0
7

8

9

10
11
3
x10

12

13

14

Figure 3.	Count histogram distribution for the x-projection
data (a) with original discriminator cards, and (b)with new discriminator cards. A whole detector
area is irradiated with neutrons from a 252Cf neutron
source [4].

Figure 4 shows a typical detector count measured
with (a) a flood neutron illumination and (b) projected
count distributions for x and y directions. The detector
exhibited similar count uniformity of 4-5% for x and yprojections. The other three detector modules also exhibited count uniformities in between 3-5%. Regarding
the detection efficiency all the four detector modules
exceeded 1.0~1.2-fold compared with the original detector for neutron-wavelengths from 1 to 12 Å. The detection efficiencies become 50-55% for the 2-Å neutron.

4. Conclusions
The new two-dimensional scintillation detector wasdeveloped for the additional detector bank of the SENJU
neutron instrument. The produced four detectors exhibited similar detector performances to each other with
the improved count uniformities and detection efficiencies compared to the original detector. All these detectors have been implemented at the obliquely downward
scattering bank in the SENJU.
References[1] T. Ohhara, et al., J. Appl. Cryst., 49 120 (2016).
[2] T. Kawasaki, et al., Nucl. Instrum. & Meth. A, 735 444(2014).
[3] T. Nakamura, et al., JPS Conf. Proc., 33 011097 (2021).
[4] T. Nakamura, et al., Conference record, 2020 IEEE
Nuclear Science and Medical Imaging Conference,N20-215.

T. Nakamura1, K. Toh1, R. Kiyanagi2, T. Ohhara2, and K. Sakasai1
Neutron Instrumentation Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science Section, Materials and Life Science
Division, J-PARC Center
1

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Neutron Science

Locally Adaptive Kernel Density Estimation on
Quasi-Elastic Neutron Scattering Energy Profiles
1. Introduction
Shimazaki et al. reported a histogram bin-width
optimization method [1] and a kernel band-width optimization method [2] on neuron firing time data approximated as Poisson point processes. Recently, theformer was applied to inelastic neutron scattering (INS)data [3,4].
Quasi-elastic neutron scattering (QENS) data contain intense elastic scattering and their spectra generally
have larger dynamic ranges than the region of interestsin the INS, requiring to set the bin-widths or the bandwidths locally in the data space. Usually, the researchers
using QENS adopt histogramming to represent a QENS
data set, setting the bin-widths according to conventional schemes. Because the bin-widths determine theresidual constant background intensity and influence
the final results of the curve fitting analyses, the binwidths must be set accurately.
In [2], an adaptive kernel density estimation (KDE)
was proposed, where the kernel band-widths were optimized locally in the data space. Moreover, the adaptive KDE on phantom data resulted in smaller deviations
from the true probability density than the other methods including the histogram bin-width optimization.
Therefore, the adaptive KDE seems promising for a QENS
data representation.
In the present study, we tried the adaptive KDE on
the QENS experimental data and analyzed a single linewidth from the estimated energy profile.
2. Method
We simply used the open-source library of theadaptive KDE [5]. The internal procedures are briefly described in this section.
In a kernel density estimation, underlying probability density λ is estimated based on the n observed dataaswith kpointsbeing a kernel, e.g., a Gaussian of a standard deviationis the set ofh, h regarded as the kernel bandwidth.
the detected neutrons’ energies. The method searches
h minimizing the mean integrated square errors (MISE)
between and [2]. Assuming the data points as a
Poisson point process and the count in any part of thedata space follows the Poisson distribution, MISE is separated into two terms, depending on and depending, respectively. The latter ison the observed data set

as follows:
,

(1)

.
where
For h fixed over the whole data space, the optimal.
h is
For h optimized locally in the data space, we firstconsider h* minimizing the local cost function.
,(2)
where ρ is a window function with a width W, e.g., a
Gaussian function with a standard deviation W (Fig. 1b).
We obtain one h* for each of all possible configurations(W, x). In order to select one pair of h* and W for each x,
h*/W is set as a constant value γ .
Since the data points are discrete, h*(x, γ ) abruptly
changes over x. Smooth band-widths are estimatedby Nadaraya-Watson kernel regression,(3).
Finally, by finding γ * minimizing the cost function, the optimized band widths (Fig. 1c) and(Fig. 1d) are obtained.
3. Application of the method on QENS data
For the input data of the method, we obtained ahistogram with a small bin-width of a QENS data set
without the usual corrections in the data reduction processes, keeping the number of the detected neutrons ineach of the bins. Because the method requires observed
data points of energies as the input, we randomly generated energy points at each bin while keeping the countwithin the bin.
The locally adaptive KDE had the larger bin-widths
at the low-count region (Fig. 1e). They resulted in a density curve being smoother in that region than the nonlocally adaptive KDE (Fig. 1g).
We compared the results of a curve fitting on theusual histograms and the profiles by the locally adaptive KDE. We treated the QENS energy spectra collectedfrom a sample at T = 50, 253, 303K. In the fitting, we regarded the spectrum at T = 50K as the device resolutionfunction and fitted each of the other spectra by the convolution of a Lorentzian and a delta function with thedevice resolution function, and a constant background.
HWHM of the Lorentzian corresponds to the inverse of
the lifetime of the dynamical phenomenon invoked in
the sample during the measurement. The HWHM values
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Figure 1.	Schematic of the adaptive KDE with the band-widths locally optimized (a-d): an input data set of Poisson point process{xi (i = 1, .., n)} (a), integrand of global cost function ĉ, window function ρ, and local cost function ĉ local (b), smoothedband-widths hγ with different flexible parameters γ (c), estimated density λ̂ and true density λ generating the data (d).
Trial application of the present method on a QENS data set (e-g): optimized band-widths (e), estimated density andinput histogram in non-log (f ) and log scales (g). Local and non-local are the results of the adaptive KDE with the bandwidths locally and non-locally optimized, respectively.

were 12.4 ± 0.3 (303K) and 3.9 ± 0.08 (253K) in units of
μeV for the histograms, while 12.3 ± 0.12 (303K) and
3.9 ± 0.03 (253K) for the adaptive KDE. The adaptive KDE
showed lower uncertainties by factors than the usual
histograms, probably because the adaptive KDE moreaccurately estimated .
4. Future plans
By extending the method to the 2D spectra on the
momentum transfer and energy, and replacing the usual
2D histograms by the 2D adaptive KDE, more accurate
time and space correlation functions might be obtained;
the 2D adaptive KDE as the input data for the mode

distribution analysis using a maximum entropy method[6] might be promising.
References[1] H. Shimazaki et al., Neural Comput., 19 1503 (2007).
[2] H. Shimazaki et al., J Comput. Neurosci. 29 171(2010).
[3] K. Muto et al., J. Phys. Soc. Jpn., 88 044002 (2019).
[4] Manuscript in preparation[5] https://github.com/cooperlab/AdaptiveKDE, http://
github.com/shimazaki/density_estimation[6] T. Kikuchi et al., Physica B, 567 51 (2019).

K. Tatsumi1, M. Matsuura2, H. Shimazaki3, and Y. Inamura4
Technology Development Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS;
3
Center for Human Nature, Artificial Intelligence, and Neuroscience, Hokkaido University; 4Neutron Science Section, Materials and Life
Science Division, J-PARC Center

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MUSE Facility Overview
1. Development of real-time temperature monitoring system for the muon target
Real-time monitoring of the target temperature is
extremely important to prevent the rotating target system from severe accidents. While thermocouples havebeen installed on the cooling jacket to measure the temperature rise due to thermal radiation from the rotatingtarget, the slow response of thermocouples (typically inminutes) makes it difficult to detect a sudden temperature rise caused by some serious trouble, such as target
rotation stop-page. For real-time temperature detection,
we have been developing a monitoring system basedon an infrared (IR) camera.
Figure 1(a) shows the temperature distribution of therotating target during the 1 MW operation observed by
the IR camera. The high-temperature part (shown in yellow) can be observed covering the area from the centerof the target to the right (the direction of rotation). The
measured temperature rise of the rotating target at thestart of the beam operation is shown in Fig. 1(b), where
it takes about one hour using thermocouples to reachthe actual temperature inferred from the IR camera.
The real-time sensitivity of the IR camera is also

demonstrated by the temperature fluctuations associated with the fluctuations of the irradiated beam shownin Fig. 1(b). The analysis regarding the relationship between the temperature change and thermal conductivity upon proton beam irradiation is in progress for the
1 MW operation.
2. Construction of the H-Line
The H-line is a new beamline under construction
since FY2012 in Experimental Hall No.1 of the MLF building. Its layout drawing is shown in Fig. 2. It is a general-purpose beamline that can deliver both decay andsurface muons and has branches to two experimental
areas named H1 and H2. The designed surface muon
flux reaches 108 muons/s with a proton beam powerof 1 MW owing to a large acceptance (108 mSr) capture solenoid and other beamline magnets with large
apertures.
In FY2020, construction of the main (upstream) partof the H-line and the first branch (to the H1 Area) progressed to secure the minimal components required todeliver muons to the H1 Area for beam commissioning. All vacuum devices were connected (see Fig. 2),

(a)

(b)
Figure 1. (a) An infrared (IR) camera image of the rotating target during 1 MW-beam operation. (b) Temperatureof the rotating target rises upon the resumption of the beam operation. The temporary beam halt ataround 18:50 is clearly identified by the target temperature monitored by the IR camera.

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Muon Science

Figure 2. (a) A layout drawing of the H-line, and (b) a snapshot showing
vacuum devices for the beamline to the first branch, which wereconnected during the summer shutdown in FY2020.

electrical cabling and cooling water piping for two
bending magnets (HB1 and HB2) were conducted, anda safety interlock system was implemented to be incorporated into the whole MLF system. Although the capture solenoid (HS1), transportation solenoids (HS2 andHS3), focusing quadrupole triplets, and a DC-separator
are not ready, the surface muon flux is expected to be
6 × 105 muons/s without these components. In the next
summer shutdown, we plan to conduct the remaining
works, such as electrical cabling and cooling water piping of all magnets and installation of a DC separator andbeam slits, so that the design in-tensity of 108 muons/s
will be achieved.
Progress was also made in preparing the second
branch of the H-line (to the H2 Area). Since the muon
g-2/EDM experiment proposed for the H2 Area requires
a 50-meter LINAC to accelerate muons to 212 MeV, theconstruction of an extension building is planned on theeast side of the MLF where the parking lot is located.
In FY2020, the detailed design of the extension building was completed, and geotechnical investigation andburied cultural property research was conducted on theconstruction site.
3. Laser system for Ultra-slow muon
Ultra-slow muons can be generated by resonant
optical ionization of thermal muonium from hot-W foil
target. The light pulses of 122.09 nm (Lyman-α) and 355
nm are required for the 1s to 2p state excitation and
2p to ionization, respectively. The high power pulsed

coherent Lyman-α light source is one of the key elements for the efficient generation of ultra-slow muons.
In FY2020, more than 10 µJ Lyman-α pulses havebeen stably generated from 212.556 nm and 820 nm
light pulses using the two-photon-resonant four-wavemixing method attained by nonlinear wavelength conversions of a 100 mJ 1062.78 nm pulse delivered from
Nd:YGAG (1 at.% Nd doped Y3Ga2Al3O15) ceramic
laser amplifiers. Although we are targeting 1J-level1062.78 nm pulses to achieve the required Lyman-αout-put power, the problem of Ga inhomogeneity in
Nd:YGAG has precluded for years to obtain the largeaperture laser medium (> 10 mm in diameter) for theamplifier required for this purpose.
To overcome this problem, we have been developing Nd:YSAG ceramic (Ga substituted with Sc), and a
newly fabricated middle-size (ϕ9 mm, 112 mm long)
Nd:YSAG ceramic was delivered for testing the amplification gain and wave-front distortion. While the amplification gain was satisfactory, the distortion of transmitted
wavefront was revealed, which resulted in the reductionof the wavelength conversion efficiency in the sub-sequent stages due to the collapsed beam shape. In order
to compensate for the distortion occurring inside the
Nd:YSAG ceramic, we introduced an active 40-segment
deformable mirror combined with the Shack-Hartmannwave-front sensor that was placed before and after amplifier, respectively. The measured wave-front distortionis shown in Fig. 3, where the distortion is removed after the compensation. The method obtained by these131

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MLF Annual Report 2020

(a)

(b)
Figure 3. The wave-front distortion in Nd:YSAG ceramic for final amplifier before (a) andafter (b) after the compensation by a deformable mirror system.

Figure 4. A snapshot of the S2 Area (with roofs temporally
removed) and laser hut viewed from the downstreamof the S-line.

studies will be applied to a practical laser system to implement the enhancement of Lyman-α optical intensity.
4. Construction of the S2 Area
The S2 Area is under construction for the precise
measurement of the muonium 1s-2s transition energy
by the resonant laser ionization (S1-type proposal by
Okayama U. group, supported by Kakenhi). To allow for
the laser experiment, the entire area is shaded by walls
and removable roofs to ensure safety. The muon beaminterlock system is almost the same as that for the S1
Area. A laser hut has been installed next to the S2 Area
for the immediate access. The hut is made of a marine
container, so that it can be easily moved by crane. The
construction of the S2 Area was nearly completed in
the summer shutdown of FY2020. The rest of the work
will be completed after the approval from the Nuclear
Regulatory Commission to deliver the first beam in theearly FY2021.

R. Kadono 1,2, K. Shimomura 1,2, A. Koda 1,2, P. Strasser 1,2, T. Yamazaki 1,2, S. Kanda 1,2, S. Takeshita 1,2, Y. Ikedo 1,2, Y. Kobayashi 1,2,
J. Nakamura1,2, T. Yuasa1,2, N. Kawamura1,2, Y. Oishi1,2, Y. Nagatani1,2, S. Matoba1,2, S. Nishimura1,2, S. K. Dey1,2, W. Higemoto1,3, and T. U. Ito2,3
1
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK; 3Advanced Science Research Center, JAEA

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Muon Science

Present Status of the Muon-Beam Source
1. Introduction
The muon production target and the front-end partof each muon beamline, as well as the primary beamline, are located in the M2 tunnel, as shown in Fig. 1.
This area is crucial for the stable and safe operation of
the whole MLF facility, which contains not only MUSE
but also JSNS.
2. Muon production target
In FY2019, the rotating target was replaced with a
new one due to trouble in the first rotating target. The
second target has been operated without any essential
troubles. So far, the new target has been working stably
under the 500/600 kW proton-beam operation.
In addition to the conventional monitors like thermometers on the cooling jacket and the torque meter,
an infra-red thermometer that monitors the target temperature more directly is under development. The details are reported separately [1]. The new monitor will be
added to the target safety system to compose a layered
system.
To secure a spare target in advance, fabrication of
the third target starts in the next fiscal year under themulti-year plan.
3. Buffer tank system
Due to spallation reactions, lots of radioisotopes are
generated in the target. The main residual activities inS

HExp. Hall #1

Muon target
U

D
Exp. Hall #2

Figure 1.	The horizontal (upper) and the vertical sectionalview (lower) of the M2 tunnel. The proton beam istransported from the left side to the right side of
the neutron target through the tunnel.

the target are tritium and 7Be after a short cooling period. The tritium is generated by 0.5 TBq/year under the
1 MW operation according to a simulation. The radiationdose from the residual activities in the target is orders ofmagnitude lower than that in the surrounding metallic
parts in the target assembly. In addition to this, tritium
emits only low-energy β rays. Thus, the contribu-tion of
the tritium to the external exposure is not serious, if it
stays in the target. However, tritium can diffuse in the
hot graphite and evaporate from the target surface.
In general, tritium forms a volatile chemical state, easily spreads out and sticks to the surface of devices, andeventually increases the risk of internal exposure.
The buffer tank system [2] accumulated the operation data of the released tritium from the target. Since
the second target’s installation in the summer of 2019,
the data of the fresh target was were obtained. Figure 2
shows the tritium release rate determined by the tritiumcontained in the vacuum exhaust gas. The emission rate
is presumed to be proportional to the square root of the
diffusion coefficient, D, leading to the estimation that
D is about 60 times greater at 1 MW (700˚C) than thatat 600 kW (500˚C) . This seems consistent with the reported value of ~40 in similar isotropic graphite (IG-110
by TOYO TANSO Inc.) [3], although the absolute value of
D seems different.
This kind of data accumulation is important fora safe and continuous operation. Toward a comprehensive understanding of tritium behavior, we are promoting collaboration with the experts in the Hydrogen
Isotope Research Center (HRC), Toyama University. The
elementary process is studied using the equipment in
HRC. The results are fed back to the MUSE operation,
not only to the regular operation, but also to the reconstruction of the scenario of storing the spent targets.
The original scenario was considered at the early stageof the facility construction. Since then, the situation
has changed: (1) early realization of the rotating target whose lifetime is expected to be around 10 years,(2) more serious contamination in the hot cell where thespent target will be cut into three pieces to reduce thevolume, (3) potentially more serious effect of tritium inthe target, and so forth. We will start to consider the new
scenario taking all these issues into account.
4. The H line construction
The H line devices in the M2 tunnel were mainly installed in 2012 [4] and 2014 [5]. In this fiscal year, we133Muon Science

MLF Annual Report 2020

Figure 2.	The released tritium from the target. The vacuum exhaust from the beamline around themuon target and its downstream is stored in the buffer tank during the beam operationand is exhausted on the maintenance day after the radiation survey with the liquid scintillator (blue lines) and the ionization chamber (orange lines). The tritium release rate wasdetermined by the stored tritium in the buffer tank divided by the accumulation period,
which corresponds to each line length. The amount of tritium was measured either by aliquid scintillator after pre-treatment of leachate in water (blue lines) or by an ionizationchamber (orange lines).

performed the cabling and piping works connecting
the line to the magnets and the vacuum components.
Almost all the work on the H line in the M2 tunnel wascompleted in this fiscal year. Figure 3 shows a snapshot
taken in the beginning of October, just before closing
the radiation shield on the H line. Before releasing thefirst beam in the H line, the radiation application was
submitted to the regulatory agency on October 5,
2020, and the permission was issued on June 15, 2021.
Details of the present status in the H line are reported
separately [6].

Figure 3. Top view of the H line taken on October 5, 2020.

References[1] S. Matoba et al., ibid.
[2]	N. Kawamura et al., JPS Conf. Proc. 33 (2021) 011146,
HTTPS:// doi.org/10.7566/JPSCP.33.011146.
[3] H. Atsumi et al., J. Vac. Soc. Jpn. 49 (2006) 49.
[4] N. Kawamura et al., KEK Prog. Rep. 2012.
[5] N. Kawamura et al., KEK Prog. Rep. 2014.
[6] T. Yamazaki et al., ibid.

S. Matoba1,2 and N. Kawamura1,2
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK

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Muon Science

Development of Monitoring System for the Muon
Rotating Target Using an Infrared Camera
It is important to measure the temperature of themuon-production rotating target (hereinafter referred
to as “rotating target”) in order to detect quickly problems in it.
Thermocouples have been installed on the coolingjacket to measure the temperature rise due to thermalradiation from the rotating target. Since the time constant of the thermocouples is in the order of minutes,
it is not possible to stop the accelerator quickly in caseof a significant temperature rise. In order to construct a
rapid temperature detection system for rotating targets,
we have installed an infrared camera (ULVVIPS-04171SL
made by Vision-Sensing Co., Ltd.).
Figure 1 shows the temperature distribution of therotating target during the 1 MW operation observed by
the infrared camera. The high-temperature part (shownin yellow) can be observed flowing from the center of
the target to the right, the direction of rotation.
Figure 2 shows the measured temperature rise of
the rotating target at the start of the beam operation.
The temperature rise is saturated in about one hour ofusing the thermocouples attached to the cooling jacket,
while the temperature is constant in 30 minutes of using
the infrared camera.
The infrared camera is also sensitive to the temperature change when the beam is temporarily stopped. As
described above, rapid detection of temperature fluctuation by beam irradiation was achieved.
The beam power dependence of the temperature
at the center of the rotating target is shown in Fig. 3,
which is considered to be the beam spot temperatureof the rotating target. As the beam power increases, thetemperature of the rotating target also increases. We are
analyzing the change of temperature and thermal conductivity by proton beam irradiation.
The infrared camera has been irradiated with cobalt-60 gamma rays and has been confirmed to be able
to withstand up to 5 Gy of exposure. A glass dosimeter
installed near the camera has been used to measure theradiation dose, which was estimated to be about 3 Gy atthe end of March 2021. However, due to frequent errors
in the electronic circuitry, which are presumably causedby the single event upset by neutrons, the camera operation time is low at about 30% of the available operation time. We are planning to develop a new infrared
camera with measures such as shielding of the circuitry
to increase the camera uptime.

Figure 1.	Infrared camera image of the rotating target during
the 1 MW beam operation.

Figure 2.	Temperature rise of the rotating target at the startof the beam operation. At around 18:50, the beam
was temporarily stopped and the temperature of
the target decreased.

Figure 3.	Beam power dependence of the temperature at
the center of the rotating target.

S. Matoba1,2 and N. Kawamura1,2
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK

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Muon Beamlines and Control System
1. Introduction
We report on the manufacturing of spare coils fora bending magnet in D-line and the installation of thepersonnel protection system (PPS) for the H1 experimental area.
The bending magnet DB2 is installed in the decay
muon beamline (D-line) at the Materials and Life Science
Facility (MLF) of J-PARC. The existing DB2 is a dipole
magnet which has been manufactured over 40 years
ago; therefore, we plan to exchange the degraded coilswith new ones. The production and performance inspection of the new coils were carried out. The hollow
conductor, which was produced last year, was used forthe new coils as coil material [1].
The installation of the PPS equipment for the H1area in the first experimental hall of MLF started in
FY2020. The first experimental area constructed on the
H-line is called H1 area. The PPS for the H1 area was installed, and status signals from the power supplies of themagnets, which bring muon beams to the H1 area, wereconnected to the PPS, and the existing PLC was updatein the first experimental hall.
2. Manufacturing of spare coils
As shown in Fig. 1, DB2 bends muon beams by 40°
and transports them to the downstream experimental areas. We calculated the field of DB2 with a 3-dimensional
field analysis program OPERA-3d. The analysis modeland actual DB2 are shown in Fig. 2.
In FY2020, we manufactured two spare coils withthe same size as the existing coils so that they can beinstalled in the existing yoke and poles. The production drawing and the manufactured coils are shown in
Figs. 3 and 4, respectively.
Table 1 shows the performance test results, andFig. 5 shows a comparison between the measured andcalculated central magnetic field values of the coil. The
reason why the calculated and measured values do notmatch exactly is expected to be due to the presence ofmagnetic materials (reinforcing steel bars) under thefloor at the measurement location.

Figure 3. Drawing of the new coil.

Figure 1. Decay muon beamline (D-line).

Figure 2. Analysis model (left) and existing DB2 (right).

136

Figure 4. Manufactured coil.

MLF Annual Report 2020

Muon Science

3. Installation of PPS equipment for H1 area
3.1 PPS devices for H1 area
Similar to other muon experimental areas [2], the
PPS for the H1 area comprises an emergency beam stop
button (Panic Button), a search button, a muon blocker,
a safety magnet and an entrance door to the experimental area, as shown in Fig. 6. The safety magnet for the H1area is HB2 and the muon blocker is HBB1, as shown in
Fig. 7.

rack is equipped with three PLCs; magnet power supplies control panel, vacuum equipment control panel,and muon blocker drive panel, respectively. Regarding
the magnet power supplies, it is necessary to be able toread all status signals of all the magnet power supplies.
This fiscal year, the status signal of the safety magnet
HB2 was added to the PPS, and the wiring for the magnet excitation permission signals was connected. The
wiring system for each device is shown in Fig. 8.

3.2 Wiring of the PPS devices to H1 PPS
The PPS devices to display statuses and operate the
PPS were wired to two control systems. One is the PPS
panel located on the east side of the first experimental
hall that is used to send the status signals from the PPS
devices to the MLF control room, and the other is the
PLC rack located on the west side of the hall. The PLC

3.3 Software modification
With the construction of the H1 area, it was also
necessary to modify the software to properly display
the new H1 area in the existing control panels. Figure 9shows one of the screen of the control panel related to
the H1 area.

Table 1. Result of the inspection test.
measurement

calculation

Coil Resistance [mΩ](at 20°C)

52.25

58.2

Inductance [mH](at 120 kHz)

14.44

Inductance [mH](at 1 MHz)
Water pressure drop
[MPa]
Water flow [ℓ/min](at 0.5 MPa)
output current [A]output voltage [V]Temperature rise incooling water Δt [°C]

14.86
13.06
0.32

0.33

17.5

17.4

500
25.97

500
29

7.9

12.0

Figure 6.	PPS devices at the H1 area: entrance door
(left), panic button (top right) and searchbutton (bottom right).

Figure 5.	Comparison between measurement and calculation of the central magnetic field.

Figure 7.	The H1 area in the first experimental hall of the MLF.

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Figure 9.	Screen of the magnet power supplies control panel
for S-line & H-line.

Figure 8. PPS wiring system diagram.

4. Summary
We completed the manufacturing of the spare coils
for DB2, and measured the magnetic field in FY2020. As
a result, it was confirmed that the calculated and measured magnetic field values were almost identical. We
plan to replace the existing coils with the newly manufactured coils in the summer of 2021. This project is currently in progress.
The installation of the PPS equipment for the H1area was completed, and we updated the PPS wiring
accordingly in the first experimental hall in FY2020. We
are now ready to start experiments.

References[1] H. Fujimori and T. Yuasa et al., Muon Beamlines andTarget Control System, KEK-MSL REPORT 2019, KEK
Progress Report 2020-4 (October 2020), pp. 13-15.
[2] K. Sakai, et al., Progress of General Control System
for Materials and Life Science Experimental Facility
at J-PARC JAEA-Technology 2018-011.

T. Yuasa1,2, Y. Kobayashi1,2, H. Fujimori1,2, N. Kawamura1,2, Y. Ikedo1,2, T. Yamazaki1,2, A. Koda1,2, K. Sakai3, A. Watanaebe4, S. Sakata4,
M. Meguro4, and K. Kawabata4
1
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK; 3Japan Atomic Energy Agency, JAEA; 4NAT Corporation

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Current Status of the µSR Experiment at D1
1. Introduction
At the D-line, muons are delivered to D1 and/or
D2. At the D1-area, the µSR spectrometer is installed
as a main and fixed instrument. Since high momentum
muon, surface muon, and negatively charged muon areavailable at D1, all types of µSR measurements, except
for the ultra-slow µSR, can be carried out. In particular,
unique sample environments, such as very low temperature by using the dilution refrigerator, high pressure etc.
were possible to carry out only at D1. Figure 1 shows
the µSR spectrometer with the dilution refrigerator andthe fly-past chamber. Here, we report the recent zeromagnetic field condition of D1.
2. Zero-field condition at D1
Normally, a very weak magnetic field exists at theexperimental hall. The main source of the magnetic
field is the terrestrial magnetism with a magnitude of
0.2–0.3 G. In addition, normal and superconducting
magnets are used to obtain muon beams, adding extra
magnetic fields to the sample position. For a µSR experiment, a zero magnetic field condition at the sample
position is one of the important experimental prerequisites to obtain information about the precise stateof a sample. In particular, a superconductors are quitesensitive to an external magnetic field (by Meissner effect or formation of flux line lattice) and the reductionof a residual field is crucial to understand the essential
properties of materials.
At D1, the magnetic fields at the sample position

Figure 1.	µSR spectrometer with the dilution refrigerator andthe fly-past chamber at D1.

are estimated by using four triple-axis flux-gate magnetic probes, which are located near the center of the D1
spectrometer. To obtain a zero magnetic field condition,
feedback currents are applied to three pairs of the correction coils. This feedback system was installed to the
Iroha system, and a zero field can be obtained dynamically when we are measuring µSR data.
However, we found out recently that sometimes
the zero-field feedback system is not working well anda finite residual magnetic field exists at the sample position. Unfortunately, this problem was discovered in
2020A and it was not possible to confirm the zero-field
condition for some zero field µSR data. Currently, tocheck a magnetic field condition, we put another 3-axis
magnetic probe close to the sample position.
We also checked the magnetic field distribution under the zero magnetic field condition. Figure 2 shows
the position dependence of the residual magnetic fields.
When the zero-field feedback system is working correctly, the residual magnetic field at the center of the D1
spectrometer is less than 0.02 G for all directions. Thismagnitude is small enough for the usual sensitivity of
our measurements.
For µSR, a magnetic field condition is very important, and we need further development to monitor themagnetic status of the experiment.

Figure 2.	Position dependence of the residual magnetic field
for each direction. For these measurements, nosample is mounted to the D1 spectrometer.

W. Higemoto1,2,3 and A. Koda2,4Advanced Science Research Center, Japan Atomic Energy Agency; 2Muon Section, Materials and Life Science Facility Division, J-PARC
Center; 3Department of Physics, Tokyo Institute of Technology; 4Muon Science Laboratory, Institute of Materials Structure Science, HighEnergy Accelerator Research Organization (KEK)1139Muon Science

MLF Annual Report 2020

Development of Sample Environment at the S1 Area
1. Introduction
SR experiments often use helium (He) as cryogen, which is collected in the recovery line after use.
However, helium gas is a precious resource, and it is
known that there is a global supply problem, so it is important to prepare a cryogen-free cryostat for the futuresustainability of cryogenic experiments. In order to settle this issue, we have commissioned a new cryogenfree cryostat based on a commercially available model:
the DRY ICE 1.5 K Beamline LEMON system (Dry Lemon),supplied by ICEoxford Ltd. [1]. It is a Gifford-McMahon(GM) cooled cryogen-free variable temperature cryostat.
Figure 1 shows a snapshot of this cryostat.

140

approximately 8 mbar, liquid He can be stored in a reservoir and VTI can be cooled at the same time. He gas
is introduced into the sample chamber to provide heatexchange between VTI and the sample. The temperature of VTI is controlled by using PID heater parameters,
and this process is not perfectly optimized yet. For hightemperature operation (above room temperature), thesample chamber is kept in vacuum, and the sample rod
for high temperature is also equipped with a heater near
the sample.

The cryostat can be operated at a lowest temperature of ~1.5 K and a highest temperature of 500 K,
whereas the lowest temperature achieved by existing
cryogen-using top-load cryostats is 2 K [2]. The cryostat
consists of a sample chamber with a variable temperature insert (VTI), a He circulation line, and a GM cryocooler operated by a dedicated compressor (Fig. 2).
Before reporting the specific work, we will de-scribe
the regular cooling procedure. The GM refrigerator isoperated in an outer vacuum chamber (OVC), and thecirculation of He is started to cool VTI. In one day, GM
stage 2 (GM2) temperature reaches approximately 4.2 K,
which is slightly above the temperature at which He becomes liquid. After that, by adjusting the needle valve
until the pressure gauge on the circulation line shows

Other features of this cryostat are the relatively
large beam window size and the top-loading system.
The former is for relatively low background of the µSR
spectra, and the latter is for sample mounting without
increasing the temperature up to room temperature.
There are three beam windows in front of the sample.
These window sizes are, from the outside, ϕ 55 mm: theOVC window (A), ϕ 50 mm: the 50K shield window (B),and ϕ 40 mm: the sample chamber window (C). As previously reported in the case of the 3He cryostat [3], allwindows are ϕ 35 mm in size, and the cryostat is notdesigned for the top-loading sample rods but is using
a dedicated sample holder, which is in contrast to thecase of Dry Lemon.
With this top-loading cryostat, various sample rods
can be used. Currently, in addition to one fixed sample
rod for low temperature and one for high temperature, a rod for sample rotation was prepared for low

Figure 1.	Snapshot of the new cryogen-free variable temperature cryostat placed at the test bench.

Figure 2.	Schematic diagram of the cryostat with a blue line
showing the He circulation line, where GM, VTI andOVC respectively denote the Gifford-McMahon refrigerator, the variable temperature insert and theouter vacuum chamber.

MLF Annual Report 2020

temperature. Figure 3 shows a schematic diagram anda snapshot of the rotating rod, on which the sample canbe mounted on a ϕ 30mm aluminum disk, which canbe rotated by a stepping motor in the radial direction.
We are currently commissioning this cryostat for
user experiments and are dealing with the following
problems. A typical problem in this cryostat is the vacuum leakage in two areas. One is a leak from the window,
and the other is a leak from the He circulation line.
The most common leak at room temperature, theleak from the window, happens as follows. In the cryostat, there are two pairs of vacuum windows: A and C,
shown in Fig. 2. The windows are aluminized polyimide
films. The following procedure is used to leak-checkbefore operation. First, all closed systems, i.e., He circulation line, sample chamber, and OVC, are evacuated.
Then, while connecting the helium leak detector to OVC,
He gas is introduced into the sample chamber using a
gas bag. This is used to check for leaks from the sample
chamber to OVC. Figure 4 shows schematic diagram of
the trend of the leak detector. The red line is the casewhere there is a leak through the window C, and within
1–2 minutes, there is a sharp increase in the rate of e.g.,10−3 Pa m3 s−1 for a typical pinhole. The black line shows
the trend when there is no leak, and the rate increases
slowly to approximately 10−6 Pa m3 s−1. This is because
the He gas can gradually penetrate the window at room
temperature. The leak rate increases both with and without leaks, but the quantitative difference makes it possible to distinguish the presence of a leak. When a 5 L gas
bag is introduced, the pressure in the sample chamberincreases to approximately 70 mbar at room temperature, but if there is a leak, the pressure decreases noticeably within a few minutes: e.g., to 30 mbar in 10 min fora typical pinhole.

Figure 3.	Schematic diagram (left) and snapshot (right) of therotating sample rod for the top-loading cryostat.

Muon Science

Before circulating He, the leak detector connection is changed to the He circulation line and He gas issprayed on the line from the outside to check for leaks.
The leak-checking can be performed, because the background rate of the line is approximately 10−6 Pa m3 s−1,
after the circulation line has been sufficiently evacuated.
After connecting the leak detector to OVC again, the He
circulation is started and we can check for leaks fromthe circulation line to OVC at room temperature. Then,
He gas is sprayed on OVC from the outside to check forleaks. When leak-checking window A, the trend of theleak rate is similar to that shown in Fig. 4. In this outer
window A, it is easier to identify the leak position compared to the inner window C, because the He sprayed
position can be controlled. If there are leaks in thesewindows, it is necessary to repair them with epoxy glue:
in window A, the glue can be applied from the outside,
but in the window C, it is necessary to disassemble thecryostat (Fig. 5).
The next problem is a leak at low temperature,
called a cold leak. If the leak is observed near the nitrogen liquefied temperature (~ 77 K), it is most likely due
to thermal contraction. For example, if the leak is foundafter the VTI has reached at the low temperatures, it islikely to be a cold leak from the indium seal on a sample
chamber flange.
As the cooling progresses and the VTI temperature
decreases near the lowest level, another cold leak may
be observed. Liquid He under saturated vapor pressuretransitions to a superfluid state below 2.2 K. As a result,
He has no viscosity and passes through a pinhole thatviscous fluids cannot pass through, a phenomenon
known as a super leak. Figure 6 shows an example of thetemperature trend when the super leak was observed.
The initial temperature increases up to 7 K, as seen

Figure 4.	Schematic of the leak rate trends. The black line
represents the case of gradual He gas penetration
through a leakless window. The red line represents
the case where there is a leak through the window.

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MLF Annual Report 2020

in Fig. 6, was due to He gas leaked into OVC by the superleak, which acted as the heat exchange gas to increase
the temperature of VTI. The heat shot also increased
the temperature at the leak point above the superfluid
transition temperature, and the leak was immediately
stopped. The temperature increase of VTI stimulated release of He gas adsorbed on the vessel wall, which led
to a further temperature increase (the second peak).
Since evacuating was continued during this period, it isseen that the temperature increase of VTI was slowing
down from around 20 K. Besides this, decreasing of theflow rate through the needle valve due to the temperature increase of VTI also reduced the heat load at GM2,
suggested by the fact that the temperature of GM2 wasslightly decreasing, as shown in Fig. 6. As a result, liquid He that started to accumulate in the He reservoir
gradually cooled the needle valve, and when the liquid
He began to flow through the needle valve (at the VTI
temperature of 25 K), rapid cooling reoccurred.
In the case of the cold leak, as described above, thecryostat needs to be disassembled and the following
procedure is used for maintenance. An indium sealed
flange, used for the circulation line (lower right part of
Fig. 5), should be replaced first during maintenance. At

that time, for increasing the circulation line pressure toatmospheric pressure, He gas is introduced into the line
to prevent air from contaminating the line and blocking
it during cooling. In addition, stainless steel tubes withan outer diameter of 2–3 mm are used for the part of thecirculation line in OVC (upper right part of Fig. 5). If there
is an oxidized solder part (shown in Fig. 5), it is necessary
to replace it using solder and flux for stainless steel. The
old solder should be removed with sandpaper before
soldering, and it is important to remove any remaining
flux as it may cause oxidation.
Because the impedance (conductance) of the He circulation line is always important, it is necessary to confirm that the impedance has not changed before andafter the maintenance as follows. First, a gas bag filledwith He is connected to the circulation line on the GM
refrigerator side (right side of Fig. 2), the needle valve
is closed, and then the circulation line on the sample
chamber side is evacuated with a vacuum pump. Afterthe vacuum pump has been stopped, the needle valve isfully opened and the pressure rise in the circulation line
is observed to roughly check the impedance. For example, a pressure rise of 300 mbar/10 sec can be checked
before and after the maintenance.
References[1] https://www.iceoxford.com/[2] https://mslnfo.jp/en/s1/se.html[3] J.G. Nakamura et. al., KEK Progress Report 2019-3
KEK-MSL REPORT 2018 (2019) 23.

Figure 5.	Snapshot of disassembling the cryostat. The sample
chamber tail is shown by removing the 50 K shield.

Figure 6.	Temperature trend of VTI and GM 2nd stage (GM2)with the cold leak from a circulation line.

J. G. Nakamura1,2, A. Koda1,2, M. Hiraishi1, S. Doiuchi1, S. Nishimura1,2, H. Okabe1, A. Hashimoto1, H. Li1, and R. Kadono1,2
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK

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Muon Science

S2 Area Construction - Recent Progress
1. Introduction
To realize the precise measurement of the Mu 1s–2stransition frequency [1] (KAKENHI 19H05606), the construction of the S2 area has been started. The S2 area
is an experimental area of the surface muon beamline(S-line) in experimental hall No.1 of the Materials andLife science experimental Facility (MLF) building. The
S-line is designed to have four experimental areas; onearea (S1 area) is already constructed and in operation[2, 3].
2. Overview of S2 area
The S2 area is located at the opposite side of the
S-line from the S1 area. A top view of the S2 area isshown in Fig. 1. The kicker (SK12) can split a doublepulsed muon beam to two single-pulsed muon beams
for both areas. A septum magnet (SSPTM2) leads muons
to the S2 branch and two triplets (SQ16-18 and SQ19-21)
guide them to the S2 area.
The Mu 1s–2s experiment uses lasers at the S2 area.
So, the area is completely surrounded by walls and roofs,
as shown in Fig. 2. The roofs are removable for installing experimental setups. LED lights (5000 lm, 6 units)
and ventilation fans (900 m3/h, 2 units) are installed on

the walls. A manifold of cooling water (50 l/min, 2 ports)
and a power distribution board (100 V, 15 A, 4 ports) exist in the area. The beam interlock system is almost thesame as the one at the S1 area. The door of the S2 area
is hand-operated.
To provide lasers, a laser hut is located next to theS2 area. The laser hut is a custom-made 20-ft container,
so that it can be easily craned and moved as necessary.
The laser hut has no floor and the laser table or other instruments in the laser hut will be directly placed on thefloor of the experimental hall. Figure 3 shows the laser
hut hoisted with a crane. The laser hut has LED lights(2500 lm, 4 units), precision air-conditioner (Coolingpower 7000 W), and double doors for light shielding.
3. Construction
The construction of the S2 areanwas almost finishedin the summer shutdown of 2020. Figure 4 shows theexperimental hall No.1 before and after the construction. The remaining construction works will be done
after theepermit frof the Nuclear Regulation Authority.
The first beam of the S2 area is expected early in fiscal
year 2021.

Figure 2. An aspect of the S2 area.

Figure 1.	A top view of the S2 area. Beamline components toward the S2 area are a kicker (SK12), a septum magnet (SSPTM2), a beam blocker (SBB2-2), a set of slits(SSL2-2), and two triplets (SQ16-18 and SQ19-21).

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MLF Annual Report 2020

Figure 3.	The laser hut hoisted with a crane. Large instruments like a laser table can be installed by moving
the hut to another place.
Figure 4.	Experimental hall No.1 before (upper) and after(lower) the construction. The roofs of the S2 area
are temporary removed.

References[1] Ce Zhang et al., JPS Conf. Proc. 33 (2021) 011125.
[2] A. Koda et al., KEK-MSL REPORT 2013 (2014) 12-13.
[3] P. Strasser et al., KEK-MSL REPORT 2016 (2017)17-18.

T. Adachi1,2, N. Kawamura1,2, A. Koda1,2, T. Masuda3, K. Shimomura1,2, P. Strasser1,2, S. Uetake3, and T. Yamazaki1,2
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK; 3Division of Quantum Universe, Research Institute for Interdisciplinary Science, Okayama University

1

144

MLF Annual Report 2020

Muon Science

Commissioning of the μSR Spectrometer at U1A
1. Introduction
At J-PARC MLF, MUSE provides the world’s highest flux of pulsed muon beams. U-Line, one of the four
beamlines in the facility, features an intense surface
muon beam from Super-Omega [1] and Ultra Slow Muon
(USM) by laser ionization of thermal muonium. The
beamline has two branches: U1A for μSR studies using
USM and U1B for the transmission muon microscope.
The surface muon beam irradiates a resistively heated tungsten film to obtain thermal muonium atoms ina vacuum. Two laser beams resonantly ionize the muonium atoms with wavelengths of 355 nm and 122 nm.
The ionized muonium has a thermal velocity corresponding to the target temperature of 2000 K, which
results in a seven-digit cooling from 4 MeV to 0.2 eV.
An electrostatic extractor and immersion lens focuses
the ionized muonium and accelerates it to 30 keV. The
extracted muons are transported to the experimental
areas through a magnetic bend for mass separation,
electric bends for energy selection, and electric quadrupoles for focusing. Micro channel plate (MCP) detectors are placed at focal points along the transport optics
to measure the flux and profile of USM. In the U1A area,
a muon spin spectrometer is placed on a high-voltage
stage to control injection energy from zero to 30 keV.
2. The U1A μSR spectrometer
The muon spin spectrometer at U1A consists of alongitudinal field coil and a positron detector segmented into 16 modules, 512 channels. The coils can generate a magnetic field of up to 0.4 T along the beam axis.
The USM spins are rotated 90 degrees at the magnetic
bend during transport, so the longitudinal field at the
spectrometer is orthogonal to the average muon spin
vector. The detector consists of plastic scintillator blocks,
silicon photomultipliers (SiPM), and dedicated front-end
electronics. A sample is placed inside the main chambersurrounded by the coils, and a helium flow cryostat controls the temperature. A load lock chamber next to themain chamber allows sample exchange while maintaining a high vacuum.
3. Project status and tasks
Following the successful USM generation in 2016 [2]and the demonstration of USM-μSR at U1A in 2018 [3],preparations for the start of user experiments are steadily underway. In 2019, implantation depth control by thehigh-voltage stage was successfully demonstrated [4]. To

proceed from the demonstration to the practical stage,
several issues need to be addressed. The key issues are improving beam flux and quality, optimizing the spectrometer’s performance, and preparing the sample environment.
For the USM flux, pulse energy improvement andspectral linewidth optimization are being studied. We
are also working on a step-by-step study to quantify
the generation rate of muonium and the extraction efficiency of the USM with sufficient precision. The typical
USM flux is about 2 × 102 Hz after the first electric bendwith the Lyman-α light’s pulse energy of 5 μJ.
Concerning the beam quality, the beam profile,energy, and time-of-flight spread are the performance
to be considered. A simulation study has been done
to optimize the parameters of the transport optics,
and a computational solution has been found [5].
Experimental validation is also being understood qualitatively, and further systematic comparison of measurements and calculations will be performed.
For the spectrometer, the signal-processing electronics have been upgraded to improve its performance. The operating parameters of the electronics
and the SiPMs needed to be optimized, so they were
determined in laboratory tests and commissioning withthe beam. Positrons from the upstream of the beamline
were observed at the spectrometer and reduced the μSR
asymmetry. As a countermeasure for the positron background, additional lead shields were installed in frontof the spectrometer. These details are described in thenext section.
As of the sample environment, the electric noisefrom the power supply of the longitudinal field coils has
been disturbing the deceleration potential of the highvoltage stage. The frequency of the noise was 50 Hz, andthe amplitude was 28 V peak-to-peak. This noise level
limits the implantation-depth resolution of the USM, so
a countermeasure is required.
4. Progress in this fiscal year
In FY2020, the muon beam was delivered from
Run84 to Run86 operation cycles. There was a period
in April and May when the beam was stopped due tothe spread of COVID-19. After the resumption of the accelerator operation, we continued to prepare the commissioning to start user programs while making efforts
to prevent the spread of infection. In this section, we
report on the three main results obtained during thisfiscal year.
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4.1. Tests of upgraded front-end electronics for the
positron detector
The spectrometers of MUSE use the dedicatedfront-end electronics for the positron detector. A seriesof ASICs called VOLUME perform analog signal processing. This year, the U1A spectrometer has been upgradedfrom VOLUME2012 (V2012) to a new version named
VOLUME2014 (V2014).
V2014 has a pole-zero-cancelation circuit in the amplifier, which provides an undershoot-free output withappropriate parameters. As a part of the commissioning,
the biases given to the amplifier were determined byobserving the output waveform. In addition, the comparator threshold was determined from the relationshipbetween the threshold and the SiPM’s dark count rate.
The operating voltages of SiPMs were optimized fromthe pulse height distribution depending on the bias
voltage.
The detection efficiency of the detector for decay
positrons was almost 100%, the timing resolution was
2.5 ns in the standard deviation, and no significant pileup was observed.
4.2. Suppression of decay positron background byadding the lead shield
The muonium production target is made thickenough to stop half of the beam to maximize the muonium emission rate. Muons not stopping at the target
are the origin of background events at the spectrometer.
Since these background muons are spread by Coulomb
multiple scattering, shielding the upstream side of thespectrometer is an effective countermeasure.
A lead shield with a thickness of 5 cm was installed
to cover the detectors. The shield reduced the background rate, as shown in Fig.1. The integrated rate of
background events was suppressed to about 1/5.
4.3. Improvement in the injection energy resolution
by modifying the power supply wiring
Electrical noise at the high-voltage stage causes
uncertainty in the USM implantation depth. We modified the power supply wiring to the longitudinal fieldcoils. The noise level was reduced to 4 V peak-to-peak,i.e., improved by a factor of seven. This level of uncertainty is small compared to the energy spread due to the

Figure 1.	Background positrons at the spectrometer: (a) comparison of the background rate before and after the
installation of shielding; (b) geometrical arrangement of the detector module. Directions are fromthe beam perspective.

position dependence of the accelerating electric field
for the USM extraction.
5. Summary and outlook
The commissioning in FY2020 completed the preparation of the U1A spectrometer for use in materials
science using USM. To start user programs, the beam
intensity needs to be improved, which will require optimization of the extraction and transport optics. We willattempt to increase the number of USMs and to evaluate
the number precisely in parallel.
References[1] The total beam flux is 6.4×107μ+/s at 212 kW. Y. Miyake
et al., JPS Conf. Proc. 21, 011054 (2018).
[2] T. Adachi, A. D. Pant, and Y. Ikedo, KEK Prog. Rep. 2017-4(2017) 12.
[3] T. Adachi, A. D. Pant, and Y. Ikedo, KEK Prog. Rep. 2018-2(2018) 13.
[4] T. Adachi and Y. Ikedo, KEK Prog. Rep. 2019-3 (2019) 17.
[5] A. D. Pant et al., Nucl. Instrum. Methods Phys. Res. A
929 (2019) 129-133.

S. Kanda1,2, T. Adachi1,2, Y. Ikedo1,2, Y. Oishi1,2, H. Li1,2, T. Yuasa1,2, and H. Fujimori1,2
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK

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Muon Science

Construction of Transmission Muon Microscope at U1B
1. Introduction
At the U1B area, a 5 MeV transmission muon microscope is being constructed. It will visualize thick objects(>10 µm) in nanometer resolution. Quantum coherenceof the ultraslow muon beam, and deep-penetration
power of the muon beam accelerated over 5 MeV provide it with the necessary capabilities. In this fiscal year,
we have constructed a 5 MeV AVF-type muon-cyclotron(see Fig. 1) using flat-top RF acceleration.
2. 3D magnetic field measurement and shimming of
the cyclotron magnet
The cyclotron should have quite small energy dispersion (ΔE/E~10–5) to reduce the chromatic aberrationof the microscope. The magnet of the cyclotron should
give us the precisely designed magnetic field, and thediscrepancy should be reduced to the order of 10 –5.
We have developed a 3D measurement system of themagnetic field, which uses a search coil (see Fig. 2). We
iteratively tuned the magnet by iron-shims of 184-pieces with 0.1 mm precision after the field measurements.
Finally, the expected energy dispersion simulated basedon the final field-measurement became ΔE/E ~ 6 × 10–5.
3. RF Cavities of the cyclotron
Two main RF-cavities of 108 MHz (main Dee) and aflat-top RF-cavity of 324 MHz (flat top Dee) for muon-cyclotron are being designed and constructed (see Fig. 3).
4. RF Power Amplifier
The cyclotron requires CW 108 MHz RF of 12−20 kW
to accelerate the muon beam to 5 MeV energy. It also
requires CW 324 MHz RF less than 1 kW for flat-top acceleration. The controlling system of the RFs is describedin Fig. 4. The main RF is generated by combining 16 RFamplifiers of 1.5 kW (Fig. 5 right-up) by using a 16-way
RF-combiner (Fig. 5 center).

Figure 1. Muon-cyclotron (left) and its inside.

Figure 2. Search Coil (left) and iron-shims.

Figure 4. Block Diagram of the RF System.
Coaxial Tube

Monitor

1.5kW RF Ampliﬁre
RF Combiner
Tuner

RF-Power Input（WX-77D）

Ampliﬁers
ComplexAmpliﬁers
Complexes
RF- Isolator

Figure 3.	Design of the main Dees (left), RF fields by simulation (right-up) and the constructed body of themain Dee (right-down).

Figure 5. 108 MHz, 20 kW RF Amplifier System.

Y. Nagatani1,2, T. Yamazaki1,2, J. Ohnishi3, A. Goto2, T. Yuasa1,2, S. K. Dey1,2, T. Adachi1,2, and Y. Ikedo1,2Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK; 3Nishina Center, RIKEN

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MLF Annual Report 2020

The Progress of the Laser System for Ultralow Muon
Generation
1. Introduction
The Lyman-α laser system for the ultra-slow muon
generation is operating stably. In order to increase theoutput laser pulse energy, several kinds of laser gain
medium for an additional laser amplifier are being
developed.
2. Laser System for Ultra Slow Muon Generation
Ultra-slow muons can be generated by resonant
optical ionization of thermal muonium from hot-W foil
target. Light pulses of 122.09 nm and 355 nm are required for 1s to 2p state excitation and 2p to ionization,
respectively. The high-energy pulsed coherent Lyman-α
light (122.09 nm) source is one of the most important elements for the efficient generation of ultra-slow muons.
The design of the Lyman-α light source system is
described in Ref. 1 and a schematic of the light sourceis shown in Fig.1. Lyman-α pulse of more than 10 µJ
is stably generated in a krypton/argon mixture filled
gas-cell by the method of two-photon-resonant fourwave-mixing. This method requires 212.556 nm and820 nm pulses. These pulses are generated by nonlinear wavelength conversions of a 100 mJ 1062.78 nm
pulse which is obtained by Nd:YGAG (1 at.% Nd doped
Y3Ga2Al3O15) ceramic laser amplifiers. We intended toobtain 1 J level 1062.78 nm pulse in the initial designof the amplifiers’ system, but there was a problem in alarge-aperture laser medium (>10 mm diameter) for the
final amplifiers. The fabrication of ceramic as a gain medium is very difficult due to the nature of Gallium in the
Nd:YGAG. In order to overcome the difficulties, we havedeveloped Nd:YSAG (1 at.% Nd doped Y3Sc2Al3O15)
ceramic and optimized the composition ratio between
Scandium and Aluminum which was reported in thelast year’s MSL progress report. Newly fabricated middle
size (ø9 mm, 112 mm long) Nd:YSAG(1 at.% Nd doped
Y3Sc1.5Al3.5O15) ceramic was delivered and inspectedin the property of amplification gain at 1062.78 nm lightand wavefront distortion. The amplification gain was
satisfactory, but the transmitted wavefront distortion
was still present, and the collapsed beam shape by the
wavefront distortion caused the reduction of the wavelength conversion efficiency in the subsequent stages.
The measured wavefront distortion is shown in Fig. 2.
3. Wavefront compensation
In order to compensate for the transmitted wavefront distortion inside the Nd:YSAG ceramic, we introduced an active deformable mirror. The deformablemirror was introduced with Shack-Hartmann wavefront
sensor that placed before and after the amplifier, respectively, as shown in Fig. 3. While a deformable mirror cancompensate for wavefront distortion, it can also focus
the high-power laser beam to an arbitrary position in
the laser system if it malfunctions, which can easily destroy not only exchangeable optical components but
also expensive nonlinear crystals. Therefore, a preliminary wavefront compensation using a nearly practical
optical configuration and a He-Ne laser was used toevaluate the performance. Initially, the wavefront of the
optical system was measured without the laser ceramic
and with a flat mirror in place of the deformable mirror.

Figure 1. Schematic of the Lyman-α laser system for the Ultra-slow muon
generation.

148

Figure 2.	The measured wavefront distortion in newly fabricated Nd:YSAG
ceramic for the final amplifier.

MLF Annual Report 2020

Next, the flat mirror was replaced by a deformable mirror and the wavefront was measured. Finally, the wavefront of the entire optical system was measured after
inserting the laser ceramic into the optical path. The distorted wavefront was compensated to a plane wave byadaptively applying and controlling the voltage of eachpiezoelectric element of the 40-segment deformablemirror. The measured wavefront of every step is shown

Figure 3.	The experimental setup of the final amplifier and wavefront compensation system by a deformable mirror
with wavefront sensor.

Figure 4(a). The measured initial optical system wavefront
with a flat mirror.

Figure 4(b). The measured wavefront with a deformable mirror.

Muon Sciencein Figs. 4(a)−(d).
It was shown that the wavefront distortion causedby the laser ceramic can be compensated to a plane
wave using a deformable mirror. The method obtainedby these studies will be applied to a practical laser system to implement the enhancement of the Lyman-α
optical intensity.

Figure 4(c). The measured wavefront with a deformable mirror and a laser ceramic.

Figure 4(d). The measured wavefront after compensation.

Reference[1] N. Saito et. al., Opt. Express 24, 7566-7574 (2016).

Y. Oishi1,21Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK

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MLF Annual Report 2020

H-Line Construction – Recent Progress
The H-line is a new beamline under construction in
the east #1 experimental hall of the MLF. Its layout drawing is shown in Fig. 1. It is a general-purpose beamline[1] that can generate both decay and surface muons andhas two branches named H1- and H2-area. Its design intensity of surface muons reaches 108 muons/s with aproton beam power of 1 MW thanks to a large acceptance (108 mSr) capture solenoid and other beamline
magnets with large apertures.
At the H-line, precision measurements such as thehyperfine splitting measurement of muonium (MuSEUM
experiment) [2] and the muon g-2/EDM experiment [3]are planned. Its intense beam is also suited to search
for a rare process such as cLFV (charged Lepton Flavor
Violation), which is forbidden in the Standard Model ofparticle physics (DeeMe experiment [4]). In addition, atransmission muon microscope (TμM) project, whichenables us to observe thick samples non-destructively,is planned for the H2 area.
The construction of the H-line started in FY2012 andprogressed intermittently. Its front-end devices, suchas the capture solenoid, were installed in FY2012 andFY2014. Its radiation shields and beam blockers were installed in FY2016. From FY2017 to FY2019, a new electric
substation for the H-line was constructed.
In FY2020, the core part and the first branch (H1Figure 1. A layout drawing of the H-line.

150area) of the H-line were constructed. The construction
was the minimum required to deliver muons to the H1area and enable us to start beam commissioning. All
vacuum apparatuses were connected (see Fig. 2), electrical cabling and cooling water piping for two bending
magnets (HB1 and HB2) were conducted, and a safety
interlock system was implemented and combined withthe whole MLF system. Though the capture solenoid(HS1), transportation solenoids (HS2 and HS3), focusing
quadrupole triplets, and a DC-separator are not available yet, the rate of surface muons is expected to be
6 × 105 muons/s. In the next summer shutdown, we plan
to conduct the remaining works, such as electrical cabling and cooling water piping of all magnets, and theinstallation of a DC separator and beam slits, and thenthe design intensity of 108 muons/s will be achieved.
The preparation for the second branch of the H-line(H2 area) also progressed. An extension building must
be built for the H2 area on the east side of the MLF, wherea parking lot is located because the muon g-2/EDM experiment planned at the H2 area needs to acceleratemuons up to 212 MeV using a linac of about 50 m. In
FY2020, the design of the extension building was detailed, and geotechnical investigation (Fig. 3) and buried
cultural property research of the construction site wereconducted.

Figure 2.	All vacuum apparatuses for the first branchof the H-line were connected during thesummer shutdown in FY2020.

MLF Annual Report 2020

Muon Science

Figure 3.	Geotechnical investigation of the construction siteof the extension building for the H2 area.

References[1] N. Kawamura, et al., Prog. Theor. Exp. Phys. 2018,
113G01 (2018).
[2] K. Shimomura, AIP conf. proc. 1382, 245 (2011).
[3] T. Mibe, et al., Chin. Phys. C 34, 745 (2010).
[4] H. Natori, et al., Nucl. Phys. B (Proc. Suppl.) 248-250,
52 (2014).

T. Yamazaki1,2 and N. Kawamura1,2
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, Institute of Material Structure
Science, KEK

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MLF Annual Report 2020

Radiological license upgrade
The applications for radiological license upgrades in
FY2020 were approved on April 28, 2020.
The following items were updated after the application approval in FY2020:(1) Construction of High momentum decay muon instrument (H-line).
(2) Change of Accelerator experimental room followed by the construction of H-line.
(3) Extension of Surface muon instrument (S-line).
2. Chemical safety
This year, due to space limitations, only statisticsof the chemical safety check are shown in Fig. 1. Their
number decreased due to the effect of the COVID-19
pandemic.
3. Crane safety
Also, this year, due to space limitations, only statistics of the crane usage are shown in Fig. 2. The usage
was not affected by the COVID-19 pandemic.

154

8000
6000
4000
2000

20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18
20
19
20
20

0

Year

Figure 1.	Trend of the amount of user-brought chemical materials for chemical safety check from the start of
the MLF operation to the last year.

25
Number of crane usage

1. Radiation safety
Radiation safety for users and increase of radio-activatedsamples
The low-surface contamination area that has been
adopted at the MLF experimental halls from November
2016 is essential for avoiding surface-contamination
problems caused by a sample, an environmental atmosphere, and so on. Several experiments with gaseous or
liquid samples or atmospheres have been conducted at
the MLF, showing that it was useful to expand the flexibility of the experiments.
On the other hand, as the proton beam power increases, neutron flux proportionally rises, resulting inhigher radioactivity in the sample. The MLF radiation
team, in cooperation with CROSS, supports user experiments by measuring radio-activated samples and devices with Ge detectors. Co-60 (T1/2 = 5.271 y) and Mn-54(T1/2 = 312.1 d) as radio-activated ferrous samples are themain contributors. Ag-110 m (T1/2 = 249.8 d) and Ta-182(T1/2=114.4 d) are also usually found in radio-activatedsamples. Characteristics of these radio-active nuclides
are the large reaction cross section and long lifetime.
The easily activated nuclides should be avoided if thesample needs to be brought from the MLF.

Number of chemical materials

Research Safety

in-house staff
constructor

20
15
10
5
0

4

5

6

7

8

9 10 11 12 1
Month

2

3

Figure 2. Trend of the total crane usage in one year.

4. COVID-19 pandemic measures(1) General overview
The MLF division handled the COVID-19 pandemic
under the guidelines of the JAEA and KEK measures. On
March 1, the first COVID-19 infection occurred in Ibaraki
prefecture, where Tokai-mura is located. After that, thenumber of infected persons gradually increased up toaround 10 per day in the early April, so, on April 8, theMLF division decided to stop the users from coming to
the MLF facility. Then, on April 20, J-PARC stopped all
operations. In the case of the MLF, the operation was restarted on May 15, and the user access was restored on
May 22, under the conditions of the individual measures
mentioned below. As a result, there were no COVID-19
infections among the users and the pandemic did notaffect the operation.

MLF Annual Report 2020(2) Individual measures
First, when users came to the Users Office (U.O.),
their physical condition and behavioral history werechecked with interview sheets, behavioral history charts,
health management charts, and contact person lists.
The basic measures for COVID-19 in the MLF arehealth check and avoidance of the following “Three Cs’’:
1. Closed spaces with poor ventilation.
2. Crowded places with many people nearby.
3. Close-contact settings, such as close-range conversations. Other actions included disinfection of the common areas, dissemination of information, and posting
posters about COVID-19. Figure 3 shows various measures as a record for posterity.

(a)

(c)

(e)

MLF Safety

(g)

(h)

(i)

(j)

(k)

(b)

(d)

Figure 3.	Various measures for COVID-19, (a) automatic alcohol atomizer at the entrance of radiation-controlledarea, (b) non-contact infrared forehead thermometer at the entrance of the radiation-controlled area,(c) access record book in the radiation-controlledarea, (d) non-contact trash can, (e) users’ own shoes
for the radiation-controlled area, (f) collection
box of used shoes for the radiation controlled area,(g) air cleaner in a cabin, (h), (i) UV locker for yellow
robe for the radiation-controlled area in the experimental preparation room No. 3, ( j) an example ofa disinfection location: tables at the MLF entrance
lobby, (k) an example of a disinfection location:
doorknob in the radiation controlled area.

(f )M. Harada1, M. Ooi1, M. Sekijima1, K. Kawakami2, K. Aizawa2, A. Hori2, H. Tanaka2, W. Kambara2, M. Sawabe2, K. Suzuya3,
N. Kawamura4, Y. Sakaguchi5, R. Takahashi2, Y. Yamaguchi5, and K. Soyama6
1
Neutron Source Section, Materials and Life Science Division, J-PARC Center, 2Technology Development Section, Materials and Life Science
Division, J-PARC Center, 3Neutron Science Section, Materials and Life Science Division, J-PARC Center, 4Muon Science Section, Materials
and Life Science Division, J-PARC Center, 5Neutron Science and Technology Center, CROSS, 6Materials and Life Science Division

155

MLF Operations in 2020

MLF Operations in 2020

MLF Annual Report 2020

Beam Operation Status at the MLF
1. Overall
In Japanese Fiscal Year (JFY) 2020, the beam operation at the MLF started on April 1, 2020 and ended on
March 31, 2021. In JFY2020, the beam operation started
with a power of 500 kW with a double-bunch beam.
After May 18, the beam power was increased from500 kW to 600 kW. For tuning the accelerator and theproton beam transport, the user beam operation was interrupted for 1 hour on May 18 morning. Table 1 shows
the scheduled time and availability in JFY2020. In theschedule, the beam period of 2020A switched to 2020B
on November 30. The records of the beam power andthe availability are shown in Fig. 1. A long uninterrupted
work period of 3,121 h was attained in JFY2020.
Due to the COVID-19 situation, the beam operation
at the J-PARC was stopped from April 20 to May 14. The
duration of the beam operation loss was 262 hours. The
beam stop duration due to the COVID-19 was excluded
from the beam operational schedule to evaluate theavailability. Fortunately, the beam stop caused by the
COVID-19 had less influence on the operation because

we had planned to stop the operation during the national holidays from the end of April to the beginningof May.
As shown in Table 1, a stable beam operation with
a 93% availability was maintained from April 1 to June
27, just before the summer outage. A high-intensity
beam operation for users was carried out. To minimize
the negative influence on the users’ program caused bypotential target failure, we made it before the summer
outage period. In the last year, the high-intensity demonstration was achieved without any radiation issues,and the radiation safety group granted permission forthe operation with a beam power of ~1 MW. Despitesome failures at RCS, a successful high-intensity beam
operational with 920 kW was accomplished with a fairy
high beam availability of 69.6% for 3 days from June
25 to 27. It should be noted that the allowable highintensity beam power is limited to ~920 kW because wemust have a safety margin of the beam power against
the beam power of 1 MW authorized by the radiation
license. The personnel protection system (PPS) is limited

Table 1. Run cycle, scheduled time, actual beam time, and availability.
Run cycle

Duration

Scheduled time (h)Beam time (h)Avilability (%)

85
86
2020A
2020B
Overall

Apr 1 – Jun 27
Nov 9 – Dec 22
Apr 1 – Dec 12
Dec 13 – Mar 31
Apr 1 – Mar 31

1,337
2,587
2,031
1,893
3,924

1,244
1,884
1,465
1,662
3,127

93.0
72.8
72.2
87.8
79.7

Figure 1. Beam power trend (blue line) at the MLF and availability per day (red line).

158

MLF Annual Report 2020

MLF Operations in 2020

Table 2. Events that stopped the beam and reduced the daily availability to less than 80%.
Stop date
Apr 20 - May 1 andMay 11 – May 14
May 22
May 26
June 25
Nov 9 – Dec 1
Jan 14January 14 – January 15
Jan 22 – Jan 27
Feb 14
February 18

Cause of beam stop

Stop durationfor each event [h]COVID-19

262.0

RCS RF power supply failure for RF2
3NBT power supply failure for B1U
RCS RF power supply failure for RF3 and RF8Delay of mercury target vessel replacement
RCS kicker magnet power supply failure for KM5
LINAC klystron failure at HV4 for SDTL 9 to 12
3NBT water pump annomaly at 20 system
LINAC klystron failure at HV9 for ACS 9 to 12
RCS charge exchange foil failure

10.4
13.2
7.0
456.2
11.6
7.0
141.0
14.0
3.9

to a beam power of 950 kW, which automatically stops
the beam at the ion source when the power exceeds thelimit. Another safety margin of 3% limits is required forthe actual beam operation. To increase the beam power,
the safety margin or the license must be changed.
After the summer outage period, the beam operation was planned to be resumed on November 9. Due tothe failure of the target replacement, we failed to resume
as scheduled. The spent target #9 had been planned tobe replaced with new target #13. During replacement,
mismatch position was found at the water coolingflange of target #13. Instead of target #13, another new
target, #10, was used. The second replacement took along time. As a matter of fact, the delay of the target
replacement made the most impact on the overall availability in JFY2020. After the outage, the beam operation
was resumed on December 6. Eventually, the overall
availability in JFY2020 was 79.7%.
The beam operation was stopped on several occasions due to minor failures. Typical causes of the beamstop with daily availability of less than 80% are summarized in Table 2 and described below.
2. Causes of the beam stop
LINAC:
During JFY2020, there were no shortages of waterflow for the magnet at LINAC, which had been the main
reason for beam stops so far. In JFY2020, we had two
failures on the klystron providing the RF to the cavities.
3 GeV Rapid Cycling Synchrotron (RCS):
During the high-intensity operation from June 25
to 27, failures of power supplies of Radio Frequency(RF) cavities occurred due to insufficient cooling power
for the RF at RCS. The failure of the power supplies is
not considered directly related to the beam power. We
expect the cooling power to be improved by clearing
the heat exchanger for the RF cooling water system.
Except in the high-intensity operation, the power supplies for the RF cavities failed on two other occasions.
Also, failures of the kicker magnet power supply and of
the charge exchange foil introducing the H- beam from
LINAC to RCS also occurred.
Beam transport from RCS to the MLF (3NBT)
An anomaly was detected at the vibrator of the water pump for the 20 system on January 16. The 20 system serves the cooling water to the magnets and thebeam scraper placed around at the muon production
target. Because the water in the system was highly contaminated, mainly by tritium, it was difficult to replacequickly the pump with the new one. By changing thewater pressure at the exit of the pump to sustain theflow, the vibration was decreased to be at the allowed
level. It should be noted that the pump violation wasrectified within a few days. When the anomaly happened, it was difficult to estimate the recovery period.
Therefore, a longer than the expected stop period wasannounced to users, which affected the duration of thebeam period.
Last summer, all clamps, vulnerable to cracking
used for the coupler for the vacuum duct’s flanges, were
exchanged for robust ones. As a result, in JFY2020, thebeam did not stop due to cracked clamps, which happened frequently in the past.

S. Meigo
Neutron Source Section, Materials and Life Science Division, J-PARC Center

159

MLF Operations in 2020

MLF Annual Report 2020

Users at the MLF
In fiscal year (FY) 2020, the MLF was running stably with a beam power of 600 kW throughout the year,
except for the first three weeks from April 1, when theoperation ran at 500 kW. Due to the COVID-19 situation, the overall availability in JFY2020 was decreased
to 79.7%. In addition, before the summer maintenanceperiod, the 920 kW beam test was successfully operated

from June 25 to 27, 2020, with a remarkably high beam
delivery. The total number of users of the neutron andmuon experimental facilities in FY2020 was 581, a decrease compared with FY2019, due to COVID-19.
The trend for the number of users at the MLF since
the start of the operations in FY2008 is summarized inTable 1 and Fig. 1.

Table 1. The number of domestic and foreign users by fiscal year.

105

FY2008FY2009FY2010FY2011FY2012FY2013

FY2014

Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Neutron
Muon

107
95

317
12

303

0

38

18

476
14

432

2

42

40

18
FY2015

259
44

238

8

21

50

FY2016

708
21

628

2

46

23

FY2017

449
80

399

10

50

56

FY2018

824
50

711

11

78

61

FY2019

Muon

559
476

852
83

744

10

83

69
59

927
108

742

16

149

99

965
185

789

30

146

179

176

827

15

127

161

448

11

88

138

Neutron (Japanese)

Neutron (Foreigners)

Muon (Japanese)

Muon (Foreigners)

30

489
113

15

41
92

30

1050

4

15
11
146

16

149

127

13

900

83

78
10
46

750

10

600
8
42
44

450

300

2
38
14

150

303

59

4

83

88

50
50

41
744

711

432
18
12
95

11

2
21
21

113

185
108

113

80

176

742

789

827

628
399

476

448

238

0
FY2008 FY2009 FY2010 FY2011 FY2012 FY2013 FY2014 FY2015 FY2016 FY2017 FY2018 FY2019 FY2020

Figure 1. The number of domestic and foreign users by fiscal year.

160

60

13

45

FY2020

940

75

113
91

Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Neutron90

MLF Annual Report 2020

MLF Operations in 2020

MLF Proposals Summary – FY2020
Due to the COVID-19 situation, 2020B and 2021A were combined into one proposal round. The experiment period for the proposals
for “2020B+2021A” was from December 2020 to July 2021. Therefore, the proposals for 2021A are included in the FY2020 data as theycannot be counted separately.

Table 1. Breakdown of Proposals Numbers for the 2020 Rounds.
Beamline

2020A
Instrument

Full Year

Submitted Approved Submitted Approved Submitted Approved

BL01 4D-Space Access Neutron Spectrometer - 4SEASONS
BL02 Biomolecular Dynamics Spectrometer - DNA
BL03 IBARAKI Biological Crystal Diffractometer - iBIX
BL04

2020B+2021A(100−β)(β)‡†

Accurate Neutron-Nucleus Reaction Measurement Instrument ANNRI

BL05 Neutron Optics and Physics - NOP

GU

GU

GU

GU

PU/S

IU

PU/S

IU

25(0)

10(0)

31(0)

11(0)

0

1

0

1

24(0)

5(0)

36(2)

15(1)

2

2

2

2

0

0

3

3

0

0

0

0

0

0

0

0

48

0

47

5

4

11

5

1

1

1

1

2

2

4

4

1

0

1

0

※

※

0

BL06 Village of Neutron Resonance Spin Echo Spectrometers - VIN ROSE

1

1

7

4

1

0

1

0

BL08 Super High Resolution Powder Diffractometer - Super HRPD

13

8

19

11

1

0

1

0

BL09 Special Environment Powder Diffractometer - SPICA

2

2

1

1

1

0

1

0

BL10 Neutron Beamline for Observation and Research Use - NOBORU

10

7

15

10

3

1

3

1

BL11 High-Pressure Neutron Diffractometer - PLANET

21(0)

15(0)

14(0)

12(0)

0

1

0

1

BL12 High Resolution Chopper Spectrometer - HRC

5

4

11

8

1

0

1

0

BL14 Cold-Neutron Disk-Chopper Spectrometer - AMATERAS

25

8

36

7

3

1

3

1

BL15 Small and Wide Angle Neutron Scattering Instrument - TAIKAN

35(0)

15(0)

50(2)

20(2)

2

3

2

3

BL16 Soft Interface Analyzer - SOFIA

14

14

29

25

0

1

0

1

BL17 Polarized Neutron Reflectometer - SHARAKU

18(2)

11(1)

20(1)

14(1)

2

3

2

3

BL18 Extreme Environment Single Crystal Neutron Diffractometer - SENJU

18(0)

9(0)

28(0)

10(0)

1

1

1

1

BL19 Engineering Materials Diffractometer - TAKUMI

14

11

31

21

1

1

1

1

9

6

8

6

0

0

0

0

26

26

36

36

22

0

22

0

BL20 IBARAKI Materials Design Diffractometer - iMATERIA(100−β)(β)‡†

BL21 High Intensity Total Diffractometer - NOVA

25

19

20

10

1

0

1

0

BL22 Energy Resolved Neutron Imaging System - RADEN

10(0)

10(0)

24(0)

16(0)

2

3

2

3

BL23 Polarized Neutron Spectrometer - POLANO

1

1

2

2

1

0

1

0

D1

Muon Spectrometer for Materials and Life Science Experiments - D1

15(0)

6(0)

20(0)

12(0)

1

1

1

1

D2

Muon Spectrometer for Basic Science Experiments - D2

3(1)

3(1)

8(0)

4(0)

1

1

1

1

S1

General purpose µSR spectrometer - ARTEMIS

22(2)

16(2)

46(0)

24(0)

1

1

1

1

U1A Ultra Slow Muon Microscope - U1A

0

0

0

0

0

1

0

1

U1B Transmission Muon Microscope - U1B

0

0

0

0

0

1

0

1

343

213

509

290

87

24

86

24

Total

GU : General Use
PU : Project Use or Ibaraki Pref. Project Use
S : S-type Proposals
IU : Instrument Group Use‡ : J-PARC Center General Use Beamtime (100−β = 20% in FY2020)† : baraki Pref. Exclusive Use Beamtime (β = 80% in FY2020)( ) : Proposal Numbers under the New User Promotion (BL01, BL02, BL11, BL15, BL17, BL18, BL22) or P-type proposals (D1,D2, S1) in GU※ : Proposal rounds are held twice per year (for each of the A and B periods), with only the yearly total shown above.
The actual total number of proposals in each beamline named in the table does not match the number shown in the “Total” cell,because some proposals are submitted or approved across multiple beamlines.

Table 2.	Proposals Numbers of Long Term Proposal for the 2020 Rounds.
Application FY

Submitted

Approved

2018

9

5

2019

9

4

2020

13

3

161

MLF Operations in 2020

MLF Annual Report 2020

Figure 1. MLF Proposal Numbers over Time.

Figure 2. Origin of Submitted Proposals by affiliation - FY2020 (2020A, 2020B + 2021A).

)

Figure 3. Submitted Proposals by Sub-committee/Expert Panel - FY2020 (2020A, 2020B + 2021A).

162

MLF Operations in 2020

MLF Annual Report 2020

MLF Division Staff 2020
Toshiya Otomo (Head)

Eiichi Wakai

Kazuya Aizawa (Deputy Head)

Izumi Kuwahara

Kenji Nakajima (Deputy Head)
Koichiro Shimomura (Deputy Head)

Neutron Source Section

*: additional duties<JAEA>
Katsuhiro Haga (Leader)

Shiho Masuda

Hiromi Inoue

Kenji Sakai (Sub-Leader)

Yuji Yamaguchi

Noriyuki Morikawa

Makoto Teshigawara

Toshiaki Uehara

Shigeto Tanaka

Masahide Harada

Akihiko Watanabe

Shizuka Yoshinari

Tomokazu Aso

Hideki Muto

Rie Nemoto

Hiroyuki Kogawa

Akiyoshi Futakawa

Hiroshi Takada *Hidetaka Kinoshita

Mitsuaki Sekijima

Shoichi Hasegawa *Takashi Wakui

Yoshinori Kikuchi

Eiichi Wakai *Motoki Ooi

Masakazu Nakamura

Shin-ichiro Meigo *Takashi Naoe

Hidemitsu Hosokawa

Kenichi Oikawa *Masakazu Seki

Atsushi Akutsu

Tetsuya Kai *Akira Shibata

Toshiyuki Yasuhara

Hiroyuki Uehara *Neutron Science Section

*: additional duties<JAEA>
Yukinobu Kawakita (Leader)

Maiko Kofu

Itaru Tamura *Mitsutaka Nakamura (Sub-Leader)

Kousuke Hiroi

Kouji Kaneko *Kentaro Suzuya

Naoki Murai

Hiroshi Nakagawa *Ryoichi Kajimoto

Hiromu Tamatsukuri

Atsushi Moriai *Takanori Hattori

Yusuke Tsuchikawa

Satoshi Morooka *Stefanus Harjo

Kanae Ito

Atsushi Kimura *Kenichi Oikawa

Kazuhisa Isegawa

Shoji Nakamura *Takashi Ohhara

Shigeki Uzuki

Shunsuke Endo *Takenao Shinohara

Hiroyuki Dannoshita

Yosuke Toh *Hiroyuki Aoki

Tatsuya Kikuchi

Mariko Segawa *Tetsuya Kai

Masashi Harada

Masahide Harada *Seiko Kawamura

Daigo Setoyama

Masao Watanabe *Shinichi Takata

Takeshi Harada

Dai Yamazaki *Ryoji Kiyanagi

Hideaki Isozaki

Kazuo Kurihara *Kaoru Shibata

Keiichi Inoue

Tarou Tamada *Asami Sano

Misono Fujii

Yuu Hirano *Yasuhiro Inamura

Naoko Shimizu

Takeshi Hiromoto *Takuro Kawasaki

Toshiko Goto

Fumiaki Kono *163

MLF Operations in 2020

MLF Annual Report 2020

<KEK>
Testuya Yokoo (Sub-Leader)Takashi Honda

Kazutaka Ikeda

Shinichi Ito

Naokatsu Kaneko

Masato Hagihala

Hideki Seto

Shuki Torii

Takashi Saito

Toshiya Otomo *Hidetoshi Oshita

Kwanghee CHO

Takashi Kamiyama

Kaoru Taketani

Sara Yamauchi

Hitoshi Endo

Kenji Mishima

Taichi Ueta

Takashi Ino

Hiroyuki Aoki *Go Ichikawa

Norifumi Yamada

Asami Sano *Technology Development Section

*: additional duties<JAEA>
Takayuki Oku (Leader)

Wu Gong

Kaoru Sakasai *Kazuyoshi Tatsumi

Kazuhiro kawakami

Tatsuya Nakamura *Takeshi Nakatani

Hiromichi Tanaka

Yasuhiro Inamura *Masao Watanabe

Hiroyuki Asai

Masahide Harada *Yuhua Su

Yukiko Nagai

Tomokazu Aso *Ryota Komine

Kenji Sakai *Seiko Kawamura *Takuya Okudaira

Tetsuya Kai *Rumi Shimizu *The Dang Vu

Hiroyuki Kogawa *Satoru Fujiwara *Wataru Kambara

Motoki Ooi *Motoyasu Adachi *Akihiro Hori

Kentaro Suzuya *Shigeki Arai *Hideaki Takahashi

Mitsutaka Nakamura *Chie Shibazaki *Ryuta Takahashi

Shinichi Takata *<KEK>
Tomohiro Seya

Takashi Ino *Hiroshi Fujimori *Setsuo Sato

Naokatsu Kaneko *Shunsuke Makimura *Testuya Yokoo *Kaoru Taketani *Shuki Torii *Naritoshi Kawamura *Neutron Instrumentation Section

*: additional duties<JAEA>

164

Kaoru Sakasai (Leader)

Tatsuya Nakamura

Yukio Hishinuma

Dai Yamazaki

Ryuji Maruyama

Yukiko Uno

Kentaro Toh

Tomokatsu Koizumi

MLF Operations in 2020

MLF Annual Report 2020

Muon Science Section

*: additional duties<KEK>
Ryosuke Kadono (Leader)

Yasuhiro Miyake

Motonobu Tanpo

Naritoshi Kawamura (Sub-Leader)

Yu OishiTaihei Adachi

Koichiro Shimomura *Yukinori Nagatani

Amba Datt Pant

Akihiro Koda

Shiro Matoba

Tatsuhiko Tachibana

Patrick Strasser

Soshi Takeshita

Hua LiTakayuki Yamazaki

Hiroaki Natori

Shogo Doiuchi

Sotaro Kanda

Shoichiro Nisimura

Akiko Hashimoto

Yutaka Ikedo

Sourav Kumar Dey

Yoshinori Ito

Yasuo Kobayashi

Hiroshi Fujimori

Izumi Umegaki

Junpei Nakamura

Masatoshi Hiraishi

Takashiro Yuasa

Hirotaka Okabe<JAEA>
Wataru Higemoto *Takashi Ito *165

MLF Operations in 2020

MLF Annual Report 2020

CROSS Staff 2020
Director

Mitsuhiro Shibayama

Science Coordinators

*: additional duties

Shamoto Shinichi

Takashi Noma *Kazuhisa Kakurai

Jun Sugiyama

Hibi Masaaki

Midori Kamimura

Research & Development Division*: additional duties

Jun-ichi Suzuki (Head)<BL15 Group><Technical Support Group>

Kenichi Funakoshi (Deputy Head)

Kazuki Ohishi (Leader)

Takayoshi Ito (Leader)

Tsukasa Miyazaki * (Deputy Head)

Jun-ichi Suzuki *Koji Kiriyama * (Sub-Leader)

Hiroki Iwase

Keiichi Ohuchi

Yukihiko Kawamura

Masae Sahara<BL01 Group>

Yoshihiko Honda

Kazuya Kamazawa (Leader)
Kazuki Iida

<BL17 Group>

Yoshifumi Sakaguchi

Kazuhiko Ikeuchi

Noboru Miyata (Leader)

Hiroshi Kira

Kazuhiro Akutsu

Motoyuki Ishikado

Takayasu Hanashima

Shuoyuan Zhang<BL02 Group>

Toshiaki Morikawa

Masato Matsuura (Leader)Takeshi Yamada<BL18 Group>

Hiroshi Arima

Taiki Tominaga

Akiko Nakao (Leader)

Nobuo Okazaki

Koji Munakata

Satoshi Kasai

Yoshihisa Ishikawa

Kentaro Moriyama<BL11 Group>
Kenichi Funakoshi * (Leader)
Jun Abe<BL22 Group>

Shinichi Machida

Hirotoshi Hayashida (Leader)
Joseph Don Parker
Yoshihiro Matsumoto

Safety Division

166*: additional duties

Mitsuhiro Shibayama * (Head)

Tazuko Mizusawa *Koji Kiriyama (Leader)

Masae Sahara *Yasuhiro YamaguchiMLF Operations in 2020

MLF Annual Report 2020

Utilization Promotion Division*: additional duties

Takashi Noma (Head)

Miho Igarashi

Nobuo Okazaki *Tsukasa Miyazaki * (Deputy Head)

Atsuko Irie

Rie Kurosawa *Seiya Konishi (Leader)

Kaoru Ohuchi

Taeko Ishikawa

Toshiki Asai (Leader)

Emi Goto

Maya Endo

Junichi Sato (Leader)

Tazuko Mizusawa

Hideyuki Niitsuma

Takayoshi Ito *Tomoko Ishikawa

Administration Division
Michihiko Murasawa (Head)

Rei ItoMutsumi Shiraishi

Takashi Hikita (Leader)

Tomoko Sakuma

Shinobu Matsumoto

Industrial Collaboration Promotion Division*: additional duties

Tsukasa Miyazaki (Head)

Noboru Miyata *Yoshihiro Matsumoto *Takashi Noma *Jun Abe *Hiroki Iwase *Seiya Konishi *Takeshi Yamada *167

MLF Operations in 2020

MLF Annual Report 2020

Ibaraki Neutron Beamline Staff in 2020

Ibaraki Prefectural Government<Senior Director for Neutron Promotion><Neutron Beamline Coordinator>

Hironori Kodama

Michiko Konno
Tetsuroh Minemura

Ibaraki University ** Trustee of the Beamline operations<BL03 iBIX Group><BL20 iMATERIA Group><Technical Support Group>

Katsuhiro Kusaka (Leader)

Toru Ishigaki (Leader)

Junichi Hiroki

Taro Yamada

Satoshi Koizumi

Tomoyuki Nakazawa

Naomine Yano

Akinori Hoshikawa

Mitsuyuki Fujii

Ichiro Tanaka

Shigeo Sato

Shinju Shibata

Takaaki Hosoya

Yusuke Onuki

Takumi Inada

Yohei Noda
Tomoki Maeda
Takeshi Matsukawa

168

MLF Operations in 2020

MLF Annual Report 2020

Proposals Review System, Committees and Meetings

Proposal Review System
The JAEA-KEK-CROSS Agreement of Cooperation on the Promotion of Public Utilizationof the Speciﬁc Neutron Beam Facilities at J-PARC (Enacted on 1 April 2011)
President
JAEA

Director General
KEK

J-PARC
Center(JAEA/KEK)

President
CROSS

Collaboration
Committee

Director
J-PARCAll except Public Beamlines

Director
CROSS-Tokai

Registered
Institution(CROSS)

Public Beamlines Only

Selection
Committee

MLF Advisory
Board

Task Forces

Joint Meeting

All except Contract
Beamlines
Muon Instrument
Proposal Rev. Comm.

Muon Science
Proposal Rev. Comm.

All except Public
Beamlines

Public Beamlines Only

Neutron Science
Proposal Rev. Comm.

Proposal
Evaluation Comm.

Contract Beamlines
Only

Neutron Instrument Contract Beamline
Proposal Rev. Comm. Evaluation Comm.
Joint Meeting

Muon
Instrument
Proposals

Joint Meeting

Neutron Instrument
Proposals
Muon Program
Advisory Comm.

Muon Scientiﬁc Proposals

Report the results to J-PARC
and CROSS-Tokai Directors

Public Beamlines Only
All except Public Beamlines
Neutron Program
JAEA Research
CROSS Development
Advisory
Proposal Advisory Proposal Evaluation
Committee
Committee
Panel
Joint Meeting

Neutron Scientiﬁc Proposals

UniﬁedAccess Point

ALL Proposals submitted via the J-PARC Users Oﬃce
Figure 1. Proposals Review System Framework.

169

MLF Operations in 2020 MLF Annual Report 2020

Materials and Life Science Facility Advisory Board

170

Toshiya Otomo

High Energy Accelerator Research
Organization

Yoshiharu Sakurai

Japan Synchrotron Radiation
Research InstituteKazuya Aizawa

Japan Atomic Energy Agency

Hiroshi Amitsuka

Hokkaido University

Taka-hisa Arima

The University of Tokyo

Taku Sato

Tohoku University

Shinich Itoh

High Energy Accelerator Research
Organization

Hideki Seto

High Energy Accelerator Research
Organization

Ryosuke KadonoHigh Energy Accelerator Research
Organization

Koichiro Shimomura

High Energy Accelerator Research
Organization

Kazuhisa Kakurai

Comprehensive Research
Organization for Science and Society

Kazuhiko Soyama

Japan Atomic Energy Agency

Takashi Kamiyama

High Energy Accelerator Research
Organization

Masaaki Sugiyama(chair)

Kyoto University

Takashi Kamiyama

Hokkaido University

Jun-ichi Suzuki

Comprehensive Research
Organization for Science and Society

Yukinobu Kawakita

Japan Atomic Energy Agency

Atsushi Takahara

Kyushu University

Takamitsu Kohzuma

Ibaraki University

Masayasu Takeda

Japan Atomic Energy Agency

Yoji Koike

Tohoku University

Toshio Yamaguchi

Fukuoka University

Kenya Kubo

International Christian University

Osamu Yamamuro

The University of Tokyo

Kenji Nakajima

Japan Atomic Energy Agency

Term: through March 31, 2021

Neutron Science Proposal Review Committee

Jun’ichiro Mizuki

Kwansei Gakuin University

Hiroshi Abe

Kenji Ohoyama

Ibaraki University

Taka-hisa Arima (chair) The University of Tokyo

Toyotaka Osakabe

Japan Atomic Energy Agency

Hiroyuki Kagi

The University of Tokyo

Toshiya Otomo

Ryosuke KadonoHigh Energy Accelerator Research
Organization

High Energy Accelerator Research
Organization

Hideki Seto

Yukinobu Kawakita

Japan Atomic Energy Agency

High Energy Accelerator Research
Organization

Masaaki Kitaguchi

Nagoya University

Naoya Torikai

Mie University

Takatsugu Masuda

The University of Tokyo

Noriyuki Tsuchida

University of Hyogo

Tsukasa Miyazaki

Comprehensive Research
Organization for Science and Society

National Defense Academy of Japan

Term: through September 30, 2021

Muon Science Proposal Review Committee

Katsuya Inoue

Hiroshima University

Tadashi Adachi

Sophia University

Shinichi Itoh

Kenta Amemiya

High Energy Accelerator Research
Organization

High Energy Accelerator Research
Organization

Ryosuke Kadono

Hidehito Asaoka

Japan Atomic Energy Agency

High Energy Accelerator Research
Organization

Toshiyuki Azuma

RIKEN

Yukinobu Kawakita

Japan Atomic Energy Agency

Katsuyuki Fukutani

The University of Tokyo

Naritoshi Kawamura

High Energy Accelerator Research
Organization

Wataru Higemoto

Japan Atomic Energy Agency

Yasushi Kino

Tohoku University

Adrian Hillier

Rutherford Appleton Laboratory

MLF Annual Report 2020

MLF Operations in 2020

Akihiro Koda

High Energy Accelerator Research
Organization

Hideki Seto

High Energy Accelerator Research
Organization

Takamitsu Kohzuma

Ibaraki University

Tatsushi Shima

Osaka University

Kenya Kubo (chair)International Christian University

Koichiro Shimomura

Roderick Macrae

Marian University

High Energy Accelerator Research
Organization

Tsutomu Mibe

High Energy Accelerator Research
Organization

Yoko Sugawara

Kitasato University

Jun Sugiyama

Yasuhiro Miyake

High Energy Accelerator Research
Organization

Comprehensive Research
Organization for Science and Society

Masaaki Sugiyama

Kyoto University

Chihiro OhmoriHigh Energy Accelerator Research
Organization

Toshiya Otomo

High Energy Accelerator Research
Organization

Selection Committee

Toshiyuki Takayanagi Saitama University
Term: through March 31, 2021

Yoshiharu Sakurai

Japan Synchrotron Radiation
Research InstituteTaku Sato

Tohoku University

Masaaki Sugiyama

Kyoto University

Taka-hisa Arima

The University of Tokyo

Yasuhiro Iye (chair)Japan Society for Promotion of
Science

Takashi Kamiyama

Hokkaido University

Atsushi Takahara

Kyushu University

Hiroyuki Kishimoto

Sumitomo Rubber Industries, LTD.

Shinji Tsuneyuki

The University of Tokyo

Hideaki Kitazawa

Research Center for Strategic
Materials

Toshio Yamaguchi

Fukuoka University

Osamu Yamamuro

The University of Tokyo

Yoji Koike

Tohoku University

Takamitsu Kohzuma

Ibaraki University

Term: through March 31, 2021

Proposal Evaluation Committee

Jun’ichiro Mizuki

Kwansei Gakuin University

Hiroshi Abe

Kenji Ohoyama

Ibaraki University

Toshiya Otomo

High Energy Accelerator Research
Organization

Naoya Torikai

Mie University

Noriyuki Tsuchida

University of Hyogo

National Defense Academy of Japan

Taka-hisa Arima (chair) The University of Tokyo
Hiroyuki Kagi

The University of Tokyo

Masaaki Kitaguchi

Nagoya University

Takatsugu Masuda

The University of Tokyo

Tsukasa Miyazaki

Comprehensive Research
Organization for Science and Society

Term: through September 30, 2021

171

MLF Operations in 2020 MLF Annual Report 2020

Neutron Advisory Committee (NAC)
NAC convened online on the 17 and 22 of February 2021.

Screenshot of NAC
Robert McGreevy (chair)

Rutherford Appleton Laboratory

Christiane Alba-Simionesco

Laboratoire Léon Brillouin

Bertrand Blau

Paul Scherrer Institut

Sung-Min Choi

Korea Advanced Institute of Science and Technology

Michael Dayton

Oak Ridge National Laboratory

Yoshiaki Kiyanagi

Nagoya University

Yoshie Ohtake

RIKEN

Christian Rüegg

Paul Scherrer Institut

Andreas Schreyer

European Spallation Source

Jamie Schulz

Australian Nuclear Science and Technology Organization

Masaaki Sugiyama

Kyoto University

Muon Advisory Committee (MAC)
MAC convened online on the 1 and 4 of February 2021.

Screenshots of MAC

172

Thomas Prokscha (chair)

Paul Scherrer Institut

Hiroshi Amitsuka

Hokkaido University

Klaus Kirch

ETH Zurich and Paul Scherrer Institut

Kenya Kubo

International Christian University

Andrew Macfarlane

The University of British Columbia

Martin Månsson

KTH Royal Institute of Technology

Takashi Nakano

Osaka University

Tadayuki Takahashi

The University of Tokyo

MLF Annual Report 2020

MLF Operations in 2020

Workshops, Conferences, Seminars and Schools in 2020

Conferences held jointly by J-PARC MLF and CROSS
2020 Z-Code Beginner Level Training Course
27 Aug.-28 Aug. 2020, Online
MRM2020
7-11 Dec. 2020, Online
2020 Z-Code Intermediate Level Training Course
25 Feb.-31 Mar. 2021, Onlineth

The 7 Workshop on Pulsed Neutron Imaging
Screenshot of CIQuS 研究会(photo courtesy of KEK)

1-2 Mar. 2021, Online
2020 Quantum Beam Science Festathth(The 12 MLF Symposium and the 38 PF Symposium)
9 -11 Mar. 2021, Online

第 3 回文理融合シンポジウム “ 量子ビームで歴史を探る－加速器が紡ぐ文理融合の地平－ ”
25 Sep. 2020, Online
第 4 回文理融合シンポジウム “ 量子ビームで歴史を探る－加速器が紡ぐ文理融合の地平－ ”
28 Jan. 2021, Online

Workshops held by KEK
Fundamental Physics Using Atoms (FPUA 2021)
4–5 Aug. 2021, Online
Screenshot of MLF Symposium(photo courtesy of J-PARC Center)

Analysis of ordered/disordered structure in functional
materials with high intensity neutron total scattering

Conferences held by J-PARC MLF and otherorganizationsrd

The 3 FC-Cubic Open Symposium
2 Feb. 2021, Tokyo International Exchange Center,
J-PARC (Satellite), Online, YouTube

Conferences held by KEK
CIQuS 研究会 “ 無機材料中の水素の存在状態と機能発現 ”
27 Aug. 2020, Online

technique (BL21)
13 Oct. 2020, Online
第 1 回 MCP 討論会
27 Oct. 2020, The University of Tokyo, Kashiwa
Study on slow dynamics by the neutron resonance spinecho spectrometers VIN ROSE (BL06)
25 Nov. 2020, Online
Studies on Dynamics in Condensed Matters by using
the High Resolution Chopper Spectrometer (BL12)25 Nov. 2020, Online

173

MLF Operations in 2020

MLF Annual Report 2020

Workshop on Neutron Powder Diffraction using

Tohoku U x CROSS x JAEA Cooperative Seminar,

SuperHRPD (BL08) and SPICA (BL09)

62 REIMEI Workshop “New excitations for spintronics

30 Nov. 2020, Online

seen with quantum beams”nd

25 Feb. 2021, Online
Study on Cross-correlated Physics by Polarized Neutron
Spectrometer, POLANO (BL23)

Workshop on Metals

1 Dec. 2020, Online“Novel structural analysis of metals by neutron
scattering -focused on light elements in metals-”

Fundamental Physics with Pulsed Cold Neutrons (BL05)

5 Mar. 2021, Online

17–18 Dec. 2020, Online
2020 Workshop on Liquids and Amorphous Materials
第 11 回 Muon 科学と加速器研究
27 Jan. 2021, Online

16 Mar. 2021, Online
2020 Workshop on Neutron Structural Biology

第 2 回 MCP 討論会
31 Mar. 2021, The University of Tokyo, Kashiwa

30 Mar. 2021, Online

Schools in 2020
Workshops and Seminars held by CROSS andother organizations

Hello Science from J-PARC “The Latest Battery Researchat J-PARC for the Innovation of Lithium-ion Batteries”

th

The 24 CROSSroads Workshop

25 Sep. 2020, iVil, Tokai“ 偏極中性子を使った磁性薄膜・多層膜研究 ”
30 Jun., 10 Jul., and 4 Aug. 2020, Online

Hello Science from J-PARC “Looking into Lithium Ion
Battery using J-PARC Negative Muon”
25 Dec. 2020, iVil, Tokai

Screenshot of CROSSroads(photo courtesy of CROSS)
2020 Neutron Experiment Technique Training Course
21 Oct. 2020, Online
Workshop on Organic materials and Polymers“Current status of structural analysis of Organic materials
and Polymers by neutron small-angle scattering”
14 Dec. 2020, Online

174

MLF Annual Report 2020

MLF Operations in 2020

Award List
Dean’s Award, School of Engineering, The Universityof Tokyo
Exploration of quantum transport phenomena via
engineering emergent magnetic fields in topologicalmagnets
Y. Fujishiro (2021-03-19)
第38回高分子学会千葉地域活動若手セミナー
奨励ポスター賞

両親媒性ロフィンダイマーが形成する分子集合体を用いた可The JSNS Technology Prize
Development of Super High-Resolution Powder
Diffractometer, SuperHRPD
S. Torii, K. Oikawa, M. Hagihara , K. Cho, T. Kamiyama(2020-11-09)
The JSNS Science Prize
Characterization of soft matter interfaces using neutronreflectometry
A. Takahara (2020-11-09)

溶化能の高速光制御
田中理紗 (2021-03-02)

Springer Theses
Exploration of quantum transport phenomena via
engineering emergent magnetic fields in topologicalmagnets
Y. Fujishiro (2021-03)
The Tawara Award of the Iron and Steel Institute ofJapan
Analysis of Tensile Deformation Behavior by in situ Neutron
Diffraction Experiments of a 1 GPa-grade TRIP Steel withHigh ElongationAnalysis of Tensile Deformation Behavior
by in situ Neutron Diffraction Experiments of a 1 GPa-grade
TRIP Steel with High Elongation
N. Tsuchida, T. Tanaka, Y. Toji (2021-03)
The JSNS President’s Choice
Localized Magnetic Excitations in the Almost Perfectly
Frustrated Spin Dimer Quantum Magnet
N. Kurita, H. Tanaka (2020-11-10)

The JSNS Outstanding Achievement PrizeContribution to the development of neutron structure
analysis and the development of the Japanese neutronscience community
Y. Noda (2020-11-09)
The JSNS Technology Prize
Proton beam control technology for highintensity pulsed
neutron production
S. Meigo, H. Fujimori, S. Sakamoto, M. Ooi (2020-11-09)
Japan Association of Mineralogical Sciences Award
Technical developments for high-pressure neutron
diffraction and analyses of phase transitions of hydrogenbearing minerals under pressure
K. Komatsu (2020-09-18)

JSNS: The Japanese Society for Neutron Science

The JSNS President’s Choice
Recent progress in the development of polarizing
supermirror
R. Maruyama (2020-11-10)
The JSNS President’s Choice
Ripple of Electronic Clouds
K. Matsuura, H. Sagayama, T. Arima (2020-11-09)
The JSNS Young Researcher Prize
Magnetic fluctuations in unconventional superconductivity
by pulsed neutron
K. Iida (2020-11-09)
175

MLF Operations in 2020

MLF Annual Report 2020

MLF Publication 20201	T. Hirata, H. Taneda, K. Nishio, M. Inutsuka, N. L. Yamada, F. Nemoto,Y. Minagawa, H. Matsuno, K. Tanaka,	A Facile Surface Functionalization Method for Polymers Using a
Non-solvent	ACS Appl. Bio Mater., 3 2170-2176 (2020).
2	J.-H. Hong, M. Totani, D. Kawaguchi, H. Masunaga, N. L. Yamada, H.
Matsuno, K. Tanaka,	Design of a Bio-inert Interface Using an Amphiphilic Block Copolymer
Containing a Bottlebrush Unit of Oligo(oxazoline)	ACS Appl. Bio Mater., 3 7363–7368 (2020).
3	K. Mori, A. Mineshige, T. Saito, M. Sugiura, Y. Ishikawa, F. Fujisaki, K.
Namba, T. Kamiyama, T. Otomo, T. Abe, T. Fukunaga,	Experimental Visualization of Interstitialcy Diffusion Pathways in
Fast-Fluoride-Ion-Conducting Solid Electrolyte Ba0.6La0.4F2.4
	ACS Appl. Energy Mater., 3 2873 (2020).
4	M. Nitta, N. Nagao, Y. Nomura, T. Hirasawa, Y. Sakai, T. Ogata, M.
Azuma, S. Torii, T. Ishigaki, Y. Inada,	High-Brightness Red-Emitting Phosphor La3(Si,Al)6(O,N)11:Ce3+ for
Next-Generation Solid-State Light Sources
	ACS Appl. Mater. Interfaces, 12 31652–31658 (2020).
5	K. Shiino, T. Otomo, T. Yamada, H. Arima, K. Hiroi, S. Takata, J.
Miyake, K. Miyatake,	Structural investigation of sulfonated polyphenylene ionomers forthe design of better performing proton-conductive membranes
	ACS Appl. Polym. Mater., 2 5558-5565 (2020).
6	T. Sato, T. Mochizuki, K. Ikeda, T. Honda, T. Otomo, H. Sagayama, H.
Yang, W. Luo, L. Lombardo, A. Züttel, S. Takagi, T. Kono, S. Orimo,	Crystal Structural Investigations for Understanding Hydrogen
Storage Properties of YMgNi4-Based Alloys
	ACS Omega, 5 31192 (2020).
7	S. Utsumi, S. Tanaka, K. Maruyama, N. Hatakeyama, K. Itoh, J.
Koike, A. Horikawa, H. Iriyama, H. Kanamaru, Y. Amako, T. Iiyama,
R. Futamura, R. Kiyanagi, A. Nakao, K. Moriyama, Y. Ishikawa, N.
Momozawa,	Flux Growth and Magnetic Properties of Helimagnetic Hexagonal
Ferrite Ba(Fe1–xScx)12O19 Single Crystals
	ACS Omega, 5 24890-24897 (2020).
8	M. Tanaka, K. Hayakawa, N. Ogawa, T. Kurokawa, K. Kitanishi, K. Ite,T. Matsui, Y. Mori, M. Unno,
	Structure determination of the human TRPV1 ankyrin-repeat domain under nonreducing conditions
	Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun., F76 130-137(2020).
9	Y. Wang, Y. Tomota, T. Ohmura, S. Morooka, W. Gong, S. Harjo,
	Real time observation of martensite transformation for a 0.4 C low
alloyed steel by neutron diffraction
	Acta Mater., 184 30-40 (2020).
10	A. S. Tremsin, D. Perrodin, A. S. Losko, S. C. Vogel, T. Shinohara, K.
Oikawa, G. A. Bizarri, E. D. Bourret, J. H. Peterson, K. P. Wang, J. J.
Derby,
	In-situ observation and analysis of solid-state diffusion and liquid
migration in a crystal growth system: A segregation-driven diffusion
couple	Acta Mater., 186 434-442 (2020).
11	Y. Wang, Y. Tomota, T. Ohmura, W. Gong, S. Harjo, M. Tanaka,	Continuous and discontinuous yielding behaviors in ferrite-cementite

176

steels	Acta Mater., 196 565-575 (2020).
12	S. Harjo, S. Kubota, W. Gong, T. Kawasaki, S. Gao,	Neutron diffraction monitoring of ductile cast iron under cyclic
tension–compression
	Acta Mater., 196 584-594 (2020).
13	D. Fukui, N. Nakada, S. Onaka,	Internal residual stress originated from Bain strain and its effect on
hardness in Fe–Ni martensite	Acta Mater., 196 660-668 (2020).
14	T.-N. Lam, S. Y. Lee, N.-T. Tsou, H.-S. Chou, B.-H. Lai, Y.-J. Chang, R.
Feng, T. Kawasaki, S. Harjo, P. K. Liaw, A.-C. Yeh, M.-J. Li, R.-F. Cai,
S.-C. Loh, E-W. Huang,	Enhancement of fatigue resistance by overload-induced deformation twinning in a CoCrFeMnNi high-entropy alloy
	Acta Mater., 201 412-424 (2020).
15	M. Morgano, N. Kalentics, C. Carminati, J. Capek, M. Makowska, R.
Woracek, T. Maimaitiyili, T. Shinohara, R. Loge, M. Strobl,	Investigation of the effect of Laser Shock Peening in Additively
Manufactured samples through Bragg Edge Neutron Imaging
	Addit. Manuf., 34 101201 (2020).
16	L. Kong, J. Gong, Q. Hu, F. Capitani, A. Celeste, T. Hattori, A. SanoFurukawa, W. Yang, H.-k. Ma,	Suppressed Lattice Disorder for Large Emission Enhancement andStructural Robustness in Hybrid Lead Iodide Perovskite Discovered by
High-pressure Isotope Effect	Adv. Funct. Mater., 31 2009131 (2020).
17	K. Hayashi, W. Saito, K. Sugimoto, K. Ohoyama, K. Hayashi, N.
Happo, M. Harada, K. Oikawa, Y. Inamura, Y. Miyazaki,	Preparation, thermoelectric properties, and crystal structure of boron-doped Mg2Si single crystals
	AIP Adv., 10 35115 (2020).
18	Umegaki, Y. Higuchi, Y. Kondo, K. Ninomiya, S. Takeshita, M.
Tampo, H. Nakano, H. Oka, J. Sugiyama, M. K. Kubo, Y. Miyake,	Nondestructive High-Sensitivity Detections of Metallic Lithium
Deposited on a Battery Anode Using Muonic X-rays	Anal. Chem., 92 8194 (2020).
19	T. Takami, T. Saito, T. Kamiyama, K. Kawahara, T. Fukunaga, T. Abe,	A new Bi0.7Fe1.3O1.5F1.7 phase: Crystal structure, magnetic properties,
and cathode performance in fluoride-ion batteries
	APL Mater., 8 051103 (2020).
20	H. Seto, T. Yamada,	Quasi-elastic neutron scattering study of the effects of metal cations
on the hydration water between phospholipid bilayers
	Appl. Phys. Lett., 116 133701 (2020).
21	Cho, H. Kim, S. Park,	Magnetic structure of undistorted hexagonal ferrites, Lu0.2In0.8FeO3
	Appl. Phys. Lett., 116 202902 (2020).
22	H. Yamamoto, S. Sekikawa, H. Taniguchi, M. Matsukawa, K.
Shigematsu, T. Honda, K. Yamauchi, K. Ikeda, T. Otomo, T. Sakakura,
M. Azuma, S. Nimori, Y. Noda, H. Kimura,	Reversible thermally controlled spontaneous magnetization switching in perovskite-type manganite	Appl. Phys. Lett., 117 112404 (2020).

MLF Annual Report 202023	Kitanishi, J. Igarashi, A. Matsuoka, M. Unno,	
Identification and Characterization of a Redox Sensor
Phosphodiesterase from Ferrovum sp. PN-J185 Containing Bacterial
Hemerythrin and HD-GYP Domains
	Biochemistry, 59 983-991 (2020).
24	H. Kawaura, M. Harada, Y. Kondo, M. MIzutani, N. Takahashi, N. L.
Yamada,	Operando Time-slicing Neutron Reflectometry Measurements ofSolid Electrolyte Interphase Formation on Amorphous Carbon
Surfaces of a Li-ion Battery	Bull. Chem. Soc. Jpn., 93 854-861 (2020).
25	H. Uchiyama, M. Dowaki, K. Kadota, H. Arima, K. Sugiyama, Y.
Tozuka,	Single-stranded β-1,3–1,6-glucan as a carrier for improved dissolution and membrane permeation of poorly water-soluble compounds
	Carbohydr. Polym., 247 116698 (2020).
26	Fujii, Y, Yoshida, Y. J. Shan, K. Tezuka, Y. Inaguma, M. Yashima,	Cation- and anion-ordered rutile-type derivative LiTeO3(OH)	Chem. Commun., 56 10042-10045 (2020).

MLF Operations in 202035	T. Yamada, H. Seto,	Quasi-Elastic Neutron Scattering Studies on Hydration Water in
Phospholipid Membranes
	Front. Chem., 8 8 (2020).
36	J. Pallbo, M. Imai, L. Gentile, S. Takata, U. Olsson, E. Sparr,	NACore amyloid formation in the presence of phospholipids
	Front. Physiol., 11 592117 (2020).
37	K. Komatsu, S. Klotz, S. Nakano, S. Machida, T. Hattori, A. SanoFurukawa, K. Yamashita, T. Irifune,	Developments of nano-polycrystalline diamond anvil cells for neutron diffraction experiments
	High Press. Res., 40 184-193 (2020).
38	T. Hattori, A. Sano-Furukawa, S. Machida, K. Ohuchi, H. Kira, J. Abe,K. Funakoshi,	Practical effects of pressure-transmitting media on neutron diffraction experiments using Paris-Edinburgh presses	High Press. Res., 40 325-338 (2020).

27	J. Yamaura, S. Maki, T. Honda, T. Otomo, H. Abe, Y. Murakami, N.
Ohashi,	Polar nano-region structure in oxynitride perovskite LaTiO2N
	Chem. Commun., 56 1385-1388 (2020).

39	S. Abe and T. Sato, J. Kuroda, S. Manabe, Y. Watanabe, W. Liao, K.
Ito, M. Hashimoto, M. Harada, K. Oikawa, Y. Miyake,	Impact of Hydrided and Non-Hydrided Materials Near Transistors on
Neutron-Induced Single Event Upsets
	IEEE International Reliability Physics Symposium Proceedings,(2020).

28	H. Yamauchi, D. P. Sari, I. Watanabe, Y. Yasui, L.-J. Chang, K. Kondo,
T. U. Ito, M. Ishikado, M. Hagihara , M. D. Frontzek , S. Chi, J. A.
Fernandez-Baca, J. S. Lord, A. Berlie, A. Kotani, S. Mori, S. Shamoto,	High-temperature short-range order in Mn3RhSi
	Commun. Mater., 1 43 (2020).

40	W. Liao, M. Hashimoto, S. Manabe, Y. Watanabe, S. Abe, M. Tampo,
S. Takeshita, Y. Miyake,	Impact of the Angle of Incidence on Negative Muon-induced SEU
Cross Sections of 65-nm Bulk and FDSOI SRAMs	IEEE Trans. Nucl. Sci., 67 1566-1572 (2020).

29	R. Sei, H. Kawasoko, K. Matsumoto, M. Arimitsu, K. Terakado, D.
Oka, S. Fukuda, N. Kimura, H. Kasai, E. Nishibori, K. Ohoyama, A.
Hoshikawa, T. Ishigaki, T. Hasegawa, T. Fukumura,	Tetragonality induced superconductivity in anti-ThCr 2Si 2-type
RE2O2Bi (RE = rare earth) with Bi square nets
	Dalton Trans., 49 3321-3325 (2020).

41	J. Kuroda, S. Manabe, Y. Watanabe, K. Ito, W. Liao, M. Hashimoto, S.
Abe, M. Harada, K. Oikawa, Y. Miyake,	Measurement of Single-Event Upsets in 65-nm SRAMs Under
Irradiation of Spallation Neutrons at J-PARC MLF
	IEEE Trans. Nucl. Sci., 67 1599-1605 (2020).

30	Kasai, R. Fujishima, N. Ishida, N. Kitamura, Y. Idemoto,	Effect of Separator and Anode on Electrochemical Characteristics
and Crystal Structure of Lithium-ion Battery Cathode Material
0.4Li2MnO3-0.6LiMn1/3Ni1/3Co1/3O2
	Electrochemistry, 89 148-156 (2020).
31	A. Kimura, S. Nakamura, O. Iwamoto, N. Iwamoto, H. Harada, T.
Katabuchi, K. Terada, J. Hori, Y. Shibahara, T. Fujii,	Neutron capture and total cross-section measurements of 155Gd and157
Gd at ANNRI in J-PARC
	EPJ Web Conf., 239 1012 (2020).
32	G. Rovira, T. Katabuchi, K. Tosaka, S. Matsuura, K. Terada, O.
Iwamoto, A. Kimura, S. Nakamura, N. Iwamoto,	Measurement of the neutron capture cross-section of 237Np using
ANNRI at MLF/J-PARC
	EPJ Web Conf., 239 1017 (2020).
33	T. Katabuchi, O. Iwamoto, J. Hori, A. Kimura, N. Iwamoto, S.
Nakamura, Y. Shibahara, K. Terada, G. Rovira, S. Matsuura,	Fast Neutron Capture Reaction Data Measurement of Minor
Actinides for Development of Nuclear Transmutation Systems
	EPJ Web Conf., 239 1044 (2020).
34	Iwamoto, S. Nakamura, A. Kimura, T. Katabuchi, G. Rovira, K. Y.
Hara, O. Iwamoto,	Evaluation of gamma-ray strength function based on measured
gamma-ray pulse-height spectra in time-of-flight neutron captureexperiments
	EPJ Web Conf., 239 17016 (2020).

42	Matsubara, T. Masese, E. Suard, O. K. Forslund, E. Nocerino, R. Palm,
Z. Guguchia, D. Andreica, A. Hardut, M. Ishikado, K. Papadopoulos,
Y. Sassa, M. Månsson,
	Cation distributions and magnetic properties of ferrispinel
MgFeMnO4
	Inorg. Chem., 59 17970-17980 (2020).
43	T. Yajima, H. Nakajima, T. Honda, K. Ikeda, T. Otomo, H. Takeda, Z.
Hiroi,
	Titanium Hydride Complex BaCa2Ti2H14 with a 9-Fold Coordination	Inorg. Chem., 59 4228-4233 (2020).
44	Y. Matsumoto, Y. Nambu, T. Honda, K. Ikeda, T. Otomo, H.
Kageyama,	High-pressure Synthesis of Ba 2CoO2Ag2Te2 with Extended CoO 2
Planes	Inorg. Chem., 59 8121–8126 (2020).
45	Y. Hosoya, Y. Matsumura, Y. Tomota, Y. Onuki, S. Harjo,	Mechanism of Improved Ductility of 1500 MPa-class Ultra-highStrength Cold-rolled Steel Sheet Produced by Rolling and Partitioning
Method	ISIJ International, 60 2097 (2020).
46	H. Sato, K. Iwase, T. Kamiyama, Y. Kiyanagi,	Simultaneous Broadening Analysis of Multiple Bragg Edges
Observed by Wavelength-resolved Neutron Transmission Imaging ofDeformed Low-carbon Ferritic Steel	ISIJ International, 60 1254-1263 (2020).
47	N. Tsuchida, T. Tanaka, Y. Toji,	Analysis of Tensile Deformation Behavior by in situ Neutron

177

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MLF Annual Report 2020

Diffraction Experiments of 1 GPa-grade TRIP Steels with HighElongation	ISIJ International, 60 1349-1357 (2020).
48	T. Wakisaka, K. Kusada, D. Wu, T. Yamamoto, T. Toriyama, S.
Matsumura, H. Akiba, O. Yamamuro, K. Ikeda, T. Otomo, N. Palina,
Y. Chen, L. S. R. Kumara, C. Song, O. Sakata, W. Xie, M. Koyama, Y.
Kubota, S. Kawaguchi, R. L. Arevalo, S. M. Aspera, E. F. Arguelles, H.
Nakanishi, H. Kitagawa,	Rational Synthesis for a Noble Metal Carbide	J. Am. Chem. Soc., 142 1247 (2020).
49	Zhang, X. Tang, Y. Wang, X. Wang, D. Gao, Y. Li, H. Zheng, Y. Wang,
X. Wang, R. Fu, M. Tang, K. Ikeda, P. Miao, T. Hattori, A. SanoFurukawa, C. A. Tulk, J. J. Molaison, X. Dong, K. Li, J. Ju, H. Mao,	Distance-Selected Topochemical Dehydro-Diels-Alder Reaction of
1,4-Diphenylbutadiyne toward Crystalline Graphitic Nanoribbons
	J. Am. Chem. Soc., 142 17662-17669 (2020).
50	N. L. Yamada, T. Hosobata, F. Nemoto, K. Hori, M. Hino, J. Izumi,
K. Suzuki, M. Hirayama, R. Kanno, Y. Yamagata,	Application of Precise Neutron Focusing Mirror for Neutron
Reflectometry - Latest Results and Future Prospects
	J. Appl. Crystallogr., 53 1462-1470 (2020).
51	Y. Akahama, M. Miyakawa, T. Taniguchi, A. Sano-Furukawa, S.
Machida, T. Hattori,
	Structure refinement of black phosphorus under high pressure	J. Chem. Phys., 153 014704 (2020).
52	J. Matsuno, T. Kanamaru, K. Arai, R. Tanaka, J.H. Lee, R. Takahashi, K.
Sakurai, S. Fujii,	Synthesis and characterization of nanoemulsion-mediated corecrosslinked nanoparticles, and in vivo pharmacokinetics dependingon the structural characteristics
	J. Control. Release, 324 405 (2020).
53	Aggarwal, M. H. Meylan, B. P. Lamichhane, C. M. Wensrich,	Energy Resolved Neutron Imaging for Strain Reconstruction Using
the Finite Element Method	J. Imaging, 6 13 (2020).
54	T. Aoyagi, Y. Honda, H. Iked, M. Ikeno, K. Kawagoe, T. Kohriki, T.
Kume, T. Mibe, K. Namba, S. Nishimura, N. Saito, O. Sasaki, N. Sato,
Y. Sato, H. Sendai, K. Shimomura, S. Shirabe, M. Shoji, T. Suda, T.
Suehara, T. Takatomi, M. Tanaka, J. Tojo, K. Tsukada, T. Uchida, T.
Ushizawa, H. Wauke, T. Yamanaka, T. Yoshioka,
	Performance evaluation of a silicon strip detector for positrons/electrons from a pulsed a muon beam	J. Instrum., 15 P04027 (2020).
55	S. Okada, T. Azuma, D. A. Bennett, P. Caradonna, W. B. Doriese,
M. S. Durkin, J. W. Fowler, J. D. Gard, T. Hashimoto, R. Hayakawa,
G. C. Hilton, Y. Ichinohe, P. Indelicato, T. Isobe, S. Kanda, M.
Katsuragawa, N. Kawamura, Y. Kino, Y. Miyake, K. M. Morgan, K.
Ninomiya, H. Noda, G. C. O’Neil, T. Okumura, C. D. Reintsema, D.
R. Schmidt, K. Shimomura, P. Strasser, D. S. Swetz, T. Takahashi, S.
Takeda, S. Takeshita, H. Tatsuno, Y. Ueno, J. N. Ullom, S. Watanabe,
S. Yamada,X -ray Spectroscopy of Muonic Atoms Isolated in Vacuum withTransition Edge Sensors
	J. Low. Temp. Phys., 200 445-451 (2020).
56	T. E. Ashton, P. J. Baker, D. Bauer, A. R. Groves, C, Sotelo-Vazquez, T.
Kamiyama, T. Matsukawa, K. M. Kojima, J. A. Darr,
	Multiple diffusion pathways in LixNi0.77Co0.14Al0.09O2 (NCA) Li-ion battery cathodes	J. Mater. Chem. A, 8 11545-11552 (2020).
57	H. Abe, A. Takeshita, H. Sudo, K. Akiyama,	CO2 capture and surface structures of ionic liquid-propanol solutions
	J. Mol. Liq., 301 112445 (2020).

178

58	K. Sakai, M. Motoki, M. Teshigawara, T. Naoe, K. Haga, A. Watanabe,	Conceptual design of an abnormality sign determination system
for the general control system of the Materials and Life Science
Experimental Facility at J-PARC	J. Neutron Res., 22 337-343 (2020).
59	Kajimoto, M. Nakamura, K. Iida, K. Kamazawa, K. Ikeuchi, Y.
Inamura, M. Ishikado,	Energy resolution and neutron flux of the 4SEASONS spectrometer
revisited	J. Neutron Res., 22 99-107 (2020).
60	T. Ishida, E. Wakai, S. Makimura, A. M. Casella, D. J. Edwards, R.
Prabhakaran, D. J. Senor, K. Ammigan, S. Bidhar, P. G. Hurh, F.
Pellemoinee, C. J. Denshamf, M. D. Fitton, J. M. Bennett, D. Kim,
N. Simos, M. Hagiwara, N. Kawamura, S. Meigo, K. Yonehara, On
behalf of the RaDIATE COLLABORATION,	Tensile behavior of dual-phase titanium alloys under high-intensity
proton beam exposure: Radiation-induced omega phase transformation in Ti-6Al-4V
	J. Nucl. Mater., 541 152413 (2020).
61	Y. Kameda, S. Saito, A. Saji, Y. Amo, T. Usuki, H. Watanabe, N. Ara, Y.
Umebayashi, K. Fujii, K. Ueno, K. Ikeda, T. Otomo,	Solvation Structure of Li+ in Concentrated Acetonitrile and N,NDimethylformamide Solutions Studied by Neutron Diffraction with6
Li/7Li Isotopic Substitution Methods	J. Phys. Chem. B, 124 10456 (2020).
62	K. Yoshimoto, A. Masuno, I. Sato, Y. Ezura, H. Inoue, M. Ueda, M.
Mizuguchi, Y. Yanaba, T. Kawashima, T. Oya, Y. Onodera, S. Kohara,
K. Ohara,	Principal Vibration Modes of the La 2O 3−Ga 2O 3 Binary Glass
Originated from Diverse Coordination Environments of Oxygen
Atoms
	J. Phys. Chem. B, 124 5056-5066 (2020).
63	Y. Zhou, T. Yamaguchi, K. Ikeda, K. Yoshida, T. Otomo, C. Fang, W.
Zhang, F. Zhu,
	Dihydrogen Bonds in Aqueous NaBD4 Solution by Neutron and X-Ray
Diffraction	J. Phys. Chem. Lett., 11 1622 (2020).
64	M. A. González, O. Borodin, M. Kofu, K. Shibata, T. Yamada, O.
Yamamuro, K. Xu, D. L. Price, M.-L. Saboungi,	Nanoscale Relaxation in “Water-in-Salt” and “Water-in-Bisalt”
Electrolytes	J. Phys. Chem. Lett., 11 7279 (2020).
65	Z. Liu, C. Yang, L. Zhang, Y. Yu, M. Yu, V. G. Sakai, M. Tygai, T. Yamada,
L. He, X. Zhang, L. Hong,	Heterogeneity of Water Molecules on the Free Surface of Thin
Reduced Graphene Oxide Sheets	J. Phys. Chem. C Nanomater. Interfaces, 124 11064-11074 (2020).
66	Hiroto, T. J Sato, H. Cao, T. Hawai, T. Yokoo, S. Itoh, R. Tamura,	Noncoplanar ferrimagnetism and local crystalline-electric-field anisotropy in the quasicrystal approximant Au70Si17Tb13
	J. Phys. Condens. Matter, 32 415802 (2020).
67	M. Abe, T. Tanimori, A. Takada, Y. Mizumura, S. Komura, T.
Kishimoto, T. Takemura, K. Yoshikawa, Y. Nakamura, Y. Nakamasu,
T. Taniguchi, K. Onozaka, K. Saito, T. Mizumoto, S. Sonoda, J. D.
Parker, K. Miuchi, T. Sawano,	Development of a µ-PIC with glass substrate aiming at high gas gain	J. Phys. Conf. Ser., 1498 012002 (2020).
68	S. Ikeda, K. Kaneko, Y. Tanaka, T. Kawasaki, T. Hanashima, K.
Munakata, A. Nakao, R. Kiyanagi, T. Ohhara, K. Mochizuki, A.
Kondo, K. Kindo, Y. Homma, M. D. Frontzek, H. Kobayashi,	Multi-Step Magnetic Transitions in EuNiIn4
	J. Physical Soc. Japan, 89 14707 (2020).

MLF Annual Report 2020

MLF Operations in 2020

69	Otomo, K. Ikeda, T. Honda,
	Structural Studies of Hydrogen Storage Materials with Neutron
Diffraction: A Review
	J. Physical Soc. Japan, 89 51001 (2020).

Migas, T. Suemasu,	Hydrogen states in hydrogen-passivated semiconducting barium
disilicide measured via muon spin rotation	Jpn. J. Appl. Phys., 59 071004 (2020).

70	T. U. Ito, W. Higemoto, K. Shimomura,	Negatively Charged Muonium and Related Centers in Solids
	J. Physical Soc. Japan, 89 51007 (2020).

83	S. Makimura, J. Park, A. Sato, S. Matoba, N. Kawamura, T. Yamazaki,
K. Ninomiya, D. Tomono, N. Nakazato, M. Calviani, I. L. Garcia,
	Feasibility Study for NITE SiC/SiC as the Target Material for Pions/
Muons Production at High-Power Proton Accelerator Facilities	JPS Conf. Proc., 28 031005 (2020).

71	K. Sato, K. Ikeuchi, R. Kajimoto, S. Wakimoto, M. Arai, M. Fujita,	Coexistence of Two Components in Magnetic Excitations of
La2-xSrxCuO4 (x = 0.10 and 0.16)
	J. Physical Soc. Japan, 89 114703 (2020).
72	M. Komabuchi, D. Urushihara, T. Asaka, K. Fukuda, T. Ohhara, K.
Munakata, Y. Ishikawa,	Crystal Structure and Cation Distribution of the X-type Hexaferrite
Sr2Co2Fe28O46
	J. Physical Soc. Japan, 89 034601 (2020).
73	M. Kofu, O. Yamamuro,	Dynamics of Atomic Hydrogen in Palladium Probed by Neutron
Spectroscopy	J. Physical Soc. Japan, 89 051002 (2020).
74	K. Iida, M. Kofu, K. Suzuki, N. Murai, S. Ohira-Kawamura, R.
Kajimoto, Y. Inamura, M. Ishikado, S. Hasegawa, T. Masuda, Y.
Yoshida, K. Kakurai, K. Machida, S.-H. Lee,
	Horizontal line nodes in Sr2RuO4 proved by spin resonance	J. Physical Soc. Japan, 89 053702 (2020).
75	T. Noda, Y. Doi, Y. Ohta, S. Takata, A. Takano, Y. Matsushita,	Preparation, characterization, and dilute solution properties of four‐
branched cage‐shaped poly (ethylene oxide)	J. Polym. Sci., 58 2098-2107 (2020).
76	R. Iizuka-Oku, W. Gui, K. Komatsu, T. Yagi, H. Kagi,
	High-pressure responses of alkali metal hydrogen carbonates,
RbHCO3and CsHCO3: Findings of new phases and unique compressional behavior	J. Solid State Chem., 283 121139 (2020).
77	J. Hendriks, N. O’Dell, A. Wills, A. Tremsin, C. Wensrich, T. Shinohara,	Bayesian non-parametric Bragg-edge fitting for neutron transmission strain imaging
	J. Strain Anal. Eng. Des., (2020).
78	D. Kitahara, H. Arima, T. Kawamata, K. Sugiyama, T. Mikouchi,	The location of Mn and Fe in axinite–(Fe) from Nandan, China determined by anomalous X–ray scattering (AXS)	Journal of Mineralogical and Petrological Sciences, 115 227-235(2020).
79	M. Nagashima, Y. Sano, T. Kochi, M. Akasaka, A. Sano–Furukawa,	Crystal chemistry of Sr–rich piemontite from manganese ore depositof the Tone mine, Nishisonogi Peninsula, Nagasaki, southwest Japan	Journal of Mineralogical and Petrological Sciences, 115 391-406(2020).
80	F. Funama, M. Hino, T. Oda, H. Endo, T. Hosobata, Y. Yamagata, S.
Tasaki,	Observation of TOF-MIEZE Signals with Focusing Mirrors at BL06,
MLF, J-PARC
	Journal of Surface Investigation: X-ray, Synchrotron and Neutron
Techniques, 14 S50-S55 (2020).
81	K. Kataoka,
	Oxide single crystals with high lithium-ion conductivity as solid electrolytes for all-solid-state lithium secondary battery applications
	Journal of the Ceramic Society of Japan, 128 7-18 (2020).
82	Z. Xu, T. Sato, J. Nakamura, A. Koda, K. Shimomura, A. Filonov, D.

84	T. Naoe, S. Harjo, T. Kawasaki, Z. Xiong, M. Futakawa,
	Change in Mechanical Properties by High-Cycle Loading Up to
Gigacycle for 316L Stainless Steel	JPS Conf. Proc., 28 061009 (2020).
85	N. Nakamura, R. Higashinaka, K. Fushiya, R. Tsubota, T. U. Ito,
W. Higemoto, A. Nakao, R. Kiyanagi, T. Ohhara, K. Kaneko, T. D.
Matsuda, Y. Aoki,
	μSR and Neutron Scattering Studied on Possible Partially-Disordered
Magnetic State Coexisting with Heavy Quasiparticles in SmPt2Si2
	JPS Conf. Proc., 29 012009 (2020).
86	D. Hirai, A. Koda, A. Matsuo, K. Kindo, T. Yajima, Z. Hiroi,	Muon Spin Rotation, High-Field Magnetization, and Structural Studyon a Spin–Orbit-Entangled Mott Insulator Ba2MgReO6
	JPS Conf. Proc., 30 11143 (2020).
87	S. Tsunoda, K. Horigane, H. Okabe, K. Machida, M. Akimitsu, K.
Kawashima, R. Horie, K. Kobayashi, A. Koda, R. Kadono, J. Akimitsu,
	μSR study of the magnetic state in hole and electron doped Sr2IrO4
	JPS Conf. Proc., 30 11145 (2020).
88	N. Metoki, A. A. Aczel, D. Aoki, S. Chi, J. A. Fernandez-Baca, J.-C.
Griveau, M. Hagihala, T. Hong, Y. Haga, K. Ikeuchi, Y. Inamura, K.
Kamazawa, R. Kajimoto, H. Kitazawa, T. Masuda, M. Matsuda, M.
Nakamura, J. Ohtsuki, D. Pajerowski, H. S. Suzuki, E. Yamamoto, H.
Yamauchi,	The f-electron State of the Heavy Fermion Superconductor NpPd5Al2
and the Isostructural Family
	JPS Conf. Proc., 30 011123 (2020).
89	S. Nakazato, K. Iwasa, D. Hashimoto, M. Shiozawa, K. Kuwahara,
H. Nakao, H. Sagayama, M. Ishikado, T. Ohhara, A. Nakao, K.
Munakata, R. Kiyanagi,	Successive Phase Transitions in R3Ir4Sn13 (R: La and Ce) Investigated
Using Neutron and X-ray Diffraction	JPS Conf. Proc., 30 011128 (2020).
90	K. Iba, T. Matsumura, A. Nakao, Y. Ishikawa, K. Ohishi, R. Kiyanagi, Y.
Kousaka, S. Ohara,	Magnetic Structure of a Chiral Magnet DyNi3Al9
	JPS Conf. Proc., 30 011164 (2020).
91	K. Akutsu-Suyama, K. Park, R. Takakura, K. Tamura, M. Cagnes, T.A.
Darwish, T. Yamada, Y. Sawama, H. Sajiki,	Metal catalyzed H-D exchange methods using D2O as a deuterium
source: A comparative study in different sealed devices
	JPS Conf. Proc., 33 011150 (2020).
92	T. Yoshimura, N. K. Kawano, S. Yada, H. Iwase,	Adsorption and aggregation properties of Gemini-type amphiphilic
dendrimers	Langmuir, 36 563 (2020).
93	Y. Higaki, M. Kobayashi, A. Takahara,	Hydration State Variation of Polyzwitterion Brushes throughInterplay with Ions	Langmuir, 36 9015 (2020).
94	K. Ito, M. Harada, N. L. Yamada, K. Kudo, H. Aoki, T. Kanaya,	Water Distribution in Nafion Thin Films on Hydrophilic and179

MLF Operations in 2020

MLF Annual Report 2020

Hydrophobic Carbon Substrates	Langmuir, 36 12830–12837 (2020).
95	T. Miyazaki, K. Shimokita, K. Yamamoto, H. Aoki, N. L. Yamada, N.
Miyata,	Neutron Reflectivity on the Mobile Surface and Immobile Interfacial
Layers in the Poly(vinyl acetate) Adsorption Layer on a Si Substratewith Deuterated Toluene Vapor-Induced Swelling	Langmuir, 36 15181-15188 (2020).
96	T. Miyazaki, N. Miyata, T. Yoshida, H. Arima, Y. Tsumura, N. Torikai,
H. Aoki, K. Yamamoto, T. Kanaya, D. Kawaguchi, K. Tanaka,	Detailed Structural Study on the Poly(vinyl alcohol) Adsorption
Layers on a Si Substrate with Solvent Vapor-Induced Swelling	Langmuir, 36 3415-3424 (2020).
97	T. Sugahara, M. Akamatsu, H. Iwase, Y. Takamatsu, K. Sakai, H.
Sakai,
	Structural change of α-gel (α-form hydrated crystal) induced by temperature and shear flow in an oleic acid-based gemini surfactant
system	Langmuir, 36 4695-4701 (2020).
98	T. Kimura, T. Kawamoto, M. Aoki, T. Mizusawa, N. L. Yamada, K.
Miyatake, J. Inukai,	Sublayered Thin Films of Hydrated Anion Exchange Ionomer for
Fuel Cells Formed on SiO2 and Pt Substrates Analyzed by Neutron
Reflectometry under Controlled Temperature and Humidity
Conditions
	Langmuir, 36 4955-4963 (2020).
99	K. Igata, T. Sakamaki, Y. Inutsuka, Y. Higaki, M. K. Okajima, N. L.
Yamada, T. Kaneko, A. Takahara,	Cationic Polymer Brush/Giant Polysaccharide Sacran Assembly:
Structure and Lubricity
	Langmuir, 36 6494-6501 (2020).
100	S. Yada, H. Shimosegawa, H. Fujita, M. Yamada, Y. Matsue, T.
Yoshimura,	Microstructural Characterization of Foam Formed by a HydroxyGroup-Containing Amino Acid Surfactant Using Small-Angle
Neutron Scattering	Langmuir, 36 7808–7813 (2020).
101	C.I. Gupit, X. Li, R. Maekawa, N. Hasegawa, H. Iwase, S. Takata, M.
Shibayama,	Nanostructures and viscosities of nafion dispersions in water/ethanol from dilute to concentrated regimes
	Macromolecules, 53 1464 (2020).
102	M. Ohira, Y. Tsuji, N. Watanabe, K. Morishima, E. P. Gilbert, X. Li, M.
Shibayama,	Quantitative structure analysis of a near-ideal polymer network with
deuterium label by small-angle neutron scattering	Macromolecules, 53 4047 (2020).
103	T. Nishimura, L. de Campo, H. Iwase, K. Akiyoshi,	Determining the hydration in the hydrophobic layer of permeable
polymer vesicles by neutron scattering	Macromolecules, 53 7546 (2020).
104	Y. Oda, M. Inutsuka, R. Awane, M. Totani, N. L. Yamada, M.
Haraguchi, M. Ozawa, H. Matsuno, K. Tanaka,	Dynamic Interface based on Segregation of an Amphiphilic
Hyperbranched Polymer Containing Fluoroalkyl and Oligo(ethyleneoxide) Moieties
	Macromolecules, 53 2380-2387 (2020).
105	A. Izumi, Y. Shudo, M. Shibayama, T. Yoshida, N. Miyata, T. Miyazaki,
H. Aoki,	Interfacial Cross-Link Inhomogeneity of a Phenolic Resin on a Silica
Surface As Revealed by X-ray and Neutron Reflection Measurements

180

	Macromolecules, 53 4082-4089 (2020).
106	K. Tashiro, K. Kusaka, H. Yamamoto, M. Hanesaka,	Introduction of Disorder in the Crystal Structures of Atactic Poly(vinyl
Alcohol) and Its Iodine Complex To Solve a Dilemma between X-ray
and Neutron Diffraction Data Analyses
	Macromolecules, 53 6656-6671 (2020).
107	Y. Cui, C. Li, S. Harjo, C. Zhang, R. Li, W. Zheng, Y. Wang,	A study on the micromechanical behavior of Ti-55531 titanium alloy
with lamellar microstructure byin-situ neutron diffraction
	MATEC Web of Conferences, 321 11013 (2020).
108	Y. Tomota, T. Murakami, Y. X. Wang, T. Ohmura, S. Harjo, Y. H. Su, T.
Shinohara,
	Influence of carbon concentration and magnetic transition on theaustenite T lattice parameter of 30Mn-C steel	Mater. Charact., 163 110243 (2020).
109	D. Ma, P. Yang, X.-F. Gu, Y. Onuki, S. Sato,	In-situ neutron diffraction investigation on the martensite transformation, texture evolution and martensite reversion in high manganese TRIP steel	Mater. Charact., 163 110244 (2020).
110	Z. Wei, P. Yang, X. Gu, Y. Onuki, S. Sato,	Transformation textures in pure titanium: Texture memory vs surface
effect	Mater. Charact., 164 110359 (2020).
111	K. Itoh, J. Saida, T. Otomo,	Structural study of Ni67Zr33 amorphous alloy: Interatomic space analysis approach	Mater. Chem. Phys., 240 122214 (2020).
112	Woo, M. Naeem, J.-S. Jeong, C.-M. Lee, S. Harjo, T. Kawasaki, H. He,
X.-L. Wang,
	Comparison of dislocation density, twin fault probability, and stacking fault energy between CrCoNi and CrCoNiFe medium entropy alloys deformed at 293 and 140K
	Mater. Sci. Eng. A Struct. Mater., 781 139224 (2020).
113	S. Harjo, K. Aizawa, W. Gong, T. Kawasaki,	Neutron Diffraction Monitoring of As-Cast Mg 97Zn 1Y 2 during
Compression and Tension
	Mater. Trans., 61 828-832 (2020).
114	J. W. Bae, J. Jung, J. G. Kim, J. M. Park, S. Harjo, T. Kawasaki, W. Woo,
H. S. Kim,
	On the phase transformation and dynamic stress–strain partitioningof ferrous medium-entropy alloy using experimentation and finite
element method
	Materialia, 9 100619 (2020).
115	O. Holderer, M. Carmo, M. Shviro, W. Lehnert, Y. Noda, S. Koizumi,
M.-S. Appavou, M. Appel, H. Frielinghaus,	Fuel Cell Electrode Characterization Using Neutron Scattering	Materials, 13 1474 (2020).
116	T. Kai, K. Hiroi, Y. Su, M. Segawa, T. Shinohara, Y. Matsumoto, J. D.
Parker, H. Hayashida, K. Oikawa,	Feasibility Study of Two-Dimensional Neutron-Resonance
Thermometry using Molybdenum in 316 Stainless-Steel	Materials Research Forum LLC, 15 149-153 (2020).
117	K. Oikawa, Y. Kiyanagi, H. Sato, K. Ohmae, A. H. Pham, K. Watanabe,
Y. Matsumoto, T. Shinohara, T. Kai, S. Harjo, M. Ohnuma, S. Morito,
T. Ohba, A. Uritani, M. Ito,	Pulsed Neutron Imaging Based Crystallographic Structure Study of aJapanese Sword made by Sukemasa in the Muromachi Period	Materials Research Forum LLC, 15 207-213 (2020).

MLF Annual Report 2020118	J. D. Parker, M. Harada, H. Hayashida, K. Hiroi, T. Kai, Y. Matsumoto,
T. Nakatani, K. Oikawa, M. Segawa, T. Shinohara, Y. Su, A. Takada, T.
Tanimori, Y. Kiyanagi,	Development of Event-Type Neutron Imaging Detectors at theEnergy-Resolved Neutron Imaging System RADEN at J-PARC
	Materials Research Proceedings, 15 102-107 (2020).
119	Y. Oba, D. Ito, Y. Saito, Y. Onodera, J. D. Parker, T. Shinohara, K.
Oikawa,	Neutron Transmission Spectrum of Liquid Lead Bismuth Eutectic	Materials Research Proceedings, 15 160-164 (2020).
120	H. Sato, Y. Kiyanagi, K. Oikawa, K. Ohmae, A. H. Pham, K. Watanabe,
Y. Matsumoto, T. Shinohara, T. Kai, S. Harjo, M. Ohnuma, S. Morito,
T. Ohba, A. Uritani, M. Itoh,	Crystallographic Microstructure Study of a Japanese Sword made by
Noritsuna in the Muromachi Period by Pulsed Neutron Bragg-Edge
Transmission Imaging
	Materials Research Proceedings, 15 214-220 (2020).
121	Y. Matsumoto, K. Watanabe, K. Ohmae, A. Uritani, Y. Kiyanagi, H.
Sato, M. Ohnuma, A. H. Pham, S. Morito, T. Ohba, K. Oikawa, T.
Shinohara, T. Kai, S. Harjo, M. Ito,	Comparative Study of Ancient and Modern Japanese Swords using
Neutron Tomography	Materials Research Proceedings, 15 221-226 (2020).
122	K. Ohmae, Y.i Kiyanagi, H. Sato, K. Oikawa, A. H. Pham, K. Watanabe,
Y. Matsumoto, T. Shinohara, T. Kai, S. Harjo, M. Ohnuma, S. Morito,
T. Ohba, A. Uritani, M. Ito,	Crystallographic Structure Study of a Japanese Sword Masamitsu
made in the 1969 using Pulsed Neutron Imaging
	Materials Research Proceedings, 15 227-232 (2020).
123	T.-N. Lam, C.-W. Tsai, B.-K. Chen, B.-H. Lai, H.-C. Liu, T. Kawasaki, S.
Harjo, B.-H. Lin, E-W. Huang,	Element Effects of Mn and Ge on the Tuning of Mechanical Properties
of High-Entropy Alloys
	Metall. Mater. Trans. A Phys. Metall. Mater. Sci., 51 5023-5028(2020).
124	Tanaka, T. Chatake, S. Fujiwara, T. Hosoya, K. Kusaka, N. Niimura, T.
Yamada, N. Yano,	Current status and near future plan of neutron protein crystallography at J-PARC
	Methods Enzymol., 634 101-123 (2020).
125	M. Budayova-Spano, K. Koruza, Z. Fisher,	Large crystal growth for neutron protein crystallography	Methods Enzymol., 634 21-46 (2020).
126	S. Urakawa, T. Inoue, T. Hattori, A. Sano-Furukawa, S. Kohara, D.
Wakabayashi, T. Sato, N. Funamori, K. Funakoshi,	X-ray and neutron study on the structure of hydrous SiO2 glass up to
10 GPa	Minerals, 10 84 (2020).
127	S. Kajiyama, H. Iwase, M. Nakayama, R. Ichikawa, D. Yamaguchi, H.
Seto, T. Kato,	Shear-induced liquid-crystalline phase transition behaviour of colloidal solutions of hydroxyapatite nanorod composites
	Nanoscale, 12 11468-11479 (2020).
128	Watanabe, S. Katsuhara, H. Mamiya, Y. Kawamura, T. Yamamoto, K.
Tajima, T. Isono, T. Satoh,	Highly asymmetric lamellar nanostructures from nanoparticle–linear hybrid block copolymers
	Nanoscale, 12 16526-16534 (2020).
129	Komatsu, S. Machida, F. Noritake, T. Hattori, A. Sano-Furukawa, R.
Yamane, K. Yamashita, H. Kagi,
	Ice Ic without stacking disorder by evacuating hydrogen fromMLF Operations in 2020

hydrogen hydrate	Nat. Commun., 11 464 (2020).
130	Li, P. Liu, E. Zhao, Z. Zhang, T. Guidi, M. D. Le, M. Avdeev, K. Ikeda, T.
Otomo, M. Kofu, K. Nakajima, J. Chen, L. He, Y. Ren, X.-L. Wang, B.
Wang, Z. Ren, H. Zhao, F. Wang,	Ultralow Thermal Conductivity from Transverse Acoustic Phonon
Suppression in Distorted Crystalline α-MgAgSb	Nat. Commun., 11 942 (2020).
131	Zhang, K. Fujii, E. Niwa, M. Hagihala, T. Kamiyama, M. Yashima,	Oxide-ion conduction in the Dion–Jacobson phase CsBi2Ti2NbO10−δ	Nat. Commun., 11 1224 (2020).
132	Q. Ren, C. Fu, Q. Qiu, S. Dai, Z. Liu, T. Masuda, S. Asai, M. Hagihala,
S. Lee, S. Torri, T. Kamiyama, L. He, X. Tong, C. Felser, D. J. Singh, T.
Zhu, J. Yang, J. Ma,	Establishing the carrier scattering phase diagram for ZrNiSn-basedhalf-Heusler thermoelectric materials	Nat. Commun., 11 3142 (2020).
133	Fujihala, K. Morita, R. Mole, S. Mitsuda, T. Tohyama, S. Yano, D. Yu,
S. Sota, T. Kuwai, A. Koda, H. Okabe, H. Lee, S. Itoh, T. Hawai, T.
Masuda, H. Sagayama, A. Matsuo, K. Kindo, S. Ohira-Kawamura, K.
Nakajima,	Gapless spin liquid in a square-kagome lattice antiferromagnet
	Nat. Commun., 11 3429 (2020).
134	T. Yamamoto, A. Chikamatsu, S. Kitagawa, N. Izumo, S. Yamashita,
H. Takatsu, M. Ochi, T. Maruyama, M. Namba, W. Sun, T. Nakashima,
F. Takeiri, K. Fujii, M. Yashima, Y. Sugisawa, M. Sano, Y. Hirose, D.
Sekiba, C. M. Brown, T. Honda, K. Ikeda, T. Otomo, K. Kuroki, K.
Ishida, T. Mori, K. Kimoto, T. Hasegawa, H. Kageyama,	Strain-induced creation and switching of anion vacancy layers inperovskite oxynitrides	Nat. Commun., 11 5923 (2020).
135	F. B. Li, M. Li, X. Xu, Z. C. Yang, H. Xu, C. K. Jia, K. Li, J. He, B. Li, H.
Wang,
	Understanding colossal barocaloric effects in plastic crystals	Nat. Commun., 11 4190 (2020).
136	R. Bauer, J. S. Tse, K. Komatsu, S. Machida, T. Hattori,	Slow compression of crystalline ice at low temperature	Nature, 585 E10 (2020).
137	P. Wu, F.-R. Fan, M. Hagihala, M. Kofu, K. Peng, Y. Ishikawa, S. Lee, T.
Honda, M. Yonemura, K. Ikeda, T. Otomo, G. Wang, K. Nakajima, Z.
Sun, T. Kamiyama,	Strong lattice anharmonicity exhibited by the high-energy opticalphonons in thermoelectric material	New J. Phys., 22 083083 (2020).
138	Xu, G. Dai, Y. Li, Z. Yin, Y. Rong, L. Tian, P. Liu, H. Wang, L. Xing, Y.
Wei, R. Kajimoto, K. Ikeuchi, D. L. Abernathy, X. Wang, C. Jin, X. Lu,
G. Tan, P. Dai,
	Strong local moment antiferromagnetic spin fluctuations in V-doped
LiFeAs	NPJ Quantum Mater., 5 11 (2020).
139	T. Okudaira, T. Oku, T. Ino, H. Hayashida, H. Kira, K. Sakai, K. Hiroi, S.
Takahashi, K. Aizawa, H. Endo, S. Endo, M. Hino, K. Hirota, T. Honda,
K. Ikeda, K. Kakurai, W. Kambara, M. Kitaguchi, T. Oda, H. Ohshita, T.
Otomo, H.M. Shimizu, T. Shinohara, J. Suzuki, T. Yamamoto,	Development and application of a 3He neutron spin filter at J-PARC
	Nucl. Instrum. Methods Phys. Res. A, 977 164301 (2020).
140	T. Naoe, H. Kogawa, T. Wakui, M. Teshigawara, K. Haga, M.
Futakawa,	Pressure wave induced sound measurement for diagnosing the operation status of the J-PARC pulsed spallation neutron source	Nucl. Instrum. Methods Phys. Res. A, 982 164566 (2020).

181

MLF Operations in 2020

MLF Annual Report 2020141	Zhoua, T. Yamaguchi, W. Zhang, K. Ikeda, K. Yoshida, F. Zhu, H. Liu,	Structure of Aqueous H3BO3 Solutions by DFT and Neutron Scattering	Phys. Chem. Chem. Phys., 22 17160-17170 (2020).
142	Kawano, K. Sadakane, H. Iwase, M. Matsugami, B. A. Marekha, A.
Idrissi, T. Takamuku,
	Mixing states of imidazolium-based ionic liquid, [C 4mim][TFSI],
with cycloethers studied by SANS, IR, and NMR experiments and MD
simulations
	Phys. Chem. Chem. Phys., 22 5332-5346 (2020).
143	Y. Higuchi, D. Setoyama, K. Isegawa, Y. Tsuchikawa, Y. Matsumoto,J. D. Parker, T. Shinohara, Y. Nagai,	Pulsed neutron imaging for differentiation of ice and liquid water
towards fuel cell vehicle applications
	Phys. Chem. Chem. Phys., 23 1062-1071 (2020).
144	Nagashima, T. Armbruster, M. Akasaka, A. Sano-Furukawa, D.
Nishio-Hamane, A. Malsy, T. Imaoka, K. Nakashima,	Multi-methodical study of the Ti, Fe2+ and Fe3+ distribution in chevkinite-subgroup minerals: X-ray diffraction, neutron diffraction, 57Fe
Mössbauer spectroscopy and electron-microprobe analyses	Phys. Chem. Miner., 47 29 (2020).
145	T. Oda, M. Hino, H. Endo, H. Seto, Y. Kawabata,	Tuning Neutron Resonance Spin-Echo Spectrometers with Pulsed
Beams	Phys. Rev. Appl., 14 054032 (2020).
146	Cai, S. Bao, W. Wang, Z. Ma, Z.-Y. Dong, Y. Shangguan, J. Wang, K.
Ran, S. Li, K. Kamazawa, M. Nakamura, D. Adroja, S.-L. Yu, J.-X. Li, J.
Wen,	Spin dynamics of a magnetic Weyl semimetal Sr1-xMn1-ySb2
	Phys. Rev. B, 101 134408 (2020).
147	M. M. R. Bhuiyan, X.-G. Zheng, M. Hagihala, S. Torii, T. Kamiyama, T.
Kawae,
	Spin order in the classical spin kagome antiferromagnet
MgxMn4−x(OH)6Cl2
	Phys. Rev. B, 101 134424 (2020).
148	S. Asai, T. Oyama, K. Nawa, A. Nakao, K. Munakata, K. Kuwahara, M.
Hagihala, S. Itoh, Z. Hiroi, T. Masuda,
	Helical and collinear spin density wave order in the S=1/2 one-dimensional frustrated chain compound NaCuMoO4(OH) investigatedby neutron scattering	Phys. Rev. B, 101 144437 (2020).
149	H. Masuda, H. Sakai, H. Takahashi, Y. Yamasaki, A. Nakao, T.
Moyoshi, H. Nakao, Y. Murakami, T. Arima, S. Ishiwata,	Field-induced spin reorientation in the antiferromagnetic Dirac material EuMnBi2 revealed by neutron and resonant x-ray diffraction
	Phys. Rev. B, 101 174411 (2020).
150	C. Tan, Z. F. Ding, J. Zhang, Z. H. Zhu, O. O. Bernal, P. C. Ho, A. D.
Hillier, A. Koda, H. Luetkens, G. D. Morris, D. E. MacLaughlin, L. Shu,	Slow magnetic fluctuations and critical slowing down in Sr2Ir1−xRhxO4
	Phys. Rev. B, 101 195108 (2020).
151	S. Bao, Z. Cai, W. Si, W. Wang, X. Wang, Y. Shangguan, Z. Ma, Z.-Y.
Dong, R. Kajimoto, K. Ikeuchi, S.-L. Yu, J. Sun, J.-X. Li, J. Wen,	Evidence for magnon-phonon coupling in the topological magnet
Cu3TeO6
	Phys. Rev. B, 101 214419 (2020).
152	M. Soda, S. Itoh, T. Yokoo, G. Ehlers, H. Kawano-Furukawa, T.
Masuda,	Magnetic correlations in YBaCo4O7 on kagome and triangularlattices	Phys. Rev. B, 101 214444 (2020).
153	E. Fogh, T. Kihara, R. Toft-Petersen, M. Bartkowiak, Y. Narumi, O.

182

Prokhnenko, A. Miyake, M. Tokunaga, K. Oikawa, M. K. Sørensen, J.
C. Dyrnum, H. Grimmer, H. Nojiri, N. B. Christensen,	Magnetic structures and quadratic magnetoelectric effect in LiNiPO4
beyond 30 T	Phys. Rev. B, 101 024403 (2020).
154	T. Uchino, N. Teramachi, R. Matsuzaki, E. Tsushima, S. Fujii, Y. Seto,
K. Takahashi, T. Mori, Y. Adachi, Y. Nagashima, Y. Sakaguchi, K.
Ohishi, A. Koda, T. Sakurai, H. Ohta,
	Proximity coupling of superconducting nanograins with fractal
distributions
	Phys. Rev. B, 101 035146 (2020).
155	T. Sato, Y. Araki, A. Miyake, A. Nakao, N. Abe, M. Tokunaga, S.
Kimura, Y. Tokunaga, T. Arima,	Magnetic phase diagram enriched by chemical substitution in anoncentrosymmetric helimagnet
	Phys. Rev. B, 101 054414 (2020).
156	S. Klotz, K. Komatsu, A. Polian, S. Machida, A. Sano-Furukawa, J.
Itié, T. Hattori,	Crystal structure and magnetism of MnO under pressure	Phys. Rev. B, 101 064105 (2020).
157	K. H. Lee, I. Y. Hwang, J.-H. Chung, H. Ishibashi, Y. Kubota, S.
Kawaguchi, S. Lee, S. Torii, M. Hagihala, T. Kamiyama,	Stabilization of orthorhombic distortions in Cu- and Co-doped ferrimagnetic Mn3O4
	Phys. Rev. B, 101 085126 (2020).
158	H. Ueda, S. Onoda, Y. Yamaguchi, T. Kimura, D. Yoshizawa, T.
Morioka, M. Hagiwara, M. Hagihala, M. Soda, T. Masuda, T.
Sakakibara, K. Tomiyasu, S. Ohira-Kawamura, K. Nakajima, R.
Kajimoto, M. Nakamura, Y. Inamura, N. Reynolds, M. Frontzek, J. S.
White, M. Hase, Y. Yasui,	Emergent spin-1 Haldane gap and ferroelectricity in a frustrated
spin-1/2 ladder	Phys. Rev. B, 101 140408(R) (2020).
159	Abe, S. Shiozawa, K. Matsuura, H. Sagayama, A. Nakao, T. Ohhara,
Y. Tokunaga, T. Arima,	Magnetically induced electric polarization in Ba3Fe2O5Cl2 with tunable direction in three dimensions
	Phys. Rev. B, 101 180407(R) (2020).
160	M. Hirschberger, T. Nakajima, M. Kriener, T. Kurumaji, L. Spitz, S.
Gao, A. Kikkawa, Y. Yamasaki, H. Sagayama, H. Nakao, S. OhiraKawamura, Y. Taguchi, T. Arima, Y. Tokura,	High-field depinned phase and planar Hall effect in the skyrmion
host Gd2PdSi3
	Phys. Rev. B, 101 220401(R) (2020).
161	K. Iida, H. K. Yoshida, A. Nakao, H. O. Jeschke, Y. Iqbal, K. Nakajima,
S. Ohira-Kawamura, K. Munakata, Y. Inamura, N. Murai, M. Ishikado,
R. Kumai, T. Okada, M. Oda, K. Kakurai, M. Matsuda,	
q = 0 l o n g - ra n g e m a g n e t i c o r d e r i n ce n t e n n i a l i t e
CaCu3(OD)6Cl2⋅0.6D2O: A spin-1/2 perfect kagome antiferromagnet
with J1−J2−Jd	Phys. Rev. B, 101 220408(R) (2020).
162	S. Uechi, K. Ohoyama, Y. Fukumoto, Y. Kanazawa, N. Happo, M.
Harada, Y. Inamura, K. Oikawa, W. Matsuhra, F. Iga, A. K. R. Ang, K.
Hayashi,	Behavior of Sm in the boron cage of Sm-doped RB6 (R =Yb, La) observed by multiple-wavelength neutron holography	Phys. Rev. B, 102 54104 (2020).
163	Y. Araki, T. Sato, Y. Fujima, N. Abe, M. Tokunaga, S. Kimura,
D. Morikawa, V. Ukleev, Y. Yamasaki, C. Tabata, H. Nakao, Y.
Murakakmi, H. Sagayama, K. Ohishi, Y. Tokunaga, T. Arima,	Metamagnetic transitions and magnetoelectric responses in the chiral polar helimagnet Ni2InSbO6

MLF Annual Report 2020	Phys. Rev. B, 102 54409 (2020).
164	J. Sugiyama, I. Umegaki, S. Takeshita, H. Sakurai, S. Nishimura, O.
K. Forslund, E. Nocerino, N. Matsubara, M. Månsson, T. Nakano, I.
Yamauchi, K. Ninomiya, M. K. Kubo, K. Shimomura,	Nuclear magnetic field in Na0.7CoO2 detected with μ−SR	Phys. Rev. B, 102 144431 (2020).
165	H. Takahashi, K. Aono, Y. Nambu, R. Kiyanagi, T. Nomoto, M.
Sakano, K. Ishizaka, R. Arita, S. Ishiwata,	Competing spin modulations in the magnetically frustrated semimetal EuCuSb	Phys. Rev. B, 102 174425 (2020).
166	C. Kim, J. Jeong, P. Park, T. Masuda, S. Asai, S. Itoh, H.-S. Kim, A.
Wildes, J.-G. Park,	Spin waves in the two-dimensional honeycomb lattice XXZ-type vander Waals antiferromagnet CoPS3	Phys. Rev. B, 102 184429 (2020).
167	D. Zhang, X. Hu, T. Chen, D. L. Abernathy, R. Kajimoto, M. Nakamura,
M. Kofu, B. J. Foley, M. Yoon, J. J. Choi, S.-H. Lee,	Temporally decoherent and spatially coherent vibrations in metal
halide perovskites
	Phys. Rev. B, 102 224310 (2020).
168	H. Tamatsukuri, Y. Murakami, Y. Kuramoto, H. Sagayama, M.
Matsuura, Y. Kawakita, S. Matsuishi, Y. Washio, T. Inoshita , N.
Hamada, H. Hosono,	Magnetism induced by interlayer electrons in the quasi-two-dimensional electride Y2C: Inelastic neutron scattering study	Phys. Rev. B, 102 224406 (2020).
169	S. Gao, F. Xiao, K. Kamazawa, K. Ikeuchi, D. Biner, K. W. Krämer, C.
Rüegg, T. Arima,	Crystal electric field excitations in the quantum spin liquid candidate
NaErS2	Phys. Rev. B, 102 024424 (2020).
170	M. Fujita, K. M. Suzuki, S. Asano, H. Okabe, A. Koda, R. Kadono, I.
Watanabe,	Magnetic behavior of T’-type Eu2CuO4 revealed by muon spin rotation and relaxation measurements	Phys. Rev. B, 102 045116 (2020).
171	N. Katayama, H. Takeda, T. Yamaguchi, Y. Yamada, K. Iida, M.
Takigawa, Y. Ohta, H. Sawa,
	Robust atomic orbital in the cluster magnet LiMoO2
	Phys. Rev. B, 102 081106(R) (2020).
172	T. Yamamoto, T. Okudaira, S. Endo, H. Fujioka, K. Hirota, T. Ino, K.
Ishizaki, A. Kimura, M. Kitaguchi, J. Koga, S. Makise, Y. Niinomi,
T. Oku, K. Sakai, T. Shima, H. M. Shimizu, S. Takada, Y. Tani, H.
Yoshikawa, T. Yoshioka,	Transverse asymmetry of γ rays from neutron-induced compoundstates of 140La
	Phys. Rev. C, 101 064624 (2020).
173	H. Singh, D. Ray, S. Kumar, S. Takata, V. K. Aswal, H. Seto,	Probing the adsorption of nonionic micelles on different-sized
nanoparticles by scattering techniques	Phys. Rev. E, 102 62601 (2020).
174	S. Allenspach, A. Biffin, U. Stuhr, G. S. Tucker, S. Ohira-Kawamura,
M. Kofu, D. J. Voneshen, M. Boehm,B. Normand, N. Laflorencie, F.
Mila, Ch. Rüegg,	Multiple Magnetic Bilayers and Unconventional Criticality without
Frustration in BaCuSi2O6
	Phys. Rev. Lett., 124 177205 (2020).
175	J. Guo, X. Zhao, S. Ohira-Kawamura, L. Ling, J. Wang, L. He, K.
Nakajima, B. Li, Z. Zhang,

MLF Operations in 2020

	Magnetic-ﬁeld and composition tuned antiferromagnetic instability
in the quantum spin-liquid candidate NaYbO2
	Phys. Rev. Mater., 4 64410 (2020).
176	K. Kuramochi, T. Shimano, T. Nishio, H. Okabe, A. Koda, K. Horigane,
J. Akimitsu, H. Ogino,	Synthesis and physical properties of the new iridium oxyfluoride
Sr2Ir(O,F)6-d using a topochemical reaction method	Phys. Rev. Mater., 4 013403 (2020).
177	R. Takahama, T. Ishii, D. Indo, M. Arizono, C. Terakura, Y. Tokura, N.
Takeshita, M. Noda, H. Kuwahara, T. Saiki, T. Katsufuji , R. Kajimoto,
T. Okuda,
	Structural, magnetic, transport and thermoelectric properties of thepseudobrookite AlTi2O5-Ti3O5 system	Phys. Rev. Mater., 4 074401 (2020).
178	S. Shamoto, Y. Yasui, M. Matsuura, M. Akatsu, Y. Kobayashi, Y.
Nemoto, J. Ieda,
	Ultralow-energy magnon anomaly in yttrium iron garnet	Phys. Rev. Res., 2 33235 (2020).
179	T. Nakajima, T. Oda, M. Hino, H. Endo, K. Ohishi, K. Kakurai, A.
Kikkawa, Y. Taguchi, Y. Tokura, T. Arima,	Crystallization of magnetic skyrmions in MnSi investigated by neutron spin echo spectroscopy	Phys. Rev. Res., 2 43393 (2020).
180	K. Nawa, D. Hirai, M. Kofu, K.i Nakajima, R. Murasaki, S. Kogane, M.
Kimata, H. Nojiri, Z. Hiroi, T. J. Sato,	Bound spinon excitations in the spin- 1/2 anisotropic triangular antiferromagnet Ca3ReO5Cl2
	Phys. Rev. Res., 2 043121(11pages) (2020).
181	Y. Sakaguchi, T. Hanashima, A.-A. A. Simon, M. Mitkova,
	Excitation Light Energy Dependence of Silver Photodiffusion into
Amorphous Germanium Sulfide: Neutron and X-Ray Reflectivity and
X-Ray Diffraction
	Phys. Status Solidi. B Basic Solid State Phys., 257 2000178 (2020).
182	N. Kitamura, Y. Araki, N. Ishida, Y. Idemoto,	Local Structures in Disordered Rocksalt-Type Li3NbO4- Based Positive
Electrode Materials for a Lithium-Ion Battery	Phys. Status Solidi. B Basic Solid State Phys., 257 2000112-1-7(2020).
183	H. Saitoh, A. Machida, T. Hattori, A. Sano-Furukawa, K. Funakoshi,
T. Sato, S. Orimo, K. Aoki,	Neutron diffraction study on the deuterium composition of nickel
deuteride at high temperatures and high pressures
	Physica B Condens. Matter., 587 412153 (2020).
184	Y. Sue, M. Yotsuzuka, K. Futatsukawa, K. Hasegawa, T. Iijima, H.
Iinuma, K. Inami, K. Ishida, N. Kawamura, R. Kitamura, Y. Kondo,
T. Mibe, Y. Miyake, T. Morishita, Y. Nakazawa, M. Otani, N. Saito, K.
Shimomura, Y. Takeuchi, T. Ushizawa, T. Yamazaki, H. Yasuda,	Development of a bunch-width monitor for low-intensity muon
beam below a few MeV	Physical Review Accelerators and Beams, 23 022804 (2020).
185	S. Meigo, M. Ooi, H. Fujimori,	Two-parameter model for optimizing target beam distribution withan octupole magnet
	Physical Review Accelerators and Beams, 23 062802 (2020).
186	Y. Kimura, M. Ouchi, T. Terashima,	Folded amphiphilic homopolymer micelles in water: uniform selfassembly beyond amphiphilic random copolymers
	Polym. Chem., 11 5156 (2020).
187	D. Ito, Y. Kimura, M. Takenaka, M. Ouchi, T. Terashima,	Single-chain crosslinked polymers via the transesterification of183

MLF Operations in 2020

MLF Annual Report 2020

folded polymers: from efficient synthesis to crystallinity control
	Polym. Chem., 11 5181 (2020).
188	K. Akutsu-Suyama, H. Kira, N. Miyata, T. Hanashima, T. Miyazaki, S.
Kasai, D. Yamazaki, K. Soyama, H. Aoki,	Fine-structure analysis of perhydropolysilazane-derived nano layers
in deep-buried condition using polarized neutron reflectometry
	Polymers, 12 2180 (2020).
189	S. Makimura, S. Matoba, N. Kawamura,	Status and Future Prospect of Muon Target at J-PARC MLF
	PoS (NuFACT2019), 369 124 (2020).
190	H. Natori,	Development of very slow negative muon beam
	PoS (NuFACT2019), 369 090 (2020).
191	T. Murakawa, K. Kurihara, M. Shoji, C. Shibazaki, T. Sunami, T.
Tamada, N. Yano, T. Yamada, K. Kusaka, M. Suzuki, Y. Shigeta, R.
Kuroki, H. Hayashi, T. Yano, K. Tanizawa, M. Adachi, T. Okajima,	Neutron crystallography of copper amine oxidase reveals keto/enolate interconversion of the quinone cofactor and unusual proton
sharing	Proc. Natl. Acad. Sci. U. S. A., 117 10818-10824 (2020).
192	Y. Fukuda, Y. Hirano, K. Kusaka, T. Inoue, T. Tamada,	High-resolution neutron crystallography visualizes an OH-boundresting state of a copper-containing nitrite reductase
	Proc. Natl. Acad. Sci. U. S. A., 117 4071-4077 (2020).
193	K. Komatsu, S. Klotz, S. Machida, A. Sano-Furukawa, T. Hattori, H.
Kagi,
	Anomalous hydrogen dynamics of the ice VII-VIII transition revealedby high-pressure neutron scattering	Proc. Natl. Acad. Sci. U. S. A., 117 6356-6361 (2020).
194	K. Moriyama, T. Nakatani,	Public cloud-based remote access infrastructure for neutron scattering experiments at MLF, J-PARC
	Proceedings of the 17th International Conference on Accelerator
and Large Experimental Physics Control Systems, 707-713 (2020).
195	J. Beare, G. Beer, J. H. Brewer, T. Iijima, K. Ishida, M. Iwasaki, S.
Kamal, K. Kanamori, N. Kawamura, R. Kitamura, S. Li, G. M. Luke,
G. M. Marshall, T. Mibe, Y. Miyake, Y. Oishi, K. Olchanski, A. Olin, M.
Otani, M. A. Rehman, N. Saito, Y. Sato, K. Shimomura, K. Suzuki, M.
Tabata, H. Yasuda,	Study of muonium emission from laser-ablated silica aerogel	Prog. Theor. Exp. Phys., 2020 123C01 (2020).
196	K. Hirota, G. Ichikawa, S. Ieki, T. Ino, Y. Iwashita, M. Kitaguchi, R.
Kitahara, J. Koga, K. Mishima, A. Morishita, N. Nagakura, H. Oide,
H. Okabe, H. Otono, Y. Seki, D. Sekiba, T. Shima, H. M. Shimizu, N.
Sumi, H. Sumino, T. Tomita, H. Uehara, T. Yamada, S. Yamashita, M.
Yokohashi, T. Yoshioka,	Neutron lifetime measurement with pulsed cold neutrons	Prog. Theor. Exp. Phys., 2020 123C02 (2020).
197	T. Tanaka, K. Hagiwara, E. Gazzola, A. Ali, I. Ou, T. Sudo, P. K. Das, M.
S. Reen, R. Dhir, Y. Koshio, M. Sakuda, A. Kimura, S. Nakamura, N.
Iwamoto, H. Harada, G. Collazuol, S. Lorenz, M. Wurm, W. Focillon,
M. Gonin, T. Yano,	Gamma-ray spectra from thermal neutron capture on gadolinium-155 and natural gadolinium	Progress of Theoretical and Experimental Physics, 2020 043D02(2020).
198	A. Momose, H. Takano, Y. Wu, K. Hashimoto, T. Samoto, M. Hoshino,
Y. Seki, T. Shinohara,	Recent Progress in X-ray and Neutron Phase Imaging with Gratings	Quantum Beam Science, 4 9 (2020).

199	O. Takahashi, Y. Shibui, P. G. Xu, S. Harjo, T. Suzuki, Y. Tomota,
	Microstructural Features and Ductile-Brittle Transition Behavior in
Hot-Rolled Lean Duplex Stainless Steels
	Quantum Beam Science, 4 16 (2020).
200	Y. Wang,	Phase Stress Measurement of Centrifugally Cast Duplex StainlessSteel by Neutron Diffraction	Quantum Beam Science, 4 28 (2020).
201	Y. Noda, H. Izunome, T. Maeda, T. Inada, S. Ueda, S. Koizumi,	The Large-Area Detector for Small-Angle Neutron Scattering on iMATERIA at J-PARC
	Quantum Beam Science, 4 32 (2020).
202	Y. Noda, T. Maeda, T. Oku, S. Koizumi, T. Masui, H. Kishimoto,	First Experiment of Spin Contrast Variation Small-Angle Neutron
Scattering on the iMATERIA Instrument at J-PARC
	Quantum Beam Science, 4 33 (2020).
203	K. Nakagawa, M. Hayashi, K. Takano-Satoh, H. Matsunaga, H. Mori,
K. Maki, Y. Onuki, S. Suzuki, S. Sato,	Characterization of Dislocation Rearrangement in FCC Metals during Work Hardening Using X-ray Diffraction Line-Profile Analysis
	Quantum Beam Science, 4 36 (2020).
204	S. Koizumi, Y. Noda, T. Maeda, T. Inada, S. Ueda, T. Fujisawa, H.
Izunome, R. A. Robinson, H. Frielinghaus,	Advanced Small-Angle Scattering Instrument Available in the Tokyo
Area. Time-of-Flight, Small-Angle Neutron Scattering Developed on
the iMATERIA Di ractometer at the High Intensity Pulsed Neutron
Source J-PARC
	Quantum Beam Science, 4 42 (2020).
205	Y. Onuki, S. Sato,	In Situ Observation for Deformation-Induced Martensite
Transformation (DIMT) during Tensile Deformation of 304 StainlessSteel Using Neutron Diffraction. PART I: Mechanical Response	Quantum Beam Science, 4 44227 (2020).
206	V. Sonnenschein, Y. Tsuji, S. Kokuryu, W. Kubo, S. Suzuki, H. Tomita,
Y. Kiyanagi, T. Iguchi, T. Matsushita, N. Wada, M. Kitaguchi, H. M.
Shimizu, K. Hirota, T. Shinohara, K. Hiroi, H. Hayashida, W. Guo, D.
Ito, Y. Saito,
	An experimental setup for creating and imaging 4He2∗ excimer cluster
tracers in superfluid Helium-4 via neutron-3He absorption reaction
	Rev. Sci. Instrum., 91 33318 (2020).
207	T. Shinohara , T. Kai , K. Oikawa , T. Nakatani, M. Segawa, K. Hiroi,
Y. Su, M. Ooi, M. Harada, H. Iikura, H. Hayashida, J. D. Parker , Y.
Matsumoto, T. Kamiyama, H. Sato, Y. Kiyanagi,	The energy-resolved neutron imaging system, RADEN
	Rev. Sci. Instrum., 91 043302 (2020).
208	K. Arai, Y. Horikawa, T. Shikata, H. Iwase,	Reconsideration of the conformation of methyl cellulose and hydroxypropyl methyl cellulose ethers in aqueous solution
	RSC Adv., 10 19059 (2020).
209	M. Naeem, H. He, F. Zhang, H. Huang, S. Harjo, T. Kawasaki, B.
Wang, S. Lan, Z. Wu, F. Wang,	Cooperative deformation in high-entropy alloys at ultralow
temperatures	Sci. Adv., 6 eaax4002 (2020).
210	Y. K. Kshetri, T. Kamiyama, S. Torii, S. H. Jeong, T.-H. Kim, H. Choi, J.
Zhou, Y. P. Feng, S. W. Lee,	Electronic structure, thermodynamic stability and high temperaturesensing properties of Er-α-SiAlON ceramics
	Sci. Rep., 10 4952 (2020).
211	H. Saitoh, A. Machida, R. Iizuka-Oku, T. Hattori, A. Sano-Furukawa,

184

MLF Annual Report 2020

K. Funakoshi, T. Sato, S. Orimo, K. Aoki,	Crystal and Magnetic Structures of Double Hexagonal Close-Packed
Iron Deuteride	Sci. Rep., 10 9934 (2020).
212	S. Sato, S. Irie, Y. Nagamine, T. Miyazaki, Y. Umeda,
	Antiferromagnetism in perfectly ordered L10-MnAl with stoichiometric composition and its mechanism	Sci. Rep., 10 12489 (2020).
213	S. Yamamoto, K. Ninomiya, N. Kawamura, Y. Hirano,	Optical imaging of muons	Sci. Rep., 10 20790 (2020).
214	R. Inoue, T. Oda, H. Nakagawa, T. Tominaga, T. Saio, Y. Kawakita,
M. Shimizu, A. Okuda, K. Morishima, N. Sato, R. Urade, M. Sato, M.
Sugiyama,	Dynamics of proteins with different molecular structures under solution condition
	Sci. Rep., 10 21678 (2020).
215	W. Woo, J. S. Jeong, D.-K. Kim, C. M. Lee, S.-H. Choi, J.-Y. Suh, S. Y.
Lee, S. Harjo, T. Kawasaki,	Stacking Fault Energy Analyses of Additively Manufactured StainlessSteel 316L and CrCoNi Medium Entropy Alloy Using In Situ Neutron
Diffraction
	Sci. Rep., 10 43845 (2020).
216	E. Shoji, S. Isogai, R. Suzuki, M. Kubo, T. Tsukada, T. Kai, T. Shinohara,
Y. Matsumoto, H. Fukuyama,	Neutron computed tomography of phase separation structures insolidified CuCo alloys and investigation of relationship between the
structures and melt convection during solidification
	Scr. Mater., 175 29 (2020).

MLF Operations in 2020224	Y. Onuki, T. Masumura, T. Tsuchiyama, S. Sato, T. Tomida, S. Takaki,	Mutual Verification of Phase Fraction Analysis Techniques for Steels
Comprising Deformation Induced Martensite Phases: NeutronDiffraction-Based Rietveld Texture Analysis and Saturation
Magnetization Measurement
	Tetsu to Hagane, 106 457 (2020).
225	Y. Hosoya, Y. Matsumura, Y. Tomota, Y. Onuki, S. Harjo,	Mechanism of improved ductility of 1,500 MPa-class ultra-highstrength cold-rolled steel sheet produced by rolling and partitioning
method	Tetsu to Hagane, 106 154-164 (2020).
226	Y. Tomota, Y. X. Wang, T. Ohmura, N. Sekido, S. Harjo, T. Kawasaki,
W. Gong, A. Taniyama,	In situ Neutron Diffraction on Ferrite and Pearlite Transformations
for a 1.5Mn-1.5Si-0.2C Steel	Tetsu to Hagane, 106 262-271 (2020).
227	Y. Sakaguchi, T. Hanashima, A.-A. A. Simon, M. Mitkova,
	Silver photodiffusion into amorphous Ge chalcogenides - Excitation
photon energy dependence of the kinetics probed by neutronreflectivity
	The European Physical Journal Applied Physics, 90 30101 (2020).
228	Y. Sakaguchi, K. Tamura,	Photo-induced effects on amorphous and liquid selenium by pulsed
laser illumination -Photo-induced structural changes in a network of
selenium chains	Z. Phys. Chem., 235 189-212 (2020).

217	T. Yamashita,S. Morooka, S. Harjo, T. Kawasaki, N. Koga, O.
Umezawa,	Role of retained austenite in low alloy steel at low temperature monitored by neutron diffraction	Scr. Mater., 177 43992 (2020).
218	K. Cho, R. Morioka, S. Harjo, T. Kawasaki, H. Y. Yasuda,	Study on formation mechanism of {332} < 113 > deformation
twinning in metastable β-type Ti alloy focusing on stress-induced
α”martensite phase	Scr. Mater., 177 106-111 (2020).
219	Z. Deng, K. Chu, Q. Li, Y. Onuki, Q. Sun,	Elinvar property of cold-rolled NiTi alloy	Scr. Mater., 187 197-201 (2020).
220	M. Naeem, H. He, S. Harjo, T. Kawasaki, F. Zhang, B. Wang, S. Lan, Z.
Wu, Y. Wu, Z. Lu,
	Extremely high dislocation density and deformation pathway of
CrMnFeCoNi high entropy alloy at ultralow temperature	Scr. Mater., 188 21-25 (2020).
221	N. Ishida, Y. Nakamura, T. Mandai, N. Kitamura, Y. Idemoto,	Synthesis, cathode property and crystal, electronic and local structures of Mg2Mo3O8 as Mg rechargeable battery cathode material	Solid State Ion., 354 115413 (2020).
222	R. Li, Z. Liu, L. Li, J. Huang, T. Yamada, V. G. Sakai, P. Tan, L. Hong,	Anomalous sub-diffusion of water in biosystems: From hydrated protein powders to concentrated protein solution to living cells
	Struct. Dyn., 7 054703 (2020).
223	J. Kim, S. Yamanaka, I. Murayama, T. Katou, T. Sakamoto, T.
Kawasaki, T. Fukuda, T. Sekino, T. Nakayama, M. Takeda,
	Pyroelectric power generation from the waste heat of automotive
exhaust gas
	Sustain. Energy Fuels, 4 1143 (2020).

185

Editorial Board

MLF Annual Report 2020

Editorial Board - MLF Annual Report 2020

Chief Editor

Kazuhiro Akutsu

Yuhua SuTechnology Development Section

CROSS

Kazuki Iida

186

Takashi Naoe

CROSS

Neutron Source Section

Miho Igarashi

Yukinori Nagatani

CROSS

Muon Science Section

Takashi Ino

Takeshi Matsukawa

Neutron Science Section

Ibaraki University

Kenichi Oikawa

Dai Yamazaki

Neutron Science Section

Neutron Instrumentation Section

J-PARC

Japan Proton Accelerator Research Complex

High Energy Accelerator Research Organization (KEK)
Japan Atomic Energy Agency (JAEA)

http://j-parc.jp/
Materials and Life Science Division
J-PARC Center

https://mlfinfo.jp/en
Comprehensive Research Organization for Science and Society

https://neutron.cross.or.jp/en

J-PARC 21-02