J-PARC
ANNUALREPORT2 O 1 9Vol.2: Materials and Life Science
Experimental Facility

MLF
ANNUALREPORTCover photographs
1 : Experimental setup at BL11 PLANET.
2 : Poster presentation at the J-PARC Symposium 2019.
3 : Participants at the 4th Neutron and Muon School and MIRAIPhD School 2019 take a tour inside the BL15 TAIKAN detector.

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4 : Ceremony to mark the 10-year Anniversary of J-PARC at the
J-PARC Symposium 2019.
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5 : Site visit to the neutrino facility during the 4th Neutron andMuon School and MIRAI PhD School 2019.
6 : An awards ceremony at the J-PARC Symposium 2019.

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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 20-02

MLF Annual Report 2019

Preface

PrefaceToshiya Otomo

Division Head of Materials and Life Science Division, MLF
In fiscal year 2019, continuous efforts had been made for establishing stable operations of neutron and muontargets with high-power proton beam at the Materials and Life Science Experimental Facility (MLF). MLF ran the user
program for 8 months with the proton beam power of 500 kW demonstrating the durability of the neutron mercury
target and the graphite muon target under such power level. The validity of the system design to accommodate thefinal goal of 1-MW power was reconfirmed by a 1-MW test for ten hours on July 3. In the summer outage period,a newly designed mercury target vessel was installed to reduce the thermal stress on the target with the couplingfree structure between the inner mercury and the surrounding outer water. The muon target was also replaced witha brand-new spare in the summer outage. There are two lessons to be learned regarding the target operation: one is
the gas processing of the neutron target which took longer than expected to secure its operation with sufficient radiation safety and the other is the replacement of the whole muon target system after a high-proton power operation
minimizing the risk of radiation hazard during the replacement work. These experiences will result in a more robust
and reliable system improvements.
Due to the stable operation of the facility, the MLF was able to produce many outcomes in various research fields.
The research activities at the MLF resulted in more than 150 papers and 12 press releases. For realization of new
instruments, the commissioning of a polarized neutron inelastic instrument, POLANO, and the continued efforts toincrease the ultraslow muon intensity at the U-Line were in progress. New devices were developed, such as a brandnew T0 chopper, an elliptical focusing mirror and a two-dimensional neutron detector whose spatial resolution isabout 200 mm. Naturally, safety research was also essential to these research activities at MLF.
Maintaining the expansion of the total activities at MLF, we kept collaborating not only with domestic but alsowith foreign scientific facilities, such as ANSTO (Australia) and CSNS (China), in the areas of personnel, technique, andresearch exchange. Also, we were making efforts to communicate with members of the neutron and muon society
through the annual meeting of industrial application at MLF held on July 18 and 19 (282 participants), the J-PARC
symposium (909 participants), the 4th Neutron-Muon School (MIRAI PhD School) held from October 28 to November
2 (41 participants), and the CROSSroads Workshop (70 participants).
At the end of JFY2019, the COVID-19 pandemic affected the user program mainly because users could not travel
to J-PARC, even though the applied proposals reached a record number in 2019B. Some of the planned experiments
were done by instrument groups and others were carried over. Quantum Beam Science Festa, which is an annual conference mainly for domestic users of MLF J-PARC and IMSS KEK, was planned to be held in Mito on March 12 and 13,
2020, but was canceled due to COVID-19.
In the annual report, the research highlights and technical developments in 2019 are described in detail.

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

MLF Annual Report 2019

Preface

Mitsuhiro Shibayama

Director, CROSS

As a member of the Materials and Life Science Experimental Facility (MLF), the Comprehensive Research
Organization for Science and Society (CROSS) is honored to release the J-PARC MLF ANNUAL REPORT 2019, 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, appointed in 2011 by theGovernment of Japan, and it also supports the activities of the MLF. CROSS is engaged in operating the user program
and running 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 2019, the neutron beam was stably operated mostly at 500 kW, which ensured highly reliable machine operation even though in 2019B, the operation period was shortened due to a target problem. As of July 7, 2020, the total
number of neutron proposals conducted at the MLF was 357 and the number of scientific papers published from MLF
in 2019 was 153 (excluding proceedings). The details are included in the Research and Development Highlights collected in this volume. As for the Public Beamlines, 163 proposals (46% of the total neutron proposals) were conducted
and 56 papers were published. Furthermore, 9 press releases came from the Public Beamlines. These numbers illustrate
the high activities of the Public Beamlines, which have been used by a wide range of users from the academia andvarious industries.
It should be emphasized that a new web page “J-PARC MLF Next to Meet@MLF” was released in 2019(https://mlfinfo.jp/en/), which delivers up-to-date information on the MLF. For example, the “Statistics” page releasedin November 2019 (https://mlfinfo.jp/en/aboutmlf/statistics.html), reports the statistics of the user program, beam
operation, and the achieved results. The special program for new users “New User Promotion (NUP)”, which started in2016, was operated also in 2019, and 11 NUP neutron users conducted experiments at the MLF. Long-Term Proposals,
started in 2017B, continued its successful run in 2019. J-PARC Join, an entry web page of J-PARC MLF also played an important role as a window for potential users, where CROSS members, together with four Science Coordinators, served
as consultants. As a new activity of CROSS, Functional Polymer Consortium was launched in 2019. The consortium
consists of five chemical companies and universities, and it has common scientific goals, namely, understanding thestructure/properties of polymer and inorganic material interface in humid conditions.
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 extend a warm welcome tothe past, current, and future MLF users.

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
Strong Local Moment Antiferromagnetic Spin Fuctuations in V-Doped LiFeAs··········································································

2

Quantum Dynamics of Hydrogen in the Iron-Based Superconductor Measured
with Inelastic Neutron Spectroscopy····················································································································································

5

The Effects of Metal Cations on the Hydration Water between Phospholipid Bilayers·····························································

8

Sliding Motion of Ring Molecules in Polyrotaxane································································································································· 11
Neutron Crystallography Captures a Key Structure of Copper-containing Nitrite Reductase················································ 13
Discovery of a New Oxide-ion Conductor Dion–Jacobson Type CsBi2Ti2NbO10−δ and Structure Originof the High Oxide-ion Conductivity······················································································································································· 15Interstitialcy Diffusion Pathways of F-Ions in Ba0.6La0.4F2.4 Solid Electrolyte Material·································································· 18
Measurement of Neutron Scattering Cross Section of Nano-Diamond for Cold Neutron Intensity Enhancement········ 20
Ice Ic without Stacking Disorder by Evacuating Hydrogen from Hydrogen Hydrate·································································· 22
Novel Excitations Near Quantum Criticality in Geometrically Frustrated Antiferromagnet CsFeCl3···································· 24
Triplon Band Splitting and Topologically Protected Edge states in the Dimerized Antiferromagnet·································· 26
Localized Magnetic Excitations in the Fully Frustrated Dimerized Magnet Ba2CoSi2O6Cl2······················································· 28
Magnetic Skyrmion Lattice in a Centrosymmetric Breathing Kagome Lattice············································································· 31
Multiple Structural Level Morphology of Sulfonated sPS Membranes Resolved by SANS······················································ 33
Thickness of the Ethanol/Water Surface Layer········································································································································· 36
Development of Spin-Contrast-Variation Neutron Reflectometry··································································································· 38
Magnetic Multilayer with Quasi Antiferromagnetic Layer Studied by Polarized Neutron Reflectometry·························· 41
Nonlinear Piezomagnetoelectric Effect in CuFeO2·································································································································· 44
In-situ Neutron Diffraction Analysis on Dynamic Ferrite Transformation in Steels····································································· 46
Phase Stress Evolution under Cryogenic Tensile Loading···················································································································· 49
Ferroelectric Polarization in Tetragonal (Bi1/2K1/2)TiO3–(Bi1/2Na1/2)TiO3 Single Crystals································································ 51
Origin of the Mixed Alkali Effect in Silicate Glass····································································································································· 54
Neutron CT to Investigate Relationship between the Phase Separation Structures and Melt Convection
during Solidification in Cu-Co Alloys····················································································································································· 57
Electronic Structure of Hydrogen in In-Ga-Zn-O Semiconductor Simulated by Muon····························································· 59

Neutron Source
Neutron Source Section···················································································································································································· 62
Improvement of Gas Supply System for Mitigation of Pitting Damage in Mercury Target Vessel········································· 64
Nuclide Analysis of the Irradiated Target Vessel······································································································································ 66
The Status of the Cryogenic Hydrogen System······································································································································· 69

Neutron Science
Neutron Science Section·················································································································································································· 74
BL01: 4D-Space Access Neutron Spectrometer 4SEASONS················································································································· 76
Current Status of BL02 DNA in 2019····························································································································································· 78
Current Status of iBIX (BL03) in 2019··························································································································································· 80
Stellar Neutron Capture Cross Section of 191Ir··········································································································································· 82
Status of Fundamental Physics Beamline BL05 (NOP) in 2019······································································································· 84
BL06: Commissioning Status of Village of Neutron Resonance Spin Echo Spectrometers (VIN ROSE)······························· 86
Commissioning of 3He Cryostat on Super-HRPD····································································································································· 88
Current Status of BL09 (SPICA) in 2019······················································································································································· 90
BL10: NOBORU····································································································································································································· 92
Recent Developments in High-PT Experiments Using the Multi-Anvil Press “ATSUHIME” at BL11········································ 93
High Resolution Chopper Spectrometer HRC·········································································································································· 95
BL14 AMATERAS·································································································································································································· 97
Upgrading TAIKAN······························································································································································································ 99
Neutron Reflectometry Using Focusing Mirror at BL16 SOFIA··········································································································· 100
Current Status of SHARAKU: Polarized Neutron Reflectometer········································································································· 102
Status of SENJU 2019························································································································································································· 104
Engineering Material Diffractometer TAKUMI·········································································································································· 106
The Current Status of the Versatile Neutron Diffractometer, iMATERIA·························································································· 108
Status of the High Intensity Total Diffractometer (BL21, NOVA)········································································································ 110
Status of the Energy-Resolved Neutron Imaging System RADEN····································································································· 112
Polarized Neutron Spectrometer POLANO················································································································································ 114
AFP NMR Amplifier for 3He Neutron Spin Filter········································································································································ 116
Sample Environment at MLF··········································································································································································· 118
Development and Application of 3He Spin Filter····································································································································· 120
Statistically Optimal Bin-widths Prediction to Histogram Experimental 4D Inelastic Neutron
Scattering Intensity Distributions··························································································································································· 121
Real-Time Data Display and Storage Device with Simple Functions for Easy Adjustmentsof a Two-Dimensional Detector······························································································································································· 124Muon Science
MUSE Facility Overview···················································································································································································· 128
Present Status of Muon-Beam Source, M2 Tunnel·································································································································· 130
Report of Rotating Target at MLF·································································································································································· 132
Monitoring System for the Muon Rotating Target·································································································································· 134
Current Status of μSR Experiment at D1····················································································································································· 135
Negative Muon Commissioning at D1/D2 Areas····································································································································· 136
Development of Sample Environment at S1 Area·································································································································· 138
USM Commissioning at U1B area·································································································································································· 140
H-Line Construction – Recent Progress······················································································································································· 141

MLF Safety
Research Safety···································································································································································································· 144

MLF Operations in 2019
Beam Operation Status at the MLF······························································································································································· 148
Users at the MLF·································································································································································································· 150
MLF Proposals Summary – FY2019······························································································································································· 151
MLF Division Staff 2019····················································································································································································· 153
CROSS Staff 2019································································································································································································· 156
Ibaraki Neutron Beamline Staff in 2019······················································································································································ 158
Proposals Review System, Committees and Meetings·························································································································· 159
Workshops, Conferences, Seminars and Schools in 2019···················································································································· 163
Award List·············································································································································································································· 166
MLF Publication 2019························································································································································································ 167
Editorial Board - MLF Annual Report 2019················································································································································· 176

Organization Chart

MLF Annual Report 2019

Organization 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 legislation that supports the
Public Neutron Beam Facility, CROSS is entrusted withspecific responsibilities. In practical terms, the corefunctions of CROSS can be summarized as follows:•	Proposal Selection and Beamtime Allocation on the
Public Beamlines•	User Support on the Public Beamlines•	Establishment of an Information Resource for Facility
Users•	Outreach and Facility Utilization Promotion•	Contract Beamline Assessment and Selection

MLF Annual Report 2019

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

25 m

1m

As of March 2020

MLF Annual Report 2019

400 ｍmMuon and Neutron Instruments

Research and Development
Highlights

Research and Development Highlights

MLF Annual Report 2019

Strong Local Moment Antiferromagnetic Spin
Fuctuations in V-Doped LiFeAs
1. Introduction
Orbital selectivity plays an important role iniron-based superconductors, which are essentiallymulti-orbital systems. Our previous inelastic neutron
scattering study reveals that Fermi surface nesting
can tune the strength of spin excitations due to intraorbital scattering and further affect the superconductivity in LiFeAs [1]. However, the effect of inter-orbital
scattering on spin excitations and superconductivity is
still unknown. In Vanadium-doped LiFeAs, a combined
study of angle-resolved photoemission spectroscopy(ARPES) and transport measurements have demonstrated that the non-Fermi-liquid behavior is associated with the Fermi surface (FS) nesting between thehole Fermi pocket of dyz/dxz orbital at the Brillouin zone
center and the electron pocket of dxy orbital characterat the corner [2]. However, the evidence of whether
such kind of FS nesting could affect spin excitations isstill missing.
In addition, based on the previous inelastic neutron
scattering experiments on the total spin-fluctuating
moment, the “122” and “111” families of iron pnictides
are suggested to have the same nature, where the effective spin-fluctuating moment Seff ≈ 1/2, except for
the LiFeAs and “11” families. Therefore, to fully understand the key ingredients of magnetism in iron-based
superconductors, it is important to figure out the evolution of Seff and the role of the itinerant or localized
moment plays in different hole-doped families, which
are believed to be more correlated and have large effective local moment.
2. Experiment
We prepared 7.2 g of LiFe0.955V0.045As single crystals,
which have a nearly perfect nesting between the dyz/dxz
hole pockets and the dxy electron pocket, and the superconductivity in this compound is completely suppressed. Among them, 1.8 g of the single crystals weresynthesized by using isotope 7Li to reduce the neutron
absorption. All samples were co-aligned and glued on
five 40 × 40 mm aluminum plates with the mosaic lessthan 5° in the glove box because of the air and humidity sensitivity of the samples. The inelastic neutron scattering experiment was carried out on the time-of-flight
4D-Space Access Neutron Spectrometer (4SEASONS) at
Materials and Life Science Experimental Facility (MLF).
2

The spectrometer was equipped with a highly efficientFermi chopper, which could provide the multi-Ei modewith moderate resolution to collect the weak inelastic
signals during the experiment.
3. Data analysis method
Due to the considerable unknown amount ofVanadium-containing flux from the growth of the single crystals used in our experiment, the traditional
normalized method to get the absolute magnetic
neutron-scattering intensity (by comparing it with the
Vanadium standard) is unreliable, therefore we used
the phonon normalization method, where we dealt
with our data of V-doped samples by comparing theintensity of its phonon with the same phonon of othersamples, which we have already carried out experiments on. Furthermore, we used the DFT+DMFT calculations to compute the electronic structure and spin
dynamics of V-doped LiFeAs in the paramagnetic state.
The DFT part is based on the full-potential linear augmented plane wave method implemented in WIEN2k
in conjunction with Perdew–Burke–Ernzerhof generalized gradient approximation [3] of the exchange correlation functional. DFT+DMFT is implemented on top of
WIEN2k and documented in ref. [4].
4. Results and conclusion
Our results compare the energy evolution of thespin excitations in LiFe0.955V0.045As with the calculations
based on the DFT+DMFT method for 10%-hole doping(about LiFe0.967V0.033As) (Fig. 1). Spin excitations display
a small elongation along the longitudinal direction at
3 ± 1 meV, as the energy transfer increases from E = 3
to E = 18 meV, the elongation of the elliptical spin fluctuations changes from the longitudinal to transverse
direction, which is similar to that in the hole-doped
Ba1−xKxFe2As2, indicating the hole–electron Fermi surface nesting contribution from itinerant electrons.
From the energy dependence of theoretical and experimental local dynamical spin susceptibility depictedin the illustration (Fig. 2(a)), the low-energy magnetic
excitations show a dramatical enhancement in the
Vanadium doping LiFeAs, and this is double-checked
through the constant-energy cuts result (Fig. 2(b)). We
argue that such a strong enhancement of observed
spin excitations cannot be simply attributed to theMLF Annual Report 2019

extra moments introduced by magnetic impurities.
Instead, we attributed the origin of such enhancement
to a “spin mixing” process with enhanced inter-orbital
scattering between dxz/yz and dxy orbitals. Our results
suggest that the inter-orbital scattering between dxz/yz
and dxy orbitals are bad for superconductivity and may
dynamically mix the spin states of Fe2+ ions.
Moreover, we summarize the evolution of the

Figure 1.	
The two-dimensional image of energy dependence of the magnetic scattering of LiFe0.955V0.045As
with that of the DFT+DMFT calculations.

Research and Development Highlights

effective magnetic moment Seff in different families,
including the results of the Vanadium doping in LiFeAs
from our experiment, and introduce a spin crossoverground state from the inter-orbital scattering of itinerant electrons to understand the enlarged Seff by doping
holes with Vanadium in LiFeAs (Fig. 3).
The work has been recently published in ref. [5].

Figure 2.	(a) Constant-energy cuts of spin excitations along
the transverse [1,K] (left) and longitudinal [H,0](right) directions for LiFeAs, LiFe0.88Co0.12As (electron
doping), and LiFe0.955V0.045As (hole doping) at E = 5± 1 meV, respectively. (b) Theoretical and experimental local dynamical spin susceptibility in LiFeAs,
LiFe0.88Co0.12As, LiFe0.955V0.045As, and BaFe2As2.

Figure 3.	(a) The effective spin Seff in various iron pnictide/chalcogenides superconductors obtained
from neutron-scattering experiments. NFA, BFA, and LFA represent NaFeAs, BaFe2As2, and
LiFeAs families, respectively. The energy integration range of χ” (E) for the LiFeAs family of materials varies from 0 to about 60 mev and thus does not represent the total local dynamic
susceptibility. (b) Schematics of the dynamic mixing of spin states with S = 0 and 1.

3

Research and Development Highlights

MLF Annual Report 2019

References[1] Y. Li et al., Phys. Rev. Lett., 116 247001 (2016).
[2] L. Y. Xing et al., Phys. Rev. B., 94 094524 (2016).

[3] J. P. Perdew et al., Phys. Rev. Lett., 77 3865 (1996).
[4] K. Haule et al., Phys. Rev. B, 81 195107 (2010).
[5] Z. Xu et al., npj Quantum Materials, 5 1 (2020).

Z. Xu1, R. Kajimoto2, K. Ikeuchi3, X. Lu1, and P. Dai4
1
Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University; 2Neutron Science Section, Materials and Life
Science Division, J-PARC Center; 3Neutron Science and Technology Center, CROSS; 4Department of Physics and Astronomy, Rice University

4

MLF Annual Report 2019

Research and Development Highlights

Quantum Dynamics of Hydrogen in the Iron-Based
Superconductor Measured with Inelastic Neutron
Spectroscopy
1. Introduction
In this study, we propose a direct method of detecting the superconducting gap in an iron-based superconductor via coupling to the hydrogen motion atinterstitial sites. If there are two or more interstitial sitesof hydrogen in the neighborhood, the overlap of wave
functions gives rise to the splitting of the hydrogen energy levels [1, 2]. This is known as tunneling splitting aspreviously observed in superconductors using inelastic
neutron scattering (INS) [1, 3]. The magnitudes of thetunneling splitting are usually much smaller in comparison with the superconducting gap. Here, we report thatthe hydrogen vibration in iron-based superconductors
is highly anharmonic at the interstitial sites. As a result,generalized tunneling splitting has an exceptionallylarge energy of the order of 10 meV. This means thatthe hydrogen motion serves as a good probe to thesuperconductivity. Such the local dynamics is not affected by the sample quality; thus, the hydrogen probe
has a unique advantage compared to conventional
spectroscopies.

were replaced for O2− anions. In addition, owing to atiny amount of H in the deuterated reagents, H and D
mixture is inevitable with the H/D ratio ~0.02. We also
prepared LaFeAsO0.9F0.1 (F-sample) under ambient pressure as the reference of D-sample. INS intensities for
D- and F-samples were measured using a chopper spectrometer (4SEASONS) [4] at BL01 in the pulsed-neutron
source in MLF at J-PARC. Data were collected at incident
neutron energies of Ei = 9.3, 17.5, and 44.5 meV [5]. The
time-of-ﬂight data from position-sensitive detectors
were converted into the Q-angle average S(Q, ħω) angle of the dynamical structure factor by the UTSUSEMI
program [6].
3. Results and discussion
Figure 1 illustrates S(Q, ħω) for D- and F-samples(SD and SF) with their difference SD−F [7]. We ﬁnd three
excitations at 6 K below Tc [Fig. 1(a)], all of which are insensitive to Q. However, they exhibit a strong diffusive
character over the entire energy range at 41 K above Tc[Fig. 1(b)]. In sharp contrast to SD, the results of SF exhibit
neither ﬂat excitations at 6 K [Fig. 1(c)] nor diffuse scattering at 41 K [Fig. 1(d)]. Instead, temperature-insensitive phonon scatterings are visible at ħω ≈ 12 meV. In
the difference map SD−F, the three distinct features U,

2. Experimental
We prepared a powder sample of FeAsO 0.9D 0.1(D-sample) under high pressure. Hydrogen anions (D−)

6K

(d)

(b)

(f)

41 K

5
0

1

2

30

1

2

Q (Å-1)

30

1

2

3

5
4

3
2

ћ ΓM

6K

TM

M

M
U
8

U

10 12 14 16ћω (meV)

ћΓU

3

1

15
10

(g)

TU

0

2

L

1

10

4

M

5
15

5

U

(e)

ћ Γ (meV)(c)ћω (meV)(a)

S D-F (Q 0 , ћω ) (arb. unit)

SD-F

SF

0

ћω (meV)

10

SD

Intensity (mbarn sr-1 meV-1 f.u.-1)

15

TU

2∆

ћω U

(h)
U
M

ћω M

TM

5
0
0

10

20

T (K)

Tc

30

Figure 1.	Color plots of S(Q, ħω) at 6 K (a), (c), (e), and 41 K (b), (d), (f ). The incident neutron energy is Ei = 17.5 meV. (a), (b) SD from Dsample; (c), (d) SF from F-sample; (e), (f ) the difference map SD−F. Temperature dependence of (g) the linewidth ħΓ(T) and (h)the peak position ħω for the U and M modes. Inset of (g) represents scattering intensities with incident neutron energy Ei =17.5 meV at 6 K for Q0 = 2.15 ± 0.15 Å−1. The green solid line shows the temperature dependence of the BCS gap function 2Δ(T).

5Research and Development Highlights

MLF Annual Report 2019M, and L are clearly observed in Fig. 1(e). Since D- andF-samples have almost the same electric and superconducting properties, the strong excitations in SD−F mustarise from hydrogen.
Inset of Fig. 1(g) displays the energy spectra of SD−F
at 6 K with Q0 = 2.15 ± 0.15 Å−1 [7]. We fit the scatteringpeaks by using a Lorentzian spectrum with a linewidthħΓ(T). Figure 1(g) plots the temperature dependence ofħΓ(T) for U and M modes. They indicate minute temperature dependence for T < 15 K, but increase rapidly
at around 20 K. Eventually, both linewidths are weakly
temperature dependent toward Tc ~ 26 K. Contrastingly,
each peak position ħω is nearly constant against temperature [Fig. 1(h)].
We deem that the rapid increase of ħΓ at T < Tc arises
from the coupling of the hydrogen motion and the electronic excitations. With increasing temperature toward
Tc, the superconducting gap Δ(T) decreases so as to satisfy ħω > 2Δ(T). Based on this mechanism, SD−F serves
as a probe for detecting the superconducting gap. Thechange of width is interpreted in terms of a Korringatype relaxation due to the conduction electrons, whichbecomes active as the superconducting gap decreases.

(b)

(a)

Firstly, we determine the inflection point of ħΓ at
TU and TM. Next, we evaluate the superconducting gap
Δ0 assuming the BCS-type gap dependence. The estimated value Δ0 = 7.8 ± 0.7 meV, which agrees reasonably well with the relation ħω = 2Δ(Tα) (α = U and M)[Fig. 1(h)]. The Δ0 gives the ratio 2Δ0 /kBTc = 7.0, whichcharacterizes this compound as a strong-coupling superconductor. According to the point-contact spectraon LaFeAsO0.9F0.1 [8], two gaps have been reported, Δ1 ≈7.9 meV and Δ2 ≈ 2.8 meV, the former of which matches
our result.
We proceed to consider the microscopic origin of
the observed excitations. In order to investigate the stable positions of the interstitial hydrogen, we carried out
ﬁrst-principles calculations using VASP code. Figures 2(a)and 2(b) illustrate the crystal structure LaFeAsO0.9D0.1
and the contour map of the calculated effective potential ΔE(r) on the xy plane at z = 0.425 [7]. Four potential
minima appear in at (0.11, 0.11, 0.425) and their crystallographically equivalent positions related by the fourfold rotational symmetry at Hint. A Bader charge analysis
gives the charge of hydrogen at Hint to be 1.33, implying
the interstitial hydrogen to be hydride.

0.5
H int
+
A

0.4

H int
+
D

(H,D)int
c
b

a

y

0.3
Fe
As

-2.3

0.2
B
+

O/(H,D)

0.1

La

0.0
0.0

-2.4
-2.5

-2.6

-2.4
-2

H int

0.1

0.3

0.2

C
+

-2.6

H int

0.4

0.5

x

(c)

(d)
3
2

A

1
2

– ћω 0

d

Vb
B

ψe

∆E

∆E

– ћω 0

C

D

A

ψg
– /d

0

/d

k
Figure 2.	(a) Crystal structure of LaFeAsO0.9D0.1 with the interstitial site Hint. (b) Contour map of hydrogen potential ΔE in
units of eV on the xy plane at z = 0. 425. (c) The line proﬁles of ΔE through the minima A-B-C-D-A of (b) on z =0.425. The tunneling distance d and the potential barrier Vb between the minima are described. The black andred dashed lines represent the ground state and the ﬁrst excited state, respectively. (d) The black line shows
the spectrum of the tunneling splitting, and the red line shows that of the highly anharmonic phonons called
as quantum rattling.

6

MLF Annual Report 2019

We consider the dynamics of the interstitial hydrogen. Figure 2(c) plots the line proﬁle through the minima A-B-C-D-A as seen in Fig. 2(b) [7]. This corresponds
to the pathway of hydrogen migration. The proﬁle features a periodic potential with a tunneling distance d =1.13 Å and potential barrier Vb = 102 meV. Assuming thesinusoidal potential, the angular frequency ω0 is givenby ω02 = 2π2Vb/(md2), where m is the isotope mass. We
obtain ħω0,H = 81 meV for H and ħω0,D = 57 meV for D.
Considering the cross section ratio σinc(H)/σinc(D) ≈ 40
and the concentration ratio nH/nD ≈ 0.02, the scattering
intensities from the two isotopes should be comparable. Hence, we propose that the U and M modes comefrom the interstitial H and D, respectively. The ratio ωU/ωM ≈ 1.3 is rather close to the square root of the atomic
mD/ˉ
mH = √ˉ
2. This might be regarded as themass ratio √ˉisotope effect for harmonic phonons.
We now check the possibility tunneling motion ofhydrogen for U and M modes. The magnitude of the tunneling splitting is known to be sensitive to the distanceand mass of the isotopes [1, 3]. For example, the tunneling splittings ratio ωH/ωD ≈ 10 for Nb [9] and ωH/ωD ≈4 for α-Mn [10] were reported. Hence, the present value
ωU/ωM ≈ 1.3 is not consistent with the identiﬁcation oftunneling splitting.
We here propose that the excitations at ħωU andħωM are associated with a different type of extremely
anharmonic phonons, which can be called quantum
rattling. In this consideration, the potential barrier is so
low that the ordinary excited state is actually extended
along the pathway connecting the four potential minima [Fig. 2(c)]. In the four potential minima system, theeigenstates are characterized by the wave numbers k= 0, ±π/(2d), and ±π/d, as described in Fig. 2(d). In addition, the eigenstates are related to the superpositionof localized phonons, which have energies (n+1/2)ħω0
with n = positive integer. If we assign ħωM = 11.1 meVResearch and Development Highlights

as the deuterium excitation from Ψg (k = 0) to Ψe (k =π/d), the corresponding protium excitation is expected
at 16.6 meV, which agrees with the experimental valueħωU = 14.5 meV.
4. Future Plans
The hydrogen spectroscopy has a unique feature
to scan along the temperature axis with a ﬁxed energy
against other spectroscopies scanning along the energy
axis. The hydrogen interstitial sites as calculated in thepresent work may be common in iron-based superconductors. Thus, we will try to determine the superconducting gaps for iron-based materials that lack single
crystals and include magnetic impurities. With a further
reﬁnement of both measurement and analysis, the hydrogen probe should provide more useful information
for clarifying the superconducting gap.
References[1] Y. Fukai, The Metal-Hydrogen System: Basic Bulk
Properties, Springer series in materials science Vol.
21 (Springer, Berlin, 2003).
[2] Hydrogen in Metals I: Basic Properties, Topics inApplied Physics Vol. 28, ed. by G. Alefeld and J. Völkl(Springer, Berlin, 1978).
[3] Hydrogen in Metals III: Properties and Applica-tions,
Topics in Applied Physics Vol. 73, ed. by H. Wipf
(Springer, Berlin, 1997).
[4] R. Kajimoto et al., J. Phys. Soc. Jpn., 80 SB025 (2011).
[5] M. Nakamura et al., J. Phys. Soc. Jpn., 78 093002(2009).
[6] Y. Inamura et al., J. Phys. Soc. Jpn., 82 SA031 (2013).
[7] J. Yamaura et al., Phys. Rev. B, 99 220505(R) (2019).
[8] R. S. Gonnelli et al., Eur. J. Phys., 7 251 (2009).
[9] A. Magerl et al., Phys. Rev. Lett., 56 159 (1986).
[10] A. I. Kolesnikov et al., Physica B, 263–264 421 (1999).

J. Yamaura1, H. Hiraka2, S. Iimura1, Y. Muraba1, J. Bang1, K. Ikeuchi4, M. Nakamura5, Y. Inamura5, T. Honda3, M. Hiraishi3, K. M. Kojima6,
R. Kadono3, Y. Kuramoto3, Y. Murakami1,3, S. Matsuishi1, and H. Hosono1
1
Materials Research Center for Element Strategy, Tokyo Institute of Technology; 2Korea Atomic Energy Research Institute; 3Institute ofMaterials Structure Science, KEK; 4Neutron Science and Technology Center, CROSS; 5Neutron Science Section, Materials and Life Science
Division, J-PARC Center; 6Centre for Molecular and Materials Science, TRIUMF

7

Research and Development Highlights

MLF Annual Report 2019

The Effects of Metal Cations on the Hydration Water
between Phospholipid Bilayers
1. Introduction
Specific ion effects on biological systems have attracted considerable attention in recent decades [1].
For biological membranes in physiological environments, the interactions between metal cations and lipid
headgroups are essential and significant. Monovalentand divalent cations such as Na+, K+, Mg2+, and Ca2+ exist in high concentrations in biological environments
and play important roles in regulating cell polarization and action potentials. The interactions of ions withmembranes also influence biological functions. Ions
bound to biological membranes reduce the membrane
dipole potential and influence the hydration structure.
Specific ion interactions with proteins are also important for various biological functions. For example, divalent cations such as Mg2+, Fe2+, and Zn2+ are importantfor certain enzymatic reactions.
Although the effects of salts on lipid bilayers havebeen intensively studied, several aspects of the mechanism by which salts affect the physical properties oflipid bilayers remain unclear. Recently, Alsop et al. studied the effects of divalent cations on lipid membranes
in stacked 1,2-dimyristyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers using high-resolution X-ray
diffraction (XRD) [2]. The location of cation bindingon the lipid membrane was found to depend on the
cation; Ca 2+ and Zn 2+ preferred to bind close to theglycerol group, while Mg2+ and Fe2+ bound near thephosphate group. Owing to the size effect, Fe 2+ receded further from the glycerol group compared to
Mg2+. The distance of the binding site from the lipidwater interface was found to increase in the following
order: Fe2+ < Mg2+ < Ca2+ < Zn2+. The number of watermolecules, nw, interacting with metal ions, was shownto correlate with the distance from the interface withapproximate nw values of 12 for Fe2+, 9 for Mg2+ and
Ca2+, and 8 for Zn2+. The results also suggested that thelocation of the ion could be related to the swelling of
the lipid bilayer. Yang et al. systematically calculated
the free energies of Na+, K+, Ca2+, and Mg2+ bound tophospholipids, and the calculation results were consistent with the XRD analysis [3]. These findings areimportant to understand the effects of metal cations
on lipid membranes and their biological functions.
However, several questions remain unanswered. How
8do divalent cations modify the hydration structure?
How is the number of hydration water molecules determined? What is the role of the Hofmeister effects? Whatis the molecular mechanism involved in increasing theintermembrane distance?
Biological molecules such as nucleic acids, proteins, and carbohydrates are surrounded by watermolecules, and function in complex environments.
While the importance of the structure and dynamics
of water molecules near biological molecules is acknowledged, few detailed studies have been carriedout on these systems due to experimental difficulties.
Quasi-elastic neutron scattering (QENS) is a powerful
technique to investigate the dynamic behavior of water molecules around biological molecules [4]. In ourrecent QENS study on water molecules sandwiched
between perdeuterated lipid bilayers of multilamellar vesicles (MLV) [5], the QENS spectra were analyzed
in terms of the dynamic behaviors of three types ofhydration water: (1) free water, whose dynamics areslightly different from those of bulk water due to theconfinement effect; (2) loosely bound water, for which
the dynamics are one order of magnitude slower thanthose of free water; and (3) tightly bound water, which
exhibits cooperative dynamics with DMPC molecules.
The number of tightly bound water molecules per lipid molecule was found to be approximately 7 at 275 K
and was reduced to 2 when the temperature was increased to 316 K. In contrast, the number of looselybound water molecules per lipid molecules was also
~7 at 275 K and increased to 12 at 316 K. The number of free water molecules remained constant in themeasured temperature range. The results suggest thatchanging the temperature can modulate the ratioof tightly to loosely bound water molecules withoutchanging their sum.
In this work, further QENS experiments were carried out on the effects of metal cations on hydrationwater between phospholipid bilayers. The binding of
Mg2+ and Fe2+ to lipid headgroups was found to drastically change the number of tightly bound water molecules, whereas the binding of Ca2+ did not affect the
dynamic behavior of hydration water to a significant
extent [6].

2. Experimental
Perdeuterated lipid d67DMPC with an isotopic purity of more than 99% was purchased from Avanti Polar
Lipids Inc.; it was used without further purification. The
QENS measurements were carried out using the timeof-flight near-backscattering spectrometer DNA (BL02).
The power of the injected proton beam incident on
the neutron target was 300 kW (in the case of CaCl2) or
500 kW (in the cases of MgCl2 and FeCl2).
3. Results and Discussion
As in the case of the mixture without salt, the hydration water sandwiched between the lipid bilayers
could be classified as one of three hydration watertypes with different dynamic behaviors: tightly boundwater molecules, loosely bound water molecules, andfree water molecules. According to this model, theobserved QENS profiles were fitted with the sum of
three Lorentz functions convoluted with the resolutionfunction.
The half-width at half-maximum (HWHM) of theLorentz function corresponding to the tightly boundwater is proportional to Q2, and the properties of thetightly bound water can be explained by simple diffusion. On the other hand, the Q2 dependence of the
HWHM’s of Lorentz functions corresponding to theloosely bound water and the free water can be interpreted using the jump diffusion model as in the casesof the bulk water with and without salt.
The diffusion coefficients D of all samples are summarized in Fig. 1 along with the data from the literature
for comparison. The D values of the samples with salts
were nearly the same as those of the sample without salt. The D value of water in an aqueous solutionof CaCl2 was in the same order of magnitude as thoseof free water incorporated between lipid bilayers andslightly less than that of bulk water.
The numbers of the three types of water moleculesin the mixtures of d67DMPC-37H2O-0.25XCl2 (X = Ca,
Mg, Fe) were estimated by analyzing the coefficientsof the Lorentz functions. The numbers of the three
types of water molecules in the sample with CaCl2 were
nearly identical to those in the sample without salt. Thissuggests that the presence of CaCl2 does not affect thehydration water to any significant extent.
In contrast, the estimated numbers of different types of water molecules in d67DMPC-37H 2O0.25MgCl 2 and d67DMPC-37H 2 O-0.25FeCl 2 were
strikingly different compared to the sample with
CaCl2. Compared to the CaCl2 system, the numbers of

Research and Development Highlights

Å

MLF Annual Report 2019

Figure 1.	Arrhenius plot of the diffusion coefficients ofd67DMPC-37H2O-0.25XCl2 (X = Ca, Mg, Fe). The
diffusion coefficients of bulk water and the three
types of hydration water in d67DMPC-37H2O without salt [5] are shown for comparison.

tightly bound water molecules were clearly higher inthe MgCl2 and FeCl2 systems, while the numbers of freewater molecules were lower. On the other hand, thenumbers of loosely bound water molecules in thesesystems, along with their temperature dependences,were nearly identical to those in the corresponding systems without salt. (See Fig. 2.)
High-resolution XRD studies have indicated that
Mg2+ and Fe2+ ions bind near the phosphate groupsof lipid molecules, while Ca2+ binds near the glycerol
group [2]. In addition, the number of hydration watermolecules (nw) seems to depend on the binding position of each cation. The findings of the present study
are consistent with these XRD results but provide amore detailed description of the hydration structuresand dynamics. The sum of tightly bound water andloosely bound water comes to approximately 21 molecules per lipid molecule for the MgCl2 and FeC2 systems;
in contrast, this sum is approximately 13 molecules per
lipid molecule for the systems without salt and with
CaCl2. The present study indicates that the number ofloosely bound water molecules does not change upon
the addition of salt, suggesting that the number ofloosely bound water molecules is determined by thenature of the DMPC membrane.
9Research and Development Highlights

MLF Annual Report 2019

Ca 2+

Mg2+or Fe 2+

free waterloosely bound watertightly bound water

(a)

(b)

(c)

Figure 2.	Schematic image of the positions of metal cations and the numbers of three types of water.

References[1] P. L. Nostro and B. W. Ninham, Chem. Rev. 112, 2286
(2012).
[2] R. J. Alsop, et al., Soft Matter 12, 6737 (2016).
[3] J. Yang, et al., J. Chem. Theory Comput. 11, 4495

(2015).
[4] T. Yamada and H. Seto, Front. Chem. 8, 8 (2020).
[5] T. Yamada et al., J. Phys. Chem. B 121 8322 (2017).
[6] H. Seto and T. Yamada, Appl. Phys. Lett. 116 133701(2020).

H. Seto1, 2 and T. Yamada3
1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3Neutron
Science and Technology Center, CROSS

10

MLF Annual Report 2019

Research and Development Highlights

Sliding Motion of Ring Molecules in Polyrotaxane
1. Introduction
Polyrotaxane (PR) is topologically connected supramolecular assembly composed of multiple ring molecules and an axial polymer chain. The unique feature of
PR is that the rings can slide along the axial chain. The
sliding motion leads to various types of applications of
PR as molecular shuttles [1], drug delivery systems [2],and slide-ring materials with slidable cross-links [3].
However, the sliding dynamics of the rings in PR has notbeen fully studied.
In this study, we investigate molecular dynamics ofpolyrotaxane (PR), composed of a-cyclodextrins (CDs)and a poly(ethylene glycol) (PEG) axis chain, in solution
by means of quasi-elastic neutron scattering (QENS)
measurements and full-atomistic molecular dynamics(MD) simulations [4]. First, we estimated the diffusion coefficients of CDs and PEG monomers in PR via QENS experiments with deuterium labelling technique. Then, we
performed molecular dynamics (MD) simulations to evaluate the sliding diffusion coefficient of CD on PEG in PR.
2. Experimental
For the QENS experiments, PR was synthesized witha-cyclodextrin (CD) as a cyclic molecule and polyethylene glycol (PEG) with an average molecular weightof 35,000 as a polymer chain. The coverage of CD on
PEG was 6.9%. In order to separate the relaxation components of CD and PEG, we prepared hPR with hydrogenated PEG and dPR with deuterated PEG (Fig. 1). The
PRs were dissolved in DMSO-d6 with concentration of
10 wt%. QENS measurements were conducted with
Biomolecular Dynamics Spectrometer (DNA) at Japan
Proton Accelerator Research Complex (J-PARC). The Q
range was 0.08 to 1.98 Å-1, the energy resolution (∆E/E)

was 3.6 μeV and the energy transfer range was -40 to
100 μeV in all the measurements. The measurements
were conducted at 30°C
For the MD simulations, we used CHARMM force
field and GROMACS2016.5. We fabricated the model of
PR with 3 CD molecules and a PEG with 80 mer (Fig. 2).
For the initial structure, one PR was set in a 15×15×15 nm
simulation box filled with DMSO molecules. We conducted a 200-ns NPT calculation at 300 K, and obtained
mean-squared displacement (MSD) of hydrogen atomof PEG and CD in PR.

Figure 2.	A smapshot of PR in the full-atomistic MD simulation and MSD corresponding to the sliding motionof CDs along PEG in PR [4].

Figure 1.	Dynamic structure factors for polyrotaxanes with hydrogenated and deutrated main chains in solution [4].

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MLF Annual Report 2019

3. Results and discussion
Figure 1 shows the dynamic structure factors S(Q, ω)of hPR and dPR in solution. From the dynamic structure
factor of dPR, we evaluated the dynamics of CD in PR.
In addition, by subtracting S(Q, ω) of dPR from that ofhPR, we can extract the dynamics of PEG in PR. The estimated diffusion coefficient of CD in PR was estimatedas 11 Å2/ns, which is a little smaller than that of freeCD, 13 Å2/ns. The topological connection with PEG in
PR hardly influences the dynamics of CD because PEG
is flexible. On the other hand, PEG in PR shows heterogeneous dynamics. The PEG monomers inside/near CDs
slowly diffuse due to the existence of CDs, whereas the
PEG monomers apart from CDs exhibit the same highmobility as the free PEG. The inhomogeneity of the PEG
dynamics in PR suggests that the sliding dynamics in
PR is slower than the observed translational diffusion
modes of CDs and PEG monomers.
For further analysis, we performed full-atomistic
MD simulations on PR solutions (Fig. 2). From the MD
simulations, we calculated the translational diffusion coefficients of CD and PEG monomers in PR solutions andconfirmed that the obtained results were in quantitative agreement with those from the QENS experiments.
By analyzing the MSD of CDs along the PEG axis (Fig. 2),

we successfully observed and quantified for the firsttime the sliding motion of CD along the PEG chain. The
diffusion coefficient for the sliding motion was almost
6 times slower than that of the translational diffusionof CD in PR at room temperature. The slowing down of
the sliding motion was caused by the energy barrier on
PEG. From the temperature dependence of the diffusion
coefficient for the sliding motion (Fig. 3), it was foundthat the sliding motion of CD on PEG did not follow the
Einstein-Stokes equation for Brownian diffusion. We
proposed a simple equation for the sliding motion composed of the Einstein-Stokes part for Brownian diffusion
and the jump diffusion part with an energy barrier along
the axial chain:
Dslide ∝E
kBT
exp  − a .
η(T ) RT 

where Dslide is the diffusion coefficient of the sliding
motion in PR, kB is Boltzmann constant, T is absolutetemperature, η is viscosity of the solvent, R is the gas
constant, and Ea is an activation energy corresponding
to the energy barrier on PEG. This work provides a general strategy for the molecular designs to control thesliding motion in PR.

Figure 3.	Temperature dependence of the normalized diffusion coefficient for the sliding motion of PR and energy
profile of CDs along PEG [4].

References[1] P. L. Anelli, N. Spencer, and J. F. Stoddart, , J. Am.
Chem. Soc., 113, 5131 (1991).
[2] N. Yui and T. Ooya, Chem, Eur. J., 12, 6730 (2006).
[3] K. Ito, K. Kato and K. Mayumi, “Polyrotaxane andSlide-Ring Materials”, Royal Society of Chemistry(2015).
[4] Y. Yasuda, Y. Hidaka, Y., K. Mayumi, T. Yamada, K.
Fujimoto, S. Okazaki, H. Yokoyama and K. Ito, J. Am.
Chem. Soc., 141, 9655 (2019).

K. Mayumi1, Y. Yasuda1, T. Yamada2, and K. Ito1
1
Graduate School of Frontier Sciences, The University of Tokyo; 2Neutron Science and Technology Center, CROSS

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MLF Annual Report 2019

Research and Development Highlights

Neutron Crystallography Captures a Key Structure of
Copper-containing Nitrite Reductase
1. Introduction
The denitrification process is one of the anaerobic
respiratory systems of microorganisms. It uses nitrogenoxide molecules as electron acceptors and releases dinitrogen back into the atmosphere. Copper-containing
nitrite reductases (CuNIRs) catalyzes the important stepin denitrification: one-electron reduction of nitrite to nitric oxide (NO2− + 2H+ + e− → NO + H2O), which generates
gaseous NO and results in the removal of terrestrial fertilizer. Despite many X-ray crystallographic studies [1–3],
the reaction mechanism of CuNIRs has not been clarified yet. Among the steps of the chemical reaction, themechanism of proton transfer (PT) coupled with electron transfer (ET) [4] is the most ambiguous because of
the difficulty in detecting the positions of hydrogen (H)atoms by X-ray diffraction (XRD) analysis. Neutron diffraction (ND) crystallography is an alternative tool to visualize H atoms. Neutrons are diffracted by atomic nuclei
and the amplitude of neutron scattering depends on
the structures of the atomic nuclei. Therefore, H atoms
and atoms of its isotope deuterium (D) can contributeto neutron scattering to the same extent as C, N, and O
atoms. Another advantage of neutron crystallography inprotein science is the much weaker energy of neutron
beams than X-ray ones, which enables determinationof intact protein structures. To understand the reaction
mechanism of CuNIRs, we performed time-of-flight neutron diffraction experiment at BL03 iBIX in the Materials

and Life Science Experimental Facility (MLF) of the Japan
Proton Accelerator Research Complex (J-PARC) andobtained a high-quality ND structure of CuNIR from
Geobacillus thermodenitrificans (GtNIR) [5].
2. Protonation states at the catalytic site
We collected ND and XRD data from a single GtNIR
crystal at 100 K. We then performed joint neutron and
X-ray refinement. The final Rwork/Rfree values for the ND(1.50 Å resolution) and XRD (1.30 Å resolution) data were14.1/15.8 and 9.73/11.2%, respectively, which showedthat the obtained structure was of high quality. The dataclearly visualized the locations of H/D atoms in GtNIR.
A total of 3,043 H/D atoms and 285 hydrating water
positions were identified. The catalytic site of CuNIRs is
composed of a Cu ion, called T2Cu, and three histidine
residues coordinating to T2Cu. There are two essential
catalytic residues above the T2Cu site: aspartate (AspCAT )and histidine (HisCAT ). Previous XRD analyses showed thepresence of five water molecules located around the
GtNIR T2Cu site (Wat0, Wat0’, Wat1, Wat2, and BW). We
were able to observe all of these water molecules in thepresent study and determine the positions of D atoms
on them (Fig. 1). Moreover, we could show that AspCAT
was deprotonated and His CAT was protonated. Theseobservations accord with the earlier density functional
theory (DFT) calculation showing that protonated HisCAT
is stabilized when AspCAT is deprotonated [6].

Figure 1.	Cartoon structure of GtNIR (left) and stick model of the catalytic site (right). A brown sphereindicates the T2 Cu ion. Positive and negative peaks of neutron scattering length density(contoured at ± 3 σ) are illustrated by green and yellow meshes.

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3. Direct observation of a hydroxide on Cu
The obtained neutron-scattering length map indicated that one of the D atoms in the Wat0 molecule
directed AspCAT. However, we could not observe thepositive peak of the other D atom. All other water molecules at the T2Cu site clearly showed two positive peaks
around them (Fig. 1). When we refined the structurewith a deuterated hydroxide model (OD−) of Wat0, it
showed good agreement with the observed data. Such
OH-type molecules are usually interpreted as a result of
the rotational disorder of water molecules. However, theobserved Wat0 molecule showed a low B-factor value
for the O atom and its rotational motion was geometrically restricted. Therefore, we concluded that Wat0 is ahydroxide ion, not a water molecule. Distinguishing water from hydroxide (the difference of only one H atom)
must be a remarkable achievement by ND analysis. A
previous quantum chemical study shows that the T2Cusite of GtNIR energetically prefers a [Cu(OH)]+ state after the nitrite reduction reaction and direct release ofNO [7]. Our structure supports this reaction mechanism.
4. Intramolecular electron transfer pathway
A previous computational study suggests that the
intramolecular ET pathway includes a hydrogen-bondjump and is not composed only of covalent peptide
bonds [8]. Neutron scattering length density aroundthe D atom on the Nδ atom in His134 was less clear
than those of other two His ligands to T2Cu. Because
the X-ray data showed the presence of the H/D atom on
the Nδ atom of His134, we considered that the neutron
scattering from the D atom at this position was canceledby negative scattering from a partially occupied H atom.
The result of the occupancy refinement was that only in

31% of the cases the H atom on the Nδ atom in His134
was replaced with the D atom, while the other two His
ligands to T2Cu showed 100% H-D exchange. This observation indicates that the proposed ET pathway has atight hydrogen bond, which suppresses H-D exchange
reactions. Such a tight hydrogen bond decreases reorganization energy in the ET reaction and thus facilitates
the efficient ET.
5. Future plans
Our study shows that neutron crystallography is a
powerful technique to investigate enzymatic mechanisms, which are difficult to reveal only by X-ray crystallography. Our data obtained from ND analysis show
good agreement with the results from quantum chemistry. Therefore, our study can seamlessly connect structural biology and theoretical chemistry, facilitating theunderstanding of biological processes at an electroniclevel beyond an atomic level. By using BL03 iBIX, wehave collected new data and solved neutron crystal
structures of GtNIR in different states. These structures
will provide further details of the chemical reaction andwe may be able to completely comprehend CuNIRs.
References[1] J. W. Godden et al., Science, 253 438 (1991).
[2] M. E. P. Murphy et al., J. Biol. Chem., 272 28455 (1997).
[3] E. Tocheva et al., Science, 304 867 (2004).
[4] S. Brenner et al., J. Biol. Chem., 284 25973 (2009).
[5] Y. Fukuda et al., Proc. Natl. Acad. Sci., 117 4071 (2020).
[6] S. Ghosh et al., J. Am. Chem. Soc., 131 277 (2009).
[7] M. Lintuluoto and J. M. Lintuluoto, Biochemistry, 55
210 (2016).
[8] R. G. Hadt et al., J. Am. Chem. Soc., 136 15045 (2014).

Y. Fukuda1, Y. Hirano2, K. Kusaka3, T. Inoue1, and T. Tamada2
Graduate School of Pharmaceutical Sciences, Osaka University; 2Institute for Quantum Life Science, National Institutes for Quantum andRadiological Science and Technology; 3Frontier Research Center for Applied Atomic Sciences, Ibaraki University

1

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MLF Annual Report 2019

Research and Development Highlights

Discovery of a New Oxide-ion Conductor Dion–Jacobson
Type CsBi2Ti2NbO10−δ and Structure Origin of the High
Oxide-ion Conductivity
1. Introduction
Oxide-ion conductors have received considerable attention due to their wide applications in manyelectrochemical devices, such as solid-oxide fuel cells(SOFCs), oxygen gas sensors and oxygen separation
membranes [1, 2]. Since oxide-ion conductivity in solidoxides is strongly related to their crystal structure, highoxide-ion conductivities have been achieved in a limited
number of structure families. Therefore, it is important
to explore a new structure family of oxide-ion conductor
for further development in this field.
Recently, we have discovered CsBi2Ti2NbO10-δ­ as thefirst example of the Dion–Jacobson-type oxide-ion conductor [3]. Dion-Jacobson-type structure is one of the layered perovskites. Various layered perovskites are known
to exhibit high oxide-ion conductivity. However, there
are no reports on oxide-ion conduction in the Dion–
Jacobson phases, although several Dion-Jacobson-typematerials are known as cation conductors, such as proton,lithium, and sodium conductors. We have targeted theDion-Jacobson-type oxides, because it is a layered perovskite, and some compositions, such as CsBi2Ti2NbO10-δ­,
are found to show relatively low bond-valence-based energy barrier for the oxide-ion migration. In this report, we
briefly describe the electrical properties, crystal structure,and origin of the high oxide-ion conductivity of the newoxide-ion conductor CsBi2Ti2NbO10-δ.

2. Synthesis and electrical conductivity
CsBi2Ti2NbO10-δ was synthesized by a solid-state-reaction method using Cs2CO3, Bi2O3, TiO2, and Nb2O5 as starting materials. The electrical conductivities were measured
by the AC impedance method in the temperature range of573–1173 K. The equivalent circuit analyses were carriedout to extract the bulk conductivity and grain boundary
conductivity at each temperature. The bulk conductivityof CsBi2Ti2NbO10-δ is 8.9 × 10-2 S cm-1 at 1073 K. The bulk
conductivities of CsBi2Ti2NbO10-δ were higher than thoseof YSZ and comparable with those of the best oxide-ion
conductors (Fig. 1), which indicates the high potentialof the Dion–Jacobson phase CsBi2Ti2NbO10-δ as a basic
composition for oxide-ion conductors. Oxygen concentration cell measurements were performed to determine
the oxide-ion transport number (tion). The tion values were1.00–0.98 between 873 and 1173 K in air/O2, 0.97–0.95 between 873 and 1173 K in air/N2, and 0.87 at 873 K in air/5%
H2 in N2. The dc conductivities of CsBi2Ti2NbO10-δ under
wet and dry condition agreed well. Therefore, the major
charge carrier in CsBi2Ti2NbO10-δ was shown to be oxideion. No significant change was observed before and after
the conductivity measurements, which indicated the highphase stability of CsBi2Ti2NbO10-δ. The bulk conductivities
abruptly increased between 673 and 873 K on heating,which was attributed to the increase in the carrier (oxygen vacancy) concentration and the phase transition.

Figure 1.	Comparison of the bulk conductivity of CsBi2Ti2NbO10−δ with that of the best oxide-ion conductors:(Y2O3)0.08(ZrO2)0.92 (YSZ), Na0.5Bi0.49Ti0.98Mg0.02O2.965 (NBTM), Ba3MoNbO8.5 (BMN), Ce0.9Gd0.1O1.95 (GDC),
La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM), and La1.54Sr0.46Ga3O7.27 (melilite). Copyright © 2020, Springer Nature

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3. Crystal structure
In order to understand the origin of the high oxideion conductivity in CsBi2Ti2NbO10-δ, the crystal structureof CsBi2Ti2NbO10-δ was investigated at various temperature using the neutron diffraction data taken on the
SuperHRPD diffractometer [4]. The diffraction data wereanalyzed by the Rietveld method using the Z-Rietveld
program [5]. The neutron scattering length density distribution in CsBi2Ti2NbO10-δ at 973 K was investigated using the maximum-entropy method (MEM). Furthermore,
the Bond-valence-based energy of CsBi2Ti2NbO10-δ at
973 K was calculated to investigate the anisotropic thermal motions and diffusion paths of the oxide ions.
The Rietveld refinements of the neutron-diffraction
data of CsBi2Ti2NbO10-δ were successfully carried out using a single orthorhombic Ima2 structure at 297–813 K
regions and a single tetragonal P4/mmm structure at
833–1073 K regions on heating (Fig. 2), showing a layered Dion–Jacobson type perovskite structure. The
presence of oxygen vacancies (δ) was confirmed fromthe refined occupancy factors of oxygen. The δ are responsible for the novel oxide-ion conductivities of
CsBi2Ti2NbO10-δ as described below.

Figure 2.	Rietveld patterns at 297 K and 973 K of neutrondiffraction data taken by the backscattering bank of
the SuperHRPD diffractometer. The observed andcalculated intensities and difference plots are shownby red marks, light blue and blue solid lines, respectively. Green tick marks stand for calculated Bragg
peak positions. Copyright © 2020, Springer Nature

16

The tetragonal structure of CsBi2Ti2NbO10-δ (973 K)
consists of an oxide-ion conducting inner perovskite
layer, two outer perovskite layers, and an insulatingrock-salt layer (Fig. 3a). The refined equivalent isotropic
atomic displacement parameters of the equatorial oxygen atom, O1, and apical oxygen, O2, in the oxide-ion
conducting inner perovskite layer were much higher
than those of the equatorial O3 and apical O4 atoms
in the outer perovskite layers. Therefore, the O1 andO2 atoms exhibited larger thermal motions than the
O3 and O4 atoms. In particular, the anisotropic atomic displacement parameters of the O1 and O2 atoms
were extremely large. The large values of the anisotropic atomic displacement parameters indicate highanisotropic thermal motions along the c and a axes,
respectively, which suggests the O1–O2 oxide-ion diffusion. Similarly, the O1–O1 oxide-ion diffusion was
confirmed. The bond-valence-based energy landscapes(BVELs, blue isosurfaces in Fig. 3b) and the isosurfacesof the neutron scattering length density obtained by
the maximum-entropy method (MEM) (yellow isosurfaces in Fig. 3c) showed the O1–O2 and O1–O1 oxideion diffusion paths. In addition, the O2–O3 diffusion
path was observed in the BVELs (the black dotted arrows in Fig. 3b). These results indicate two-dimensional(2D) oxide-ion diffusion along the edges of the octahedron in the oxide-ion conducting inner perovskite
layer. We attribute the high oxide-ion conductivity of
CsBi2Ti2NbO10-δ not only to the existence of oxygen vacancies but also to the 2D oxide-ion diffusion and theextremely high atomic displacement parameters of theO1 and O2 atoms.
At last, we proposed a new concept to explain the
structural origin of the high oxide-ion conductivity of
CsBi2Ti2NbO10-δ. Large bottlenecks for oxide-ion migration was created by the large size of Cs + and Bi3+ displacement. The bottlenecks in the CsBi2Ti2NbO10-δ are
the Bi–Bi–Ti triangles (the yellow and pink triangles inFig. 4. The large bottlenecks can be explained using
the new concept: Cs+ expands the Bi–Bi distance along
the b axis due to the occupational ordering of the large
Cs+ cations. Bi3+ is displaced along the c axis apart fromthe Ti/Nb1–O1 layer by electrostatic forces. The Bi3+ displacement increases the Bi–Bi distance along the c axis.
The increase in the Bi–Bi distances along both the b (=a)
and c axes leads to large bottlenecks for the O1–O2(the yellow areas) and O1–O1 (the pink areas) oxide-ion
diffusion.

MLF Annual Report 2019

Research and Development Highlights

Figure 3.	(a) Refined crystal structure of CsBi2Ti2NbO9.80(2) at 973 K, which was obtained by Rietveld analysis of neutron-diffraction
data. (b) Blue isosurfaces of the bond-valence-based energy for an oxide ion at 0.6 eV for the structure at 973 K. (c) Yellow
isosurfaces of the neutron scattering length density at 1.0 fm Å−3 with the structure (973 K). Copyright © 2020, Springer Nature

4. Conclusion
CsBi 2 Ti 2 NbO 10-δ is the first example of DionJacobson-type oxide-ion conductor, which is one of thebest oxide-ion conductors. Through the neutron diffraction study using SuperHRPD diffractometer, we haveclarified the oxide-ion migration path in CsBi2Ti2NbO10-δ.
Furthermore, a new concept of large bottlenecks foroxide-ion migration by large size of Cs+ and Bi3+ displacement was proposed based on the analyzed crystal
structure. This proposed new concept should facilitate
further developments of oxide-ion conductors.

Figure 4.	New concept of enlarged bottlenecks for oxideion migration created by large size of Cs+ and Bi3+
displacement in Dion–Jacobson-type Cs/Bi-cationordered CsBi2Ti2NbO10−δ. Copyright © 2020, Springer
NatureReferences[1] M. Yashima, J. Ceram. Soc. Jpn., 117 1055 (2009).
[2] M. Yashima, Catal. Today 253 3 (2015).
[3] W. Zhang et al., Nat. Commun., 11 1224 (2020).
[4] S. Torii et al., J. Phys. Soc. Jpn. 80 3 (2011).
[5] R. Oishi et al., Nucl. Instruments Methods Phys. Res.
Sect. A Accel. Spectrom. Detect. Assoc. Equip. 600 94(2009).

W. Zhang, K. Fujii, and M. Yashima
Department of Chemistry, School of Science, Tokyo Institute of Technology

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MLF Annual Report 2019

Interstitialcy Diffusion Pathways of F-Ions in Ba0.6La0.4F2.4
Solid Electrolyte Material18

1. Introduction
The fluorite-type structure is one of the key frameworks considered to ensure the high mobility of fluoride anions (hereafter referred to as F− ions) [1, 2]. F− ionsshow the highest electronegativity (= 3.98) in the periodic table and because F− ion-conducting materials
possess very high conductivity and chemical stability,
there is a growing demand for them. In particular, allsolid-state fluoride shuttle batteries (FSBs) have received
a lot of attention as the next-generation rechargeable
battery with high power density, a wide electrochemical potential window, high reliability, and a long lifespan. In “metal (anode)/metal fluoride (cathode)” cells,
the chemical reaction of a couple of F− ions (nF−) witha metal (M) leads to the formation of a metal fluoride(MFn), resulting in the release of several electrons (ne−)
per metal atom. The theoretical energy density of FSBs
(approximately 5000 Wh/L) is ten times higher than thatof commercial lithium-ion batteries [3]. In recent studies,a “Ce or Li (anode)/BiF3 (cathode)” pair was assembled
experimentally and was characterized using Ba0.6La0.4F2.4(fluorite-type) and La0.9Ba0.1F2.9 (tysonite-type) solid electrolytes [4, 5]. However, currently all-solid-state FSBs
only operate at elevated temperatures. In addition, thespecifications for working all-solid-state FSBs have notyet been standardized.
In this study, we performed structural investigations

3. Crystal structure and diffusion pathways of F− ions
The Rietveld refinement pattern of Ba0.6La0.4F2.4 at
512 K is shown in Fig. 2; there is excellent agreement
between the observed and calculated intensities (Rwp =Figure 1.	Temperature dependence of the electrical conductivities for Ba0.6La0.4F2.4 (red circles) and BaF2 (bluetriangles).

Figure 2.	The neutron diffraction pattern of Ba0.6La0.4F2.4 at
512 K. In the Rietveld analysis result, plus marks(red) indicate the observed neutron diffraction data
while the solid line (dark-light blue) indicate thecalculated neutron diffraction data. Vertical marks(green) below the neutron diffraction data denotepositions of the Bragg reflections. The curve (blue)
at bottom indicates the difference between observed and calculated intensities.

of the fluorite-type solid electrolyte Ba0.6La0.4F2.4 using a
cutting-edge neutron diffractometer, SPICA, and a suiteof analysis programs, Z-Rietveld [6, 7]. Additionally,
we elucidated the diffusion pathways of F− ions in
Ba 0.6La 0.4F 2.4 using the maximum entropy method(MEM) [8]. We showed that the excessive F− ions, located at the specific interstitial sites, migrate to the neighboring F− ion sites based on the interstitialcy diffusion
mechanism at the operating temperature for all-solidstate FSBs [9].
2. Electrical conductivities
Figure 1 shows the temperature dependence of theelectrical conductivity, σ(T), of Ba0.6La0.4F2.4 along withthat of BaF2. It is worth noting that the σ value includes
the contributions of the bulk and the grain boundaries. With the substitution of La3+ for Ba2+, σ increasedby four to five orders of magnitude. This massive improvement in σ may be ascribed to the introduction ofexcessive F− ions. The σ value for Ba0.6La0.4F2.4 increased to10−4 S/cm at temperatures higher than 430 K; this should
be enough for creation of all-solid-state FSBs.

MLF Annual Report 2019

3.5263%; S = 4.0550). All the Bragg reflections of MF2.4(M = Ba0.6La0.4) could be indexed to the fluorite-type
structure. Thus, the space group Fm3̄m (cubic system), was chosen for the crystal structure refinement.
Furthermore, we used the split-atom model to provide
the interstitial site for the excessive F− ions, F2(x, x, x)
in the 32f site, along with the M(0, 0, 0) in the 4a site
and F1(1/4, 1/4, 1/4) in the 8c site, where x is the atomic
position. The crystal structure of MF2.4 at 512 K is illustrated in Fig. 3. The a, g(F1), and g(F2) values were determined and found to be a = 6.10751(8) Å, g(F1) = 0.675(3),and g(F2) = 0.1312(7), respectively. Interestingly, theF-vacancies account for approximately 30% of the regular F1 sites. In the figure, the anisotropic displacement of
F2 was more pronounced towards the F1 site (i.e. in the<111> direction), whereas those of M and F1 continued
to exhibit isotropic behavior.
Next, we performed MEM calculations to visualize
the diffusion pathways of the F− ions in MF2.4 at 512 K.
Figure 3 shows the three-dimensional nuclear density
distribution at 0.55 fm Å−3. It seems that the F− ion diffusion in Ba0.6La0.4F2.4 can be explained based on the

Figure 3.	Crystal structure (left) and nuclear density distributions (right) calculated by the Rietveld method
and the maximum enthalpy method (MEM) using
neutron diffraction data for Ba0.6La0.4F2.4 collected at
512 K. The red arrow indicates the predicted conduction pathways of F− ions: F1–[F2–F2]–F1.

Research and Development Highlights

interstitialcy diffusion mechanism. Along the F1–[F2–F2]–F1 diffusion pathways, an F− ion at the F2 site moves
to the neighboring F1 site, and then an F− ion at the F1site is kicked out by the F− ion.
4. Concluding remarks
The diffusion pathways of F− ions in the fluorite-typesolid electrolyte Ba0.6La0.4F2.4 at 512 K were visualizedusing the cutting-edge neutron diffractometer, SPICA.
Of the various known fluoride-based solid electrolytes
such as fluorite- and tysonite-type ones [10], Ba0.6La0.4F2.4
shows higher conductivity at 430 K. However, its conductivity is not as high at room temperature. As such, it
is essential to elucidate the F− ion diffusion mechanismin these materials in greater detail. We believe that the
proposed diffusion pathways of the F− ions will aid thedevelopment of fluoride-based solid electrolytes for the
next-generation all-solid-state FSBs.
References[1] N. I. Sorokin, B. P. Sobolev, Crystallogr. Rep., 52 842(2007).
[2] L. N. Patro, K. Hariharan, Solid State Ionics, 239 41(2013).
[3] F. Gschwind et al., J. Fluorine Chem., 182 76 (2016).
[4] C. Rongeat et al., J. Phys. Chem. C, 117 4943 (2013).
[5] M. A. Reddy et al., J. Mater. Chem., 21 17059 (2011).
[6] M. Yonemura, K. Mori et al., J. Phys. Conf. Ser., 502
012053 (2014).
[7] R. Oishi et al., Nucl. Instrum. Methods Phys. Res. A,
600 94 (2009).
[8] Y. Ishikawa et al., Physica B, 551 472 (2018).
[9] K. Mori et al., ACS Appl. Energy Mater., 3 2873
(2020).
[10] K. Mori et al., J. Phys. Chem. C, 124 18452 (2020).

K. Mori1, A. Mineshige2, T. Saito3,4, M. Sugiura2, Y. Ishikawa5, F. Fujisaki6, K. Namba3,4, T. Kamiyama3,4, T. Otomo3,4, T. Abe7,
and T. Fukunaga6
1Institute for Integrated Radiation and Nuclear Science, Kyoto University; 2Department of Applied Chemistry, Graduate School of Engineering,
University of Hyogo; 3Neutron Science Section, Materials and Life Science Division, J-PARC Center; 4Institute of Materials Structure Science,
KEK; 5Neutron Science and Technology Center, CROSS; 6Office of Society-Academia Collaboration for Innovation, Kyoto University;
7
Graduate School of Engineering, Kyoto University

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MLF Annual Report 2019

Measurement of Neutron Scattering Cross Section of
Nano-Diamond for Cold Neutron Intensity Enhancement
1. Introduction
Slow neutrons, as unique probes, constitute a powerful tool in advanced material research and fundamental physics. However, additional intensity enhancement,
especially below the cold neutron energy, is strongly
desired.
Recently, researchers have focused on nano-diamond (ND) as attractive neutron reflection materials.
Because the carbon in NDs is characterized by low neutron absorption and the sizes of NDs are comparable to
the wavelengths of the neutrons of interest in the very
cold energy region, NDs can serve as a good reflection
material with heightened cold neutron intensity owing
to coherent scattering. Although experimental studies
evaluating the neutron reflection performance of NDs areunderway, total neutron cross section data are unavailable for use in neutron source conceptual design studies.
Therefore, we conducted an experiment involving
neutron transmission measurement to determine the total
neutron cross section. In addition, we performed inelastic
neutron scattering measurements to confirm the contribution of inelastic scattering to the total cross section.
2. Experiment
ND powder with the size of 5.1 nm produced by
explosive synthesis at Ray Techniques Ltd. was used, as
shown in Fig. 1(a). The powder was shaped into a plate byusing a pressing jig in a glovebox, as shown in Fig. 1(b).
The successful forming of the plate from ND powder depended on the pressing pressure. The appropriate pressing pressure was approximately 10 MPa. The ND plateweighed 0.0375 g, and its size was 10 × 10 × 0.57 mm3,
resulting in a density of 0.658 g/cm3, which is lower thatits theoretical density of about 3.6 g/cm3. The plate wasstored in a pure aluminum capsule with thickness of
0.3 mm inside the same glovebox. A 0.3-mm-thick cadmium plate with an 8-mm hole at its center was placednext to the specimen to collimate the neutron beam.
Neutron transmissions with and without the ND plate
were measured using a 3He detector at BL10. The 3He detector was covered with boron carbide resin and equippedwith an opening slit of 10 × 20 mm2 to reduce the background noise of the scattered neutrons. The pulsed neutron beams emitted from a decoupled moderator wereused for transmission measurement.
20

(a)

1 cm
(b)

Nano-diamond plate

1 cm

Figure 1.	Nano-diamond: (a) Photograph of the nano-diamond powder, (b) Nano-diamond plate.

3. Results and Discussion
Figure 2 [1] shows the measured total cross section data with errors. The cross section of carbon in
JENDL-4.0 [2] and that of graphite in ref. 3 are shown in
Fig. 2 for comparison. The total cross section of the ND
specimen increased with the decrease of the neutronenergy to 0.2 meV. It was approximately two orders ofmagnitude greater than that of carbon at 0.2 meV. The
total cross section of the ND plate was consistent withthose of carbon and graphite within the error range atneutron energies higher than 100 meV. It is critical tounderstand the scattering mechanism that leads to anincrease in the total cross section of the ND plate in thecold neutron energy region. First of all, inelastic neutron
scattering measurement of the ND plate was performed
at BL14 with incident neutron energies (Eis) of 1.2, 1.5,
1.9, 2.6 and 5.9 meV to investigate the contribution of
inelastic neutron scattering to the total cross section.
Figure 3 [1] shows a 2D contour map of energy transfer(ET) versus the scattering vector, q. The various colors
denote the scattering intensity of the ND specimen.
The horizontal zone indicated by arrow A (ET = 0,
meaning no energy transfer) represents elastic scattering of the incident neutron energy at 1.2 meV.
The high scattering intensities indicated by red color
were observed in the small q (0.1< q < 0.3) region.
Another zone shown by arrow B denotes elastic

MLF Annual Report 2019

Research and Development Highlights

2θ=0.422θ=14.5
θ=14

8

Wave length (Å)

Energy (meV)

104

6

103

5

102

4

101

dσ/dΩ (bam)

105

7

3
2
1
0

0.01

0.1

1

q(Å-1)

Figure 2.	Total cross sections of the nano-diamond. The crosssections of carbon (JENDL-4.0, [2]) and graphite(C.D. Bowman et al., [3]) are shown for comparison.

Ei = 1.2 meV

B

104

0.5

103

Intensity (A. U.)

Energy transfer (meV)

1

102
101
100

0

10-1
10-2

-0.5

-1

0

0.2

0.4

0.6

0.8

q(Å-1)

1

1.2

1.4

1.6

Figure 3.	Result of the inelastic scattering measurement of
the ND specimen at neutron incident energy (Ei) of
1.2 meV.

scattering corresponding to the next incident neutrons
at 0.95 meV. The white slanting lines indicated by arrow
C denote gaps in the detector arrays. No visible scattering intensities were observed in the background signalof blue color, except at ET = 0.
A similar tendency was observed for the other energies of 1.5, 1.9, 2.6, and 5.9 meV. Thus, inelastic scattering does not contribute to cold neutron energy.
To understand the large cross section at low energies, we performed small-angle neutron scattering(SANS) measurements at BL15 in J-PARC and analyzed
the measured SANS data by plotting q versus energy(wavelength). We assumed that inelastic scattering
did not contribute to the SANS data based on the result of the inelastic neutron scattering measurement.

Figure 4.	Two-dimensional distribution (q, E) of the scattering intensity of the ND specimen.

Figure 4 [1] shows a two-dimensional (2D) contour mapof the neutron energy versus the scattering vector q,
with the color bars representing the scattering cross section. The scattering cross section increases with decreasing the neutron energy and scattering angle, resulting
in greater scattering cross sections along the forward
direction at lower neutron energies. Thus, there is potential to use the ND specimen to increase the neutron
intensity below the cold neutron energy.
Acknowledgements
This work was conducted under the IAEA CoordinatedResearch Project (Project No. F12026). The experiment at
the MLF of J-PARC was performed under the user program (Proposal No. 2016P0802, 0803 and 0804).
We are grateful to K. Aizawa, group leader of theTechnical development section at JAEA, and the section members W. Kambara, R. Takahashi, A. Hori, H.
Tanaka, M. Sawabe, H. Isozaki and K. Aoyama for thetimely help with machining, etc. We would like to thankA. Birumachi, group leader of the Machinery engineering and electronics section at JAEA, and its members M.
Usami, K. Horiguchi, T. Neya and T. Abe for manufacturing the specimen holder and many jigs.
References[1] M. Teshigawara et al., Nucl. Inst. and Meth. Phys. Res.
A, 929 113 (2019).
[2] K. Shibata et al., J. Nucl. Sci. Technol. 48 (1) (2011) 1.
[3] C.D. Bowman, et al., NSE 159 (2008) 182–198.

M. Teshigawara1, Y. Tsuchikawa2, G. Ichikawa2, S. Takata3, K. Mishima4, M. Harada1, M. Ooi1, Y. Kawamura5, T. Kai3,
S. Ohira-Kawamura3, K. Nakajima3, Y. Ikeda6, and Y. Kiyanagi2
1
Neutron Source Section, Materials and Life Science Division, J-PARC Center; 2Laboratory for Particle Properties, Nagoya University;
3
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 4Institute of Materials Structure Science, KEK; 5Neutron
Science and Technology Center, CROSS; 6J-PARC Center21

Research and Development Highlights

MLF Annual Report 2019

Ice Ic without Stacking Disorder by Evacuating Hydrogenfrom Hydrogen Hydrate
1. Introduction
Water freezes below 0°C at atmospheric pressure,usually to ice Ih with a hexagonal stacking sequence.
However, under certain laboratory conditions, it isalso known to produce “ice Ic”, nominally with a cubic
stacking sequence [1]. Among over 19 polymorphs innumerous ice polymorphs, “ice Ic” has a special importance, since “Ice Ic” could ubiquitously exist in Earth’s
atmosphere, in comets, or even in frozen food. Despite
the numerous studies on “ice Ic”, its structure has notbeen fully verified, because the diffraction patterns of“ice Ic” show signatures of stacking disorder (hereafter,
called ice Isd for clarity), and ideal ice Ic without stacking
disorder had not been formed until very recently [2].
In this study, we noticed that a high-pressure form ofhydrogen hydrate, called C2, has the same hydrogenbonding framework as ice Ic. Once C2 was synthesizedunder high-pressure, then it metastably recovered indecompression at low temperature for keeping theframework, and finally we managed to degas hydrogenfrom C2, so that the ideal ice Ic without stacking disorder
was obtained.

2. Experiments
A mixture of D2O and MgD2 was used as a starting
material, where MgD2 is an internal deuterium source tosynthesize C2. After loading the mixture into a pressuretemperature controlling ‘Mito system’ [3], MgD2 wasdecomposed by heating at 403 K and 0 GPa for 1 h (atb in Fig. 1). Then, the samples were cooled to room temperature (at c) and compressed up to ~3 GPa until a C2
phase was observed (at d). The sample was then cooled
from 300 K to 100 K at around 3 GPa (path d → e), decompressed at 100 K (path e → f), and finally heated(path f → g). Neutron diffraction experiments were conducted at the beamline PLANET in the MLF of J-PARC.
3. Results and discussion
Deuterium was released from MgD 2 and D 2O
through a nominal reaction of MgD2 + 3D2O → Mg(OD)2+ 2D2 + D2O, forming C2 above ~3 GPa. The neutron diffraction pattern for the C2 phase obtained at 3.3 GPaand 300 K (at d in Fig. 1) was analyzed by the Rietveld
method, and the calculated diffraction pattern was ingood agreement with the observed one. The C2 phase

Figure 1.	Phase diagram of hydrogen hydrate and ice with experimental P-T paths in this study.

22

MLF Annual Report 2019

Research and Development Highlights

Figure 2.	Neutron diffraction patterns showing the transformation from C2 to ice Ic. The patterns were obtainedwith decreasing pressure at 100 K (path e → f ) and with increasing temperature at 0 GPa (path f → g).

persisted at pressures at least as low as 0.5 GPa on decompression at 100 K (path e → f). However, quite unexpectedly, the Bragg peaks of C2 mostly disappeared at
0.2 GPa (Fig. 2), showing that the C2 transforms to amorphous-like state. The sample was further decompressed
to 0 GPa and evacuated using a turbo-molecular-pump.
The broad peaks corresponding to ice Ic appeared at
this stage, showing that the amorphous-like form is
an intermediate transition state from C2 to ice Ic, whichforms while hydrogen (deuterium) molecules are partially degassed. The broad peak of ice Ic sharpened withthe temperature increase at 0 GPa (path f → g), and theobtained neutron diffraction pattern fitted well using
the ice Ic structure model. The Rietveld refinement using the C2 structure model showed that the occupancy
of guest deuterium molecule was zero, within the experimental error. Also, no sign of stacking disorder was
confirmed. This should be a clear indication of the presence of ideal ice Ic without stacking disorder.
It is also noteworthy that the ice Ic surprisingly
persists up to at least 240 K until ice Ih starts to appear
at 250 K (Fig. 2). The temperature of 240 K is significantly higher than the (meta)stability limit of previously known ice Isd [1]. The notable stability of the ice
Ic compared to ice Isd would be derived from the lack of
stacking disorder. The stacking disordered ice has moredislocations, which promote the phase transformationfrom ice Isd to ice Ic by reducing the activation energy
required to change the stacking sequence.
4. Future prospects
The discovery of ideal ice Ic will allow us to research
the real physical properties of ice Ic without stacking
disorder. For example, accurate heat capacity or vapor
pressure measurements from low temperature will provide the free energy of ice Ic, which would settle thelong-standing argument about the thermodynamic
stability of ice Ic compared to ice Ih. The physical properties of the ideal ice Ic are also important to understandthe role played by stacking disorder in the physicalproperties of ice Isd. For instance, since the thermal conductivity of ice Isd is significantly lower than ice Ih, thedifference of thermal conductivities between ices Ih andIc will emboss the effect of stacking disorder.
References[1] W. F. Kuhs, C. Sippel, A. Falenty, and T. C. Hansen,
Proc. Nat. Acad. Sci. 109, 21259 (2012).
[2] L. del Rosso, M. Celli, F. Grazzi, M. Catti, T. C. Hansen,
A. D. Fortes, and L. Ulivi, Nature Materials 19, 663(2020).
[3] K. Komatsu, M. Moriyama, T. Koizumi, K. Nakayama,
H. Kagi, J. Abe, and S. Harjo, High. Press. Res. 33, 208(2013).

K. Komatsu1, S. Machida2, F. Noritake3,4, T. Hattori5, A. Sano-Furukawa5, R. Yamane1, K. Yamashita1, and H. Kagi1
Geochemical Research Center, Graduate School of Science, The University of Tokyo; 2Neutron Science and Technology Center, CROSS;
3
Graduate Faculty of Interdisciplinary Research, University of Yamanashi; 4Computational Engineering Applications Unit, RIKEN; 5Neutron
Science Section, Materials and Life Science Division, J-PARC Center

1

23

Research and Development Highlights

MLF Annual Report 2019

Novel Excitations Near Quantum Criticality inGeometrically Frustrated Antiferromagnet CsFeCl3
1. Introduction
The investigation of the collective excitation in the
low-energy range is indispensable for understanding
condensed matter. According to the quantum field theory, the excitation in a system with spontaneous symmetry broken is characterized by phase and amplitude
fluctuations of order parameters. The former is known
as Nambu-Goldstone (NG) mode, and the latter is called
amplitude mode. Even though these modes are usually
separated, they are hybridized under certain conditions,and interesting phenomena are induced; for example, ina crystal lattice system, an acoustic phonon (NG mode)
and an optical phonon (amplitude mode) are hybridized
through anharmonic terms in a thermoelectric material
PbTe, which renormalizes the phonon spectrum andleads to low thermal conductivity and a high figure of
merit in thermoelectric property [1]. Such a hybridization effect could exist in other types of elementary excitations, however, as far as we know, no research has
been reported, partially because the longitudinal mode
itself is not trivial.
Spin S = 1 easy-plane antiferromagnet is one ofthe prototypical quantum spin systems that allows to
explore the quantum phase transition (QPT) [2]. Whenthe anisotropy D is large, the ground state is a quantum
disordered (QD) singlet, as shown in Fig. 1, left panel.
When D is small and the exchange interaction is large,
the ground state is a magnetically long-range orderedstate. A remarkable feature in the renormalized energy
scheme in Fig. 1, right panel, is that the second excitedstate can be excited only by the longitudinal component of spin operator S∥, meaning that the longitudinal
Quantum disordered state

Ordered state

±1
S,S
x

y

D

Local site

S
S

|0

||

⊥

Local site
1

|L

|T
|G
J e ff / D

Figure 1.	Schematic diagram of the S = 1 easy-plane antiferromagnet. In the ordered state, the doublet excitedstates |±1⟩ splits into |L⟩ and |T⟩. Here, the former
and latter have longitudinal and transverse fluctuations, respectively.

24mode is allowed in the system. Because the geometricalfrustration in magnets could induce the hybridizationof the transverse (T) and longitudinal (L) modes, spin S= 1 easy-plane antiferromagnet, with its geometricallyfrustrated lattice, is the best playground for the researchof hybridized modes in magnetic materials.
CsFeCl3 is the S = 1 easy-plane triangular antiferromagnet. The inelastic neutron scattering (INS) study
at ambient pressure revealed that the ferromagnetic
chains along the crystallographic c axis are antiferromagnetically coupled in the ab plane [3]. The groundstate is the QD state because of large single-ion anisotropy. The magnetic susceptibility measurement underpressures exhibited a pressure-induced magnetic order
above a critical pressure of about 0.9 GPa [4]. Owing to
the strong easy-plane anisotropy, the ordered momentaligns in the ab plane; the neutron diffraction revealed
the noncollinear 120° structure in the LRO phase [5].
CsFeCl 3 is, thus, a promising host for the pressureinduced QPT in the geometrically frustrated lattice. In
2019, our group reported a new hybridization of thephase and amplitude fluctuations of the order parameter near QCP in CsFeCl3[6].
2. Results
The INS spectrum measured at 0.0 GPa by using
chopper spectrometer in Fig. 2(a) exhibits a single dispersive excitation with an energy gap of 0.6 meV atwave vectors q = (-k, 2 k, 0) for k = 1/3 and 2/3. The energy gap at 0.3 GPa in Fig. 2(b) softens when approaching the ordered state. A qualitatively different spectrum
is observed in the ordered state at 1.4 GP in Fig. 2(c).
A well-defined gapless excitation emerges at k = 1/3
and 2/3 and another dispersive excitation is observedin the higher energy range. The INS spectra were collected also by using a triple-axis spectrometer in order
to cover wide ℏω-q range, and the extracted peak energies are overplotted by open symbols in Figs. 2(a)-2(c).
At 1.4 GPa, the spectral lineshape at k = 5/6 is reproduced by double Lorentzians with broad widths, whichis reflected by large error bars. The dispersion relations
calculated by the extended spin-wave theory (ESW) [7]
are indicated by the solid yellow curves. The calculationis consistent with the experiment in both the QD and
LRO phases.

MLF Annual Report 2019

2.0

1.0

(c) 1.4 GP a P > Pc(b) 0.3 G Pa P < Pc

0.8

(QHUJ\ PH9

1.5

0.6

1.0

0.4

0.5
0

(QHUJ\JDS

00.2(QHUJ\
*DS

0.4
0.6
0.8
1.0
1/3
2/3
Wave number (r.l.u.)

1.5(d) 1.4 GP a
$QWLFURVV

0.4
0.6
0.8
1.0
1/3
2/3
Wave number (r.l.u.)Hybridization(e) 1.4 GP a

0.2

0.4
0.6
0.8
1.0
2/3
1/3
Wave number (r.l.u.)

No Hybridization$QWLFURVV

0
0

0.8

0.4
&URVV

0.5
0.2

0.4
0.6
0.8
1.0
Wave number (r.l.u.)

0.2

&URVV

0.4
0.6
0.8
1.0
Wave number (r.l.u.)

0

1.0

0.6

1.0

0.2

0.2

Intensity (arb. units)(QHUJ\ PH9

2.0

0.2

1RHQHUJ\JDSIntensity (arb. units)(a) 0.0 G Pa P < Pc

Research and Development Highlights

0

Figure 2.	Inelastic neutron scattering spectra. The spectra obtained at a chopper spectrometer under (a) 0.0 GPa at 6 K, (b) 0.3 GPa
at 2.7 K and (c) 1.4 GPa at 0.9 K sliced by the energy transfer - wave vector (ℏω − q) plane for q = (−k, 2 k, 0). The yellow
circles, squares, and red diamonds are the peak positions of the excitations obtained from the constant-q scans using a
triple-axis spectrometer. The solid yellow curves are the dispersions calculated by ESW. Calculated neutron cross-section
by the ESW under (d) 1.4 GPa at 0 K. Calculated neutron cross-section in the absence of the off-diagonal elements under(e) 1.4 GPa at 0 K. The black and red solid curves in (d) and (e) are gapless and gapped modes, respectively.

3. Discussion
In the ESW calculation, one can notice that noncollinearity of the magnetic structure creates off-diagonal
elements in the Hamiltonian nonzero, leading to thehybridization of the L and T modes in one-magnon
process. To understand the effects of LT-hybridization,
we demonstrate the INS spectra after dropping the offdiagonal element. The results are shown in Fig. 2(e),where the black-gapless (red-gapped) modes are puretransverse (longitudinal) modes in this case. The result isinconsistent with the experiment in Fig. 2(c). When theLT-hybridization is taken into account, the off-diagonal
elements lead to anticross of the modes at k ~ 5/6 in
Fig. 2(d), and novel magnetic excitations are formed;
both gapless and gapped modes are accompanied bystrong longitudinal and transverse fluctuations. The result is consistent with the experiment, proving that theLT-hybridization plays an important role in magnon dynamics in the noncollinear magnet near QCP.
4. Future plans
Since the newly found excitation exists in a noncollinear spin structure, the search for excitation in different types of noncollinear structures, such as a cycloidal
structure, all-in all-out structure, and skyrmion latticewould be an interesting topic. The search for the hybridized mode in other systems, including charge density
wave, spin density wave, and ultra-cold atoms, would
also be important. Finally, the effect of hybridization on
the lifetime of the magnon and other elementary excitations would be worth exploring as well.
References[1] O. Delaire, J. Ma, K. Marty, A. F. May, M. A. McGuire,
M. H. Du, D. J. Singh, A. Podlesnyak, G. Ehlers, M. D.
Lumsden, B. C. Sales, Nat. Mat. 10, 614 (2011).
[2] M. Matsumoto, M. Koga, J. Phys. Soc. Jpn. 76, 073709(2007).
[3] H. Yoshizawa,W. Kozukue, K. Hirakawa, J. Phys. Soc.
Jpn. 49, 144 (1980).
[4] N. Kurita, H. Tanaka, Phys. Rev. B 94, 104409 (2016).
[5] S. Hayashida, O. Zaharko, N. Kurita, H. Tanaka, M.
Hagihala, M. Soda, S. Itoh, Y. Uwatoko, T. Masuda,
Phys. Rev. B 97, 140405 (2018).
[6] S. Hayashida, M. Matsumoto, M. Hagihala, N. Kurita,
H. Tanaka, S. Itoh, T. Hong, M. Soda, Y. Uwatoko and
T. Masuda, Sci. Adv. 5, eaaw5639 (2019).
[7] R. Shiina, H. Shiba, P. Thalmeier, A. Takahashi, O.
Sakai, J. Phys. Soc. Jpn. 72, 1216 (2003).

S. Hayashida1, M. Matsumoto2, M. Hagihala1,4, N. Kurita3, H. Tanaka3, S. Itoh4, T. Hong5, M. Soda1, Y. Uwatoko1, and T. Masuda1,4
ISSP, the University of Tokyo; 2Shizuoka University; 3Tokyo Institute of Technology; 4KEK; 5Oak Ridge National Laboratory

1

25

Research and Development Highlights

MLF Annual Report 2019

Triplon Band Splitting and Topologically Protected Edge
states in the Dimerized Antiferromagnet
1. Introduction
Topology is a branch of mathematics that classifies
objects in terms of invariant properties under smooth
deformations. A classification between a ball and a coffee cup is a common example to illustrate this concept.
A ball cannot be deformed into a coffee cup without
cutting or pasting its part, and in this sense, these objects are topologically distinct. It has been understoodthat the topological classification can be also applied
to electron wavefunctions defined across a momentum
space, after the discovery of a topological insulator [1,2]. A topological insulator is an insulator that has conducting edge states due to the difference in topologicalinvariants between inside and outside of the material.
Topological invariants cannot be changed as long as thematerial remains insulating. At the edge, the material
cannot remain insulating because of abrupt change inthe topological invariants. Since the conducting edge
states are protected by symmetry and free from dissipation, they are expected to be utilized for the future energy-efficient information transmission and processing.
The concept of topology has been extended not
only to electron wavefunctions but also to wavefunctions of bosonic quasiparticles, such as magnons. Thesequasiparticles carry heat in magnetic materials as electrons carry charges in metallic compounds. Indeed, occurrence of heat flow perpendicular to both a thermal
gradient and a magnetic field was discovered in the
ferromagnetic insulator Lu2V2O7 [3]. This phenomenon
is called thermal Hall effect, and its origin is explainedby the Dzyaloshinskii-Moriya (DM) interactions. The
DM interactions induce complex hopping amplitudes
of magnons, leading to the nontrivial band topology
and the associated edge magnons carrying heat [4]. On
the other hand, the nontrivial band topology has beenrarely reported for triplons: triply degenerate excitations
defined on an antiferromagnetic dimer with a singlet
ground state. A rare example is SrCu2(BO3)2, where interdimer DM interactions induce complex triplon hopping
amplitudes [5, 6].
2.	Dispersion relation of triplons in the dimerized
antiferromagnet Ba2CuSi2O6Cl2.
In this report, we show that triplons can constructtriplon bands with topologically protected edge statesin the spin-1/2 dimerized antiferromagnet Ba2CuSi2O6Cl2.
26

In this compound, an antiferromagnetic dimer is formed
by a pair of CuO4Cl pyramids, and these dimers form arectangular lattice on the ab-plane [7], as shown in
Fig. 1(a). Its triplon dispersion relations were investigated by inelastic neutron scattering experiment using thecold-neutron disk chopper spectrometer AMATERAS [8].
Twenty pieces of single crystals prepared by the selfflux method were coaligned on a rectangular Al plate.
Intensities were collected by rotating the sample by almost 90° around the c* axis.
A spin excitation spectrum has indicated propagation of triplons across the rectangular lattice. Figure 2(a)shows a color contour map of the excitation spectrum
sliced by K = 0. It is overlapped by that sliced by H =0 due to crystallographic domains. The intensity is integrated over the L direction since these branches are
dispersionless along the L direction. The two dispersive
branches between 2 and 3 meV indicate the dispersion
along H and K direction. In addition, the intensity of thetriplon excitations decreases at 2.6 meV, independentlyof the scattering wave vector.
The intensity decrease is not allowed in a regular
rectangular lattice of antiferromagnetic dimers and is
only possible under the small distortion in the rectangular lattice. Under the space group of this compound(Cmc21), a bond alternation in interdimer interactions
is allowed, as illustrated in Fig. 1(a). The alternationinduces a band inversion between the bonding- andanti-bonding triplon bands, resulting in an energy gap

Figure 1.	(a) Interdimer network in Ba2CuSi2O6Cl2 equivalentto (b) SSH chains weakly coupled by interchain
hopping terms. Solid black circles represent triplons
localized at the edge of the chains.

MLF Annual Report 2019

Figure 2.	(a) Energy-momentum maps of the scattering intensities along the (H, 0) or (0, K) direction comparedwith (b) dispersion relations of the weakly coupled
SSH model. The intensity is integrated for the K or H
range of ±0.10 and the entire observed L range.

between them. If the alternation is very small, the structure factor of both bands becomes almost the same asthat without the alternation. Thus, for the most part, theanti-bonding triplon bands are almost undetectable.
The dispersion relation with the parameter sets thatmost accurately reproduces the experimental results isshown in Fig. 2(b).
3. Nontrivial topology induced by bond alternation
The nontrivial topology in triplon bands is inducedby the distortion of the rectangular lattice. The distorted
rectangular lattice can be regarded as a weakly coupled
Su-Schrieffer-Heeger (SSH) model [9], as illustrated schematically in Fig. 1(b). The SSH model has been originallyconstructed to explain the electron motions of polyacetylene. The bond alternation induces an energy gap
between two electron bands, and effectively introducescomplex hopping amplitudes of electrons. They resultin both the topologically trivial and nontrivial states
depending on the hopping amplitudes. Both statescannot be connected without closing the energy gap,

Research and Development Highlights

and in this sense, edge states expected in the nontrivial
state are called topologically protected. The presence ofthe edge states under the bond alternation is apparent
when they are described in a real space: localized electrons that cannot form a pair are left at the edge undercertain hopping amplitudes.
The inelastic excitation spectrum has revealed that
Ba2CuSi2O6Cl2 can be regarded as the quasi-two-dimensional variant of the SSH model. The topologically protected triplon edge states are induced by the bipartite
nature of the distorted rectangular lattice. The edge
states should be present at the center of the energy gap,
2.6 meV, and can be formed only by thermal activation.
4. Future plans
Bosonic quasiparticles, such as magnon andtriplons, should exhibit different topological properties from those expected for electrons. The difference
would be enhanced under strong interactions between
the quasiparticles. A dimer antiferromagnet is a goodplayground to investigate the topological characterof bosonic quasiparticles, since triplon density can betuned by a magnetic field. Additional research may leadto further development of our understanding of energyefficient information transmission and processing utilizing heat transport of the edge states.
References[1] D. Hsieh et al., Nature 452, 970–974, (2008).
[2] M. Z. Hasan and C. L. Kane, Rev. Mod. Phys. 82,
3045–3067 (2010).
[3] Y. Onose et al., Science 329, 297–299 (2010).
[4] L. Zhang et al., Phys. Rev. B 87, 144101 (2013).
[5] J. Romhanyi et al., Nat. Commun. 6, 6805 (2015).
[6] P. A. McClarty et al., Nat. Phys. 13, 736 (2017).
[7] M. Okada et al., Phys. Rev. B 94, 094421 (2016).
[8] K. Nakajima et al., J. Phys. Soc. Jpn. 80, SB028 (2011).
[9] K. Nawa et al., Nat. Commun. 10, 2096 (2019).
[10] W. P. Su et al., Phys. Rev. Lett. 42, 1698 (1979).

K. Nawa1, K. Tanaka2, N. Kurita2, T. J. Sato1, H. Sugiyama3, H. Uekusa3, S. Ohira-Kawamura4, K. Nakajima4, and H. Tanaka2
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University; 2Department of Physics, Tokyo Institute of Technology;
3
Department of Chemistry, Tokyo Institute of Technology; 4Materials and Life Science Division, J-PARC Center1

27

Research and Development Highlights

MLF Annual Report 2019Localized Magnetic Excitations in the Fully Frustrated
Dimerized Magnet Ba2CoSi2O6Cl2
1. Introduction
A coupled spin dimer system, in which antiferromagnetic dimers interact with one another throughinterdimer exchange interactions, provides an opportunity for correlating condensed matter physics with particle physics. This system often exhibits a nonmagnetic
ground state with a finite excitation gap. In an external
magnetic field exceeding the gap size, magnetic quasiparticles, magnons (or triplons), are created on the dimer.
As illustrated in Fig. 1, magnons move to neighboring dimer lattice and interact with one another owing to thetransverse and longitudinal components of the interdimer exchange interactions, respectively. One intriguingfeature is the crystallization of magnons, in the form ofa Wigner crystal, which could be a key to understanding
exotic quantum phases such as supersolids [1–4] andflatband solid states [5]. The crystallized phase of magnons is expected to emerge when the frustration of theinterdimer exchange interactions is so strong that magnons become localized [6–8]. To our best knowledge, until recently, the experimental studies have been limited
to the Shastry-Sutherland compound SrCu2(BO3)2 [6, 7].
Recently, we found that a new series of two-dimensional spin dimer systems, Ba2CoSi2O6Cl2, exhibitsa sharply stepwise magnetization process with a plateau at one half of saturation magnetization Ms [8]. Thissuggests that the interdimer exchange interactions of
this compound are almost perfectly frustrated. On theother hand, a spin dimer system can give rise to a similar(1/2)Ms plateau provided that there exist two kinds ofisolated dimer with equal populations. For a definitive
conclusion, it is important to elucidate the magnetic
excitations of this compound.

Here, we report on the results of inelastic neutron
scattering (INS) measurements of Ba 2CoSi 2O 6Cl 2 [9],using the cold-neutron disk chopper spectrometer
AMATERAS installed in the Materials and Life Science
Experimental Facility (MLF) at J-PARC, Japan [10].
2. Experimental details
Single crystals of Ba2CoSi2O6Cl2 were grown by theflux technique [8]. INS measurements were performedat several temperatures from 4 to 240 K with two sets ofincident neutron energies Ei = (2.6, 5.9, 10.5, 23.6) meVand (2.9, 4.7, 7.7, 15.2) meV. Approximately 60 platelike
single crystals with a total mass of ~1 g were glued on
an aluminum plate, where the a axis (or b axis) for eachcrystal was aligned parallel to the horizontal direction.
The fluoropolymer (CYTOP® [11]) employed as the glue
had a negligible contribution to the background. The
wave vector ki of an incident neutron was set parallel tothe c axis. All the data were analyzed using the software
suite Utsusemi [12].
b (or a)a (or b)c*

Figure 2.	Photograph of a sample setup used for the inelastic
neutron scattering experiment of Ba2CoSi2O6Cl2.

Figure 1.	Image of magnons which hop to a neighboring dimer site and interact with a neighboring magnon.

28

3. Results and discussion
Figures 3(a) and 3(b) show the energy-momentum
map of the scattering intensity along Q = (Qa, 0, 0) at
4 K measured with Ei = 15.2 and 23.6 meV, respectively,
where the scattering intensities were integrated overQb and Qc [9]. The directions of Qa (Qb) and Qc are parallel and perpendicular to the dimer layer, respectively,
in Ba2CoSi2O6Cl2. One can confirm three strong dispersionless excitations at 4.8, 5.8, and 6.6 meV and two

MLF Annual Report 2019

weak ones at higher energies of 11.4 and 14.0 meV. The
noteworthy feature of the three low-energy excitationsat 4–7 meV is that the scattering intensities exhibit different Q dependencies. This is more evident in the constant-energy slices of the scattering intensity shown in
Figs. 3(d)–(f ), where the scattering intensity is integrated
over Qc, considering the good two dimensionality, as
evidenced by the observed dispersionless excitations
along Qc. The intensity of the middle excitation with thehighest intensity at 5.8 meV is nearly independent of(Qa, Qb). On the other hand, the intensities of the upperside (6.6 meV) and lower-side (4.8 meV) excitations exhibit local maxima when both Qa and Qb are integers
and half-integers, respectively.
It is considered that when an excited triplet is localized, the single singlet-triplet excitation is dispersionless and its intensity is independent of Qa and Qb. Thus,
the middle excitation peak at 5.8 meV can be assigned
to the single singlet-triplet excitation to the |t±1⟩ state.
Assuming that the excitation at 11.4 meV corresponds
to the single singlet-triplet excitation to the |t0⟩ state,
we obtain J⊥ = 11.4 meV and J|| = 0.16 meV. This meansthat the intradimer exchange interaction closely approximates the XY model.
Because there is no other single-triplet excitation
to the |t±1⟩ states, we can deduce that all the dimers
are magnetically equivalent. Thus, the sharply stepwise
magnetization process with a (1/2) magnetization plateau can only be described in terms of the crystallizationof localized magnons owing to the strong frustration of

Research and Development Highlights

interdimer exchange interactions [8]. From these observations, we can safely conclude that the interdimer
interactions in Ba2CoSi2O6Cl2 almost satisfy the perfectfrustration condition.
Next, we discuss the origin of the anomalous side
peaks observed at 4.8 and 6.6 meV. Given that the
Ba2CoSi2O6Cl2 crystals employed in this study are perfect
crystals, the side-peak structure will be absent from theexcitation spectrum. It is natural to assume that theseside peaks are produced by interdimer interactions, because the energy difference between these side peaks
and the middle peak is on the order of the interdimer
interactions and the intensities of these side peaks arecommensurate with a and b.
One plausible scenario is that the observed side
peaks are caused by the three-body problem among
dimer spins and a neighboring undimerized single spin
produced by a vacancy of Co2+. To confirm the above
hypothesis based on the existence of undimerized spins
and to explain the periodic intensity oscillations in the
excitations at 4.8 and 6.6 meV, we calculated the differential cross section of the inelastic neutron scattering
for the decoupled-dimer excitation and the excitations
mediated by undimerized spins. As shown in Figs. 3(d)–(i), the calculated results provide an excellent agreementwith the observed scattering intensities. We also foundthat a crucial factor to produce the Q-dependent oscillation was the weak mixing of singlet and triplet components in the ground and excited states owing to theentanglement with the undimerized spin state.

Figure 3.	Energy-momentum maps of the scattering intensity along Qa at the base temperature of 4 K measured with
Ei = (a) 15.2 meV and (b) 23.6 meV, which were integrated over Qb and Qc. (c) Energy vs scattering intensity
measured with Ei =23.6 meV, where the scattering intensity was integrated over the complete Qa, Qb, and Qc
range. (d)–(f ) Constant-energy slices of the scattering intensity, where the scattering intensity was integrated
over Qc, and (g)–(i) the calculated ones (arb. units). In (a) and (c), vertical bars denote the energy resolution.

29

Research and Development Highlights

MLF Annual Report 2019

4. Conclusion and future plans
To summarize, we have probed the magnetic excitations of Ba2CoSi2O6Cl2 directly via inelastic neutron
scattering measurements. The five observed types ofmagnetic excitation were dispersionless within the resolution limits, and hence triplet excitations were verified to be localized. Unexpectedly, three low-energy
excitations at 4–7 meV exhibited characteristic Q dependencies of scattering intensities. It was found thatthe excitation spectra could reasonably be explainedby considering two mechanisms independently: a “perfect frustration” scenario for interdimer interactions in
the host system, and emergent three-body quantum
states owing to undimerized spins induced by vacancies in the crystals. This work shows that the highly
frustrated quantum magnets provide the various playgrounds of interacting quantum particles, and shows atypical case in which a small amount of vacancy has alarge effect on the excitation spectra, although the vacancy effect is usually hidden by the spectra of the hostsystem. To obtain further experimental findings to increase the understanding of this system, it is important
to elucidate the field evolution of each excitation by,
for example, in-field neutron scattering and electron
spin resonance experiments.

References[1] P. Chen, C. Y. Lai, and M. F. Yang, Phys. Rev. B 81,
020409 (R) (2010).
[2] A. F. Albuquerque, N. Laflorencie, J. D. Picon, and F.
Mila, Phys. Rev. B 83, 174421 (2011).
[3] Y. Murakami, T. Oka, and H. Aoki, Phys. Rev. B 88,
224404 (2013).
[4] D. Yamamoto and I. Danshita, Phys. Rev. B 88,
014419 (2013).
[5] J. Richter, O. Krupnitska, V. Baliha, T. Krokhmalskii,
and O. Derzhko, Phys. Rev. B 97, 024405 (2018).
[6] H. Kageyama et al., Phys. Rev. Lett. 82, 3168 (1999).
[7] S. Miyahara and K. Ueda, Phys. Rev. Lett. 82, 3701
(1999).
[8] H. Tanaka et al., J. Phys. Soc. Jpn. 83, 103701 (2014).
[9] N. Kurita, D. Yamamoto, T. Kanesaka, N. Furukawa,
S. Ohira-Kawamura, K. Nakajima, and H. Tanaka,
Phys. Rev. Lett. 123, 027206 (2019). See Supplemental
Material at http://link.aps.org/supplemental/
10.1103/PhysRevLett.123.027206 for additional
information on the experimental data and thetheoretical calculations.
[10] K. Nakajima et al., J. Phys. Soc. Jpn. 80, SB028 (2011).
[11] https://www.agcchem.com/products/specialtymaterials/cytop[12] Y. Inamura, T. Nakatani, J. Suzuki, and T. Otomo, J.
Phys. Soc. Jpn. 82, SA031 (2013).

N. Kurita1, D. Yamamoto2, T. Kanesaka2, N. Furukawa2, S. Ohira-Kawamura3, K. Nakajima3, and H. Tanaka1
Department of Physics, Tokyo Institute of Technology; 2Department of Physics and Mathematics, Aoyama-Gakuin University; 3Materials andLife Science Division, J-PARC Center

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MLF Annual Report 2019

Research and Development Highlights

Magnetic Skyrmion Lattice in a Centrosymmetric
Breathing Kagome Lattice
1. Introduction
Topological spin orders have been of great interest
since the discovery of magnetic skyrmion lattice (SkL),
which is a periodic array of vortex-like spin objects, ina chiral magnet MnSi [1, 2]. Owing to the chiral crystal
structure, MnSi has uniform Dzyaloshinski-Moriya (DM)interactions. Combining the DM interaction with ferromagnetic exchange interactions, MnSi exhibits longperiod-modulated magnetic orders including SkLs. Thisestablished that chiral magnets with ferromagnetic
interactions are promising candidates for skyrmionhost materials. In fact, there were a lot of reports on
emergence of SkLs in chiral magnets such as FeGe [3],(Fe,Co)Si [4], Cu2OSeO3 [5], and Co-Zn-Mn alloys [6].
Subsequent theoretical studies have pointed out that
centrosymmetric magnets can also host SkL without
relying on DM interactions. Specifically, Okubo et al.
revealed that magnetic frustration can induce SkL andanti-skyrmion lattice states in a centrosymmetric twodimensional triangular lattice model [7]. Hayami et al.
also revealed that a coupling between localized spinsand conduction electrons can be a source of topological spin orders composed of multiple magnetic modulation wave vectors (q-vectors) [8]. Motivated by these
theoretical studies, we study a centrosymmetric kagome lattice magnet Gd3Ru4Al12.
2. Experiment
A single crystal of Gd3Ru4Al12 was grown in a floating zone furnace. To avoid strong neutron absorption of
Gd in natural abundance, we substituted it with isotope
enriched 160Gd. The sample was cut into a plate shapewith dimensions of 2.5 × 2.0 × 0.6 mm3. We performed
small- and wide-angle neutron scattering measurements at TAIKAN instrument in BL15 of the Materials
and Lifescience Experimental Facility (MLF) of J-PARC.
The sample was loaded into the 4T-horizontal-magnet
of BL15. An external magnetic field was applied parallelto the c axis of the sample.
3. Results and discussions
Figures 1(a) and 1(b) show schematic images of thecrystal structure of Gd3Ru4Al12. Gd3+ ions with spin S =7/2 are arranged on kagome lattices, which are stacked
along the c axis. Ru and Al atoms are located between
the Gd kagome layers. In Fig. 1(c), we show a magnetic

phase diagram of Gd3Ru4Al12 exhibiting a variety ofmagnetic phases below TN1 = 18.6 K and magnetic fieldof up to 4 T. We first investigated magnetic phases inzero field. By using the small angle detectors of TAIKAN,
we successfully revealed that the zero-field phases arecharacterized by incommensurate q-vectors of (q,0,0)
and its equivalents, where q shows weak temperaturedependence. The length of magnetic modulation, λm =2π/q, is 2.8 nm, which is about one order of magnitude
shorter than that of MnSi.
We measured field dependence of the magneticreflections, revealing that all the magnetically orderedphases have the (q,0,0)-type q-vectors. In Fig. 2, weshow the field dependence of the integrated intensity
and the wavenumber q of the magnetic reflection at(q,0,0) measured at 2.4 K, as functions of magnetic fieldalong the c axis. We found that the integrated intensity
shows a sharp drop upon the phase transition from theground state to the 1st-field-induced phase. This implies that the orientations of the magnetic moments
abruptly change at this magnetic phase transition. To
gain more insight into the magnetic structures, we also
performed resonant X-ray magnetic scattering experiments on this system at BL-3A in the Photon Factory in
KEK, and found that the magnetic structure changes
from a screw-type structure to a cycloid-(transverseconical) type structure upon the field-induced phasetransition at the lowest temperature.

Figure 1.	[(a), (b)] Schematic illustrations of the crystal structure of Gd3Ru4Al12. (c) Magnetic phase diagram of
Gd3Ru4Al12 for magnetic field along the c axis. Color
scale shows the real part of ac magnetic susceptibility. [cited from Ref. 10]

31

Research and Development Highlights

MLF Annual Report 2019

Having established the magnetic structures at thelowest temperature, we investigated the thermallyinduced phase under magnetic field labeled “SkL” in
Fig. 1(c). Similarly to the other magnetic phases, weobserved three incommensurate q-vectors perpendicular to the c axis; specifically (q,0,0), (0,q,0) and (-q,q,0).
Interestingly, we found that the Hall conductivity showsa hump anomaly in this phase, which is quite reminiscentof the topological Hall effect in the SkL phase of MnSi [9].
We thus expect that the spin texture of this phase is described by a superposition three q-vectors, which leads
to a SkL as shown in Fig. 3(a). To obtain real-space imageof the spin texture, we performed Lorentz transmission
electron microscopy on a (001) thin plate of Gd3Ru4Al12,and finally found that particle-like objects are arranged
to form triangular lattice domains as shown in Fig. 3(b).
This is the direct evidence of the SkL formation in thiscompound [10].
4. Summary
We have demonstrated that the centrosymmetrickagome lattice compound Gd3Ru4Al12 exhibits magnetic skyrmion lattice in the thermally induced phase
under a magnetic field, suggesting that various topological spin orders can be realized in centrosymmetricsystems, as evidenced by recent studies on Gd-based
triangular and tetragonal systems [11, 12]. It has been
established that the magnetic skyrmions in chiral magnets can be controlled by various external stimuli, suchas electric current, its combination with thermal gradient, and hydrostatic/uniaxial pressure. We thus planning to explore the possibility of external field control
of SkLs in cetrosymmetric crystals.

Figure 2.	Field dependence of the integrated intensity, peak
position and width along the radial direction for themagnetic reflection at (q,0,0) measured at 2.4 K.

Figure 3.	(a) Schematic illustration of the magnetic skyrmion
on the kagome lattice of Gd3Ru4Al12. (b) Real-spaceobservation of the spin texture on the (001) planeof Gd3Ru4Al12 by Lorentz transmission electron microscopy. [cited from Ref. 10]

References[1] S. Muhlbauer et al., Science 323, 915 (2009).
[2] Y. Tokura and N. Nagaosa, Nat. Nanotech. 8, 899(2013).
[3] X. Z. Yu et al., Nat. Mater. 10, 106 (2011).
[4] W. Munzer et al., Phys. Rev. B 81, 041203 (2010).
[5] S. Seki et al., Science 336, 198 (2012).
[6] Y. Tokunaga et al., Nat. Commun. 6, 7638 (2015).
[7] T. Okubo et al., Phys. Rev. Lett. 108, 017206 (2012).
[8] S. Hayami et al., Phys. Rev. B 95, 224424 (2017).
[9] A. Neubauer et al., Phys. Rev. Lett., 110, 209902(2013).
[10] M. Hirschberger et al., Nat. Commun. 10, 5831
(2019).
[11] T. Kurumaji et al., Science 365, 914 (2019).
[12] N. D. Khanh et al., Nat. Nanotech. 15, 444 (2020).

M. Hirschberger1, T. Nakajima1, S. Gao1, L. Peng1, A. Kikkawa1, T. Kurumaji1, M. Kriener1, Y. Yamasaki2,3, H. Sagayama4, H. Nakao4,
K. Ohishi5, K. Kakurai1,5, Y. Taguchi1, X. Z. Yu1, T. Arima1,6, and Y. Tokura1,7
1
RIKEN Center for Emergent Matter Science (CEMS); 2Research and Services Division of Materials Data and Integrated System (MaDIS);
National Institute for Materials Science (NIMS); 3PRESTO, Japan Science and Technology Agency (JST); 4Institute of Materials Structure
Science, High Energy Accelerator Research Organization; 5Neutron Science and Technology Center, Comprehensive Research Organizationfor Science and Society (CROSS); 6Department of Advanced Materials Science, University of Tokyo; 7Department of Applied Physics and Tokyo
College, University of Tokyo

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MLF Annual Report 2019

Research and Development Highlights

Multiple Structural Level Morphology of Sulfonated sPS
Membranes Resolved by SANS
1. Introduction
The proton exchange membrane (PEM) fuel cells(PEMFC) are considered an attractive energy conversion technology with a potential to become an alternative to the current fossil fuel technologies in light-dutytransportation. The PEM separates the anode from thecathode and conducts at very high rates the protons
emerging from the catalyst facilitated hydrogen oxidation in the anode chamber. PEM materials are characterized by a nanoscale phase separation into hydrophilic
domains and hydrophobic regions, a combination thatenables high-proton conductivity and provides a goodchemical and mechanical stability of the membrane.
The proton conduction in PEMs depends on water andis governed by the water behavior at different lengthscales [1]. However, due to the membrane swelling,
there is always a trade-off between reaching optimal
conductivity and mechanical stability. Moreover, themembrane durability is affected by chemical decomposition caused by the free radicals produced during the
PEMFC operation. The design of new PEM materials isthus a prerequisite to understanding the morphology
of hydrated domains at different length scales and the
behavior of the hydrophobic domains under PEMFC operation conditions.
Nafion (Du PontTM) is the best-known PEM material
and although it has been established as a benchmark forsuch applications, it presents several drawbacks, such as
the high cost, lack of safety during manufacturing anduse, need of supporting equipment and temperature
related limitations. As alternatives, different crystallineamorphous polymeric architectures with similar conductive and chemo-mechanical properties as Nafion
have been extensively studied in recent years.
2. The syndiotactic-polystyrene as model PEM
Given the recent developments, which enable acontrolled functionalization by sulfonation of only theamorphous phase, thus preserving the crystallinity ofthe material [2], and an improved resistance to oxidation decomposition when fullerenes are added [3], thesulfonated syndiotactic polystyrene (s-sPS) in its b-form
may become a good PEM material candidate, as it displays high proton conductivity, comparable to Nafion,high chemical and thermo-mechanical stability and a
low cost. Starting from the d-form (clathrate with guest

molecules), which enables a homogeneous sulfonationof the amorphous regions, the membrane can be subsequently transformed by annealing into the thermodynamically stable b-form.
3. Micro-structural characterization of s-sPS
In a preliminary study [4], highly sulfonated s-sPS
membranes with d-clathrate co-crystalline form were
explored at different relative humidity (RH) levels bysmall-angle neutron scattering (SANS). Besides the
structural characterization of the crystalline lamellar
stacks and the water cluster morphologies, the preservation of crystallinity was assumed only indirectly fromthe SANS data.
In the current study, membranes with different sulfonation degrees and crystallinity (pre-characterized
conditions) were systematically investigated at room
temperature in controlled hydrated states by using theextended Q-range available at the TAIKAN (BL-15) SANS
diffractometer [5]. A Q-range from 0.005 to 2 Å-1 wascovered, which enabled a structural investigation overa wide-length scale, from the crystalline structure to themesoscale size. The deuterated s–sPS films (ca. 100 mm),used to assure a low incoherent background, were
doped with different guest molecules: with fullerenes in the amorphous regions, to reproduce the conditions
that prevent the membrane’s chemical decomposition [3], and with protonated toluene – in the crystalline
regions, to provide the right contrast at the local scale. A
humidity chamber (Anton Paar, Graz, Austria) was used
to control the RH between 5% and 85%. To understandthe nature of the hydrated domains, contrast variation
SANS was done using different H2O/D2O mixtures.
Figure 1 presents a selection of one-dimensional
scattering data from a stretched s-sPS film with a low
degree of sulfonation (S = 19.3%) and low crystallinity(22%) that was loaded with C60 fullerenes and hydrated
at RH = 80% using different H2O/D2O mixtures. The useof uniaxially deformed film samples allowed the clear
separation of scattering contributions from different
morphologies and structural levels on different detection sectors (equatorial or meridional), depending on
their size and orientation. Thus, the scattering featuresfrom the crystalline regions – the inter-lamellar correlation peak and the crystalline structure peaks – areanisotropic due to the orientation of structures as a33

Research and Development Highlights

34

MLF Annual Report 2019

Figure 1.	SANS patterns from a s-sPS film hydrated at RH =80% using different H2O/D2O ratios. Symbols denote the experimental data, while the red lines correspond to the model interpretation of the data, asreported in [5].

Figure 2.	The high-Q range of the SANS patterns on theequatorial direction measured for different hydration levels with H2O (left) and at RH = 80% using
different H2O/D2O mixtures.

consequence of the film stretching, while the hydrated
domains that are randomly distributed in the amorphous region yield isotropic scattering features.
The scattering patterns present three distinct peaklike features, which are also visible for all RH conditions(a selection of high-Q range data is shown in Fig. 2).
These features are indicative of structural correlations
occurring at different length scales in the complex morphology of the polymer films. The 010 crystalline peakvisible in equatorial sectors at high Q values may beascribed to the mean repeating distance between thesPS sheets and appears due to the neutron contrast
provided by the protonated guest loaded in the cavities between deuterated host helices. The peak does notchange its profile with the increase of RH or the variationof the SLD of hydrated water, which indicates the preservation of the membrane crystallinity, hence stability,
during hydration-drying processes.
The ionomer peak, which occurs due to correlations between the ionic clusters, represents a scatteringfeature characteristic of the sulfonation and hydration in the amorphous regions, and is thus isotropic
distributed on the detection area. The peak intensity
is sensitive to the contrast between the hydration water and hydrophilic polymer segments, while the peak
position Qion depends on the RH (Fig. 2), i.e. the correlation length x increases when the water cluster grows in
size. No matching of scattering features characteristicof hydrated clusters was observed for the 70/30 H2O/
D2O contrast condition corresponding to the SLD ofsulfonic group, only the global intensity was lower, due
to the lower contrast achieved between the hydrated

and non-hydrated components of the film morphology. For hydration with 100% D 2O the ionomer peakvanishes, which indicates that the matching of the scattering properties of ionic clusters and surrounding water renders the correlation between the ionic clusters
no longer visible. We concluded that the ionic clusters
promoting the water uptake by the membrane consistof associations of larger sections of neighboring s-sPS
chains in the region of the benzene ring and the sulfonic acid terminal group, which are correlated over the
distance 2p/Qion.
In the low Q region, the inter-lamellar peak characteristic of the oriented lamellar stacks can be observedin the meridian scattering patterns, with a stronger
profile for the 100% H2O contrast condition. The peak
position remains almost unchanged with increasing RH,
even in the case of samples with higher crystalline degree. The equatorial scattering pattern exhibits towards
low Q a kind of plateau when hydration is achieved with
100% H2O, which resembles characteristics of a spherical form factor, while a Q-1 power law behavior of thescattered intensity may be observed when 100% D2O
is used. Apparently, the water accumulates in clusters
along groups of elongated s-sPS chains (SLD similar tothat of D2O) and highlights in this case the hydrated
regions as one-dimensional arrangements against thehydrophobic environment (SLD lower than that of sSPS). The upturn of intensity at low Q, which appears
stronger on the equator direction due to the stretchingof a sample on the vertical axis, arises from the largescale fractal-like character of the membranes (Q-3 powerlaw behavior).

MLF Annual Report 2019

Research and Development Highlights

Figure 3.	Schematic view of the experimental approach used to study the multiple structural level of the s-sPS morphology.

According to our qualitative and quantitative analysis of SANS data in terms of structural models [5], wateris taken-up in clusters and is distributed to the same extent in the inter-lamellar and bulk amorphous regions
at low hydration levels, whereas with increasing thehydration level the water accumulates predominantlyin the bulk amorphous region favored by the increased
flexibility of the sPS chains in these domains. At a very
high RH cylindrical channel morphologies are yieldedwhen the water clusters in the bulk amorphous regions
grow and interconnect with each other [4].
Figure 3 shows the global picture of the multiple

structural level character of the membrane as resolved
using this specific SANS setup.
References[1] A. Kusoglu, A.Z. Weber, Chem. Rev. 117, 987 (2017).
[2] G. Fasano, et al., Int. J. Hydrog. Energy 36, 8038
(2011).
[3] S. Saga, et al., J. Power Sources 176, 16 (2018).
[4] M-M. Schiavone, et al., Solid State Ionics 320, 392,
(2018).
[5] M-M. Schiavone et al., Membranes 9, 136, (2019).

M-M. Schiavone1, H. Iwase2, S. Takata3, and A. Radulescu1
Jülich Centre for Neutron Science, Forschungszentrum Jülich GmbH; 2Neutron Science and Technology Center, CROSS; 3Neutron Science
Section, Materials and Life Science Division, J-PARC Center

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Research and Development Highlights

MLF Annual Report 2019

Thickness of the Ethanol/Water Surface Layer
1. Introduction
The thickness of the surface layer of amphiphilic molecules is a crucial parameter for many physical processes. The essential processes involved in theinterfacial layer include the evaporation rates andvapour/liquid equilibrium. Due to the thinness andfragile nature of the interface, such thickness remains
improbable. The early studies (Li and co-authors, 1993)
assumed the thickness is independent of concentrationand equal to the length of the amphiphilic molecules.
However, recent advances in the field have indicatedthat the interface layer is variable with the composition. Yet, the application of thermodynamic analysis
leads to conflicting prediction. For the ethanol/water
surface, which is important for many physical, chemicaland biological processes, there are at least two contradicting predictions. One predicted that the thickness
increases with ethanol concentration (Santos and Reis,
2018), whereas the other predicted a decreasing trend(Bagheri and co-authors, 2016).
2. New Method
We applied a new mathematical framework to relate the adsorption, composition and thickness. And
the molar fraction at the surface is then:xb
Γe(w)+ e b Nws
1−xe
δ
xes =
(1)
b
(w)
x
Γ
e
 e +
s 
+ s
1−xeb Nw  Nw
 δ
The above equation links the surface concentration to the Gibbs excess, Γe(w), at any given xeb and δ. The
thickness, δ, cannot be determined experimentally. As
mentioned above, the assumption of constant thickness is no longer valid. In this study, xes is determined
via simulation as a function of xeb. The surface adsorption, Γe(w), is determined experimentally from neutronreflectometry. The combined NR and simulation results,
xes and Γe(w), are then applied to Eq.(1) to determine δ via
numerical iterations. The results are used to verify, orotherwise, the proposed relationship between the interfacial thickness and bulk concentration.
The experimental work was carried out at BL16 in
the MLF facility (Fig. 1). The mixture of H2O, D2O anddeuterated ethanol C2D6O were used to get the scattering and serves as input for calculation. The NR data wasanalysed using the software MOTOFIT.
36

Figure 1. Neutron reflectometer SOFIA at BL16 in J-PARC MLF.

3. Results and Interpretation
The vacuum/solution (d-ethanol and water) interface was simulated. From the density profiles, the bulk
and interfacial composition were calculated (Fig. 2).
The simulation and NR data were combined to calculate the surface composition (Fig. 3). Reconciliation
between neutron reflectometry data and simulated
xes for each solution indicated a decreasing trend of δas the solution concentration increased. The following
equation relating the interfacial thickness to the bulk
concentration is proposed:δ = δ0 exp(λ xeb) + δinf(2)where δ0 and δinf are the theoretical limits at xeb = 0 and
xeb = 1, respectively, and λ is the rate of decay.
The consistent results show (Fig. 4) that the thickness decays and reach a plateau around 8 Å.

Figure 2.	Density of d-ethanol within air/water interfacial
layer.

MLF Annual Report 2019

Figure 3.	Ethanol surface composition surface tension, molecular simulation and NR experiments (this study).

Research and Development Highlights

4. Implication and Future Plans
The combination of NR, molecular dynamics andtheoretical analysis provides an objective determination of the interfacial thickness. The decreasing behaviour was reported for the first time.
The findings confirm that the interfacial thickness
is not constant and instead decreases with increasing
ethanol concentration. The result is consistent with arecent thermodynamic analysis and demonstrated thelimitation of the conventional theory, which oversimplified the interfacial layer. The new insights provide atheoretical framework to describe the interfacial layerof water/alcohol mixtures. Our next step is to cooperate
the results with thermodynamic analysis to correctly
calculate the surface activities and related parametersfrom the molecular structure of alcohols.
References[1] Li, Z.X., et al., Mol. Phys., 80 925 (1993).
[2] A. Bagheri, M. Fazli, M. Bakhshaei, J. Mol. Liq., 224
442 (2016).
[3] M.S.C.S. Santos, J.C.R. Reis, J. Mol. Liq., 255 419(2018).
[4] A.E. Hyde, M. Ohshio, C.V. Nguyen, S. Yusa, N.L.
Yamada, C.M. Phan, J. Mol. Liq., 290 111005 (2019).

Figure 4.	Surface thickness as a function of ethanol composition.

C. Phan1 and N. Yamada2
Chemical Engineering, Curtin University, Australia; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center, Instituteof Materials Structure Science, KEK

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MLF Annual Report 2019

Development of Spin-Contrast-Variation Neutron
Reflectometry
1. Introduction
Neutron reflectivity (NR) is used to determine thenanostructure of surfaces and interfaces of thin film
samples. Because of the relatively high transmittance ofneutron beams, NR has an advantage over X-ray reflectivity for measuring deeply-buried interface of materials. However, it is difficult to determine the structure ofcomplex multiple surface and interfaces of the thin film
from a single reflectivity curve.
To overcome this problem, we developed a newtechnique called “spin-contrast-variation neutron reflectometry (SCV-NR)”, which utilizes the property that
coherent polarized-neutron scattering length of a proton remarkably varies as a function of the proton polarization, PH, against the neutron polarization direction. As
PH increases, the scattering length density (SLD) of eachlayer proportionally increases with the number densityof protons, resulting in the variation of NR curves. The
structure of multiple surface and interfaces of a thin film
specimen can be determined from the PH-dependent
multiple NR curves. Here, we report the results of a polystyrene (PS) monolayer film to demonstrate the ability
and reliability of the SCV-NR technique [1].
2. Experiment
The PS thin film was prepared by spin-coating toluene solution containing 2 wt.% of PS and 0.016 wt.%of 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine
1-oxyl free radical (TEMPO methacrylate) at 5000 rpm
on a 20 mm × 20 mm × 0.5 mm single-crystalline Si substrate, and then annealed in a vacuum at 85°C for 4 days.
Protons in the PS thin film were polarized using a
dynamic nuclear polarization (DNP) apparatus, which
was built by setting a microwave device, a NMR circuit,and an insert to the cryogen-free split-pair transverse
magnetic field magnet used as a sample environment
equipment at BL15 (Fig. 1) [2, 3]. The protons in the thinfilm samples were dynamically polarized by irradiating
94 GHz and 600 mW microwaves from the Gunn oscillator (VCSS, GDO-10-9417F) and the amplifier (Keycom,
MPA95GHz-01) at 3.36 T and 2.4 ± 0.1 K. Whereas the
DNP condition was tuned by monitoring an enhancement of a NMR signal of a bulk reference sample near
the thin film sample, the thin film sample is too thin
to measure its NMR signal. Instead, PH was determinedfrom the analysis of the SCV-NR curves (see below).
38

Figure 1.	DNP apparatus for SCV-NR measurements using
the cryogen-free transverse magnetic field magnet
of BL15 [2, 3].

The PS thin film in the DNP apparatus was set into
BL17 (SHARAKU) to perform the SCV-NR measurement
using pulsed neutrons with wavelength from 0.24 to
0.88 nm and polarization of 98.5%. The positive andnegative polarization was switched by inverting thepolarization of the incident neutrons every 30 s while
maintaining the proton polarization of the samples.
3. Results and analysis
Figure 2 compares the NR curves of the positivelypolarized (POS), unpolarized (UNP), and negatively-polarized (NEG) PS thin film. The following PH-dependent
behaviors were observed. First, the reflectivity of NEG
is higher than that of UNP, but the reflectivity of POS
is even higher than that of NEG in the whole Q range.
Second, the oscillation amplitude of NEG is much smaller than that of the others, and the oscillation of POS isalmost inverted as compared with those of the others.
Third, the oscillation period of POS is slightly shorter
than those of the others. Forth, the critical Q-value Qcof the total reflection of POS is higher than those of theothers.

MLF Annual Report 2019

Figure 2.	SCV-NR curves of the PS thin film. Solid lines depict
the simulation curves using the SLD profiles in theright inset. The left inset shows the enlarged curves
near Qc [1].

The PH-dependent NR curves, POS, UNP, and NEG,
are reproduced by the simulation using a common setof structural parameters and SLD of PS at PH = +16, 0, and-16% in the right inset, respectively. The variation of SLD
across the free surface facing to vacuum at PH = +16% islarger than any other variation across the surface andinterface at PH = 0 and -16%, which results in the largest
reflectivity at PH = +16%. In contrast, the variation acrossthe free surface at PH = -16% is so small that the oscillation due to the interference between reflected neutrons
from the free surface and the interface damps remarkably. The SLD of PS, ρPS, is higher than that of Si, ρSi, at
PH = -16 and 0% but smaller at +16%, which results in
the inversion of the oscillation, i.e., the open reflection
point at the interface becomes a fixed one. According
to Snell’s law, the angle of refracted neutrons inside thefilm decreases with increasing ρPS, resulting in shorter
oscillation period at higher PH. The total reflection occurs
on the PS-Si interface at PH = -16 and 0%, but on the freesurface at +16%, because ρPS exceeds ρSi. In this case, ρPS
is obtained from Qc using the equation,ˉρˉ
Qc = 4√π
PS .(1)PH, which is a simple function of ρ PS, is most reliably
determined from the Qc. As opposed to Qc, the otherPH-dependent parameters, such as oscillation period
and amplitude, are not always suited to determine PH,
because they are not a simple function of PH, especiallywhen reflection from many surfaces and interfaces areinterfering.

Research and Development Highlights

4. Discussion
DNP is sensitive to many environmental factors,
such as concentrations of the doped free radicals andO2 impurity, which acts as a depolarizer. Thus, PH could
be considered inhomogeneous in the depth directionof the thin film sample due to localization of the TEMPO
methacrylate and/or O2 near the surface or interface.
However, such a possibility can be ruled out due tothe fact that all of the SCV-NR curves are reproducedby the simulation using homogeneous distribution of
PH in depth direction. It is well known that samples arehomogeneously polarized at least in submicron lengthscale due to the spin diffusion mechanism, in which theneighboring spins continually exchange through theenergy conserving flip-flop transitions of the dipolar
Hamiltonian [4, 5]. We demonstrated that poly (styrene-b-isoprene) (PSPI) samples were polarized almost
homogeneously even when TEMPO radicals were selectively doped in the microphase-separated polystyrene
or polyisoprene domains [6]. In this manner, the homogeneity of polarization in a submicron length scale isguaranteed by spin diffusion even if free radicals are
more or less localized at a specific surface, interface,or layer. We can safely assume homogeneous polarization on analyses of SCV-NR curves of submicron-thicksamples.
SCV-NR determines the structure of multiple surfaces and interfaces through the global fit of the PHdependent multiple curves, whereas multiple structuralparameters have to be determined from a single curvein conventional NR. Thus, SCV-NR can exclude incorrect
sets of structural parameters that accidentally reproduce
a single curve of an unpolarized sample [1]. In particular,
the SCV-NR curve can selectively pick up structural information of a specific surface or interface by matching out
the SLDs of other surfaces and interfaces.
5. Future plans
Taking advantage of SCV-NR, we recently measured
the structure of silica coating for plastic dishes. We will
pick up the structural information of the silica–polymer
interface, which is related to the peeling property of
the coat. Very recently, PH ≈ 40% was achieved in thesilica-polymer multilayer film using a cryogen-filled
DNP system at 3.36 T and 1.2 K. Simultaneously, we aredeveloping a 6.7 T higher-field DNP system to increase
PH further. We expect that the structural parameters ofmultilayer films will be determined more accurately andprecisely by increasing PH.
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Research and Development Highlights

MLF Annual Report 2019

References[1] T. Kumada et al., J. Appl. Cryst., 52, 1054 (2019).
[2] T. Kumada et al., JPS Conf. Proc., 22, 011015 (2018).
[3] T. Kumada et al., PoS, Proc. Sci. 324, 009 (2018).

[4] B. van den Brandt et al., Eur. Phys. J. B, 49, 157 (2006).
[5] T. Kumada et al., J. Chem. Phys., 133, 54504 (2010).
[6] Y. Noda et al., J. Appl. Cryst., 44, 503 (2011).

T. Kumada1, K. Akutsu2, K. Ohishi2, T. Morikawa2, Y. Kawamura2, M. Sahara2, J. Suzuki2, D. Miura1,3, and N. Torikai4
Materials Sciences Research Center, JAEA; 2Neutron Science and Technology Center, CROSS; 3Department of Physics, Yamagata University;
4
Graduate School of Engineering, Mie University

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Research and Development Highlights

Magnetic Multilayer with Quasi Antiferromagnetic Layer
Studied by Polarized Neutron Reflectometry
1. Introduction
Recently, antiferromagnetic (AFM) spintronics had
attracted high attention because it has an advantage
over ferromagnetic (FM) spintronics, e. g. high frequencies in spin torque oscillation (STO) and a zero-strayfield [1, 2]. However, it is difficult to obtain the practical and obvious STO because of the strong exchange
coupling between adjacent atoms. To realize STO without a stray field, we successfully created a new type ofmagnetic material, named quasi-AFM layer, whose magnetic domains are alternating antiparallel [3]. In simulation, STO was observed in the quasi-AFM layer because
it exhibits FM coupling within one domain and eachmagnetic moment can oscillate simultaneously [4]. At
the same time, a zero-stray field is expected owing to
the alternating antiparallel magnetization in the next
magnetic domains. Strictly speaking, however, even thenative antiferromagnetic materials have a Néel vector
made by deviation from perfect antiparallel magnetic
moments, which interacts with the external input, e.g.
magnetic fields, electric currents, and spin torques. In
order to investigate the Néel vector of the quasi-AFM
layer, we carried out fine magnetic structure analyses
for the quasi-AFM layer by means of Polarized Neutron
Reflectivity (PNR) measurements.

2. Experimental
The quasi-AFM layer is realized by 90° magnetic
coupling, which is an interlayer exchange interaction
between two FM layers separated by a thin layer. The 90°
coupling becomes obvious under compensation of FM
and AFM coupling between two FM layers. Figure 1(a)shows a schematic film structure. When the magnetization of the CoFe (A) layer is pinned by exchange bias
from IrMn, the CoFe (B) layer has the +/−90° magnetization to the exchange bias and that is the quasi-AFM layer.
Here, we prepared two kinds of samples with different
buffer layers, Ru and NiFeCr40/CoFe. Since the Ta/NiFeCr40
buffer makes the layers flat, there was difference in theroughness. The smaller roughness generally provides thestronger 90° coupling. We compared the roughness effect on the Néel component of quasi-AFM quantitively.
We measured PNR using a neutron wavelength of
0.24–0.88 nm at SHARAKU (BL17) in the Materials andLife Science Experimental Facility (MLF), Japan Proton
Accelerator Research Complex (J-PARC) [5]. Both the
crystal and the magnetic structures were analyzed by
X-ray Reflectometry (XRR) and PNR simultaneously. The
reflectivities were measured as a function of the wavevector transfer in applied magnetic fields along the xaxis and we found their values to be +1000 Oe, +29 Oe,(a) Sample structure(b) Fitting flow

Cap layers
Free layer

Designed structure

Quasi-AFM
90 degrees coupling
Pinned layer
Exchange bias fieldᶅʁRu 2nm
ᶆʁNiFeCr 5nm/
Co90Fe90 1nm

yx

Figure 1.	(a) Schematic image of the sputtered multilayer with the quasi-AFM layer made by 90° magnetic coupling.
(b) Fitting flow of PNR and XRR profiles by using GenX.

41

Research and Development Highlights

MLF Annual Report 2019and −28 Oe for the Ru buffer sample, and +1000 Oe,+32 Oe, and −45 Oe for the NiFeCr buffer sample at room
temperature. The data reduction software Utsusemi [6]in BL17 was applied and GenX [7] was used for the PNR
analysis. By repeating the XRR and PNR fitting as shownin Fig. 1 (b), we obtained sufficiently good agreement
between the experimental data and the calculated datawith the figure of merit less than 2e−1.

magnetic parameters, i. e. the magnitude and direction of magnetization in quasi-AFM, the magnetization
orientation can be described and compared with themagnetization curves in Fig. 3. Here, the focus is on themagnetization of the quasi-AFM layer though the magnetizations of the other layers were also obtained. As aresult, it became clear that the Néel vector was 1.35 mB
and 1.00 mB for the Ru and NiFeCr buffer samples, respectively, when the tilted angle was 1° in low appliedfields, such as several tens Oe. It was noted that, according to the magnetization curves, the magnetization
configuration in the applied field of several tens Oe wasclose to that in a nonmagnetic field.

3. Results and discussion
Figers. 2(a) and (b) show the PNR profiles for the
Ru and NiFeCr buffer samples, respectively, where thedots indicate the experimental data and the lines show
the calculated results of fitting. By using the obtained(a) Ru buffer sample
10 0
10-2

(b) NiFeCr buffer sample+1000 Oe
FOM:1.3637e-1+1000 Oe
FOM:1.7131e-1+29 OeFOM:1.4260e-1+32 OeFOM:1.3039-1-28 OeFOM:1.7901e-1-45 OeFOM:1.3904e-1

Reflectivity

10-4
10 0

10-2
10-4
10 0
10-2

10-4
0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Figure 2.	PNR profiles and fitting curves; (a) Ru buffer sample in +1000 Oe, +29 Oe, −28 Oe and,(b) NiFeCr buffer sample in +1000 Oe, +32 Oe, −45 Oe.

(a) Ru buff
bufferffer sample(b) NiFeCr buff
bufferffer

Figure 3.	Comparison between magnetization curves and schematic images of the magnetization for Co90Fe10 (B)estimated from PNR analysis for (a) Ru and (b) NiFeCr buffer samples.

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MLF Annual Report 2019

4. Future plans
The quantitative Néel vector, which we obtained
successfully in the quasi-AFM layer, can be controlled
by the buffer layer selection. The value of the Néel vector is useful to calculate the magnetization dynamics
by micromagnetic simulation. From now on, the suitable magnetic structure will be estimated by simulation, and the spin torque of the quasi-AFM layer will
be realized by direct electric current flows through thefine elements.

Research and Development Highlights

References[1] A. H. MacDonald and M. Tsoi, Phil. Trans., R. Soc. A
369 3098 (2011).
[2] R. Khymyn et al., Sci. Rep. 7 43705 (2017).
[3] G. Nagashima et al., J. Appl. Phys. 126 093901 (2019).
[4] S. Horiike et al., Jpn. J. Appl. Phys. 59 SGGI02-1~6(2020).
[5] M. Takeda et al., Chin. J. Phys. 50 161 (2012).
[6] Y. Inamura et al., J. Phys. Soc. Jpn. 82 SA031 (2013).
[7] M. Björck and G. Andersson, J. Appl. Cryst. 40 1174
(2007).

H. Yuasa1, Y. Zhong1, Y. Kurokawa1, and T. Hanashima2
Faculty of Information Science and Electrical Engineering, Kyushu University; 2Neutron Science and Technology Center, CROSS

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MLF Annual Report 2019

Nonlinear Piezomagnetoelectric Effect in CuFeO2(a)triangle

PM

15 T
N1

10

b

isosceles triangle

PD

4SL

FE-ICM[001]

scalene triangle

0

800
400

5

scalene triangle

10
μ 0 H || c (T)(a)

p = 800 MPa

T = 13.6 K
H || cp = 600 MPa

Ep > 0p = 0 Pa0

Ep < 0

-400
-800

[110]

0

(b)

p = 600 MPa

5SL[1-10]

5

2. Experiments
A single crystal of CuFeO2 synthesized by the floatingzone technique, was cut into a rectangular shape withtypical dimensions of 1.64 × 1.37 × 1.20 mm3, in which
three axes are along the [110], [1-10], and [001] directions.
Uniaxial pressure p was applied along the [1-10] direction, which is the conjugate direction to the spontaneous
lattice distortion in CuFeO2. To investigate wide reciprocal
space, neutron diffraction experiments under applied pand H || c were performed using a time-of-flight neutron
diffractometer SENJU (BL18) installed at MLF, J-PARC.

isosceles triangle

15

P[110] (μC/m2)

T (K)

T N2

Fe3+

a

Recently, we discovered phenomena correlatedwith multiple degrees of freedom in a geometricallyfrustrated magnet, CuFeO2, by applying uniaxial pressure p and magnetic field H [2]. As shown in Fig. 1(b), a
ferroelectric polarization P is induced, only when bothp and H are simultaneously applied in a specific sinusoidally amplitude-modulated magnetic structure phase(we refer to this phase as the PD phase, see Fig. 1(a)).
Significantly, for the case of H || [110] or [1-10] (Fig. 1(c)),
P is not observed even under applied p, although themagnetization measurements at ambient pressure
showed that the PD magnetic ordering persists up to
20 T, except for the spin canting toward the H direction.
In order to determine whether or not the crystal
and/or magnetic structure in the PD phase is changedby the application of p and H, we performed neutron
diffraction experiments under applied p and H.

P[110] (μC/m2)

1. Introduction
Cross-correlated phenomena in solids are not only
useful for electronic device applications, but also havepromoted fundamental studies in condensed matterphysics to understand a coupling mechanism between
several degrees of freedom. In particular, recent progressin research on spin-driven ferroelectricity or magnetoelectric effects has revealed a nonlinear cross correlation
between ferroic order parameters and nonconjugatedexternal fields, i.e., a ferroelectric polarization (a spontaneous magnetization) can be controlled by a magnetic
field (an electric field) [1]. One of the key factors governing the emergence of the spin-driven ferroelectricity is
the complex spin texture breaking inversion symmetry
in the systems. Owing to a tendency to exhibit such amagnetic structure, geometrically frustrated magnets
have been recognized as one of the candidates forspin-driven ferroelectric materials. Following this strategy, many spin-driven ferroelectric materials have beenfound during the past two decades. On the other hand,several frustrated magnets are often spin-lattice coupled systems, in which a magnetic phase transition is accompanied by a lattice distortion to partially relieve thefrustration between spins. Therefore, several degrees
of freedom in the geometrically frustrated magnets,
such as charge, spin, orbital, and lattice are potentiallyrelated to each other, and novel phenomena correlatedwith multiple degrees of freedom are expected beyond‘cross’ correlation.

p = 800 MPa

(c)
(b)

H || [110], p = 600 MPa
H || [1-10], p = 530 MPa

T = 13.1 K

400
0
0

Ep > 051015μ 0H (T)

Figure 1.	(a) Schematic magnetic phase diagram for CuFeO2 under zero applied pressure. Schematics of magnetic structures andthe magnetic Fe3+ triangular lattices in each phase are also shown. (b) Magnetic field dependence of P under applied p.
H was applied along (a) the c axis, and along (b) the [110] and [1-10] axes. A poling electric field Ep was applied at 15 T
before the measurements.

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MLF Annual Report 2019

T = 13.6 K, p = 745 MPa

1.5 (a)I (H) / I (H = 0 T)

3. Results and discussion
Figure 2 shows H dependence of the integrated intensities of both the nuclear and magnetic reflections
under p of 745 MPa [2]. Because of the complex geometry of experimental components in these measurements, such as a pressure device composed of Al andZrO2 pistons and a superconducting magnet, attenuation and absorption of the scattered neutrons could not
be corrected for; therefore, the accuracy of the integrated intensities is rather limited in spite of the small error
bars. Nevertheless, the integrated intensities of boththe nuclear and magnetic reflections exhibit almost nochange under applied H. This result clearly indicates thatthe modification of the PD crystal/magnetic structures
by application of p and H is quite small, if it exists.
Taking into account that the PD magnetic structure
does not break the inversion symmetry in this system,
this result suggests that P induced by the application of
p and H is not purely spin driven. Because the P certainly
has relationship to the sinusoidal magnetic structure, as
mentioned above, our result sharply contrasts with theconventional spin-driven ferroelectricity.
Induction of an electric polarization using two
external fields, a strain σ and H, is known as the piezomagnetoelectric (PME) effect, which is described as Pi= πijklHjσkl, where πijkl is the piezomagnetoelectric tensor [3]. However, the phenomenon observed in thepresent work should not be the PME effect. Indeed,the H dependence of the p-induced P is not linear (a pdependence of P at a fixed temperature and H are also
not linear [2]). Moreover, πijkl must vanish when the magnetic point group contains space inversion or time inversion 1’ [3]. The magnetic point group in the PD phase of
CuFeO2 is reported as 2/m1’ [4], which makes πijkl vanish.
Therefore, to classify P induced by the combined application of p and H, we propose that the phenomenon
in this work is a nonlinear PME effect. This means that
this phenomenon would be explained by an additional
coupled term in a free energy in this system, not higher
order terms of πijklHjσkl, by analogy with spin-driven ferroelectricity as a nonlinear ME effect.

Research and Development Highlights

1.0(1,1,0)(1,-2,0)

0.5(3,0,0)(2,-4,0)1.5 (b)1.0(0,-1,-2) + (q,q,3/2)(1,0,-2) + (q,q,3/2)(2,0,2) - (q,q,3/2)

0.5
0

1

2

3

μ0H (T)

4

5

6

Figure 2.	Relative integrated intensities I(H)/I(H = 0 T) of neutron diffraction from (a) nuclear reflections and (b)magnetic reflections as a function of H || c. Measurements were performed at 13.6 K under an applied pof 745 MPa.

4. Conclusion
We have searched for phenomena correlatedwith multiple degrees of freedom in the geometrically frustrated magnet CuFeO2, by applying p and H.
Ferroelectric polarization is induced in the original PD
phase by the application of p together with H. The crystal and magnetic structures seem to be unchanged by
the application of p and H, which suggests that this phenomenon differs from conventional spin-driven ferroelectricy. We propose that the induction of ferroelectric
polarization in CuFeO2 by the combined application of pand H can be regarded as a nonlinear PME effect.
References[1] Y. Tokura et al., Rep. Prog. Phys., 77, 076501 (2014).
[2] H. Tamatsukuri, et al., Phys. Rev. B, 100 201105(R)(2019).
[3] J. P. Rivera, et al., Ferroelectrics, 161 91 (1994).
[4] N. Terada, et al., Nat. Commun., 9 4368 (2018).

H. Tamatsukuri1, S. Mitsuda1, T. Shimizu1, M. Fujihala1, H. Yokota1, K. Takehana2, Y. Imanaka2, A. Nakao3, and K. Munakata3
Faculty of Science, Tokyo University of Science; 2Nano Physics Group, NIMS; 3Neutron Science and Technology Center, CROSS

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MLF Annual Report 2019

In-situ Neutron Diffraction Analysis on Dynamic Ferrite
Transformation in Steels
1. Introduction
Over the last fifty years, thermomechanical processing, which involves deformation and heat treatment, hasbeen practically used to manufacture commercial large
steel products. Recently, several researchers have foundthat grain size of ferrite (BCC phase in steel) decreases
down to approximately 1 mm through thermomechanical processing at a relatively low temperature [1-3]. In
this process, phase transformation might occur during
the deformation of the parent austenite (FCC phase insteel), because transformation kinetics is greatly accelerated by a large amount of lattice defects introduced into
austenite. To distinguish it from the normal ferrite transformation, i.e., static ferrite transformation, which occurs
during cooling or static holding, the ferrite transformation occurring during deformation of austenite has beentermed as “dynamic ferrite transformation”.
In order to study deformation and phase transformation behaviors at elevated temperature, we have recently developed a novel thermomechanical processing
simulator for in-situ neutron diffraction analysis (Fig. 1),
which is applicable to the BL19 “TAKUMI” in the MLF at
J-PARC. The incident direction of a pulsed neutron beam
is perpendicular to the compression axis, and two neutron detectors (time-of-flight detectors) are located at
the positions perpendicular to the incident neutron
beam. As a result, the lattice planes that contribute to
the diffraction intensity in these detectors are parallelto the compression axis. We reported recently on thenature of dynamic ferrite transformation revealed by insitu neutron diffraction using the newly developed thermomechanical processing simulator [4], and this reportis based on our previous paper.
2. Experimental procedure
An Fe-2Mn-0.1C, an Fe-3Mn-2Si-0.1C, and an
Fe-10Ni-0.1C alloys were used in the present study.
Cylindrical specimens 11 mm in height and 6.6 mm indiameter were prepared and subjected to in-situ neutron diffraction experiment at BL19. Each specimen was
firstly austenitized at 1000°C for 300 s, then cooled byN2 gas at a cooling rate of 30°C s-1 to the deformation
temperatures ranging from 480°C to 700°C. After holding for 10 s at the deformation temperature, a uniaxial
compressive deformation of at most 60% reduction inheight was applied at strain rates of 10-2 s-1, 10-3 s-1, and5 × 10-4 s-1. The compressed specimen was subsequently held at the same temperature for 600 s without loading. The neutron diffraction data were obtained during
the whole thermomechanical processing. To evaluate
the phase fraction and the lattice parameter, the neutron diffraction profile was analyzed by Rietveld method
using Z-Rietveld software. The dislocation density wasestimated by convolutional multiple whole profile fitting (CMWP) method [5, 6].

Figure 1.	(a) The thermomechanical processing simulator installed at the BL 19 “TAKUMI” in the MLF at J-PARC, (b) schematic illustration and snap shots during the compression experiment of the testing part of the simulator. Adapted from Ref. [4].
Reproduced with permission from Elsevier.

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3. Results and discussion
Figure 2(a) shows a plane-view neutron diffraction
profile (enlarged region around the peaks of {011}a and{111}g) during the thermomechanical processing (Fe2Mn-0.1C, deformation temperature: 700°C, strain rate:
10-2 s-1). We found that the ferrite peak started to appear
during compression, indicating that the dynamic ferrite
transformation definitely occurred during the compression, not after it. Changes in the volume fraction of
ferrite with different strain rates are shown in Fig. 2(b)(Fe-3Mn-2Si-0.1C, deformation temperature: 675°C). It
is clear that the kinetics of dynamic ferrite transformation was much faster than that of static ferrite transformation. When comparing the volume fraction of ferriteat the later transformation stage, the ferrite fraction
increased with decreasing the strain rate. This suggeststhat the period when stress was applied affected the kinetics of the dynamic ferrite transformation.
Changes in the lattice constants of ferrite during thethermomechanical processing are shown in Fig. 3 (Fe2Mn-0.1C, strain rate: 10-2 s-1). We found that the lattice
constant of dynamically transformed ferrite increased
and then decreased significantly. During the static holding after the compression, the lattice constant kept almost the same value. The changes in the lattice constantsof ferrite confirmed in Fig. 3 could be attributed to thefact that the partitioning behavior changed from para- toortho-equilibrium during dynamic ferrite transformation.
By utilizing the CMWP method [5, 6], we analyzed
dislocation density of the parent austenite phase during

Research and Development Highlights

thermomechanical processing (Fe-10Ni-0.1C, strain
rate: 10-3 s-1), as shown in Fig. 4. In the present alloy system, austenite usually transforms to martensite during
quenching so that it is nearly impossible to measure
dislocation density of the parent austenite phase. On
the contrary, the in-situ neutron diffraction technique
can directly measure the change in dislocation densityof the parent austenite phase during thermomechanical processing. We also confirmed that dynamic ferrite
transformation occurred by deformation at 520°C and
480°C, but almost never at 560°C. For the compression
at 560°C, the dislocation density of austenite increased

Figure 3.	Change in lattice constants of ferrite during thethermomechanical processing (Fe-2Mn-0.1C, strain
rate: 10−2 s−1). Adapted from Ref. [4]. Reproducedwith permission from Elsevier.

Figure 2.	(a) Neutron diffraction profile (enlarged region around {011}α and {111}γ) during the thermomechanical processing (Fe2Mn-0.1C, deformation temperature: 700°C, strain rate: 10−2 s−1), (b) changes in volume fraction of ferrite with different
strain rates during the thermomechanical processing (Fe-3Mn-2Si-0.1C, deformation temperature: 675°C).

47

Research and Development Highlights

MLF Annual Report 2019

gradually with increasing the strain, indicating that dynamic recrystallization (DRX) of austenite did not occur.
At 520°C and 480°C, on the other hand, the dislocation
density increased initially and then decreased with thestrain increase. The decreases of the dislocation density
observed at 520°C and 480°C were not due to DRX ofaustenite, because DRX of austenite did not occur evenat 560°C (higher than 520°C and 480°C). The results suggest that significant strain concentration occurred in the
dynamically transformed ferrite. Usually, the necessary

Figure 4.	Change in dislocation density of the parent austenite phase during the thermomechanical processing(Fe-10Ni-0.1C, strain rate: 10−3 s−1). Adapted from
Ref. [4]. Reproduced with permission from Elsevier.

amount of strain for the occurrence of DRX in ferrite isvery large [3]. However, the accumulation of strain in the
dynamically transformed ferrite could induce DRX evenwhen the nominal applied strain was relatively small.
Consequently, we propose that DRX of dynamicallytransformed ferrite led to the formation of ultrafinegrained structure.
Acknowledgement
This study was financially supported by JSPS KAKEHI
Grant Number JP15H05767 and JP15K14163, and the
Elements Strategy Initiative for Structural Materials(ESISM). The in-situ neutron diffraction experiments
were performed through proposals no. 2014E0003,
2014B0280, 2015A0069, 2015E0001, 2016E0003 and2018L0401 at MLF at J-PARC. The authors sincerely thankthe members of Tsuji-lab in Kyoto University for helping
with the experiments.
References[1] Y. Matsuyama et al., ISIJ Int., 27 492 (1987).
[2] P.D. Hodgson et al., Scripta Mater., 40 1179 (1999).
[3] H. Beladi et al., Int. Mater. Rev., 52 14 (2007).
[4] A. Shibata et al., Scripta Mater., 165 44 (2019).
[5] T. Ungár et al., Metall. Mater. Trans. A, 41A 1202
(2010).
[6] T. Ungár et al., Acta Mater., 66 251 (2014).

A. Shibata1–3, Y. Takeda2, N. Park2,4, L. Zhao2,5, S. Harjo6, T. Kawasaki6, W. Gong3,6, and N. Tsuji2,3Research Center for Structural Materials, National Institute for Materials Science; 2Department of Materials Science and Engineering, Kyoto
University; 3Elements Strategy for Structural Materials (ESISM), Kyoto University; 4School of Materials Science and Engineering, Yeungnam
University; 5Advanced Steel Processing and Products Research Center, Colorado School of Mines; 6Neutron Science Section, Materials andLife Science Division, J-PARC Center

1

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MLF Annual Report 2019

Research and Development Highlights

Phase Stress Evolution under Cryogenic Tensile Loading
1. Introduction
It is known that deformation-induced martensitic
transformation, which is regarded as a displace transformation of a metastable parent phase into deformation-induced martensite, results in a drastic increase inplasticity, the so-called transformation-induced plasticity (TRIP) effect [1]. Also, the formation of martensite
plays an important role in the significant increase instrain hardening, and hence, its simultaneously enhanced strength and ductility [2].
Quantitative analyses on the evolutions of phasefractions, phase stresses in a ferrous medium-entropy
alloy during deformation at cryogenic temperature,and the contributions of each phase to the flow stresswere conducted at BL19 TAKUMI [3].
2. New release
When the microstructure consists of a singlephase crystalline structure and deformation-induced
martensitic transformation occurs, it is not possible (inprinciple) to obtain the material parameter of stressfree reference martensite phase because the martensite is formed from the deformed parent phase. This
results in only a qualitative understanding of the roleof martensitic transformation in the strain hardening
behavior.
For the phase stress calculation, Young’s modulusof the parent phase was obtained from the neutron
diffraction (ND) analysis, while that of the martensite
phase was derived based on the stress equilibrium approach in the unloaded state after plastic deformation.
This was done to provide a quantitative interpretationof the role of deformation-induced martensite phaseon the strain hardening.

3. Quantitative analysis on phase stress
Here, to derive the phase stress, we obtained theaverage phase lattice strain of each phase by simply
averaging three different (hkl) lattice strains and thephase fraction of each phase by using the Z-Rietveld
software [4]. During elastic deformation, the parent
phase deformed elastically and lattice strain increased
linearly with a constant slope until yielding, and theslope was regarded as Young’s modulus of the parent
phase. Moreover, the deformation-induced martensite
phase appeared due to the occurrence of the martensitic transformation after the elasto-plastic transitionof the parent phase. Since the martensite phase wasformed from a plastically deformed parent phase, it
was not possible to obtain Young’s modulus of the martensite phase because the initial microstructure wascomposed of a single phase.
Here, we used the stress equilibrium approach todetermine Young’s modulus of the martensite phase [5].
In this regard, the sum of residual stresses of each phasemust be zero when weighted by their volume fractionin the unloaded state. Figure 1 shows the residual lattice strain of each (hkl) plane and residual phase stressof the parent phase in the unloaded state. Since wehave already obtained the phase fraction, stress values of each phase, and lattice strain of the martensite
phase, Young’s modulus of the martensite phase could
be obtained.
Finally, the strain hardening behavior and contributions of each phase during tensile loading can be analyzed by the evolution of each phase, as shown in Fig. 2.
After yielding the parent phase, the stress contribution from the parent phase began to decrease. On theother hand, the stress contribution from the martensite

Figure 1.	Residual phase lattice strain and stress in the unloaded state.

49

Research and Development Highlights(a)

MLF Annual Report 2019

ParentMartensite(b)ParentMartensite

Figure 2.	The evolution of phase and fraction-weighted phase stresses with respect to the applied strain, where FCC is parent
face-centered cubic phase and BCC is body-centered cubic martensite.

phase continuously increased and became higher thanthat from the parent phase. The increase in the stresscontribution of the martensite phase was attributed
to the increase of both the fraction and phase stress.
Finally, we obtained a comprehensive understandingof the quantitative contribution of each phase to thestrain hardening and flow stress during a low-temperature tensile test.
4. Future plans
The phase stress evolution of the martensite phasemeasured using the ND analysis may represent the sumof contributions from a series of martensite phases
formed at various strain levels. Furthermore, the results
provide no direct access to the plastic strain in either ofthe phases. These issues will be the next focus of our
future research to obtain a better understanding of thedeformation characteristics in each phase of metastablealloys at low temperatures. In this regard, concurrent
analysis of the quantitative estimation of dislocation
density, twin probability, etc. using ND analysis and numerical simulations can provide a better understandingof the deformation behavior.
References[1] F. D. Fischer et al., Int. J. Plast., 723 16 (2000).
[2] J. W. Bae et al., Acta Mater., 388 161 (2018).
[3] J. W. Bae et al., Scripta Mater., 165 60 (2019).
[4] R. Oishi et al., Nucl. Inst. Methods, 94 600 (2009).
[5] R. A. Winholtz, in: M. T. Hutchings, A. D. Krawitz(Eds.), Measurement of residual and applied stressusing neutron diffraction, Kluwer Academic,
London 1992, pp. 131–145.

J. W. Bae1,2, J. G. Kim3, J. M. Park2, W. Woo4, S. Harjo5, and H. S. Kim2
Max-Planck-Institut für Eisenforschung; 2Department of Materials Science and Engineering, POSTECH; 3Department of Metallurgical andMaterials Engineering, Gyeongsan National University; 4Korea Atomic Energy Research Institute; 5Neutron Science Section, Materials andLife Science Division, J-PARC Center

1

50

MLF Annual Report 2019

Research and Development Highlights

Ferroelectric Polarization in Tetragonal (Bi1/2K1/2)TiO3–(Bi1/2Na1/2)TiO3 Single Crystals

2. Neutron diffraction analysis
Neutron powder diffraction (NPD) data were collected [8] using iMATERIA (BL20) for (1−x)BNT–xBKT

3. Polarization of high-quality single crystals
Figure 2 shows the polarization (P) properties at
298 K. The crystal (Po2 = 0.02 MPa) [Fig. 2(a)] exhibitsa remanent polarization (Pr) of 32 μC/cm2 and a coercive field (Ec) of 23 kV/cm. By contrast, the crystal (Po2 =0.9 MPa) [Fig. 2(b)] features a well-saturated loop with alarge Pr of 48 μC/cm2 and a low Ec of 18 kV/cm (E // [111]).
The blue line in Fig. 2(b) indicates the P-E loop along[111] with a Pr of 30 μC/cm2. Our measurements along[111] and [001] lead to a Ps of 50–52 μC/cm2, which is ingood agreement with that (55.8 μC/cm2) determinedby the NPD analysis with the DFT calculations.

55.8

(b)

10 pm

Ti
Oc

Oa
Bi/Na/KTi

c axis // [001](a)powders (x = 30–35%) prepared by solid-state reaction,and the powders were found to have a tetragonal P4mm
structure. The refined crystal structure with the atomic
displacements is illustrated in Fig. 1(a). Figure 1(a) shows
the displacements of the constituent atoms along the c(polar [001]) axis. The displacement of the A-site atoms(Bi0.50Na0.35K0.15) is as large as 0.034 nm, which is about
twice that of the B-site atom (Ti). Figure 1(b) depicts
the electric dipole moments of the constituent atoms
estimated from the off-center displacements and theaveraged effective charges obtained by the DFT calculations. The cooperative displacements of the A- andB-site atoms lead to the parallel dipole moments of pA= 23.0 μC/cm2 for the A-site atoms and pB = 36.1 μC/cm2
for the B-site one. This dipole configuration provides alarge Ps of 55.8 μC/cm2.

36.1
23.0

0
 .9

Oa

a

total

5.0

c
a

10 µC/cm2

1. Introduction
In perovskite oxides, a combination of Bi with alkali
metals on the A-site enables to accommodate highervalent cations such as Ti4+ on the B site. Bismuth potassium titanate (Bi1/2K1/2)TiO3 [BKT] has ferroelectricity
in a tetragonal structure (space group P4mm) at room
temperature, which has attracted much attention as alead-free piezoelectric material. The solid solution withrhombohedral (Bi1/2Na1/2)TiO3 [BNT; space group R3c],i.e., the (1-x)BKT–xBNT system, displays a morphotropic
phase boundary, where the ferroelectric structure changes dramatically and the piezoelectric activity is maximal.
By contrast, few studies on BKT-based single crystals
have been performed to date because of the difficultyin growing high-quality samples; the crystals reported
suffer from the problems arising from point defects.
Owing to a high vapor pressure, Bi is apt to evaporate
from the lattice leaving a vacancy of Bi (VBi’’’), whichis accompanied by the formation of oxygen vacancy(VO••) [1–3]. VO•• tends to accumulate at ferroelastic domain walls, which are strongly pinned and eventuallyclamped even under high fields [4–6]. For revealing theferroelectric nature, it is desirable to develop a high-quality single crystal with a low concentration of VBi’’’ where
external fields can switch spontaneous polarization (Ps).

Bi/Na/K Ti

Oc

Oa

Figure 1.	Ferroelectric displacements and polarizations of the refined tetragonal P4mm phase of BNT-BKT (x = 30%):(a) refined crystal structure with off-center displacements and (b) dipole moments of the constituent atoms
along the c axis [7].

51Research and Development Highlights

(b)

80

Po2 = 0.02 MPa(flux growth)

Polarization / C cm

−2

(a)

MLF Annual Report 2019

40

[001]

80
40

0

Po2 = 0.9 MPa(TSSG)

[001]
[111]

0

40

40

80
80

E // [001], 1 Hz
25 °C

-40
0
40
−1
Electric field / kV cm

1 Hz, 25 °C

80
80

80

0
40
40
−1
Electric field / kV cm

80

Figure 2.	Polarization properties. Polarization-electric-field properties of BNT-BKT (x = 33%) single crystals grown at(a) Po2 = 0.02 MPa and (b) Po2 = 0.9 MPa. The index beside each curve indicates the crystallographic direction of the polarization measurements [7].

4. Origin of ferroelectricity
We investigate the electronic structures at
p ~ 13.4 GPa and -2.3 GPa; the high p stabilizes the R3cstructure (Figs. 3a–c) while the low p does the P4mm
phase (Figs. 3d–f ). We note that the marked density ofstates (DOS) of not only Ti-3d but also Bi-6p appears in
the valence band; especially the hybridized states of Bi6p and O-2p determine the bottom of the valence band.

a

At p ~ 13.4 GPa in the BNT cell, the R3c phase features
a dominant contribution of the Bi-6p (px + py) derived
states around the bottom with a minimum at -5.79 eVin the vicinity of the G point (the wavefunction is seenin Fig. 3c), which is lower by ~ 0.1 eV than the P4mm
(not shown). We found that the stabilization of the R3cphase for BNT stems from the low-lying valence statesarising from the Bi-6p and O-2p hybridization.

Rhombohedral R3c (Bi1/2Na1/2TiO3 cell, s.g.: R3, p ≈ 13.4 GPa)
6

Energy (eV)

c

b

4

Total
EF

2
0

Bi

Ti-3d
O2-2p

O1-2p

Na

Ti

6s

-2

Bi

O1

a

6p

-4

O2
a
a

-6
0

15 0

1

0

0

2 

L

Z



−1

Density of States (eV )Energy (eV)Tetragonal P4mm (Bi1/2K1/2TiO3 cell, s.g.: I4mm, p ≈ 2.3 GPa)
6
O2
f
d 4
e
Ti-3d

pz

2

EF

0

Bi

O2-2p

O1-2p

6s

-6
0

20 0

O1

Bi
1

0

K

Bi

px+py
Total

Ti

O2

-2
-4

O1

2

O2
0

2

Z



XP



N

c
a

a

Density of States (eV−1)
Figure 3.	Density of states (DOS) calculations. DFT calculation results of (a–c) the R3c structure in the BNT cell at p = 13.4 GPaand (d–f ) the P4mm structure in the BKT cell at p = −2.3 GPa; (a,d) partial DOS for Bi, O1 and O2 atom, (b,e) band
structures, and (c,f ) wave functions at the k points denoted by the dot marks in the band structures [7].

52MLF Annual Report 2019

The similar feature is also seen in the BKT cell at
p ~ -2.3 GPa; the mixed states of Bi-6p and O-2p dominate the bottom of the valence band. The maximal DOS
of Bi-6p lies at ~ -4.3 eV for the P4mm phase, which
is higher than that (~ -4.5 eV) for the R3c phase (notshown). However, the P4mm phase exhibits a markedly
large DOS arising from the Bi-6p (px + py) and O-2p inplane hybridization (see the wavefunction shown in
Fig. 3f ), which is due to a small band dispersion in theentire Brillouin zone. Indeed, the atomic partial chargeof Bi-6p is 0.89 for the P4mm phase, which is larger than
0.85 for the R3c phase. We found that the P4mm phaseof BKT is stabilized by a large DOS of the Bi-6p (px + py)
states derived from the orbital interaction with O-2p.
5. Summary and Future Plans
We uncover the ferroelectric polarization and piezoelectric strain constant in the BKT-based single crystals grown by the high-PO2 TSSG (top-seeded solution
growth) process. These properties originate from a Ps
of ~56 μC/cm2 with a c/a of ~1.6%; this Ps rivals that of
PbTiO3 (70 μC/cm2). Our theoretical calculations showthat the Bi-6p and O-2p hybridization at a moderately
negative chemical pressure stabilizes the ferroelectric
distortion in tetragonal symmetry. We could apply thehigh-PO2 process to other functional materials including
Bi and/or K in bulk and film forms, here that we have

Research and Development Highlights

developed high-quality BKT-based crystals by suppressing a defect formation reaction.
References[1] H. Matsuo, Y. Noguchi, and M. Miyayama, Nat.
Commun., 8 207 (2017).
[2] Y. Noguchi, H. Matsuo, Y. Kitanaka, and M. Miyayama,
Sci. Rep., 9 1 (2019).
[3] Y. Noguchi, Y. Taniguchi, R. Inoue, and M. Miyayama,Nat. Commun., 11 1 (2020).
[4] Y. Kitanaka, K. Yanai, Y. Noguchi, M. Miyayama, Y.
Kagawa, C. Moriyoshi, and Y. Kuroiwa, Phys. Rev. B,
89 104104 (2014).
[5] K. Yamamoto, Y. Kitanaka, M. Suzuki, M. Miyayama,
Y. Noguchi, C. Moriyoshi, and Y. Kuroiwa, Appl. Phys.
Lett., 91 162909 (2007).
[6] Y. Kitanaka, K. Hirano, M. Ogino, Y. Noguchi, M.
Miyayama, C. Moriyoshi, and Y. Kuroiwa, Sci. Rep., 632216 (2016).
[7] Y. Kitanaka, Y. Noguchi, and M. Miyayama, Sci. Rep.,
9 1 (2019).
[8] T. Ishigaki, A. Hoshikawa, M. Yonemura, T. Morishima,
T. Kamiyama, R. Oishi, K. Aizawa, T. Sakuma, Y. Tomota,
M. Arai, M. Hayashi, K. Ebata, Y. Takano, K. Komatsuzaki,
H. Asano, Y. Takano, and T. Kasao, Nucl. Instruments
Methods Phys. Res. Sect. A Accel. Spectrometers,
Detect. Assoc. Equip., 600 189 (2009).

Y. Noguchi1,2
School of Engineering, The University of Tokyo; 2(Present) Faculty of Advanced Science and Technology, Kumamoto University

153Research and Development Highlights

MLF Annual Report 2019

Origin of the Mixed Alkali Effect in Silicate Glass
1. Introduction
Silicate glasses are some of the oldest materials inhistory and are commonly used in the modern glass industry. It is well known that alkali mixing causes several
unusual phenomena in silicate glass, that is, when an alkali ion is gradually replaced by another one, some physical properties, for instance electrical conductivity [1],vary in an extremely nonlinear trend. A large numberof studies investigating this “mixed alkali effect” havebeen reported. Nevertheless, the origin of the mixedalkali effect remains unclear because the previous studies did not visualize the alkali ion coordination aroundthe non-bridging oxygen (NBO) atoms, which formed
by introducing the alkali ions into SiO2 glass, in the glass
structure to be consistent with the multiple experimental dataset, e.g., diffraction and NMR.
In this work, we investigated the structure of threekinds of 22.7R2O-77.3SiO2 glasses (R = Na, K) by using
neutron diffraction (ND) and high-energy X-ray diffraction (HEXRD) to reveal the influence of alkali ions on
the glass structure. As alkali ion components, single Na(Na100 glass), single K (K100 glass), and an equal mixture of Na and K ions (Na50K50 glass) were selected.
To obtain clear insight into the mixed alkali effect, we
performed a dedicated data driven structure modeling,
employing combined reverse Monte Carlo (RMC) [2] andclassical molecular dynamics (MD) simulations (RMC-MD
simulations) in accordance with the ND, HEXRD, andNMR [3] data. Based on the atomistic models, we carried out advanced topological data analysis [4], whichhighlighted the origin of the mixed alkali effect fromthe behavior of alkali ions around the NBO atoms in theglasses [5].
2. Methods
Alkali silicate glasses were prepared by a conventional melt quenching method from mixtures of reagent
grade SiO2, Na2CO3, and K2CO3 powders.
The ND experiments were performed on a high intensity total diffractometer, NOVA [6], installed at BL21
beamline in the Materials and Life Science Experimental
Facility (MLF) of the J-PARC. The HEXRD experiments
were conducted on a two-axis diffractometer, which isdedicated for disordered materials, at the BL04B2 beamline [7] of the SPring-8 synchrotron radiation facility.
For details about RMC-MD simulations, please refer to our original paper [5]. The starting configurations
were created using hard-sphere Monte Carlo (HSMC)
54

simulations with constraints to reproduce the Qn ratio(where, n is a number of bridging oxygen atom in a SiO4
tetrahedron) of the three glasses obtained by the NMR
study [3]. After the HSMC simulations, the RMC simulations were carried out to reproduce the neutron S(Q)and X-ray S(Q) data. Following the RMC simulations, theatomic configurations were optimized by the MD simulations. After the MD simulations, all configurations wererefined by additional RMC simulations while constraining the coordination number of silicon, the bond angle
distribution for O-Si-O, and the partial pair distributionfunctions within the first coordination distance to avoid
the formation of an unfavorable disordered structure.
The RMC simulations were performed using RMC++
code [8]. The MD simulations were performed using the
LAMMPS package [9].
The persistent homology analyses [4] were performed using the HomCloud package [10]. Given a setof points in space, persistent homology captures the
topological multiscale structures and those identified
are compactly expressed in a persistence diagram. The
detailed process of the construction of the persistence
diagram is described elsewhere [4, 5].
3. Results and discussion
We confirmed the mixed alkali effect in the electricalproperties of the alkali silicate glasses by measuring thedielectric constants, εr. Indeed, the εr exhibits a nonlinear
trend as a function of the K2O amount and has a minimum value in the Na50K50 glass [5].
Figure 1 compares the neutron and X-ray total
structure factors, SN,X(Q). The final results of the RMC-MD
simulations are plotted in Fig. 1 as solid colored curves.
A good agreement between the RMC-MD model and experimental data (black solid curves) has been obtained.
It is worth mentioning that an average of the diffraction
patterns of the Na100 and K100 glasses (black broken
curves) is almost identical to the experimental data for
the Na50K50 glass for both SN(Q) and SX(Q), implyingthat the mixed alkali effect cannot be detected easily inthe 1-dimensional diffraction data.
To obtain more clear insight to reconcile the mixedalkali effect, we applied the persistent homology analysis to the RMC-MD models. First, we obtained the alkalicentric persistence diagrams for three alkali glasses.
However, distinguishable differences among the threeglasses are not observed in the data. On the other hand,the alkali-centric persistence diagrams of Na50K50 glass

MLF Annual Report 2019

(a)

(b)

2

K100

1

Na50K50SX(Q)

S N (Q)

K100

0

0
1

Na50K50
1
0

0

Na100

1
0

for Na-centric, Na/K-centric, and K-centric data shown in
Fig. 2(a)–(c) exhibit a striking difference. We can observe
profiles along the diagonal for all the data. It is known
that the profile with a very short lifetime represents
three-body correlations, as shown in Fig. 2(d)–(f ). Boththe Na-centric (Fig. 2(d)) and K-centric data (Fig. 2(f )) do
not have any characteristic profiles, while only the Na/Kcentric persistence diagram (Fig. 2(e)) has two profiles
at dk ~5 and ~10 Å2. These profiles demonstrate that Na
and K are highly correlated in Na50K50 glass, similar to
Na-O-K. We can clearly observe the formation of specific correlations between Na and K ions as mentioned
above. Thus, the persistent diagram enables us to extract the characteristic topology in the glasses. To obtain
more crucial structural features to uncover the origin of
the mixed alkali effect, alkali-oxygen polyhedra withthe formation of edge-sharing NBO atoms in Na50K50
glass are visualized in Fig. 2(g). The K-O polyhedra that

2
1

0

5

10 15
Q ( -1)

20

Na100

1
25

0

0

5

10 15
Q ( -1)20

25

Figure 1.	(a) Neutron total structure factor SN(Q) and (b) Xray total structure factor SX(Q) for the alkali silicate
glasses [5]. The black solid curve depicts the experimental data; the colored curve represents the RMCMD model. The average experimental SN,X(Q) for the
Na50K50 glass is calculated using the Na100 glassand the K100 glass data are plotted as a dashedblack curve.

(b)
b

25

20
0
Death dj ( 2)

Death dj ( 2)

20
15
10
5
0

(c)
c

25
5

15
5
10
0
5

0

5

10 15 20
Birth bi ( 2)

0

25

25
5
20
0

Death dj ( 2)

(a)
a

15
5
10
0
5

0

5

10 15 20
Birth bi ( 2)

0

25

0

30

30

30

25

25

25

15
10

20
15
10

5

5

0

0

(g)

5

10 15 20
Death dk ( 2)

25

(f)
f

Multiplicity

Multiplicity

(e)
e 35

Multiplicity

(d)
d 35

20

Research and Development Highlights

5

10 15 20
Birth bi ( 2)25

5

10 15 20
Death dk ( 2)

25

35

20
15
10
5

5

10 15 20
Death dk ( 2)

25

0

(h)
KO6
(2NBO+4BO)

NaO4(2NBO+2BO)

NaO4(2NBO+2BO)
NaO5(2NBO+3BO)

KO6(2NBO+4BO)

KO5(2NBO+3BO)

Figure 2.	(a) Na-centric, (b) Na/K-centric, (c) K-centric persistence diagrams for the Na50K50 glass. The boxed regions follow thediagonal, and the associated profiles are plotted in (d), (e), (f ). Visualization of the alkali-oxygen polyhedra around thenon-bridging oxygen atoms in the Na50K50 glass (g) and the typical bottle neck structures consist of Na-O and K-O polyhedra (h) [5].

55Research and Development Highlights

MLF Annual Report 2019are highly coordinated with the bridging oxygen (BO)and Na-O polyhedra are highlighted in black, where thepotassium ion is trapped by a large number of BO atoms(see Fig. 2(h)). It is likely that these specific configurations involving NBO atoms are a bottleneck in ionic conduction because the trapped potassium ions disturb theionic migration.
References[1] J. O. Isard, J. Non-Cryst. Solids, 1 235 (1969).
[2] R. L. McGreevy and L. Pusztai, Mol. Simul., 1 359(1988).

[3] H. Maekawa et al., J. Non-Cryst. Solids, 127 53 (1991).
[4] Y. Hiraoka et al., Proc. Natl. Acad. Sci. USA, 113 7035
(2016).
[5] Y. Onodera et al., NPG Asia Mater., 11 75 (2019).
[6] T. Otomo et al., KENS Rep., 17 28 (2011).
[7] S. Kohara et al., J. Phys. Condens. Matter, 19 506101(2007).
[8] O. Gereben et al., J. Optelectron. Adv. Mater., 9 3021
(2007).
[9] S. Plimpton, J. Comput. Phys., 117 1 (1995).
[10] http://www.wpi-aimr.tohoku.ac.jp/hiraoka_labo/
homcloud/.

Y. Onodera1,2, Y. Takimoto3, H. Hijiya4, T. Taniguchi3, S. Urata3, S. Inaba4, S. Fujita3, I. Obayashi5,6,7, Y. Hiraoka8,5,6, and S. Kohara9,2,10,11
Institute for Integrated Radiation and Nuclear Science, Kyoto University; 2Center for Materials Research by Information Integration (CMI2),
Research and Services Division of Materials Data and Integrated System (MaDIS), National Institute for Materials Science (NIMS); 3Innovative
Technology Laboratories, AGC Inc.; 4Materials Integration Laboratories, AGC Inc.; 5Center for Advanced Intelligence Project, RIKEN;
6CREST, Japan Science and Technology Agency; 7Kyoto University Institute for Advanced Study, Kyoto University; 8Kyoto University Institutefor Advanced Study, WPI-ASHBi, Kyoto University; 9Research Center for Advanced Measurement and Characterization, NIMS; 10PRESTO,
Japan Science and Technology Agency,; 11Diffraction and Scattering Division, Japan Synchrotron Radiation Research Institute1

56

MLF Annual Report 2019

Research and Development Highlights

Neutron CT to Investigate Relationship between the
Phase Separation Structures and Melt Convection
during Solidification in Cu-Co Alloys
1. Introduction
The binary Cu-Co system exhibits a metastable miscibility gap in the undercooled state. In that state, thehomogeneous Cu-Co melt separates into two liquid
phases, i.e. Co-rich and Cu-rich phases, once the melt isundercooled below the binodal line. The solidified CuCo alloys have attracted attention because the alloys
take on various electrical and magnetic characteristics
depending on the phase separation structures.
The phase separation structures are generally controlled by the composition, the cooling rate and thedegree of undercooling. In contrast, we have focusedon and investigated the correlation between the phaseseparation structures and convection in molten Cu-Co
alloys before solidification by using an electromagnetic levitator (EML) superimposed with a static magnetic field [1, 2]. This is because the static magnetic
field is capable of controlling melt convection (e.g.,Magnetohydrodynamic, MHD convection) in the levitated molten sample. Nevertheless, in the previous studies,
only the cross-section of the solidified sample cut into
two pieces has been observed using a scanning electron microscope (SEM). Therefore, neutron computed
tomography (CT) to observe the 3D phase separation
structures of Cu-Co alloys was performed.
2. ExperimentCu with nominal purity 99.99% and Co with purity
99.9998% were used as raw substances and Cu-Co alloy samples with compositions of Cu80Co20 and Cu58Co42
were prepared. The alloy samples were melted and solidified using the EML superimposed with a static magnetic field. Figure 1 shows the schematic of the EML
system. The procedure for undercooling and solidification of the molten Cu-Co samples was the same asin our previous studies [1, 2]. The static magnetic field
was generated by a superconducting magnet to control
convection, particularly MHD convection, in the molten
samples and herein ranged from 0 to 5 T. The size of thesolidified alloy sample was approximately 5 mm.
Neutron CT experiments were performed by using
the energy-resolved neutron imaging system RADEN, in
the Material and Life Science Experimental Facility (MLF)of the Japan Proton Accelerator Research Complex

Figure 1.	Electromagnetic levitator (EML) superim-posedwith a static magnetic field to prepare solidified
Cu-Co alloy samples with phase separation structures. Melt convection in molten alloy samples canbe controlled by applying a static magnetic field.
(Adapted from Ref. 3)(J-PARC). An Al pipe (aluminum alloy 1070; length:
200 mm; inner diameter: 7 mm; outer diameter: 10 mm)
was used as a sample container because of the significantly lower attenuation coefficient of neutron beam for
Al compared with those for Cu and Co. The sample container was irradiated with 3500 pulses of neutron beam
per projection, and 300 projections were obtained every
0.6° over the span of 180°. The neutron beam passing
through the sample was converted to visible light using a 6LiF/ZnS scintillator with 50 μm thickness, and thevisible light was captured by a Charge Coupled Device(CCD) camera with a resolution of 2048 × 2048 pixels.
Although the spatial resolution of the reconstructed
tomographic images was 25 μm/pixel, the substantive
resolution might be approximately 200 μm.
3. Results and discussion
Figure 2 shows the reconstructed images of Cu80Co20
and Cu58Co42 solidified under different strengths of thestatic magnetic field. In case of Cu80Co20, the Co-richphases dispersed in the matrix of the Cu-rich phase at
fields less than 1.0 T. In contrast, the Co-rich phases at
57

Research and Development Highlights

MLF Annual Report 2019

Figure 2.	Phase separation structures in Cu-Co alloys solidified under different static magnetic fields obtained through neutron CT experiments. The brighter and darker regions indicate Co-rich and Cu-rich phases, respectively. The values
in the upper right of each image represent the cooling rate and the degree of undercooling. (Adapted from Ref. 3)

the fields exceeding 1.25 T indicated the markedly large
structures. The Cu-Co alloys at 1.25 T had a few Co-richphases with different shapes and sizes, however, at fields
greater than 2.0 T, all the Co-rich phases were elongatedalong the direction of the static magnetic field.
At the lower static magnetic fields, the phase separation structures of Cu58Co42 shown in Fig. 2(b) present
more complex shapes compared with the Cu80Co20. At
fields greater than 1.25 T, the Co-rich phases became
elongated along the direction of the static magnetic
field as well as the Cu80Co20.
4. Summary
Neutron CT to investigate 3D phase separation
structures in Cu-Co alloys solidified using the EML technique superimposed with a static magnetic field was
performed using the neutron imaging apparatus RADEN

in J-PARC MLF. The neutron CT results showed that the3D phase separation structures markedly changed depending on the applied static magnetic field, namely,
melt convection. We are now performing the computational fluid dynamics (CFD) simulation to predict thedetails of a flow field in an electromagnetically levitateddroplet. In the future, the detailed correlation between
melt convection and phase separation structures inmolten Cu-based binary alloys can be obtained by comparing these experimental and numerical studies.
References[1] K. Sugioka et al., Metall. Mater. Trans. B, 45B 1439
(2014).
[2] T. Kitahara et al., Metall. Mater. Trans. B, 46B 2706
(2015).
[3] E. Shoji et al., Scr. Mater., 175 29 (2020).

E. Shoji1, S. Isogai1, R. Suzuki1, M. Kubo1, T. Tsukada1, T. Kai2, T. Shinohara2, Y. Matsumoto3, and H. Fukuyama4
Department of Chemical Engineering, Tohoku University; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center;3
Neutron Science and Technology Center, CROSS; 4Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

1

58

MLF Annual Report 2019

Research and Development Highlights

Electronic Structure of Hydrogen in In-Ga-Zn-O
Semiconductor Simulated by Muon
1. Introduction
In-Ga-Zn oxide, widely known as IGZO, is a semiconductor used as channel material in transparent thinfilm transistors (TFTs) for display applications. IGZO has
properties superior to the conventional Si TFTs such as
relatively high electron mobility, low-temperature fabrication over a large area, uniformity and stability. However,there is a serious problem in the amorphous IGZO (aIGZO) known as negative bias illumination stress (NBIS)
instability, i.e., a negative shift of the threshold voltage
in the normal operation condition that TFTs are always
illuminated by the backlight under a negative bias voltage, whose microscopic mechanism is still under debate.
It is known that various electronic properties of
IGZO are influenced by hydrogen (H) impurity. For instance, water vapor annealing improves the carrier mobility and the S-value (sharpness of the TFT switching asa function of gate-source voltage), n-type conductivity
appears by H treatment. Recent infrared transmission
spectroscopy has revealed the subgap state near thevalence band maximum arising from two hydride ionsat oxygen vacancy (2H- at VO) [1, 2]. It is argued that thissubgap state is associated with the NBIS mechanism,
thus, understanding the microscopic mechanisms ofthese processes would be of crucial importance in controlling and stabilizing the electronic properties of IGZO.

3. Results and discussion
Figuers 1 (a) and (b) show typical zero field (ZF)
spectra of c-IGZO and as-deposited a-IGZO, respectively. Each ZF-spectrum exhibits slow Gaussian dampingwith the partial recovery of polarization at a later time
domain (t ≥ 10 ms). The spectra were analyzed by the following equations:
A0Pμ(t) = AsGKT(Δ, t) + ABG
0.20-1s )

0.8

LF 2 mT 6 K

0.6

c-IGZO

0.10

0.0
1.0 (b) a-IGZO
0.8

0.00
ZF-SR
300 K
200 K
100 K
5K

)

0.2

c-IGZO
a-IGZO
0

0.08

0.04

0.4

0.02

0.2
0

5

10
15
Time (s)

20

0.00

100
200
300
Temperature (K)
1keV
a-IGZO (d)
4keV
7keV
11keV
17keV
SiO2
24keV
28keV

0.06

0.6

0.0

(c)

0.15

0.05

0.4

-1

P (t)

2. Experiment
Conventional mSR measurements on the crystalline
IGZO (c-IGZO) were performed using ARTEMIS at MUSEof the MLF J-PARC. Meanwhile, mSR measurements on
a-IGZO and hydrogenated a-IGZO (a-IGZO:H) thin films
were performed using the low-energy muon (LEM)
beam at Paul Scherrer Institute, Switzerland. Muon stopping profiles for c-IGZO films (5.97 g/cm3) are shown in
Fig. 1(d), where most of the LEM measurements were
performed at 11 keV LEM.

(a)

1.0

Pt)

We were thus motivated to investigate the local
electronic structure of interstitial H in IGZO by the muon
spin rotation (mSR) technique [3]. We have proposed
the designation “muogen” (Mu) as the elemental name,where charge states of muogen, Mu+, Mu0, Mu- correspond to that of hydrogen H+, H0 and H-, respectively.

0

50 100 150 200
Depth (nm)Figure 1.	μSR time spectra for (a) c-IGZO and (b) as deposited a-IGZO [3]. (c) Temperature dependence of Δ. (d) Muon
stopping profiles for respective implantation energies.

59

Research and Development Highlights

1 2
Δ2t2  ,+ (1-Δ2t2) exp  3 3
 2 
O

Zn

Ga
H

Figure 2.	Ef and Δ for the candidate Mu sites, where label AiBjCk
indicates the element name and number of atoms
located within 0.3 nm from Mu. VO means Mu at oxygen vacancy site. The hatched areas represent therange of Δ for c-IGZO (blue) and a-IGZO (red). Inset
shows the local structure around H for Zn4O4. Largegray sphere represents the region of 0.3 nm from H.

1.0

a-IGZO:HZF-µSR

0.8
Pµ(t)where Pm(t) represents the time evolution of the muon
spin polarization in the sample and the sample-holder
with their respective partial asymmetry being As andABG (A0 = As + ABG). GKT(D, t) is the static Kubo-Toyabe
relaxation function, with the term D representing the
local field distribution caused by nuclear magnetic moments around muon site(s). As shown by solid curves inFig. 1(a), the spectra were perfectly reproduced by Eq.
(1), indicating that the muon is entirely in the diamagnetic state (Mu+ and/or Mu-). It is apparent from the longitudinal field (LF) spectra in c-IGZO that Mu senses thequasistatic field distribution. Temperature dependenceof D obtained by curve-fit is shown in Fig. 1(c).
Candidate Mu sites were narrowed down by simulation: (1) DFT calculation for H (to mimic Mu) using the
VASP code to estimate the structural relaxation around
H and the formation energy Ef with some initial structures around H due to the random occupation of Ga and
Zn in their crystallographically equivalent sites. (2) calculation of D at the H site in their converged structure.
The calculated Ef and D are shown in Fig. 2. It is noticeable that D tends to be reduced by the decrease in Ef,
and the tendency is that the higher Ef, the more Ga andIn ions group around Mu. These indicate that H prefers
the Ga/Zn-O layer to the InO2 layer and that H sites arestabilized by the Zn-rich structure.
The inset in Fig. 2 represents the local structurearound H for Zn4O4. Structural similarity to ZnO suggeststhat the local electronic structure of Mu/H is similar tothat in ZnO where Mu0 is presumed to be localized at
the bond center of Zn-O.
ZF spectra in a-IGZO:H are represented in Fig. 3(a). The
initial muon polarization disappears at lower temperatures [Pm(t=0) < 1], and the remaining components exhibit
a slow exponential-like relaxation. Transverse field (TF)
and LF spectra, shown in Fig. 3(b), reveal that this slow relaxation comes from diamagnetic state probing the static
field distribution due to the nuclear magnetic moments.
These features strongly suggest that the distance between
Mu and the nuclear magnetic moments is not uniform.
This leads to the presumption that another H atom may
locate around the Mu site in a-IGZO:H, which also invokes
a model of 2H- at VO proposed by the recent studies [1, 2].

In

0.6
300 K
0.4 200 K
150 K
0.2 100 K
5K
0.0
0
2

(a)
4
6
Time (µs)

1.0

8

10

LF 0.2 T
LF 5 mTLF 2 mTTF 2.5 mT

0.8
Pµ(t)

GKT(Δ, t) =MLF Annual Report 2019

0.6
0.4

ZF

0.2
0.0

(b)
0

2

4
6
Time (µs)

810Figure 3.	Temperature dependence of the ZF spectra in aIGZO:H. (b) TF, ZF, and LF spectra measured at 5 K.
TF spectra is partially represented for clarity.

References[1] J. Bang, S. Matsuishi, and H. Hosono, Appl. Phys. Lett.
110 232105 (2017).
[2] H. Li, Y. Guo, and J. Robertson, Sci. Rep. 7 16858 (2017).
[3] K. M. Kojima, et. al., Appl. Phys. Lett. 115 122194 (2019).

M. Hiraishi1, K. M. Kojima1,2, H. Okabe1, A. Koda1,2, R. Kadono1,2, K. Ide3, S. Matsuishi4, H. Kumomi4, T. Kamiya3,4, and H. Hosono3,4
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3Laboratory for
Materials and Structures, Institute of Innovative Research; 4Materials Research Center for Element Strategy. Tokyo Institute of Technology(MCES)

160

Neutron SourceNeutron Source

MLF Annual Report 2019

Neutron Source Section㻝㻚㻡㻺㼛㼞㼙㼍㼘㼕㼦㼑㼐㻌㼜㼑㼍㼗㻌㼢㼍㼘㼡㼑㼛㼒㻌㼟㼛㼡㼚㼐㻌㼟㼕㼓㼚㼍㼘The neutron source continued its stable operation in
fiscal year 2019. The beam operation of mercury target#9, which had the same design as the preceding target#8, started in late October 2018 and ended in early July
2019 with a beam power of 500 kW during almost theentire operation time. The 8-month run of the programwith such a high power was achieved for the first time,
which demonstrated the durability of the mercury target used for the 500-kW power. After the user program
was closed, a high-power operation study was held for10.5 hours at 930 kW on July 3. This made it possible toobtain significant operation data, which normally would
require long time to reach a stable value. Also, the validity of the system design with regard to the ultimate
power goal was reconfirmed.
The most important challenge to achieve 1-MW
stable operation is to mitigate the pitting damages on
the inner surface of the target vessel that are caused bypressure waves in mercury. This is achieved by two different technologies, which are micro-bubbles injectionof helium gas into mercury by a bubble generator andformation of a narrow mercury channel with a 2-mm
gap and high-speed mercury flow in it by adding an inner wall at the forefront of the mercury vessel, shown
schematically in Fig. 1. Micro-bubbles in mercury attenuate the pressure wave intensity and the efficiency
is monitored by measuring sound signals with a microphone. Figure 2 shows the dependency of the soundsignal magnitude on the beam power. The sound signal
was normalized with that in the case of 340 kW without
micro-bubble injection. The broad scatterings of target#9 data from 300 kW to 600 kW are due to the change
in the amount of the micro-bubble injection and proton beam profiles. All in all, the sound data of targets#8 and #9 showed a consistent trend, which confirmed
the efficiency of the micro-bubble injection to reducepressure waves.

1MW Study
Target #9
Target #8

㻝

㻜㻚㻡

㻜

㻜

㻞㻜㻜

㻠㻜㻜

㻢㻜㻜

㻤㻜㻜

㻝㻜㻜㻜

㻮㼑㼍㼙㻌㼜㼛㼣㼑㼞㻌㼇㼗㼃㼉
Figure 2.	Sound signal data of the target vessels at the beam
study.

Specimens were cut out from the forefront wallof target vessel #9 to see the pitting damages inside.
Figure 3 shows that the pitting damages on the outerwall that is the boundary of mercury containment were
negligibly small, even after the long run of the 500-kW
operation. This fact showed that the high-speed mercury flow and the narrow channel structure were effective to mitigate pitting damages. On the other hand,
the maximum damage depth on the inner wall, which
was protected by micro-bubbles, was 3.3 mm. R&D for atechnology to intensify the bubbling effect to mitigate
pitting damages will be continued.
Target vessel #9 was replaced to a target vessel witha new design shown in Fig. 4, in which the coupling-freestructure between the inner mercury vessel and thesurrounding outer water shroud removes the structuralcause of generating high thermal stress on the target.
The stable operation of this new type of target vessel
with over 500 kW demonstrated the successful design
improvement after the target vessel failure in 2015 andwas one of the major milestones to achieve 1 MW power.

Micro-bubbles
Protonbeam

Outer wall

Hg
Inner wall

Bubble generator

Figure 1.	Technologies to mitigate pitting damages mounted in the mercury vessel.

62

Outer wall

Inner wall

Figure 3.	Target vessel specimens of the outer and innerwalls.

MLF Annual Report 2019

Protonbeam

Water shroud

Mercury vessel

Hg

Helium layer

Figure 4.	Vertical cross-section of the mercury target vessel
consisting of the mercury vessel and the outer water shroud.

After the summer outage period, the restart of thebeam operation was delayed for about a month since
the gas processing system, which plays an importantrole in the target replacement procedure, took longer

Neutron Source

than expected to secure its operation with sufficient radiation safety. These operation experiences will result ina more robust and reliable system improvements.
The international collaboration with major foreign
institutes of spallation neutron source continues. Insitu measurement of ortho/para liquid hydrogen ratio
was carried out at the cryogenic hydrogen loop of MLF
as a collaboration with the ESS (European Spallation
Source) team in July 2019, which will be discussed inother chapter of this report. Technical workshop withSNS (Spallation Neutron Source) of Oak Ridge National
Laboratory was held in December 2019 and many collaboration items, including R&D for the pitting damage
mitigation technology, material fatigue experiments, andcryogenic moderator system operation, were confirmed.

K. Haga
Neutron Source Section, Materials and Life Science Division, J-PARC Center63

Neutron Source

MLF Annual Report 2019

Improvement of Gas Supply System for Mitigation of
Pitting Damage in Mercury Target Vessel
1. Introduction
In the mercury target for a neutron source, thepulsed proton beam injection causes rapid thermal expansion of the mercury, which generates pressure waves
in it. And those waves overload the mercury target vessel
which contains the liquid mercury. In addition, the cavitation damage caused by the interaction between thepressure waves and the deformation of the target vessel
degrades the structural integrity of the vessel. Since thevessel is made of 316L stainless steel with a 3 mm thickness at the beam entrance portion (beam window), thecavitation damage is a crucial factor to determine the lifetime of the target vessel and to schedule the rampingup of the proton beam power. To reduce the cavitation
damage, we have applied gas microbubble injection
technique into the mercury to reduce the pressure waves
by absorption of the thermal expansion due to the gas
microbubbles [1]. In addition, to reduce the possibility ofa mercury leak from the vessel, a double-walled structure
at the beam window was applied to make a narrow channel of mercury by installing an inner wall with 5 mm inthickness and 2 mm in a gap between the target vessel
and the inner wall. The narrow channel is expected to disturb the growth of cavitation bubbles by high-speed flow
and narrow gap and mitigate the cavitation damage [2].
We have demonstrated the effect of microbubbles
on pressure wave reduction by monitoring the vibrationof the target vessel during the operation [3] and so far,observed the cavitation damage after the designed lifetime of target vessel [4]. Based on the observed result,
we estimated the effect of the microbubbles and thenarrow channel and ramped-up beam power to 500 kW
in FY2018. After the 3680-h operation with the 500-kW
beam, we observed cavitation damage in 2019. It was
clear that the cavitation damage facing the narrow
channel was very shallow, but the depth of the damage(2)

mercury circulaonsystemFigure 1. Mercury target system.

Adding devices in improved

Pressure sensors
P1(6)

2. Operation of the gas supply system
Figure 1 shows the schematic of the mercury target
system. The mercury target vessel and mercury circulation system are mounted on a target trolley. The main
components of the mercury circulation system are mercury pump, heat exchanger and surge tank. Bubble generator to inject microbubbles into the mercury is installedin the target vessel. The cover gas of helium in the surge
tank is supplied to the bubble generator through the gas
supply system which mounted on the back of the target
trolley. Figure 2 shows the helium-gas-flow diagram of
the gas supply system. The main components of the gas
supply system are a bellows compressor, needle valves,
and a buffer tank. The compressor sucks in helium covergas in the surge tank of the mercury circulation systemand pressurizes it. A return line with a pressure-control
needle-valve is set between the suction and discharge
sides of the compressor to control the pressure in thebuffer tank. The helium gas stored in the buffer tank is
supplied to the bubbler via the flow-control needle-valve.

Helium gas flow in original
without compressor

Helium gas flow in original
with compressor

Surge tank offacing the bulk side exceeded 3 mm.
The reason why the damage on the bulk side was so
deep is described in this report and we propose countermeasures to mitigate it.

(1)

(4)
(5)

(3)

P2

(5)

Bubbler(In mercury target vessel)

Figure 2. Diagram of the gas supply system.

64(1) Bellows compressor(2) Pressure-control needle-valve(3) Flow-control needle-valve(4) Buffer tank(5) Bypass lines(6) Dust collector

MLF Annual Report 2019

Neutron Source

Figure 3.	History of P1, P2 and pressure-wave reduction byusing the original gas supply system without compressor.

Figure 4.	History of P1, P2 and pressure-wave reduction byusing an improved gas supply system.

Two pressure sensors are set at the inlet (buffer tank) andoutlet of the flow-control needle-valve. The flow rate of
the helium gas under standard condition could be calculated by using the opening area and pressures at the inlet
and outlet of the flow-control needle-valve.
In the initial operation, we used the compressor.
However, we stopped to using it due to potential fatigue
fail of its bellows, which could release into the atmosphere the radioactive materials mixed with the heliumgas. To do so, we improved the bubbler to be able tosuck helium gas by itself without the compressor. Whenthe system is operated without the compressor, the helium gas flows through the pressure-control needle valve
instead of through the compressor, as shown in Fig. 2.
Figure 3 shows history of pressure at the inlet andoutlet of the needle valve, P1 and P2, respectively, andthe pressure-wave reduction rate, which is defined asthat the peak amplitude of vibration under the casewith bubbles, is divided by that without bubbles. In the
300-kW beam operation, P1 and P2 were almost constant; 155 kPa abs. and 100 – 120 kPa abs, respectively.
However, at 500 kW, P2 was decreased to the lower limitof the sensor (36 kPa abs.), even though the P1 was notdecreased. And the effect of pressure wave reduction
became worse; the pressure wave reduction rate exceeded 0.6. The pressure wave reduction rate increased
with the decrease of the amount of helium gas bubbles [3]. On the other hand, P2 and the pressure wave
reduction rate were recovered after moving the valve liftof the flow-control needle-valve. From these results, we
suspected that something had clogged and the effectof the microbubbles became worse; the depth of thedamage facing the bulk side exceeded 3 mm.

3. Improvement of the gas supply system
To prevent the clogging of the needle valve, we improved the gas supply system in FY2018. The diagram of
the improved one is shown in Fig. 2. The pressure-control valve in the original system was also a needle valve
but it was not clogged since its opening area was wider
than the flow-control one. Therefore, the flow-control
needle-valve was changed to the same type with thepressure-control needle-valve. And the lift of the flowcontrol needle valve was modified to move remotely
to remove the clogging even during the beam operation. At the inlet of the gas supply system, we installed a
cyclone-type dust collector to catch the clogging material. Furthermore, bypass lines for the needle valves wereprepared as the countermeasure if the needle valve wascompletely clogged.
Figure 4 shows the history of the pressures and pressure wave reduction rate under the 500-kW operation byusing the improved gas supply system. Although clogging was still occurred, the decrease rate of P2 slowed
down. And by moving the valve lift, the pressure wave
reduction rate could be kept below 0.45.
In FY2020, we will increase the beam power up to
600 kW and will still monitor the clogging situation at
the gas supply system while taking measures to eliminate it.
References[1] H. Kogawa, et al., J. Nucl. Sci. Technol., 52 1461
(2015).
[2] T. Naoe, et al., J. Nucl. Mater., 506 35 (2018).
[3] H. Kogawa et al., J. Nucl. Sci. Technol., 54 733 (2017).
[4] T. Noe, et al., JPS Conf. Proc., 081004 (2020).

H. Kogawa, T. Naoe, T. Wakui, and K. Haga
Neutron Source Section, Materials and Life Science Division, J-PARC Center65

Neutron Source

MLF Annual Report 2019

Nuclide Analysis of the Irradiated Target Vessel
1. Introduction
Since FY2018, we have periodically measured thespectral intensity of gamma rays emitted by radioactive
nuclides produced in the irradiated mercury target vessels. This measurement has three objectives:
1) Benchmark for the calculation of radioactive nuclide
production in the target vessel.
2) Basic data for the storage, volume reduction, anddisposal plan for radioactive waste.
3) Basic data of dose evaluation in disposal and volume reduction operation.
We measured by teletector only the dose distribution data. We obtained the data on the dose contribution of each nuclide.
2. Experimental method
In this measurement, the gamma rays were measured by a portable Ge semiconductor detector (ORTEC)
cooled by liquid nitrogen. The 2.4-m thick hatch of theirradiated components storage room on the first basement floor of the MLF was opened, and the used mercury target vessel stored in the storage container, which
was temporarily placed in the irradiated components
handling room on the first floor of the MLF, was lifted
and lowered into the irradiated components handlingroom using a 20 t crane. The distance from the centerof the 2.4-m hatch to the measurement position of thedetector was 13.2 m. The detector was shielded by surrounding and stacking of the Pb blocks 150 mm in thickness in front of the detector. And the two 5 mm thick Pb
plates were put with 100 mm interspace at the centerof the front side the detector. The multi-channel analyzer (MCA) and the measurement PC were connectedby cables laid between the irradiated components
storage room and the second manipulator operation
room across the concrete wall through a through-bore.
Figure 1 shows the measurement setup.
3. Result
In FY2019, we measured the irradiated mercury target vessels No. 3, 5, 2, and 8. The ground position at thehead of the target was at 0 m from the floor, and thecrane was used to measure the 1-m and 2-m positions.
Figure 2 shows pictures from the measurement of mercury target vessel No. 8. Table 1 shows the duration ofuse, cooling time and accumulated beam power of eachof the used target vessels.
Figure 3 shows the measured gamma ray spectra ofeach target vessel at the ground position. We confirmedthat the major radioactive nuclides emitting gamma
rays were Mn-54 (835 keV) and Co-60 (1173 keV and
1333 keV). These nuclides are produced by irradiation

Figure 1.	The measurement setup. The photo at the upper left is the Ge semiconductor detector and the Pb blocks.
The two 5 mm thick Pb plates were put with 100 mm interspace at the center of detector. The lower photoin the center shows the second manipulator operation room. The lower one on the right is the view from theside of the entrance of the hot cell below the 2.4-m hatch.

66

MLF Annual Report 2019

to the stainless steel. Then, it was confirmed that themain contributors to the dose rate of the target vessel
were the activation nuclides of the stainless steel rather than the mercury in the spallation products. As thehalf-life of Co-60 (5.3 years) is longer than that of Mn-54(312 days), after long cooling times (as it is the case withtarget vessels No. 3 and 5), the contribution of Co-60 isdominant and that of Mn-54 is relatively negligible. On
the other hand, the contribution of Mn-54 is dominant
after a short cooling time (target vessels No. 2 and 8).
Since, in the simulation, Mn-54 produced in the vessel

Figure 2.	Pictures from the measurement of mercury target
vessel No.8. The height of the target was determined by the z-coordinate of the crane.

Neutron Sourceat the end of the operation is 10 times more than Co-60,
it is important to consider the Mn-54 contribution to thedose rate when replacing or storing the target vessel.
However, the contribution of Co-60 is important duringlong-term storage and disposal.
Next, Figure 4 shows the spectra of target vessel
No. 8 at each height. Compared to the ground position,
the peak intensity gradually decreased with the increaseof the height. It was assumed that most of the target
vessel was within the measurement range at the groundposition but when it was raised to 2 m, only the tip waswithin the measurement range because the latter was
narrowed by the shielding. Taking the ratio of the Mn54 and Co-60 intensities, the ratio of Mn-54 was higher
at the tip. This is because Mn-54 was more likely to begenerated at the tip of the vessel than Co-60. The reason for this can be explained by the difference in thereaction process. Since Mn-54 is produced mainly by the54
Fe (n, p) 54Mn reaction of iron, which is the main component of stainless steel, it is likely to be generated in ahigh-energy neutron field near the target head. On theother hand, Co-60 is mainly generated by 59Co (n, γ) 60Coof cobalt, which is an impurity in stainless steel, so it iseasily generated in a thermal neutron field, and is widely
produced, especially near moderators and reflectors.

Table 1.	Data for each components at ground position. The target numbering is in the order of production.
Target No.3
Target No.5
Target No.2
Target No.8

Duration of use
2011/12~2014/6
2014/10~2015/4
2016/2~2017/7
2017/10~2018/7

Cooling time (year)
5.1
4.3
2.0
1.0

Accumulated power (MWh)
2050
670
1048
1812

Figure 3.	The gamma spectra of the mercury target vessels at ground position. Inset: accumulated powervs. net count rate of the peaks of Mn-54 and Co-60.

67

Neutron Source

MLF Annual Report 2019

Figure 4.	The gamma spectra of mercury target vessel No.8. Inset: height from ground position
vs. net count rate of the peaks of Mn-54 and Co-60.

4. Summary
Using the portable Ge semiconductor detector,
gamma rays emitted by the used mercury target vessel
were measured.
1) Co-60 and Mn-54 were the main nuclides.
2) Mn-54 appeared in those with a short cooling time
but disappeared in those with a long cooling time.
3) As the height was changed, the ratio of Mn-54 andCo-60 intensities increased, which was thought toindicate that Mn-54 was generated at the tip.
Acknowledgement
We would like to thank the target group andthe remote handling group for helping us with thismeasurement.

S. Masuda, M. Harada, and H. Nemoto
Neutron Source Section, Materials and Life Science Division, J-PARC Center68

MLF Annual Report 2019

Neutron Source

The Status of the Cryogenic Hydrogen System
1. Introduction
The cryogenic hydrogen system consists of a helium
refrigerator (Brayton cycle, 6 kW refrigeration power,
17 K, 1.5 MPaG and 270 g/s helium flow rate) to produce the liquid para-hydrogen and a hydrogen circulation loop (18 K, 1.4 MPaG, and 185 g/s hydrogen flowrate) to remove the heat deposition in the moderators
as shown in Fig. 1.
Since the beginning of 2015, a pressure drop between heat exchangers (HXs) and an adsorber (2nd ADS)in the helium refrigerator gradually increased during
every operation, causing degradation of refrigerator’s
performance [1]. By cleaning the inside of the HXs andreplacing an adsorber with a new one (3rd ADS), which
was the same as the 2nd one, during the 2016 summer
outage, the refrigerator performance was restored [2].
We found out that the local accumulation of oil in membranous form on the felt at the helium entrance side of
the 2nd ADS could have caused the pressure drop. The
felt material in the 2nd ADS was changed from rock wool
to high siliceous glass fiber. In FY2018, we improved thedesign of the felt material of the 4th ADS in order to prevent oil accumulation [3].
A high-power test with 1-MW beam power, which isthe final goal of our facility, was carried out to validate
the design values, such as response between heaterand accumulator, etc. We also tried to perform an insitu para-ortho hydrogen fraction measurement for

high-power condition under the collaboration with theEuropean Spallation Source (ESS).
2. Exchanging of the ADS
We reapplied rock wool at the helium entrance side
for the 4th ADS as felt material, because we also foundout that rock wool did not accumulate oil on the felt surface. The piping connection of ADS with the helium refrigerator was changed from welding to flange to makethe future replacement easy.
It took about two weeks in September 2019 to replace the 4th ADS in the cold box, as shown in Fig. 2.
Then, the activated charcoal in the ADS was regenerated by supplying heated nitrogen gas for one week toprepare for the operation.

Flange4th ADS
FlangeFigure 2. Installed 4th ADS in the cold box.

He, H2 cylinder storage room

Compressor room
Compressor

Liq. nitrogen
tank

Oil
separators

He buffertankAcvatecharcoal(OS-5)

MLF building

H2 pumps

Heater

Accumulator

HX3

HX1

N2 flow

Safety box

TurbineHe flow

17K 1.5MPa
270g/sAdsorber(ADS)

Heater

HX2

He flowStuck

H2 cylinders
To blanket
To H2 loop

Cold box

He cylinders

Helium refrigeraon system

Ortho-parahydrogenconverter

Moderators

H2-He
HX
H2 flowP

18K 1.4MPa 185g/s

CD

Helium blanket

Hydrogen circulaon system

Figure 1. The cryogenic hydrogen system.

69

Neutron Source

MLF Annual Report 2019

1st ADS12

2nd ADS

3rd ADS

4th ADS

Rate of pressure drop increase (x10 Pa/h)(The same type with 2nd ADS)

10

Operaon with
witth Cleaning of HX
Exchange of ADS
reduced He flow

Exchange of ADS
2011(Improved ADS)

Exchange of ADS
2019

2016

8

6

4

Pressure drop began toincrease rapidly aer
18000 hours operaonof 2nd ADS.

Heat
exchangers

2

0
10000

ADS

19000 hours haveelapsed with 3rd ADS,
but no pressure dropincrease is observed.

20000

30000

40000

50000

60000

Operang me of compressor (h)Figure 3. Rate of pressure drop at each operation.

3. Pressure drop trend
The 2nd ADS caused a pressure drop after 18,000
hours of operation, resulting in performance degradation, as shown in Fig. 3. However, the 3rd ADS did notcause a similar problem, even after 19,000 hours of operation until the end of June 2019.
Further pressure drop increase was not observed
and the good performance of the refrigerator continued during the operation in the 4th ADS, except for the
New Year’s holidays.

analyzed by solvent extraction and infrared spectroscopy. The distribution of oil concentration was almost
flat in the depth of the inlet felt, showing a difference,compared to that of the 2nd ADS. The total amount of oil
was about 5.5 g which was about 1/10 of that of the 2nd
ADS. The distribution of oil was also different from thatof the 2nd ADS.
These results gave beyond our expectation fromprevious 2 nd ADS results. The details are still underinvestigation.

4. Disassembling of the 3rd ADS
The used 3rd ADS was disassembled to observe theinside contents (felt and active charcoal) and analyze theoil accumulation on them. The surface of the inlet felt inthe 2nd ADS had changed to yellowed oil color, as shownin Fig. 4(a), however, the one of the inlet felt in the 3rd
ADS was not changed (Fig. 4(b)).
The oil concentration in the felt and charcoal was

5. Measurement of Para-hydrogen concentration
5.1 1 MW beam injection test
In July 2019, proton beam power equivalent to
1 MW was injected into the spallation neutron source
for about 10 hours to validate the original design.
The cryogenic hydrogen system worked well as designed and was able to continue its stable operation.
Figure 4 shows the trend of the major parameters of thesystem at 928-kW operation. In order to compensate
the temperature rise and pressure change of the liquidhydrogen caused by the high-power injection, a heaterand an accumulator were installed in the cryogenic hydrogen system, as shown in Fig. 1. When the moderator
outlet temperature rose with the 1-MW power injection,
the heater power at the downstream of the moderators
was decreased to counteract the temperature rise andthe accumulator absorbed simultaneously the pressurechange, as shown in Fig. 5.

(a) 2nd ADS(b) 3rd ADS

Figure 4. Condition of the inlet felt of the dismantled ADS.

70

1000
750
500
250
0
23

Beam power

20
19
18

Pressure (MPa)4000

Heater inlet temperature

21

3000

Moderator outlet temperature

2000

Heater power

0

1000

17
1.50

-1000
70

1.48

65
Pressure of hydrogen loop

1.46

60

1.44

55

1.42

50

Accumulator level

1.40
-30

0

30

60

90

45
120

150

Heater power (W)

5000

22

1.38

Neutron Source

Accumulator level (mm)Temperature (K)Beam power (kW)MLF Annual Report 201940

Time (s)Figure 5. Fluctuation in the hydrogen circulation system at the 928-kW beam injection.

5.2 In-situ measurement of Para-hydrogen fraction
The hydrogen circulation system has an Ortho-parahydrogen converter in order to keep the para-hydrogen
fraction of more than 99% at the inlet of the moderator toprovide an excellent neutronic performance. It is consideredthat para to ortho back conversion caused by high neutron
irradiation would get worse in the neutronic performance.
One of the urgent issues is to develop a moderator
for a high intensity source with MW class power. In order
to investigate the para to ortho back conversion due toneutron irradiation, we set up conditions without flowing para hydrogen converter using bypass flow in thehydrogen circulation system. We tried to measure parahydrogen fraction by introducing In-situ Raman spectroscopy measurement in addition to hydrogen gas sampling method (Fig. 6). Finally, we managed to measure
the Raman spectroscopy under the condition of 2.4 MWhour beam operation and without a flowing converter.
This was conducted under the collaboration with ESS.

Raman
spectroscopy

Raman spectroscopy
controller & data logger

Ortho-Para hydrogensampling system

Hydrogen loop
temperature & pressure
monitoring

Figure 6. Measurement of the Para-hydrogen fraction.

References[1] T. Aso et al., MLF Annual Report 2015, 57–58 (2016).
[2] T. Aso et al., MLF Annual Report 2016, 72–73 (2017).
[3] T. Aso et al., Abstracts of CSSJ Conf., Vol.97 47 (2018).

T. Aso, M. Teshigawara, H. Muto, and S. Tanaka
Neutron Source Section, Materials and Life Science Division, J-PARC Center71

Neutron ScienceNeutron Science

MLF Annual Report 2019

Neutron Science Section
1. Introduction
Materials and Life Science Experimental Facility(MLF), one of the leading user facilities in the world, expands gradually its activities [1–4]. Stable 500 kW beam
power is being continuously supplied for the user program. And the beam test with the full power of 1 MW
to be used in the future operation was performed successfully. The applied proposals have increased to arecord number in the proposal round 2019B. A total of
16,204 person-day visitors was recorded in JFY2019.
To continue the constant expansion of the activities
in the Neutron Science Section (NSS) and the MLF, we
continue our efforts to collaborate not only with domestic, but also with foreign scientific facilities in the fields of
personnel, techniques, and research exchange. The firstcollaboration meeting on neutron instrumentation between China Spallation Neutron Source and the MLF washeld at J-PARC in July, 2019. Instrumental collaboration,
including researcher exchange, was established between
EMU at ANSTO (the Australian Nuclear Science andTechnology Organisation) and DNA’s two backscattering
spectrometers under the arrangement between ANSTO
and J-PARC. AMATERAS accepted an AONSA Young
Research Fellow (YRF) from Korea. However, the YRF had
to suspend his stay at J-PARC due to the COVID-19.
Also, we made significant efforts to communicate
with the neutron society through the annual meeting at the MLF about industrial applications (282participants), the J-PARC symposium (909), the 4 th
Neutron-Muon School (MIRAI PhD School) (41), and the
CROSSroads Workshop (70).
2. Instrumentation
Currently, 21 neutron instruments are under operation. POLANO is the youngest instrument, which justopened for the user program [5–7]. POLANO combines
inelastic neutron spectroscopy with polarization analysis and is one of the most complicated but desired instruments, particularly for researches of systems wheremultiple physical degrees of freedom are entangled.
Since the polarization devices on the POLANO are still
under commissioning, the proposal with unpolarized
neutrons can be currently accommodated (Fig. 1). The
polarization system (polarizer, spin flippers, analyzer
and guide fields) in the POLANO is an essential set ofdevices and is continuously developed. We expect thatthe on-beam polarization tests can be commissioned
within the next year.
74

Figure 1.	Back view of POLANO (BL23) vacuum chamberright after installation. The spectrometer started
a part of user program from 2019.

A brand new T0 chopper developed by theTechnology Development Section of the MLF debutedin the 4SEASONS spectrometer (Fig. 2). A T0 chopper isa rotating device that can eliminate unwanted gamma
flash and fast neutrons from the target source. For aweak signal experiment, like inelastic scattering, thistype of device is indispensable for accomplishing reasonable signal-to-noise ratio. After several years of design and development, the first prototype was installed
and used for real beam experiments.
We have many achievements even in the neutron device development. Neutron detectors, sample environment devices, and computing are of great
importance for realizing effective and sophisticatedexperiments; neutron optical devices such as neutron
supermirrors and lenses are also essential devices. As
shown in Fig. 3, we have successfully developed andinstalled the focusing mirrors for neutron reflectometer
SOFIA (BL16) [8]. This mirror surface was designed as elliptically curved, focusing on the sample position. The
peak intensity at the sample position has almost doubled and a much sharper peak profile can be obtained.
In addition, new focusing mirrors for GI-SANS havebeen tested in SHARAKU (BL17), and magnetic lens systems for focusing SANS measurements were tested in
TAIKAN (BL15).

MLF Annual Report 2019

Figure 2.	Brand new T0 chopper installed into the beamlineof 4SEASONS (BL01).

Figure 3.	Newly manufactured focusing mirror for neutronreflectometry at SOFIA (BL16).

Thus, we keep upgrading the whole complex, including devices, beam lines, instruments, and even thefacility itself to provide the best opportunities for thebest science.
3. User program
In fiscal year 2019, the MLF received 326 proposals for 2019A and 444 for 2019B, of which 222 and224 were approved, respectively. Also, 4 long-term

Neutron Science

proposals (LTP) were newly adjusted from 9 submissions and totally 17 LTPs were being executed in 2019B.
Due to a one-month interruption of the beam delivery
after the summer maintenance, all experiments scheduled in this term were carried over to 2020A. In the endof JFY2019, another disaster, the COVID-19 pandemic
badly affected the users. Since March, 2020, the government decision of two-week isolation for the travelers from the outbreak nations has strongly reduced
the number of foreign users. Even some domestic users could not get a permit to travel to J-PARC from theiraffiliations, which affected of course the ability of university students to get a degree. Some of those experiments were conducted by the NSS instrument groups
and the rest were carried over.
4. Scientific outcome
The research activities in neutron science at the
MLF resulted in more than 150 papers and 12 press
releases. Inelastic and quasielastic neutron scattering
measurements using AMATERAS revealed pressureinduced large entropy changes associated with themolecular order-disorder phase transition in plastic
crystals [9]. These findings can be applied to the novel
refrigeration technology.
References[1] H. Takada et al., Quantum Beam Sci., 1 8 (2017).
[2] K. Nakajima et al., Quantum Beam Sci., 1 9 (2017).
[3] K. Sakasai et al., Quantum Beam Sci., 1 10 (2017).
[4] W. Higemoto et al., Quantum Beam Sci., 1 11 (2017).
[5] T. Yokoo et al., AIP Conf. Proc.,1969 050001 (2018).
[6] T. Yokoo et al., EPJ Web Conf., 83 03018 (2015).
[7] also, see the related articles in this volume[8] T. Hosobata et al., Optics Express, 27 26807 (2019).
[9] B. Li et al., Nature, 567 506 (2019).

Y. Kawakita1, T. Yokoo1,2, M. Nakamura1, S. Itoh1,2, K. Nakajima1, and T. Otomo1,2
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK

175

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MLF Annual Report 2019

BL01: 4D-Space Access Neutron Spectrometer 4SEASONS
1. Introduction and statistics
4SEASONS is a direct-geometry time-of-flight neutron spectrometer for thermal neutrons, and one of the
Public Beamlines in the MLF [1]. The momentum-energy
region for this spectrometer occupies the middle of the
momentum-energy space covered by all the MLF spectrometers [2]. In 2019, 24 General Use (short-term) proposals, 1 New User Promotion proposal, and 1 Instrument
Group Use proposal, were approved for 4SEASONS. The
large number of international users is a characteristic of
the user group of 4SEASONS, and they were about a halfof the number of users in 2019. Unfortunately, part of
the approved proposals was postponed to 2020 due tothe COVID-19 pandemic. Conversely, 5 reserved (shortterm) proposals were given beamtime to compensate
the vacancy. About 60% of the submitted proposals
were in the field of magnetism, while the rest of themtargeted phonons and other atomic vibrations. The increased volume of research in the latter field is a notable
trend at 4SEASONS. As for the outcomes from using the
instrument, 10 peer-reviewed papers were published in
2019. 7 were papers about material science, while 3 papers were related to the instrumentation.
2. Instrument upgrade
T0 chopper: 4SEASONS utilizes the so-called T0 chopper to suppress the prompt pulse and high-energy neutron background generated by it. The required rotation
speed of the T0 chopper is 50 Hz to accommodate themaximum designed neutron energy of ~300 meV [1],the maximum speed was 25 Hz so far, which degraded
the neutron flux at high energies above ~100 meV.
Recently, the Technology Development Section of the
MLF succeeded in developing a compact T0 chopper
running at a speed of 100 Hz. In 2019, 4SEASONS replaced the T0 chopper with this new one (Fig. 1). The
new T0 chopper has been in operation since the 2019B
round. We observed a significant recovery of the neutron flux at high energies (Fig. 2).
Detectors: 4SEASONS is equipped with a number of
φ3/4 inch × 2.5 m 3He position sensitive detectors. We havebeen increasing the number of detectors since the startof the instrument’s operation. In 2019, we installed 7 detectors. As a result, the proposed detectors were installed
fully except for ones being difficult to install due to physical constraints, and the designed angular coverage of−35° – +130° was achieved. In addition, part of the power
supplies and preamplifiers for the detectors were repaired.
76

Figure 1.	The new T0 chopper being installed on 4SEASONS.

Figure 2.	Comparison of the constant-energy profile of themagnetic excitation in Ba0.75K0.25FeAs2 at the energy
transfer of 200±10 meV with the old (red) and new(blue) T0 choppers which ran at 25 Hz and 50 Hz,
respectively. The utilized incident energy was
500 meV. The intensity was normalized with proton
counts and the background intensity was subtracted. The observed intensity was increased by a factorof 2 with the new T0 chopper.

Background suppression: In the vacuum scatteringchamber of 4SEASONS, there is a square-shaped beam
catcher made of B4C resin in front of the detectors in
the direct beam. The beam catcher was surroundedby an 80-mm long Cd frame to prevent neutrons scattered at the surface of the beam catcher from reaching
any part of the detectors. However, we found that theMLF Annual Report 2019

length of the frame was not sufficient to hide detectors
recently added at high scattering angles. Then, in 2019,
we extended the frame to 340 mm. We confirmed thatthe spurious scattering caused by the reflection at thebeam catcher was successfully suppressed by this extended frame.
Re-investigation of energy resolution and flux: Theenergy resolution and flux of a direct-geometry timeof-flight spectrometer strongly depend on the incident
energy and the rotation speed of the monochromating
chopper. At 4SEASONS, the Fermi chopper was replacedwith a new model in 2015, which has a short slit-package consisting of 0.4-mm wide and 20-mm long slits [3].
Although the resolution and flux have been analyticallyand numerically investigated with the new chopper,
the systematic investigation has not been sufficient.
Accordingly, in 2019, we re-investigated the energy
resolution and intensity of the elastic scattering using
incoherent scattering of vanadium. Based on the result,simple computing tools to calculate the energy resolution and intensities were developed, which should be

Neutron Science

useful for the users to decide about the experimental
conditions [4].
Acknowledgements
We thank K. Inoue and W. Kambara for their support and advice. We also thank N. Murai for providing
unpublished data. 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] M. Nakamura and R. Kajimoto, JPS Conf. Proc. 1(2014); R. Kajimoto et al., J. Phys.: Conf. Ser. 1021,
012030 (2018).
[4] R. Kajimoto et al., J. Neutron Res., pre-press,
doi:10.3233/JNR-200146.

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 2019

Current Status of BL02 DNA in 2019
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 meV < E < 1500 meV,
thanks to the near-backscattering geometry of the instrument and its pulse-shaping options. In addition,
back-coated Si analyzers with Gd or Gd 2O3 neutron
absorber provide an extra high signal-to-noise ratio ofaround 105, which enables the detection of small scattering amplitudes or signals from small quantities ofsamples. The accessible momentum transfer range isfrom 0.08 to 1.86 Å−1 by using Si111 analyzer mirrors.
A hot topic in 2019 was the start of a close collaboration between the EMU back scattering spectrometerwith a Doppler shifter at ANSTO and DNA. The DNAteam conducted EMU experiments with less than 1 micro eV resolution in July and August for ten days. On theother hand, Dr. Nicola de Souza, an EMU instrument scientist, joined our commissioning work for two months,
from October to November. Although he was supposedto perform his own experiments by using DNA, an unexpectedly prolonged summer maintenance term unfortunately prevented him from doing so.
The number of peer-reviewed papers from DNA was
8 in 2019, almost at the average yearly level since 2017.
2. User Program in the 2019A and 2019B periods
8 General Proposals (GP) and 10 GPs (including 3
New User Promotions (NUP)) were approved for 2019A
and 2019B, respectively. The portion of approved beamtime from all requested beamtime was 59% for 2019A
and 29% for 2019B. As in 2018, there was a tendency forthe competition to be higher in the B-period (2.9) thanin the A-period (1.5). Additionally, two reserved proposals were also conducted in 2019A. One Long-Term
Proposal (LTP) has been newly adopted from 2019B. In
total, four LTP’s ran at BL02.
Due to delay of the beam delivery from November
to December, the beam operation was canceled for a total of 32.5 days. The experiments scheduled for this term
were carried over to 2020. Other than this unexpectedbeam delay, the users enjoyed a stable 500-kW beamin 2019. In March, the pandemic of COVID-19 started toaffect the experiments at DNA.
The 4th Neutron and Muon School was held from
October 28 to November 2 together with the MIRAI PhD
School (MIRAI: the consortium between Swedish and78

Figure 1.	A photo of four students of the Neutron and Muon
School & MIRAI PhD School together with four instrument scientists, including a visiting researcher,
Dr Nicolas de Souza, from ANSTO.

Japanese universities). At DNA, 4 students studied sample installation into the cryo-furnace and data analysis on
the molecular dynamics of water in Nafion membranes.
3. Beamline activities
Beamline
Additional Si311 analyzer mirrors were installed atscattering angle (2q) of -126 < 2q < -90, which extended the maximum momentum transfer range from 2.67
to 3.40 Å-1. The designed energy resolution of 12 meV for
the Si311 analyzer was confirmed with a pulse shaping
chopper rotating at 300 Hz. However, some spurious
peaks were observed, presumably due to the scatteringfrom the aluminum wall of the BL02 cryostat. We plan
to install radial collimators in 2020 to suppress those
scatterings.
When the MLF successfully achieved a continuous
10.5-hour operation at the designed largest beam power of approximately 1 MW on July 3, test measurements
were carried out to demonstrate the performance of
DNA at 1 MW. Figure 2 shows the temperature dependence of the elastic intensity and elastic incoherent structure factor (EISF) of gelatinized starch with cooling rateof 1.4 degree/min. Clear increases at about −4°C wereobserved for both parameters, which indicated thefreezing of water. This suggests that the water in the
starch is close to the properties of bulk water, despite
the fact that it interacts with the starch. Quantitative
analysis of QENS data is possible in even relatively rapid
temperature scans. The 1-MW beam power is useful toanalyze the QENS spectra to study the dynamics of nonequilibrium systems.

MLF Annual Report 2019

Neutron Science

4. Future plans
In addition to the further installation of Si311 analyzer mirrors extending the momentum transfer range
to 3.8 Å−1, new Si111 analyzer mirrors have been fabricated since some of the installed mirrors have been
already damaged after being first installed in 2012.
Correspondence against such an aging problem is essential to keep the world-class performance of DNA.

Figure 2.	Temperature dependence of the elastic intensityand elastic incoherent structure factor (EISF) of gelatinized starch measured at a beam power of approximately 1 MW with cooling rate of 1.4 degree/min.

Development of sample environments
In addition to the standard sample environmentof the cryo-furnaces, a dilution refrigerator, a sample
changer with twenty samples, and a vapor-controlled
system were under development and commissioning.
Two brand new sample sticks for the cryo-furnaces werealso developed. After the successful observation of avery weak QENS signal of Li self-diffusion [2], there has
been strong demand for in situ measurements of Li conduction under electric field. With the help of Professor
Kazuhiro Mori in Kyoto University, we developed a special sample stick which can make a battery in noble gas
atmosphere and apply an electric field at 300°C. The
other sample stick was designed to automate the sample change; it has three sample positions encoded andenables us to conduct fully automatic measurements bycontrolling it from IROHA2 [3].
Software
The software, which controls DAQ, choppers andsample environment equipment, was updated from
IROHA to IROHA2 [3], developed by the computationalteam in the MLF. The update enables the automationof measurement and facilitates the integration of newdevices into the control system.

5. Outreach activities
There were several chances to advertise the DNA
performance at international conferences, such as the
3rd J-PARC Symposium (J-PARC2019) held at Tsukuba
Epochal on September 23–26, the 3rd Asian Oceanian
Conference on Neutron Scattering (AOCNS2019) heldin Kenting, Taiwan on November 16–21 and the Material
Research Meeting (MRM2019) held in Yokohama on
December 10–14.
At J-PARC2019, together with the current status ofDNA, introducing its performance and future upgradeplan, the following topics in our research and development were presented: (1) water dynamics of double
network polymers in a primally hierarchical structure,(2) position dependency of the scattered intensity of
the DNA spectrometer, (3) Position-Encoded Automatic
Cell Elevator for DNA, (4) commissioning for QENS experiments at pressures of up to 200 MPa (a new DNA
sample environment for high pressures), (5) in-situ QENSof Nafion Membrane with water vapor pressure control
system, (6) manufacturing a double-cylindrical quartz
cell, and (7) determination of corrosion of aluminumbased containers.
6. Others
Mr. Makoto Kobayashi, an engineer of DNA, finished
his contracted term in March 2020.
References[1] K. Shibata et al., JPS Conference Proceedings, 8036022 (2015).
[2] K. Mori et al., Phys. Rev. Appl., 4 054008 (2015).
[3] T. Nakatani and K. Moriyama, MLF Annual Report
2016, 130 (2017).

Y. Kawakita1, M. Matsuura2, T. Yamada2, T. Tominaga2, M. Kobayashi2, 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 2019

Current Status of iBIX (BL03) in 2019
1. Introduction
By the complementary use of neutron diffraction
data, which include more information about hydrogenatoms, and X-ray diffraction data, which include more
information about non-hydrogen atoms (such as C,
O, N, and S), we can obtain the structure informationof all atoms in the protein samples. 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 watermolecules. The IBARAKI biological crystal diffractometer
called iBIX was constructed to realize high throughput
single crystal neutron structure analysis for mainly biological macromolecules in various life processes [1, 2].
A new photon-counting two-dimensional detector system using scintillator sheets and wavelength-shifting
fiber arrays for the X/Y axes was developed with thecooperation of JAEA to realize high measurement efficiency of the iBIX. In 2019, the iBIX diffractometer had
34 detectors and was available for user experimentson biological macromolecules and polymer samples,
supported by the Frontier Research Center of Applied
Atomic Sciences, Ibaraki University. The specificationsof the iBIX are shown in Table 1.

iBIX was 0.5–2.0 mm3. If the accelerator power reaches
1 MW, the total measurement time of the sample size
will be reduced to half of the previously necessary timeor the sample size can be reduced to half size with thesame measurement time.
In 2019, 9 test measurements for a proposal of
an innovative research project of the Ibaraki Neutron
Beamline (2019A: 3, 2019B: 6) and 5 test measurements
for a proposal of a leading research project of the Ibaraki
Neutron Beamline (2019A: 2, 2019B: 3) were performed
using the iBIX. And then, 6 biological macromoleculesand 2 polymer samples were provided to the full datacollection for neutron structure analysis. 1 test measurement for a proposal of the MLF general use was performed but it carried over to the next year. Trouble of the
air-conditioning equipment for the experimental hatchof the iBIX and a target trouble of the MLF occurred in
2019A and 2019B, respectively. So, the total amount ofbeam time for user experiments was reduced in both
2019A and B. If the accidents did not happen, 2 or 3
more protein samples could have been provided to thefull data collection.

Table 1. Specifications of iBIX.

Moderator
Wavelength of incident
neutron (Å)
Neutron intensity (n/s/mm2)(@1 MW)
L1 (m)
L2 (mm)Solid angle of detectors(% for 4π)
Detector covered region (deg.)
Detector size (mm2)
Detectors pixel size (mm2)No. of detectors

Coupled
0.7–4.0 (1st frame)
4.0–8.0 (2nd frame)
0.7 × 106
40
491
22.0
15.5–168.5
133 × 133
0.52 × 0.52
34

2. Current status
In 2019, J-PARC was operated regularly at an accelerator power of 500 kW. We were able to collect a full data
set of biological macromolecules for neutron structure
analysis with around 2.0 Å resolution in about 8 days byusing the iBIX at the accelerator power of 500 kW. The
typical crystal volume of the sample measured by the
80

Figure 1. Data acquisition system.

MLF Annual Report 2019

3. Development
The current data acquisition (DAQ) system wasinstalled in FY2013. The maintenance contract of allcomponents of DAQ system has expired in the end of
FY2019. A part of the DAQ system (storage, KVM drawer,
uninterruptible power supply and network switch) was
renewed in the end of FY2019. The new system shouldhave faster data reading and writing function and higher capacity storage than the previous one because theiBIX needs to collect the diffraction data in the 1-MW
operation of the accelerator in the near future. The large
scale 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 the iBIX, because the network,storage and connection of the MLF-ACE are redundant.
To achieve high data redundancy, a large amount of
event data is recorded on the storage of the MLF-ACE
and local storage for 4 DAQ computers of the iBIX DAQ
system at almost the same time using the newly developed components of DAQ-MW. By the end of March, we
completed their installation and at the same time, thesystem became available for user experiments.

Neutron Science

4. Future plans
It has been over 10 years since the instrument of
the iBIX was installed on the beam line, some components need replacement due to age deterioration. Next
year, 4 DAQ computers will be replaced and connectedto the iBIX DAQ system and storage of the MLF-ACE. In
the future, the accelerator power of J-PARC will increase
to about 1 MW. The iBIX should be available regularly for
full data-set measurement of samples with a volume ofless than 1 mm3. We will continue to develop the data
reduction software and the beam line instruments toimprove the measurement efficiency and the accuracyof 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. Kusaka1, T. Yamada1, N. Yano1, T. Hosoya1, I. Tanaka1, and T. Ohhara2
Frontier Research Center for Applied Atomic Sciences, Ibaraki University; 2Neutron Science Section, Materials and Life Science Division,
J-PARC Center

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MLF Annual Report 2019

Stellar Neutron Capture Cross Section of 191Ir
1. Introduction
It is widely known that among various nucleosynthesis processes, the slow neutron capture process (sprocess) involves the most stable isotopes. In addition
to the stellar temperatures at energy levels of 25 keV
and 30 keV, which have been proposed as the conditionin the s-process, another recently suggested factor involves lower temperatures such as at the 8 keV level [1].
In order to experimentally evaluate the s-process models, neutron capture cross sections have been measured
for a neutron energy of approximately 30 keV. The reliable nuclear data in wider neutron energy ranges, described above, are important to improve the accuracy ofthe s-process models. In particular, at branching points,
where the neutron capture reaction competes with theβ- decay in the s-process, the neutron capture crosssections significantly affect the abundances of heavier
nuclei. Iridium-192 is one of the branching point nuclei
in the s-process and its daughter nuclide, 192Pt, is theheaviest s-only isotope synthesized only in the s-process(Fig. 1). The abundant 192Ir and 192Pt play important roles
as probes to verify the accuracy of the statistical calculation of neutron cross sections for heavier elements.
Thus, the accurate neutron capture cross-section datafor isotopes around 192Pt have been required in the relevant neutron energy region.
Previously, Macklin and Koehler measured the neutron capture cross sections of 191Ir in the stellar neutronenergies from a few keV to about 30 keV using the timeof-flight (TOF) method [2, 3]. The discrepancies in theirresults, however, reached approximately 200% in thestellar neutron energies. Moreover, these uncertainties

were not evaluated in Ref. 2 and were approximately
20% in Ref. 3. The impurities in the samples might havecaused the discrepancies, although their experiments
were not described in detail.
We, therefore, decided to measure the neutron
capture cross section of 191Ir using the TOF method in
the range of the stellar neutron energies and an 191Ir enriched sample.
2. Experiments
Pulsed neutrons were generated by the spallation
reaction of a mercury target at Japan Proton Accelerator
Research Complex (J-PARC). The proton pulses were shotat the target every 40 ms and the proton beam power
was approximately 530 kW. The pulsed neutrons wereslowed down in a liquid hydrogen moderator and extracted in the form of neutron beam to feed the Accurate
Neutron Nucleus Reaction measurement Instrument(ANNRI) at the Materials and Life Science Experimental
Facility of J-PARC. The present experiments used the
TOF measurement system with NaI detectors located at
a distance of 27.9 m from the moderator. All our samples
had a shape of either a pellet or a foil and were wrappedwith fluorinated ethylene propylene (FEP) film, which isneutron-insensitive.
191
Ir metal of 99.9% in purity and of 90.2 mg inweight was used as a sample. In addition, a 197Au sample was used for energy calibration, and also carbon and208
Pb samples for estimation of the neutron scattering
influence, the FEP film (blank) sample for estimation of
the background level.

Figure 1. The s-process network around 192Ir.

82

MLF Annual Report 2019

Neutron Science

Figure 2.	TOF spectra obtained with the NaI detectors equipped with the ANNRI.

3. Results
The obtained TOF spectra of the 191Ir and 197Au samples, corrected by the number of proton shots and thedead time, are shown in Fig. 2. After calibrating the incident neutron energies with the resonances of 197Au,
several resonance peaks of 191Ir are clearly observed. The
resonances of 191Ir at neutron energies of 0.69 eV and
5.1 eV are consistent with these neutron energies onreported data [4]. The TOF spectra of the other samples
were also successfully obtained.
4. Conclusions
We performed the TOF experiment in order to determine the neutron capture cross section of 191Ir in thestellar neutron energy range. The TOF spectrum caused
only by 191Ir was obtained without the influence of

impurities by using the 191Ir enriched sample. Hereafter,
the obtained data of the carbon, 208Pb and the blanksamples will be used to correct data as follows: the scattering component and the self-shielding effect in thesamples. This analysis is now in progress.
This work was supported in part by Grants-in-Aid for
Scientific Research (JP17H01076).
References[1] R. Gallino et al., Astrophys. J., 497, 388 (1998).
[2] R.L. Macklin et al., Report LA-7479-MS, LOS Alamos
Scientific Laboratory (1978).
[3] P.E. Koehler and F. Käppeler, Nuclei in the Cosmos III(Proceeding of American Institute of Physics1994).
[4] H.J. Stone et al., Nucl. Instrum. Methods Phys. Res.
A, 547 601 (2005).

M. Tsuneyama1,2, M. Segawa2, S. Endo2, S. Nakamura2, M. Maeda2, A. Kimura2, and Y. Toh2
Nihon Advanced Technology, Co. Ltd.; 2Nuclear Science and Engineering Center, JAEA

1

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MLF Annual Report 2019

Status of Fundamental Physics Beamline BL05 (NOP) in
2019
1. Introduction“Neutron Optics and Physics (NOP/BL05)” at MLF in
J-PARC is a beamline for studies in the field of fundamental 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.
2.	Measurement of the neutron lifetime, and thecross section of 14N(n,p)14C reaction
A neutron decays into a proton, an electron, and an
antineutrino. The decay lifetime is an important parameter for the unitarity of the CKM matrix and also for theprimordial big bang nucleosynthesis. However, recently
reported values for the neutron lifetime deviate significantly from the systematic uncertainties. An experiment
to measure the neutron lifetime with a pulsed beam isongoing at BL05 (NOP). The lifetime is measured as aratio of the electron events of the neutron decay to the3
He(n,p)3H events caused by 3He gas precisely doped ina time projection chamber (TPC). By analyzing the data,
we obtained our first preliminary result of the neutron

898 10.

J-PARC BL05.
898

Figure 1.	The neutron lifetime measurements in the 2018
PDG [4], the storage methods are denoted as blue
squares, the beam method is shown as closed red
circles. The J-PARC result is shown as a red open
circle [3].

84

lifetime as τn = 898 ± 10 (stat.) +15-18 (sys.) [3] (Fig. 1).
The TPC was made for measurement of the neutron
decay and 3He(n,p)3H. However, it is also applied formeasurements of the other nuclear reactions. We measured the thermal neutron cross section of the 14N(n,p)14C
reaction [5]. Nitrogen makes up 78% of the atmosphereand is essential for almost all living organisms because
it is found in amino acids. The 14N(n,p)14C is a reaction,
which absorbs thermal neutrons and emits protons. This
reaction, which is produced by the absorption of atmospheric neutrons, is used for radiocarbon dating and is
the main cause of the neutron dose equivalent in humanbodies. It also plays an important role in the CNO cycle,
which occurs during stellar evolution. This reaction is
also used as a neutron flux monitor [6]. The cross section
has been measured for a long time, but the accuracyof the cross sections has been limited to about 3% dueto the number of targets. We measured the 14N(n,p)14C
thermal neutron cross section with high precision using a gas-handling system, a spin flip-chopper, and the
TPC developed for neutron lifetime experiments. The
experiment was performed by mixing N2 and 3He gaseswith high accuracy and counting the reaction number
ratios. Compared with the conventional solid target, theuncertainty of the target quantity was reduced by usinga gas target, and the reaction cross section was successfully determined to be 1.868(7) barn with an uncertaintyof 0.4%. This is about five times more accurate than theweighted mean of the previous measurements (Fig. 2).

Figure 2.	Experimental results of the cross section of
the14N(n,p)14C reaction at the neutron velocity of
2200 m/s. The weighted mean from the previous
results (open circles) and gray band. The measurement result from this work (closed circle) [5].

MLF Annual Report 20193.	Measurement of the total neutron scattering crosssection of noble gases
The thermal neutron scattering cross sections arefundamental parameters for nuclear properties. In particular, the s-wave scattering length of n-4He is importantbecause it limits the three nuclear forces. In the present
work, we have performed comprehensive measurements of neutron scattering by noble gases and derived
the scattering cross section ratios for He, Ar, Kr, and Xe
with respect to Ne [7]. The experiment was carried out
using the unknown short-range force measurement system at BL05 [8]. Scattered neutrons from the noble gas
encapsulated in a cell were detected with a position-sensitive neutron detector. The ratios of the scattering crosssections of Ar/Ne, Kr/Ne, and Xe/Ne were in agreementwith the literature values [9] in the momentum transfer
region of 1–7 nm-1. However, the value for He/Ne was
11.3% (7.6s) smaller from that obtained from the neutron interferometry (Fig. 3). The given results and theirconsistency with other n-4He measurements suggested
that there was an unaccounted systematic uncertainty in

Figure 3.	The percentage difference of the thermal neutron
scattering cross sections of noble gases between
the measured value at BL05 [7] and that in the literature [9].

Neutron Science

the scattering length of 4He in the literature. It is notablethat the newly obtained scattering length of 4He by theneutron interferometry was close to our value [10].
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] K. Hirota et al., “Neutron lifetime measurement withpulsed cold neutrons”, arXiv:2007.11293 (2020)[4] M. Tanabashi et al. (Particle Data Group), Phys. Rev.
D,98 (2018) 030001.
[5] R. Kitahara et al., “Improved determination ofthermal cross section of 14N(n,p)14C for the neutron
lifetime measurement”, Progress of Theoretical andExperimental Physics (2019) 093C01.
[6] F. Issa et al., “Characterization of thermal neutron
beam monitors.” Physical Review Accelerators andBeams 20.9 (2017) 092801.
[7] C. C. Haddock et al., “Search for deviations from theinverse square law of gravity at nm range using
a pulsed neutron beam”, Phys. Rev. D 97 (2018)062002.
[8] V. F. Sears, “Neutron scattering lengths and crosssections.”, Neutron news 3.3 (1992) 26–37.
[9] C. C. Haddock et al., “Measurement of the total
neutron-scattering cross-section ratios of noble
gases of natural isotopic composition using apulsed neutron beam”, Phys. Rev. C 100 (2019)
064002.
[10] R. Haun et al., “Precision measurement of theneutron scattering length of 4He using neutroninterferometry”, Phys. Rev. Lett. 124.1 (2020)
012501.

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, KEK85

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MLF Annual Report 2019

BL06: Commissioning Status of Village of Neutron
Resonance Spin Echo Spectrometers (VIN ROSE)
1. Introduction
BL06 consists of two types of resonance neutron
spin echo (NSE) spectrometers, a modulated intensity
by zero effort (MIEZE) instrument and a neutron resonance spin echo (NRSE) instrument. 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 in the
NSE technique is not limited by the energy spectrum of
the incoming neutrons, a moderately (10–15% FWHM)
mono-chromatic neutron beam can be acceptable. In
addition, the intermediate scattering function can bedirectly derived by NSE, so the method is suitable forinvestigating slow-relaxation dynamics in condensed
matter, and high-intensity and high-energy-resolution
NSE spectrometers have been developed and built [2].
Since 2011, Kyoto University and The High Energy
Accelerator Research Organization (KEK) have beenworking jointly on the beam line construction. The NSE
spectrometers are equipped with neutron resonancespin flippers (RSFs), which enable us to replace large
magnetic precession fields with low guide fields, thus
making possible the downsizing and adjacence of thetwo spectrometers [3].
In this report, the status of the MIEZE and NRSE
spectrometers at BL06 in FY2019 is presented.
2. Commissioning status at BL06 in FY2019
Since the 2017B proposal round, the user program
has started partially with the MIEZE spectrometer,
which will be described in detail in the following section. A two-dimensional neutron detector with a 32 ×
32 cm detecting area is now under development for the
MIEZE spectrometer, which is adopting a ZnS/6LiF scintillator and multi-pixel photon counters (MPPC). Figure 1
displays a photograph of the detector mounted at the
spectrometer (top), the measured pixel sensitivity (middle), and the scattering profile of a glassy carbon plate
as a secondary standard (bottom). We plan to start using
the detector from FY2020.
At the NRSE spectrometer, used for fine-energy
resolution, commissioning of devices, such as RSFs
and two-dimensional ellipsoidal neutron-focusing mirrors, were intensively conducted [4]. The NiC/Ti twodimensional ellipsoidal neutron-focusing supermirrors
are also under development in close collaboration with
86

Figure 1.	Top: a picture of the detector. Middle: the observed
sensitivity of the detector. Bottom: the observed
scattering profile of a grassy carbon as a standard
sample compared with the data from NIST.

the RIKEN center for advanced photonics [5]. The optical design is 1250 mm semi-major axis and 65.4 mm
semi-minor axis with 900 mm length. In Fig. 2, one example of on-beam tests is shown. More than 5Qc reflection, where xQc means that the critical angle of Ni (Qc= 0.22 Å-1) is x times larger, can be achieved, and also,
the beam can be focused properly with the mirror. This
achievement will be utilized in the development of the
NRSE spectrometer.

MLF Annual Report 2019

Neutron Sciencesuch as Skyrmion phase observed in magnetic substances. The instrument is equipped with a 4K GM cryostat
and a very compact magnet, which can add a maximumof 0.2 T at the sample position. In addition, the combination between neutron reflectometry and MIEZE measurement was tested by using a KENS S-type project, andit will be made available to public users in FY2020.
4. Summary
In this report, the current status of BL06 VIN ROSE
in FY2019 was briefly summarized. A new 2D detector
with MPPC silicon photomultipliers was tested and will
be operational soon. The public users can now use the
MIEZE spectrometer, where a 4-K GM cryostat and acompact maximum 0.2 T permanent magnet are available as sample environments. At the NRSE spectrometer,
the commissioning with two-dimensional ellipsoidal
neutron-focusing supermirrors has progressed significantly, which is essential for the further development of
NRSE to reach high-energy resolution.

Figure 2.	Top: a beam profile at the focal point, where 10
scales correspond to 1 mm. Bottom: the observedreflectivity of the mirror.

3. User Program
Currently, the MIEZE spectrometer can be opened
for the public users. The great advantage of the instrument is that a relatively strong magnetic field in any direction can be added in the sample position, while suchconditions are impossible in other types of NSE spectrometers with large solenoids generating strong precession magnetic fields. This advantage is very useful forstudies of slow spin dynamics on magnetic properties,

References[1] F. Mezei ed., Neutron Spin Echo, Lecture Notes inPhysics, (Springer, Berlin) 128, (1982).
[2] D. Richter, M. Monkenbusch, A. Arbe, J. Colmenero,Adv. Polym. Sci. 174, (2005) 1–221.
[3] M. Hino, T. Oda, N. L. Yamada, H. Endo, H. Seto, M.
Kitaguchi, M. Harada, Y. Kawabata, J. Nucl. Sci. Tech.
54, (2017) 1223.
[4] F. Funama M. Hino, T. Oda, H. Endo, T. Hosobata, Y.
Yamagata, S. Tasaki, J. Surf. Invest.: X-ray, Synchrotron
and Neutron Tech., 14, Suppl. 1, (2020) S50–S55.
[5] T. Hosobata, M. Hino, H. Yoshinaga, T. Kawai, H. Endo,
Y. Yamagata, N. L. Yamada, S. Takeda, JPS Conf. Proc.
22, (2018) 011010.

H. Endo1,2, M. Hino3, T. Oda3, 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

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MLF Annual Report 2019

Commissioning of 3He Cryostat on Super-HRPD
1. Introduction
Super-HRPD (BL08) is the highest resolution neutron
powder diffractometer (Dd/d = 0.037%) in the world [1].
Taking advantage of high resolution, we can detect symmetry lowering and distortion of crystal structure. In addition, it is possible to perform high quality structure
analysis by extraction of many distinguishable diffraction peaks. Various sample environments (SE) (temperature range from 1.3 K to 1170 K, magnetic field up to
14 T, and gas environment) have been developed. We
have done commissioning of a bottom-loading cryostat
at FY2017 [2]. It can reach up to 4 K in about 2 hours andperform relatively quick heating. Until now, many users
have used that cryostat without trouble. On the other
hand, measurement at an even lower temperature wasrequested by specific users for magnetic studies. Using
our 14 T magnet system, we can perform measurement
down to 1.3 K. But if we do not need a magnetic field, it
is unreasonable to use our magnet because its preparation involves significant labor and time. Moreover, thesignal decreases at the back scatter (BS) and the low
angle (LA) detector bank by the narrow scattering window and we cannot make available the 90-degree (QA)
detector bank because of the lack of a window. So, weneed the other cryostat that is easier to handle and canreach temperatures below 2.6 K. In this report, we introduce about the commissioning of the bottom loading
type of the 3He cryostat.
2. Spec and off-beam test
Our 3He cryostat consists of a GM refrigerator and3
a He gas circulation system. Below 30 K, the cold headof the GM refrigerator and the 1-K pot are separated
thermally by H2 gas heat switch to keep the temperature of the sample. On the neutron beam pass, there arean outer chamber with a vanadium window of 0.1 mm
thickness, and two radiation shields, located at 40 K
and 4 K stages respectively, with a vanadium window of
0.04 mm thickness.
Figure 1 shows the cooling and heating tests of thecryostat. The starting time is defined as the time of turning on the compressor. Before it starts to cool, it takes
several hours to vacuum the inner space of the outer
vacuum chamber (OVC). Unfortunately, the coolingrate is very slow, so about 40 hours are needed for the
sample mount to measurement at base temperature.
On the other hand, the temperature stability below 5 K
is good. We controlled the temperature increase from88

Figure 1.	The off-beam test on our 1K cryostat, cooling, (b)heating, and (c) approaching the lowest temperature.

2 K to 5 K with 0.5 K steps. Although the temperature isslightly unstable near the boiling point of 3He, we think
it is acceptable for general use. The base temperature
is about 1.05 K with no control. When the 3He gas flowrate is limited by controlling the needle bulb, we canensure availability to 0.87 K. At the initial tests, we could
not keep the temperature for a long time because of an
occurring stack on the narrow part of the 3He line. After
fixing the leakage, we could keep the temperature below 0.9 K for at least 2 days.
3. On-beam test
In order to check the actual sample temperature, wemeasured polycrystalline ErF3. The sample was loaded toour conventional vanadium cell (6 mm diameter) and theheight of sample was 40 mm. It has been reported that
ErF3 behaves antiferromagnetic transition at TN = 1.05(3)K and its magnetic structure is represented with k = 0 [3].
Our result showed TN = 1.04(1) K (Fig.2), consistent withthat of the reference, so the sample was cooled down
to at least 1 K. Neutron powder diffraction profiles werecollected at 1.10 K and 1.00 K to confirm the magnetic
structure. The collected data were based on three hours

MLF Annual Report 2019

Figure 2.	The temperature dependence of the magnetic peakintensity of ErF3.

(a)

per one profile with 500 kW proton beam of the MLF. The
profile looked good, so it appeared that the reduction of
intensity by the OVC and the other shield had no effect.
Our sample included a small amount of unidentified impurities. So, the profile on which the intensities of 1.00 K
were subtracted from those of 1.10 K was used for analysis. We performed Rietveld refinement using Z-Rietveld
software [3]. For accuracy, two profiles collected at the
LA and the QA detector banks were used. We could fit
the profiles adopting the model of the reference. The
strength of the magnetic moment was 4.303(8) mB per
Er3+. The value was smaller than the reported one because the magnetic moment was not saturated at 1.00 K.

(c)

c

(b)

Neutron SciencebaFigure 3.	The fitting result of the subtracted profiles of (a) the LA bank and (b) the QA bank. The χ2 were (a) 1.39 and (b) 1.26.
(c) The refined magnetic structure of ErF3. It was yielded that the component of magnetic moment on (0.3674, 1/4,
0.0619) site was (2.182, 0, 3.708) with bore magnet units.

4. Future plans
It was decided that the 3He cryostat will be madeavailable to users from the 2020B cycle. The cooling rateof the 3He cryostat is very slow, it is impossible to measure two or more samples without time lag. To solve theproblem, we will perform off-beam cooling and will arrange the beam time flexibly.

References[1] S. Torii et. al., J. Phys. Soc. Jpn. SB020 SB020-1-4 (2011).
[2] M. Hagihala et. al., MLF Annual Report 2017 p.81
(2018).
[3] K. Krämer et. al., Europ. J of Sol. Sta. and Inorg. Chem.
33, 273–283 (1996).
[4] R. Oishi-Tomiyasu et. al., J. Appl. Crystallogr. 45 a299–
308 (2012).

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

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MLF Annual Report 2019

Current Status of BL09 (SPICA) in 2019
1. Introduction
The rechargeable battery is a key component ofmobile devices and electric vehicles, and the development of new generation batteries is essential to meetthe requirements for batteries in the future. The Special
Environment Powder Diffractometer (SPICA) installed at
BL09 is a time-of-flight neutron powder diffractometerdedicated to new generation battery studies. Its design
is optimized for conducting various types of measurement for observing active materials from operating battery devices, i.e. it is a high intensity and high-resolution
diffractometer, with flexible sample environment setup.
It is also equipped with an automatic sample changer
for conventional powder diffraction measurements, aswell as off-beam charge/discharge equipment for conducting long-term deterioration tests, and a chemical
lab of its own, to provide flexible environment for handling highly reactive battery materials.
SPICA has demonstrated its ability for operandomeasurements of the charge/discharge process ofworking Li-ion batteries, as well as for precise crystal
structure analyses of various battery related materials
by the conventional powder diffraction method [1, 2].
In fiscal year 2019, several sample environments werecommissioned, and became open for general users.
2. Cryostat and cryofurnace
In fiscal year 2019, a new top-loading cryostat andcryofurnace have been commissioned, and both ofthem became available for general users.
The sample temperatures of the new cryostat andcryofurnace range from 4 K to 300 K, and from 20 K to600 K, respectively (Fig. 1). The sample temperatures
were measured at sample positions for each apparatus.
It took about 3 hours (6 hours) to reach the base temperature from 300 K for the cryostat (cryofurnace). For thecryofurnace, the sample temperature can be controlledfrom low temperatures (below 300 K) to high temperatures (above 300 K) continuously, without taking out the
sample. Figure 2 shows the temperature dependent diffraction data for BaTiO3, which demonstrates the observation of the sequential structural phase transition of
BaTiO3 on heating. Phase transitions varying as rhombo.
→ ortho. → tetra. → cubic were clearly observed as thetemperature was increased monotonically throughout
the temperature range. (The horizontal blue line around240 K corresponds to the beam stop which occurred
during that period.)
Figure 3 shows the normalized diffraction patternsof the standard sample (NIST Si) collected at the backward bank using cryostat, cryofurnace and without sample environment apparatuses. The contribution from thecryostat or cryofurnace in the raw data is corrected, andthere are no extra signals or backgrounds due to theseapparatuses.

Figure 1.	Time dependence of the temperature for the cryostat (left)
and cryofurnace (right). The temperatures were measured at
the sample positions for each apparatus.

90

Figure 2.	Temperature dependent neutron powder
diffraction patterns for BaTiO3 near 311(left) and 111 (right) reflections. The left
axis represents the control temperature,
which is somewhat higher than the actual
sample temperature.

MLF Annual Report 2019

Neutron Science

Figure 3.	Neutron powder diffraction patterns collected with the cryostat (blue), cryofurnace (red), and without sample
environment apparatus (black).

3. Fluoride shuttle battery standard cell
The fluoride shuttle battery (FSB) is one of the promising candidates for beyond–lithium–ion, innovative, rechargeable battery. FSBs work on the principle of thereversible redox transformation between a metal and its
fluoride counterpart at both the negative and positiveelectrode, under fluoride–ion shuttling.
We have studied in detail the crystal structures ofsolid electrolyte materials for FSBs using SPICA and unveiled the fluoride ion conduction mechanism in thesematerials [3, 4]. For the forthcoming operando neutron
powder diffraction experiment of all-solid-state FSBs using these solid electrolytes, we developed a standard
battery cell system for such experiments, in cooperation
with Kyoto University. Figure 4 illustrates the cell set up.
We expect to start the operando neutron powder diffraction experiments in fiscal year 2020.

4. Future plans
We will continue with the development of the cryostat/cryofurnace. The measurement control software
will be upgraded for automatic temperature control,and efforts are being made to improve the maximum
sample temperature for the cryofurnace. The commissioning of the FSB standard cell will continue as well.
Acknowledgements
The development of the FSB standard cell wasdone in collaboration with Prof. K. Mori and Assis. Prof.
F. Fujisaki at the Institute for Integrated Radiation and
Nuclear Science, Kyoto University. We would like tothank Mr. Shioya and Mr. Namba for their technical support in operating SPICA. This work was supported by
the Research and Development Initiative for Scientific
Innovation for New Generation Batteries 2 (RISING2)
project of the New Energy and Industrial Technology
Development Organization (NEDO).
References[1] N. Yabuuchi, et al., Nat. Commun., 7 13814 (2016).
[2] S. Taminato, et al., Sci. Rep., 6 28843 (2016).
[3] K. Mori, et al., ACS Appl. Energy Mater., 3 2873 (2020).
[4] K. Mori, et al., J. Phys. Chem. C, 124 18452 (2020).

Figure 4.	Schematic view of the newly developed all-solidstate fluoride shuttle battery standard cell.

T. Saito1,2, T. Kamiyama1,2, and S. Torii1,2
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK

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BL10: NOBORU
1. Introduction
In FY 2019, sixteen general-use proposals and threeproject-use proposals were carried out at NOBORU. Two
general-use proposals were postponed due to a delay
in restarting the facility operation after the summer
shutdown.
This year, the MLF successfully performed a 1-MW
test operation for 10.5 hours on July 3, and we accordingly conducted the neutron source diagnostics measurements at NOBORU. In the following sections, we briefly
describe the measurement methods and obtained results.
2.	Fixed-point observation of thermal-cold neutron
spectrum and its intensity
The neutron intensities of thermal and cold neutrons from the moderator were measured at BL10 by
the foil-activation method using gold foils. The foils
were located at the beam line center, 13.0 m from themoderator surface. Each measurement at different proton beam power was done with and without a Cd cover
to derive the thermal neutron intensity. The optical device conditions, such as collimator size and slit setting,were kept the same for all measurements for easy comparison. Figure 1 shows the thermal neutron intensities
measured by the foil activation method with the calculations. We confirmed that the neutron intensity depends
almost linearly on the proton beam power.

3. Pulse shape measurement of thermal-cold neutrons
The pulse shapes of the thermal and cold neutrons
were measured by a conventional diffraction method,where the sample and experimental setup were almost
the same as in the previous work done at NOBORU. We
confirmed that the observed Bragg peaks of the decoupled moderator below 300 kW were in good agreement with those calculated using the PHITS simulation
code [1]. Here, we compare the mica Bragg peaks atbeam powers of 150 kW and 1 MW measured in 2017and 2019, respectively. As shown in Fig. 2, we can expectthat the pulse shape does not change even in the steady
operation of 1 MW.
800

1000
mica (0026)
35 meV150 kW
1 MW

600

mica (0026)
35 meV150 kW
1 MW
100

400
10
200

0

1
5670

5700
TOF (μs)

5730

1200

900

mica (008)
3.3 meV
150 kW
1 MW

5700

1000

TOF (μs)

5800

mica (008)
3.3 meV
150 kW
1 MW

100

600
10

300
1

0
18400

18500
18600
TOF (μs)

18500

19000
TOF (μs)

19500

Figure 2.	Examples of pulse shapes for thermal and cold neutrons. Bragg peaks of (0026) and (008) of mica arerepresented in linear and log scale.
Figure 1.	Thermal neutron intensities measured by the foil
activation method using gold foils.

Reference[1] K. Oikawa et al., JPS Conf. Proc. 1, 014012 (2014).

K. Oikawa1 and M. Harada2
1
Neutron Science Section Materials and Life Science Division, J-PARC Center; 2Neutron Source Section Materials and Life Science Division,
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Recent Developments in High-PT Experiments
Using the Multi-Anvil Press “ATSUHIME” at BL11
1. Introduction
To conduct neutron diffraction experiments underhigh-pressure and high-temperature (high-PT) conditions, the PLANET [1] is equipped with the large volume 6-axis multi-anvil press “ATSUHIME” [2] that has six
independently controlled hydraulic rams. The use ofmulti-anvil assembly 6-6 (MA6-6) [3], which compresses
a cubic pressure medium with six second-stage anvils,
enables us to generate high-PT stably. However, themaximum pressure was limited below 10 GPa so far. To
extend the available pressure range, we modified the anvil shape and tested its feasibility. In addition, the MA6-8(or Kawai-type 6-8 cell assembly) which has the potential
to extend the available pressure was also tested.
2. MA6-6
Figure 1 shows MA6-6 used in this study. The sample
assembly is compressed by six tungsten carbide (WC) anvils that are shrink-fitted into steel outer jackets [3]. The
use of large anvils and the shrink-fitting increase the maximum applicable load compared with the conventional
anvils with 26 mm square base. Anvils with different
truncation edge lengths (TELs) of 3.5, 5, 7, 10 mm were
tested. A step is made on each anvil facet to increase signal intensity from the sample by reducing the blind angle.

Figure 1.	Conventional 6-6 anvils and large 6-6 anvils withshrink-fitted jackets. Guide frames and cell assemblies are also shown.

To check the pressure-load performance, diffraction
profiles of NaCl were obtained at several loads during
compression (Fig. 2). The performance improves as the
TEL is reduced: the maximum pressure reached was
15.3 GPa at 1000 kN when using anvils with TEL of 5 mm,
whereas the anvils with TEL = 3.5 mm could not exceed
the performance of TEL = 5 mm. Further optimization of
the sample assembly and the gasket that seals pressure
is necessary for TEL = 3.5 mm in the future.
As the achievable pressure increases, a problem
in heating with graphite heater arises from the transformation to diamond above approximately 12 GPaand 1400 K. To achieve stable heating, we replaced thegraphite by TiC/Al2O3 composite (Nippon Tungsten,
NPA-2). An off-line test with this heater confirmed thestable heating up to 2000 K. The developed cells are
now offered for general user experiments.
3. MA6-8
The MA6-6 generated successfully pressures up to
15 GPa, but further increase of pressure while maintaining the sample volume is difficult because of the limitation of the anvil strength. To extend the pressure range
to 20 GPa, we tested MA6-8. In this assembly, the applicable load is higher than in MA6-6. Several anvils with

Figure 2.	Pressure generation curves of a large 6-6 cell (L66)
and 6-8 cells (SD68 and WC68) with various TELs.
Pressures are calculated from lattice parameters of
NaCl on the basis of the equation of state [4]. Numbers for L66 TEL5 indicate dimensions of the gaskets. Units of TELs and gaskets are in mm.

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Figure 3.	Observed (cross), calculated (red line) and difference (gray) for the profile of Ca-perovskite. Verticalbars indicate calculated positions for reflections of
Ca-perovskite, MgO endcap and graphite capsule.
The binning width of the data is Δt/t = 0.001.

different materials and shapes were tested, including
SiC-sintered diamond (SD) and tungsten carbide (WC)
anvils with TELs of 3, 4 and 5 mm. To gain the diffraction intensity by maintaining a window for scatteredneutrons, tapers and slits are made on the facets of thefirst stage anvils.
The generated pressures are plotted in Fig. 2. The
pressure reached 23.1 GPa at 1200 kN using SD anvils
with TEL = 3 mm and it reached 16.0 GPa at 1500 kN using WC anvils with TEL = 5 mm.
A test for high-T generation and the diffraction
data collection was conducted using WC68 anvils with
TEL = 5 mm. The sample of wollastonite (CaSiO3) wascompressed to 1800 kN, then heated up using a LaCrO3
heater. After reaching 973 K at 16.2 GPa, the peaks of CaPerovskite appeared. The patterns were contaminatedby small peaks from the sample surroundings, such as
end caps and a sample capsule (Fig. 3). High quality datathat is refineable by Rietveld method were obtained by
24 h exposure.
4. Comparison of signal intensities
To evaluate efficiency in data acquisition, peak intensities of NaCl are compared at around 15 GPa among
various cell assemblies (Fig. 4). The intensity for MA6-8

Figure 4.	Comparison of normalized diffraction patterns of
NaCl obtained with MA6-6 (L66) and MA6-8 using
SD and WC anvils (SD68 and WC68) at ca. 15 GPa.
The radial collimators with diffraction gauge lengthof 3 mm and 1.5 mm were used for the experiments with MA6-6 and MA6-8, respectively. The
binning width of the data is Δt = 20 μs. Inset shows
enlarged area of NaCl 220 reflection.

using WC anvils with TEL = 4 mm is almost comparable to that of MA6-6 using WC anvils with TEL = 5 mm.
Thanks to the high neutron transparency of the sintereddiamond, MA6-8 with SD anvils provides the highest
intensity. These results demonstrate the feasibility of
MA6-8 to expand the pressure range while maintaining
sufficient signal intensity.
5. Summary
We have developed a technique for high-temperature experiments above 10 GPa with MA6-6 and MA6-8.
The MA6-6 with TEL5 anvils and MA6-8 with TEL3 anvils
extended the pressure range to 15 GPa and 23.1 GPa,
respectively. This technique is useful in a wide range offields, including Earth science and material science.
References[1] T. Hattori et al., Nucl. Inst. and Meth. Phys. Res. A,
780 55 (2015).
[2] A. Sano-Furukawa, et al., Rev. Sci. Instrum., 85113905 (2014).
[3] A. Yamada et al., Rev. High Press. Sci. Tech. 26 99(2016).
[4] J.M. Brown, J. Appl. Phys. 86, 5801 (1999).

A. Sano-Furukawa1,2, T. Hattori1, K. Funakoshi3, J. Abe3, and S. Machida3
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3Neutron
Science and Technology Center, CROSS

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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 type project, in order to study dynamics in condensed matter, especially in a wide range of correlated electron systems.
The activities of the HRC in FY2019 are summarized inthis report.
2. Maintenance of the T0 chopper
A T0 chopper was installed at the beginning of theoperation of the HRC in May 2010 [1], and this T0 chopper (T0#1) was in operation until the Hadron incident in
May 2013. After the earthquake in 2011, a spare T0 chopper was manufactured, T0#1 was replaced by the spareone (T0#2) during the recovery work from the Hadronincident, and T0#2 was in operation since February 2014.
Maintenance work was performed on T0#1 in November
2015, where the components damaged during the operation, such as the rotor bearings, the magnetic seals,
the timing belt, the vacuum seals, and the motor, were
replaced with new ones, and a trial operation was
performed for 200 hours rotating at 100 Hz to ensuresmooth rotation. T0#2 was replaced with T0#1 in July
2017, at the time the water couplers for both T0 choppers were improved to avoid water leaks [2]. T0#1 is currently in operation.
In May 2016, during the operation of T0#2, the fluctuations of the rotational period suddenly increased to±50 μs, whereas they are normally less than ±3 μs for agood phasing to the repetition of the neutron production. The fluctuation increase was caused by the decrease of the output voltage (V) of the rotational signalof the rotor and the noisy part of the signal being comparable to the reference level (VR) (Fig. 1(a)). The same
phenomena occurred in July 2017 and December 2018.
The light source is mounted in the controller, the light istransferred though an optical fiber to the marker on therotational axis of the T0 chopper rotor, where the light isshut or transmitted, and the light returns to the controller through an optical fiber for return [3]. The rotational
phase is determined from the time when V > VR. The voltage in the initial installation of the T0 chopper was V =600 mV, and the VR value was set in the electronic circuitin the controller. The fluctuation increase occurred when
the difference became V - VR < 150 mV, and recoveredby reducing VR to V - VR > 200 mV (Fig. 1(b)). These phenomena occurred more frequently with the increase of
the beam power and the decrease of V was proportional

to the integrated beam power. Therefore, we concluded
that the fluctuation increase was caused by the radiation
damage to the optical fibers.
Since V decreased to 400 mV in December 2018,
VR changed once to 200 mV. In order to estimate thelifetime of the optical fibers and extend it, we set V =500 mV by changing the parameters of the circuit to increase the light intensity, and VR = 150 mV, which is thelimit in the circuit, and started the operation in January
2019 with the beam power of 500 kW. We found that V
decreased at the rate of 6.5 mV/month until July 2019(the solid line in Fig. 1(c)). We can estimate that thefluctuation increase will occur 30 months later fromJanuary 2019, when V = 300 mV and V - VR = 150 mV.

(a)

(b)

(c)

Figure 1.	(a) Schematic drawing of the output voltage of therotational signal as a function of time (t). (b)Variations of V and VR. The T0 chopper in operation at thetime is indicated. (b) Variation of V since January 1,
2019 (Month = 0) indicated by removing the beam
off period.

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We decided to perform the maintenance work on T0#2
in 2019 and to exchange it with T0#2 in the summer of2020. In fact, the maintenance work for T0#2, which isthe same as that for T0#1 performed in 2015, was performed in November 2019. Note that the initial voltage
in this circuit condition was 750 mV and the time when
V drops by a half is estimated to be 3 years for a continuous period and 5 years if the beam off period at 1-MW
beam power is included. The lifetime was roughly estimated to be 19 years in the initial design [3].
Due to a different reason, fluctuation increase of therotational period sometimes occurred in T0#1. Since thefluctuation increase sometimes calms down in several
days, a heating in the circuit was assumed to be thereason, so we took the following measures. In the controller, there is a module, where signals generated in asynthesizer are transformed to TTL and then transferredto the servo amplifier of the motor [1]. First, this module
was replaced with an improved one, where the heating
in an operational amplifier is minimized by reducing thevoltage ratio of the operational amplifier to the resistor
connected to the amplifier increasing the resistor value.
Next, this module was replaced with a more advanced
one, where the heating in the operational amplifier isfurther reduced by transforming the synthesizer signal to TTL using a comparator. The servo amplifier was
exchanged with a spare one and so was the motor. We
found that the tension of the timing belt was reduced
from the value applied during the maintenance. The
tension increased back to the maintenance value. All
these measures failed to reduce the fluctuations. Finally,
we found that the fluctuations were caused by the noisein the electric power during the operation of the main
ring. By resurveying the control parameters of the servo
amplifier, the optimum values were found, and they
were different from those determined during the maintenance, so the fluctuations were reduced to a certain
degree. We found that the control parameters of theservo amplifier and the tension of the timing belt hadchanged after the long-time operation. The correction

works were performed from March 2019 to January
2020. Although V decreased by removing and reinstalling T0#1 for the exchange of the motor, fortunately, thedecrease rate of V was slightly reduced even at 600-kW
beam power. Therefore, V will not be reduced by muchby the summer of 2020, as shown with the dashed line
in Fig. 1(c).
3. Other instrumentations
The superconducting magnet is operated properly,
based on the decision to apply a maximum magnetic
field of 5 T. The magnet can be controlled with thecontrol program YUI. A distribution version of the data
analysis and visualization program HANA was released,
where the vanadium correction can be done for an efficiency normalization of PSDs and the par file can becreated for data analysis using Horace. A Windows PC
was installed for data analysis by Windows users. We discussed the maintenance of the chopper controller, then,the details of the descriptions of the controllers werecollected and a test environment for the Fermi chopper
was equipped for maintenance and development work.
4. Scientific results
We have some publications: a review article for neutron Brillouin scattering on the HRC [4], a discovery ofnovel excitations in a frustrated magnet CsFeCl3 [5] andsome instrumentations [6–8].
References[1] S. Itoh et al., Nucl. Insrt. Meth. A 661 86 (2012).
[2] S. Itoh et al., MLF Annual Report 2017, pp. 94–95.
[3] S. Itoh et al., Nucl. Insrt. Meth. A 654 527 (2011).
[4] S. Itoh and Y. Endoh, J. Phys. Soc. Jpn. 88 081004(2019).
[5] S. Hayashida et al., Sci. Adv. 5 eaaw5639 (2019).
[6] S. Itoh et al., Physica B 568 76 (2019).
[7] S. Itoh et al., JPS Conf. Proc. accepted.
[8] M. Watanabe et al., JPS Conf. Proc. 25 011024 (2019).

S. Itoh1,2, T. Masuda2,3, T. Yokoo1,2, T. Nakajima3, S. Asai3, H. Saito1,2, D. Kawana3, R. Sugiura3, T. Asami3, Y. Ihata4, and H. Tanino1,2
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 Center

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BL14 AMATERAS
1. Introduction
AMATERAS is a cold-neutron disk-chopper spectrometer for studies on the dynamical properties inatomic, molecular and magnetic systems from cold to
sub-thermal energy range with high efficiency and flexible resolution. Experiments of 23 general user applications and two JAEA project research applications havebeen carried out. On the other hand, we encounteredsome mechanical problems, one of which was serious
and interrupted the user program. A new member, Dr.
Naoki Murai, joined the AMATERAS team in April.
2. User program, outreach activities and outcomes
The numbers of general proposals (short-term) submitted in the 2019A and 2019B periods were 27 (accepted: 11, reserved: 15, not approved: 1) and 37 (accepted:
10, reserved: 25, not approved: 2), respectively. We
also received one long-term general proposal (not approved) and two JAEA project research proposals (bothapproved). The research fields of the majority of the general proposals were magnetism and strongly correlated
electron systems, as in the previous periods. The second
major field was liquid and non-crystalline systems, andthe third one was energy (functional) materials. Finally,in FY2019, 23 short-term general proposals and two
JAEA project proposals were carried out on AMATERAS.
In FY2019, six refereed papers covering the works
at AMATERAS were published. The topics included
quantum spin systems, thermo-electric materials andothers. Two of papers were subjects of press releases.
One was study on triplon excitations with the topologically protected edge states in a two-dimensional (2D)
dimer antiferromagnet (AF) done by Dr. Kazuhiro Nawa
(Tohoku University) and his co-workers [3]. The otherwas a work on magnetic excitations in a perfectly frustrated 2D dimer AF done by a research group headed by
Dr. Nobuyuki Kurita (Tokyo Institute of Technology) [4].
Dr. Nawa won the JSNS Young Researcher Prize in partdue to this work.
In the 4th Neutron and Muon School and MIRAI PhD
School 2019, three students conducted a hands-on experiment at AMATERAS and learned how to measure themagnetic excitations of a single crystal material.
Dr. Chi-Hung Lee visited AMATERAS as a guest researcher of AONSA Young Research Fellowship organized by the Asia-Oceania Neutron Scattering Association.
Originally, he planned to stay at J-PARC for three months
from February to April and to study a new-type ofmultiferroic material on AMATERAS. Unfortunately, however, due to the COVID-19 pandemic, he terminated his
stay before carrying out his experiment. He is planningto come again in 2020 or later.
3. Instrument related issues
In FY2019, AMATERAS encountered several mechanical problems. The most serious one was the failureof the monochromating chopper. One of the resolvers failed (Fig. 1) which caused the suspension of the
AMATERAS user program for twelve days. The details of
the incident are mentioned elsewhere [5].
The work on maintaining and upgrading the spectrometer continued. The preparation for replacementof the vacuum system of the scattering chamber also
continued. A jig for the installation and the control software was prepared. The installation will be completed
in FY2020. We started the planned installation of theextended section of the beam-transport (0.5 m after
the monochromating chopper). The jacket of the mirror
for this section was purchased. The super-mirror will bedelivered in FY2020.
In July, at the 1-MW test operation of the MLF,
we carried out a demonstration measurement on themagnetic excitations in a low-dimensional magnet byomega-rotation scans. Even with a tiny (170 mg) single
crystal sample, clear picture of the excitations in a fourdimensional space was obtained. The results will be reported in a future publication.

Figure 1.	The monochromating disk-chopper under inspection. Inset shows a failed resolver.

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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. Nawa et al., Nat. Commun. 10, 2096 (2019).
[4] N. Kurita et al., Phys. Rev. Lett. 123, 027206 (2019).
[5] K. Nakajima et al., JPS Conf. Proc. in press.

K. Nakajima1, S. Ohira-Kawamura1, M. Kofu1, N. Murai1, Y. Inamura1, D. Wakai2, and T. Kikuchi1, 3Materials and Life Science Division, J-PARC center; 2Nippon Advanced Technology Co., Ltd.; 3Chemical Analysis Center, Research &Development HQ, Sumitomo Rubber Industries, Ltd.

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Neutron Science

Upgrading TAIKAN
1. Introduction
The small and wide angle neutron scattering instrument TAIKAN (BL15) has been developed and upgradedat J-PARC to analyze precisely and efficiently the microstructures or hierarchical structures of substances invarious scientific fields with a 1-MW spallation neutron
source [1]. In FY2019, it was upgraded further to perform efficient wide-q measurement and high precision
low-q measurement.
2. Upgrading for wide-q measurement
The detector system of TAIKAN is composed of 5detector banks: small-, middle-, high-, ultra-small-angle,
and backward detector banks. On the middle-, high-angle, and backward detector banks, 128, 120, and 40 3He
PSD tubes were additionally installed, respectively. The
measurement efficiency of the middle-, high-angle, andbackward detector banks increased by about 22, 60, and200%, respectively. The number of 3He tubes then increased to 912, 720, 320, and 80 for the small-, middle-,
high-angle, and backward detector banks, respectively.
The installation ratios of the 3He tubes became 100, 100,
57, and 100% or the small-, middle-, high-angle, andbackward detector banks, respectively. Figures 1 and2 show photos of the small-, middle-, and high-angle
detector banks and the backward detector bank after
installing the 3He tubes, respectively.

Figure 2. Backward detector bank.

3. Upgrading for high precision low-q measurements
For high precision low-q measurements, an ultrasmall-angle detector and beam focusing devices consisting of a quadrupole magnet to polarize a neutron
beam, two sextupole magnets to focus the beam on theultra-small-angle detector, and three spin flippers havebeen installed in TAIKAN. The performance of the system
was evaluated with a sample of polystyrene spherical
nanoparticles. The experimental data were well fittedwith scattering functions using the hard sphere modelwith the averaged diameter of 496 nm in the q-range of
0.0007 – 0.003 A-1. This result validated the assumptionthat the qmin of TAIKAN can be extended to 0.0007 A-1.
4. Future prospects
The improvement of the measurement efficiency
by the installation of middle-, high-angle, and backward
detectors and the validation of the high precision low-q
measurement make efficient wide-q measurement easier. TAIKAN is expected to contribute to the research of
microstructures or hierarchical structures by authentic
precise measurement in a wide-q range.

Figure 1. Small-, middle-, and high-angle detector banks.

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).

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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Neutron Reflectometry Using Focusing Mirror 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 full Q-range data andonly a few seconds for a limited Q-range data in the caseof 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 the further upgrade of the SOFIA reflectometer,
we have developed an elliptical focusing mirror to illuminate a sample with a neutron beam with a large beam
divergence. In the case of conventional double slit collimation, the optimal beam divergence decreases according to the sample size. Hence, the focusing optics withthe mirror is beneficial to the beam flux, especially forsmall samples. The planned specifications of the focusing mirror and detector are a beam size of 0.1 mm at asample position with divergence of 2.5 mrad.
So far, we have developed several focusing supermirrors [3–5]. The latest mirror is capable of focusing
neutrons with a width of 0.13 mm in full width at half
maximum (FWHM), as reported last year. This mirror has
been installed in the SOFIA already, and is available tousers. This year, we report in detail the reflectivity datausing the focusing mirror.
2. Beam width at sample position
We employed the focusing mirror to converge neutrons on the sample position. In this geometry, a focal
point is on a slit working as a virtual source, and the other is on the sample position. As the image of the virtual
source is projected on the sample position, the beam
size at sample position can be controlled by changing
the slit width. The actual size at the sample is dependent
not only on the slit width but also on a figure error of
the mirror limiting the minimum beam size. Hence, we
evaluated the relation between the slit width and theactual beam size at the sample first. As shown in Fig. 1,
the beam size at the sample decreased with the slit
100

width monotonically, and saturated to be approximately
0.3 mm in the full width because of the figure error.
Next, we compared the beam intensity profiles atthe sample position with the focusing optics and conventional double slit optics, which would be used later.
The slit width for the focusing optics was adjusted toachieve a beam width of 0.42 mm at the sample position, and that for the double slit optics was to achieve
the same beam width with the largest beam intensity.
Whereas the proﬁle for the slit optics exhibited triangularshapes, that for the focusing optics exhibited Gaussianlike shape, as shown in Fig. 2. Remarkably, the peak intensity of the focusing optics was higher than that of theslit optics, and the gain factor was estimated to be 1.97
by integrating the intensities over the full width.

Figure 1.	Full width of beam at sample position depending
on slit aperture.

Figure 2.	Comparison of beam proﬁles between focusing
optics and slit optics at sample position.

MLF Annual Report 2019

3. Neutron reflectivity data
Next, we performed in-situ measurements of an LIB
with the focusing optics and compared the results withthose of the conventional slit optics. A cathode made of
LiCoO2 on SrRuO3 was fabricated on a SrTiO3 substratewith an area of 20 mm × 20 mm. This was packed with acustom-made electrochemical cell [6] and soaked in anelectrolyte LiPF6 solution of deuterated organic solvents,
with a counter-electrode made of Li metal. The neutrons
were introduced from the substrate side, the electrodein contact with the electrolyte with an area of 15 mm
× 15 mm was illuminated. The reﬂection intensity was
normalized by the direct beam intensity through thesubstrate to evaluate the reﬂectivity.
Figure 3 presents the reﬂectivity proﬁles with thetwo optics at the incident angle θ of 1.6°. The focusing
optics could not be applied for lower angles to cover
the low-Qz region, θ = 0.3° and 0.7°, owing to the limitation of the beam size. The same data at the lower angles obtained with the double slit optics were used forboth sets of data at θ = 1.6° to be merged into one setof reﬂectivity data. The two data points at θ = 1.6° wereconsistent with one another despite a slight discrepancy. To evaluate the eﬀect of the latter on the data analysis, the two data sets were analyzed by least-squares
ﬁtting with the reﬂectivity. The proﬁles could be ﬁtted
eﬀectively, except for the fringes around 0.25 nm−1,with the model taking into account an interfacial layeron the electrode, in which the scattering length densities (SLDs) of the substrate materials and electrode were
ﬁxed to be the same as those of the bulk materials. The
obtained SLD proﬁles along the direction normal to thesubstrate indicated in Fig. 4 were consistent with one
another.
Note here that the accumulation time to obtain
20000 counts was reduced by a factor of 2.16 times:
258000 neutron pulses (equivalent to 10300 s) wererequired for the double slits, whereas 119000 (equivalent to 4760 s) were required for the focusing optics at
θ = 1.6°. Hence, we concluded that the interfacial layer
related to the electrochemical reaction on the cathodewas successfully observed with and without the focusing mirror, and the optics worked eﬀectively to reduce
the exposure time.

Neutron Science

Figure 3.	Reﬂectivity proﬁles obtained with double slits andfocusing optics, and ﬁtting results. As the focusing optics cannot be applied for low incident angles owing to the limitation of the beam size, thereﬂectivity data taken with double slits at low-Qz
values are shared for two data sets on the fitting.

Figure 4.	Scattering length density of the electrode evaluated by ﬁtting the reﬂectivity data in Fig. 3.

References[1] N. L. Yamada et. al., Euro. Phys. J. Plus, 44 (2011) 9424.
[2] K. Mitamura et. al., Polymer J., 45 (2013) 100.
[3] S. Takeda et. al., Opt. Express, 24, (2016) 12478–12488.
[4] T. Hosobata et. al., Opt. Express, 25, (2017)
20012–20024.
[5] T. Hosobata et. al., Opt. Express, 27, (2019)26807–26820.
[6] M. Yonemura et. al., IOP Conf. Ser., 502, (2014)
012054.

N. L. Yamada1,2, T. Hosobata3, M. Hino4, K. Hori2,5, F. Nemoto1,2,#, J. Izumi6, K. Suzuki6,7, M. Hirayama6,7, R. Kanno6,7, and Y. Yamagata3
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3RIKEN
Center for Advanced Photonics; 4Institute for Integrated Radiation and Nuclear Science, Kyoto University; 5Sumitomo Rubber Industory;
6
Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology; 7Institute of Innovation Research, Tokyo
Institute of Technology; #Present affiliation: National Defense Academy

1101Neutron Science

MLF Annual Report 2019

Current Status of SHARAKU: Polarized Neutron
Reflectometer
1. Introduction
The neutron reflectometer SHARAKU installed at
BL17 in the Materials and Life Science Facility of J-PARC
has been used for structure analysis of the surface andinterfaces in a sample. Because it can perform spin-polarization analysis of the reflected neutrons using polarizing mirrors and spin flippers, it can be used for analysisof the magnetic structure. Various kinds of sample environments are available: strong magnetic field up to 7 T,
refrigerator, temperature/humidity chamber, and so on.
Therefore, SHARAKU has been used for structure analysis in a wide variety of research fields: polymers [1, 2],
ionic liquids [3], and magnetic thin films [4, 5]. Moreover,novel methodologies for neutron reflectometry are being developed [6, 7]. In this fiscal year, we introduced a
new sample environment for the measurement of a liquid/solid interface and the virtual server systems.
2. Development of sample environments
The surface/interface in an immersed condition ina liquid has been extensively studied by neutron reflectometry. A liquid immersion cell has been used in
SHARAKU; however, the liquid injection needs to be
performed manually by a syringe in a wet lab. Therefore,
the time-resolved measurement of the structurechange induced by the liquid immersion cannot be carried out. This year, we designed a new liquid cell shownin Fig. 1. It has a liquid reservoir tank equipped with asolenoid valve. Because the operation of the valve iscontrolled by the measurement software, the liquid injection and data acquisition can be synchronized.

Figure 1. Liquid immersion cells.

102

3. Upgrade of the computer systems
In SHARAKU, eighteen server machines are used
to control the B 4C slit devices, sample stage, polarizing optics, data acquisition, and sample environments. SHARAKU was installed at the MLF eight years
ago; therefore, the server machines and the operating
system are obsolete. Therefore, in recent years, the oldserver computers have been replaced with new ones.
In this replacement process, we apply the virtualization of the server systems. One physical machine canrun several virtual computer systems for the operationof SHARAKU, as shown schematically in Fig. 2. This year,
the server systems for the device control, data analysis,
and the document archive have been migrated to a single host computer. The important merit of the virtualization of the server system is redundancy. Each virtual
system installed in the host system is backed up to a
storage system in a different physical server machine.
Therefore, in case of a fatal failure of the computer
system, the system will be recovered with minimal

Figure 2. Virtualization of the server systems.

MLF Annual Report 2019

down-time by running the backed-up system on theother computer. Another advantage of the virtual system is the safety in the development of the software.
In the tuning and optimizing process of the device operation, an error in the program code would sometimes
cause a serious failure in the server. In that case, thewhole system can be easily rolled back to the originalstate before the failure.

Neutron Science

References[1] H. Aoki, Polym. J., 51 611 (2019).
[2] T. Miyazak et al., Langmuir, 35 11099 (2019).
[3] K. Akutsu-Suyama et al., Phys. Chem. Chem. Phys.,
21 17512 (2019).
[4] M. Mogi et al., Phys. Rev. Lett., 123 016804 (2019).
[5] Y. Zhong et al., AIP Advances, 10 015323 (2019).
[6] K. Sakurai et al., Sci. Rep., 9 571 (2019).
[7] T. Kumada et al., J. Appl. Cryst., 52 1054 (2019).

H. Aoki1,2, K. Soyama3, D. Yamazaki4, N. Miyata5, K. Akutsu5, T. Hanashima5, and S. Kasai5
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3Materials
and Life Science Division, J-PARC Center; 4Neutron Instrumentation Section, Materials and Life Science Division, J-PARC Center; 5Neutron
Science and Technology Center, CROSS

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MLF Annual Report 2019

Status of SENJU 2019
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 high-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]. Ever since SENJU was launched in 2012,
continuous commissioning and upgrading operations
have been carried out.
In 2019, we installed four new additional detectors at the obliquely downward direction of the sample position and developed a remote-access versionof the data processing and visualization software for
SENJU, STARGazer-Online. In addition, we also reporton the purposes, for which the instrument beam-time
for SENJU was used.
2. Installation of additional area detectors
The detector arrangement of SENJU was almost
cylindrical, 36 detectors were arranged cylindricallyaround the sample position and only one was positioned at its bottom. Consequently, the obliquely downward direction of the sample position was not coveredby the detector and the reciprocal space around theazimuth region of the f-axis was not measured without
pulling out the goniometer and changing the sample
orientation. To solve this problem, we have added fourarea detectors at the obliquely downward directionof the sample position. The additional detectors were

newly developed for SENJU. The detector thickness is
17 cm, 13 cm thicker than its previous version. The slimness made it possible to put the new detectors at theobliquely downward direction of the sample position.
The arrangement of the additional detectors is shownin Fig. 1.
The positional parameters of the additional detectors were accurately fixed by diffraction images of astandard single crystal, C12A7. The calibration procedure is almost the same as that described in the MLF
Annual Report 2018 [2]. After the calibration, structure
analysis of a ruby single crystal was performed by using
all detectors, including the additional four detectors.
The obtained structural parameters were reasonable
and the final R-factor (I > 5s(I)) was 5.19%. Those results
showed that the new detectors worked correctly.
3. Development of STARGazer-Online
Both the data processing software, which createsa reflection file (called “HKLF file”) from raw data, andthe data visualization software, which visualizes andanalyzes the diffraction pattern in the real-space orreciprocal-space, are essential components of a single
crystal diffractometer. For SENJU, a software suite called“STARGazer for SENJU” is used for data processing andvisualization. Although STARGazer for SENJU is an indispensable software for SENJU data, it inconveniences the
SENJU users because it works on CentOS, not Windows
or Macintosh, and the size of the raw data is very large(~50 GB). Consequently, it becomes a hurdle for the

Figure 1.	Arrangement of the additional area detectors (~ in the figure).

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MLF Annual Report 2019

Neutron Science

Figure 2.	Screenshots of the data visualization component of STARGazer Online.

SENJU users to process and visualize their data at theirlocal laboratory sites. To solve this problem, we have developed a remote-access version of the STARGazer for
SENJU, named STARGazer Online.
STARGazer Online is a web application that works
on the Google Chrome browser. The core components
for data processing and data storage work on a cloudcomputing service, Amazon Web Service (AWS). SENJU
users’ access AWS by a web browser and process theirraw data at their local laboratories. The user information
and raw data are managed by the User-ID and password.
Figure 2 shows a screenshot of STARGazer Online
working on Google Chrome. Almost all data processing

and data visualization functions of STARGazer for SENJU
work on STARGazer Online. Because of COVID-19, sucha remote data processing software becomes more andmore important.
4. Use of the instrument beam time
In 2019, the instrument beam time was used mainly
for measurements of standard samples, and a vanadium-nickel alloy for calibration of the detector efficiency.
References[1] T. Ohhara et al., J. Appl. Cryst., 49 120 (2016).
[2] T. Ohhara et al., MLF Annual Report 2018, 102 (2019).

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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MLF Annual Report 2019

Engineering Material Diffractometer TAKUMI
1. Introduction
TAKUMI is a neutron diffractometer dedicated forresearch in engineering materials sciences, which was
installed at Beamline 19 in the MLF of J-PARC. Carefulanalysis of the Bragg peaks in a neutron diffraction pattern can reveal important structural details of a sample
material, such as internal stresses, phase conditions,dislocations, texture, etc. Experiments in TAKUMI varyfrom internal strain mapping in engineering components, microstructural evolutions during deformationsof structural or functional materials at various temperatures, microstructural evolutions during manufacturing(thermo-mechanical) processes, to texture analyses ofengineering materials.
2. User program and publications
In FY2019, 25 general-use programs, 2 long-term
programs and 1 project-use program were successfully conducted on TAKUMI. However, due to the consequences of COVID-19, one general-use program has not
yet been conducted. The ratio of approved experiments
versus proposed experiments was 75% (12/16) for 2019A
and 58% (14/24) for 2019B. The statistics about the experimental types and the sample materials of conducted
experiments during FY2019 are summarized in Fig. 1.
More than half of the beamtime was occupied by in-situ
measurement during a loading test, the same as every
year. In particular, the demand for low-temperature environment has been increasing in the past few years dueto the expanding research of the deformation properties(a)of high-entropy alloys. As of the high-temperature environment, the demands are growing for in-situ measurements during thermo-mechanical controlled processes,
which include rapid heating, cooling and deformation.
Currently, the instrument “thermec-mastor” [1] is often
used for this kind of experiments. After the next year
(FY2020), the new loading machine equipped with an
induction heating system will be opened for users. On
the other hand, 14% of the beamtime was used for strain
mapping experiments for internal strain (stress) analysisof mechanical parts. Most of this kind of experiments
were proposed by industrial users. They involved measuring of iron- or aluminum-based objects. Reflecting
the importance of iron and steel as structural materials,
the percentage of these materials in all the samples was
35%. Summarizing the percentages for light metals (Al-,Mg- and Ti-based alloys, 19%) and metals and alloys (Nibased superalloy, high-entropy alloys and other alloys,32%), it becomes clear that 86% of the beamtime wasused for experiments with metallic material samples. In
contrast, the percentage of experiments with non-metallic samples (rocks and ceramics) was only 4%. Further
utilization promotion of TAKUMI to the researchers in thisfield would be effective to enhance the research fieldaround TAKUMI.
Thanks to the users and the collaborators, 18 papers
and 2 proceedings papers using the data measured at
TAKUMI have been published in FY2019. In addition, thedata were also used in 2 doctoral theses. Some of highlighted papers are introduced below:(b)

Figure 1.	The statistics of (a) the kinds of experiments conducted at TAKUMI and (b) the kinds of materials used in these experiments
in FY2019. The percentages are shown for the beamtime (days).

106

MLF Annual Report 2019(a) “Cooperative deformation in high-entropy alloys
at ultralow temperatures”, by Naeem Muhammad
et al., [2]. The interaction of a rich variety of deformation mechanisms in high-entropy alloys at 15 K,
which began with dislocation slip, followed bystacking faults and twinning, was demonstratedusing in-situ neutron diffraction.
(b) “Real time observation of martensite transformation for a 0.4 C low alloyed steel by neutron diffraction”, by Wang Yanxu et al., [3]. In-situ
neutron diffraction with a thermomechanicallycontrolled processing simulator was employed toinvestigate martensitic transformation behavior
with and without ausforming for a medium-carbon
low-alloy steel. Cutting-edge operant quantitative
measurements with neutron diffraction for steel
production were demonstrated.
(c) “Plastic anisotropy and deformation-induced
phase transformation of additive manufactured stainless steel”, by Chae Hobyung et al., [4].
Plastic anisotropy and deformation-induced phasetransformation of additively manufactured stainless steels were investigated. Different onsets ofstrain nonlinearity between different manufactured directions were closely related to martensitic
transformation.
(d) “In-situ investigation of the microstructure evolution in long-period-stacking-ordered (LPSO)
magnesium alloys as a function of the temperature”, by Máthis Kristián et al., [5]. Deformation
behavior of two Mg–Zn–Y alloys, with a different
fraction of the long-period-stacking-ordered (LPSO)
phase, was investigated by a combination of in-situ
neutron diffraction and acoustic emission. The results indicated that the twinning in the magnesium
matrix and the kinking in the LPSO phase strongly

Neutron Science

depend on the composition of the material and thetesting temperature.
(e) “Study on formation mechanism of {332} <113>
deformation twinning in metastable β-type Ti
alloy focusing on stress-induced α” martensite
phase”, by Ken Cho et al. [6]. Deformation behavior of Ti–12Mo alloy which is primarily deformed by{332}<113> deformation twinning was studied. The
formation of stress-induced α” martensite, which isacting as a nucleation site for the {332}<113> twinsat the initial stage of the plastic deformation, wasdirectly observed.
3. Future plans
To make TAKUMI more user-friendly, several upgrades on the sample environment devices and thesoftware are scheduled after FY2020, as follows:(1) Development of the new sample chamber for lowtemperature deformation tests. The sample change
and the temperature control are expected to be
more convenient with this chamber.
(2) Installation of the large tilting stage for strain mapping. Alignment of large samples (< 150 kg) will become easier to do using this stage.
(3) Upgrades of the real-time monitoring software
for the diffraction patterns and the device control
software.
References[1] A. Shibata et al., Scripta Mater., 165 44 (2019).
[2] M. Naeem et al., Sci. Adv., 6 eaax4002 (2020).
[3] Y.X. Wang et al., Acta Mater., 184 30 (2020).
[4] H. Chae et al., Mater. Sci. Eng. A, 762 138065 (2019).
[5] K. Máthis et al., Front. Mater., 6 270 (2019).
[6] K. Cho et al., Scripta Mater., 177 106 (2020).

T. Kawasaki1, S. Harjo1, and K. Aizawa2
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Materials and Life Science Division, J-PARC Center

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MLF Annual Report 2019

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]) to promote industrial applications for the neutron beam in J-PARC. iMATERIA is planned to be a high-throughput diffractometerthat could be used by materials engineers and scientists
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 length of
14.0 m. The instrumental parameters are listed in Table 1.
There are four detector banks, including a low-angle
and small-angle scattering detector bank. The angular

Figure 1.	IBARAKI Materials Design Diffractometer, iMATERIA
without detector for each bank and instrument
shielding. The high-resolution bank, special environment bank (90-degree bank), and low-angle
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 (lefthand side of the picture).

108

Table 1.	Instrumental parameters of iMATERIA. L2 is the scattered flight path. The d-range (q-range) for each bankis the maximum value for 2-measurement mode.

L1
26.5 mGuide length
Position of Disk choppers
High
Resolution
Bank
SpecialEnvironment
Bank
Low
Angle
Bank
Small
Angle
Bank

2θ
L2
d-range2θ
L2d-range2θ
L2d-range2θ
L2
q-range

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 (Å) ≤ 5.0°
80° ≤ 2θ ≤ 100°
1.5 m
0.127 ≤ d (Å) ≤ 7.2
10° ≤ 2θ ≤ 40°
1.2 - 4.5 m
0.37 ≤ d (Å) ≤ 58
0.7° ≤ 2θ ≤ 5°
4.5 m
0.007 ≤ q (Å-1) ≤ 0.6

coverage of each detector bank is also shown in Table 1.
The rotation speeds for the disk-choppers are the same,with a pulse repetition rate of 25 Hz for the 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 banks of 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 (DF mode), we can access awider d-range, 0.18 < d (Å) < 5 with Δd/d = 0.16%, and5 < d (Å) < 800 with gradually changing resolution withdoubled measurement time compared to the SF mode.
2. Current status
All of the four banks, high-resolution bank (BS bank),
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 a ‘Rietveldquality’ data in the high-resolution bank at 600 kW
beam power for about 1 g of standard oxide samples.
Figure 2 shows a typical Rietveld refinement pattern
for LiCoO2 sample, cathode material for lithium ion battery (LIB), at the high-resolution (BS) bank by the multibank analysis function of Z-Rietveld [2]. It takes 20 min
in DF mode to collect the available Rietveld data, due tothe high neutron absorption cross section for natural Li(ssNat = 70 barn).

MLF Annual Report 2019

Neutron Science

Figure 2.	Rietveld refinement pattern for LiCoO2 at the high-resolution bank of iMATERIA.

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 without breaking the vacuum of thesample chamber.
The V-furnace (~900°C), the gas flow furnace(~1000°C), the cryo-furnace (4K) and the 1K cryo are
ready for experiments. The in-operando charge anddischarge measurement system for LIB with a sample
changer is available in cylindrical, coin, and laminatedtypes of batteries.
The rapid heating/quenching furnace with anautomatic sample changer (RT – 1273 K with heating
speed 10 K/s and cooling speed > 20 K/s) [4] and theuniversal deformation testing machine (maximum loading 50 kN with RT – 1273 K) [5] are available for texture
measurements.
References[1] T. Ishigaki et al., Nucl. Instr. Meth. Phys. Res. A, 600
189 (2009).
[2] R. Oishi et al., Nucl. Instr. Meth. Phys. Res. A, 600 94(2009).
[3] A. Hoshikawa et al., J. Phys.: Conf. Ser., 251 012083(2010).
[4] Y. Onuki et al., Metall. Mat. Trans. A., 50 4977 (2019).
[5] Y. Onuki et al., Quantum Beam Sci., 4 31 (2020).

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

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MLF Annual Report 2019

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.
The development of NOVA has three main objectives: small amount of the sample, short time measurement, and precise analysis. So far, the diffraction
pattern of only 1-mg complex hydride (YLiFeH 6) [1]and 0.3 μ B magnetic moment of a superconductor(LaFeAsO0.55H0.45) [2] have been measured. In addition,
Pd to PdD2 time-transient measurement in 10 seconds
was reported [3]. On the other hand, it is necessary toevaluate the convergence for the measurement timeto provide a method for high throughput experiments.

100

Hence, Rietveld refinement of diffraction patterns and
PDF analysis for standard materials were carried out.
2. Performance evaluation
Si powder (NIST standard reference material 640d)
was measured from 1 sec to 3 h. The structure factor S(Q)was refined by Z-Rietveld [4, 5] (Fig. 1). It is possible to analyze even a 1-sec measurement pattern. The atomic pair
distribution function G(r) was obtained by the Fouriertransformation of S(Q) and analyzed by PDFgui [6](Fig. 2). A measurement longer than 1 min is necessary
to get PDF with sufficient statistics. The Rietveld refinements were evaluated by reliability factors;
Rwp =  ∑wi [yi - f2i (x)] ∑wi yi2Re =  N - P2  ∑wi yi 

(2)

1 sec

0
-20

0
100

20
0

10 sec10 sec

-20

0
100

20
0

60 sec60 sec

-20

0
100

20
0
-2

300 sec0

G(r) / Å

S(Q)

(1)

20 Si (NIST SRM 640d)

Si (NIST SRM 640d)
1 sec

100
600 sec

300 sec-20
20
0600 sec

-20

0
100

20
0

3600 sec

3600 sec

-20

0
100

20
0

7200 sec

7200 sec

-20

0
100

20

10800 sec

010800 sec

-20

0
2

4

6

8

10

-1

Q/Å

Figure 1.	S(Q) and Rietveld refinement results of Si powder(NIST SRM 640d) measured from 1 sec to 3 h at
500 kW. The observed, calculated and difference
patterns are indicated as gray circles, red and bluelines, respectively.

110

1/2

1/2

0

2

4

6

8

10

r/Å

Figure 2.	G(r) and PDF analysis results of Si powder (NIST SRM
640d) measured from 1 sec to 3 h at 500 kW. The
observed, calculated and difference patterns areindicated as gray circles, red and blue lines, respectively.

Neutron Science

MLF Annual Report 201920 SiO2 glass
1 sec
10
0
20
0
20
0

-1

20
0
20

600 sec

100203600 sec

100
207200 sec

10
0
20
10
0
0

10800 sec

Si-O

1

2

O-O

3

4

5

r/Å

Figure 4.	RDF(r) of SiO2 glass rod measured from 1 sec to 3 h
at 900 kW.

SiO2 glass
900 kW

2

Coordination numbers

Si (NIST SRM 640d)
500 kW
900 kW

4

Reliability factor

300 sec

10

8

8
6

8
6
4

Z-Rietveld
Rwp
Re
PDFguiRw

2

0.01

60 sec101

0.1

10 sec10

RDF(r) / Å

where, wi is statistic weight, yi is observed intensity,fi(x) is theoretical intensity, N is data point number, P isparameter point number, respectively. Re is statisticallythe smallest value of Rwp that monotonically decreased
depending on measuring time, but Rwp reaches a plateau at a certain time (Fig. 3). This means that about
5-min measurement of Si powder at 900 kW operationis enough to refine the diffraction pattern. On the other
hand, PDF analysis needs a 1-h measurement according
to the reliability factor Rw similar to Rwp in the Rietveld refinements. Also, Figure 3 shows that the required measuring time is reduced by enhancing the beam power ofthe MLF at J-PARC.
In addition, S(Q) of SiO2 glass rod was obtained andthe Radial Distribution Function RDF(r) was evaluatedfor several measuring time periods (Fig. 4). The coordination numbers deduced by Gaussian fitting of RDF were
sufficiently converged for a measuring time of 200 sec ormore at 900 kW (Fig. 5). Since these evaluations dependon the statistics of background data, a comprehensive
procedure to estimate the required measuring time during experiments needs to be introduced.

8
6

10

0

6

4

2
O-O
Si-O

10

1

2

10
Time / sec

10

3

10

4

0
10

0

10

1

2

10
Time / sec

10

3

10

4

Figure 3.	Reliability factors of Rietveld refinement and PDF
analysis of Si powder.

Figure 5.	Coordination numbers obtained by Gaussian fitting
to RDF(r) of SiO2 glass.

Acknowledgement
The operation and developments of NOVA was performed under the S1-type program (2019S06) approvedby the Neutron Scattering Program Advisory Committeeof IMSS, KEK.

[3] T. Otomo et al., MLF Annual Report 2013, 113 (2014).
[4] R. Oishi et al., Nucl. Instrum. Methods Phys. Res. A,
600 94–96 (2009).
[5] R. Oishi-Tomiyasu et al., J. Appl. Cryst., 45 299–308(2012).
[6] C.L. Farrow, P. Luhás, J.W. Liu, D. Bryndin, E.S. Božin,J. Bloch, Th. Proffen and S.J.L. Billinge: J. Phys.:
Condens. Matter, 19 335219 (2007).

References[1] T. Otomo et al., MLF Annual Report 2012, 114 (2013).
[2] M. Hiraishi et al., Nature Phys., 10 300–303 (2014).

K. Ikeda1,2,3, T. Otomo1,2,3,4, T. Honda1,2,3, H. Ohshita1,2, Y. Onodera5, T. Hawai1, K. Ono1, 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;
5
Institute for Integrated Radiation and Nuclear Science, Kyoto University

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Status of the Energy-Resolved Neutron Imaging System
RADEN
1. Introduction
The energy-resolved neutron imaging system“RADEN”, installed at beamline BL22 in the Materials andLife Science Experimental Facility (MLF) of J-PARC, is a
dedicated instrument for wavelength/energy-dependent neutron imaging experiments, which fully utilizes
the nature of the short-pulsed neutron [1]. Then, varietyof imaging experiments have been conducted, such as,
the Bragg-edge imaging for crystallographic structure
information, the neutron resonance absorption imaging
for elemental or thermal information, and the polarized
pulsed neutron imaging for magnetic field information.
After the beam line construction was completed, RADEN
now accepts about 30 user programs every year, frombroad academic to industrial fields. In this report, we will
explain the current status of RADEN’s activities, including technical developments and application studies.
2. Technical development of the neutron imaging
To conduct high-spatial resolution imaging, we
tested three thin scintillator screens ( 6LiF/ZnS with
50 µm-thickness, GdOx with 50 µm-thickness, andGdOx with 30 µm-thickness) and evaluated their resolution performance by means of the Modulation Transfer
Function (MTF) method using neutron transmission
images of test patterns [2, 3]. The obtained spatial resolution values were 58.3, 42.4, and 35.9 µm for 6LiF/ZnS(50 µm), GdOx (50 µm), and GdOx (30 µm), respectively.

Although these numbers were slightly larger than thevisually recognized spatial resolution, we could achievefine spatial resolution imaging of less than 50 µm bymeans of GdOx scintillator screens (Fig. 1). Similarly, we
also studied the performance of high-resolution CT experiments using a simple sample composed of several
metallic cylinders, and spatial resolution of 115 µm wasevaluated by using the same method of analysis as innormal radiography.
Next, the neutron phase imaging apparatus basedon the Talbot-Lau interferometer for RADEN was replaced with a new one with an optimized design.
Previously, the apparatus was designed with a central
wavelength of 5 Å to fully cover the RADEN’s neutron
spectrum for achieving precise differential phase imaging. However, since the weak neutron intensity in thelonger wavelength neutron range made the measurement time longer, the central wavelength was changed
to 2.7 Å to utilize effectively the peak intensity of thespectrum (Fig. 2). As a result of the new design, theavailable wavelength range became narrower than theprevious one, but the measurement time was reducedby more than half and the scanning range of auto-correlation length by visibility contrast image, which can beobtained together with the differential phase contrast
images, became wider. The obtained visibility of the new
system was about 60% at the central wavelength witha wavelength resolution of 50%, and demonstration

Figure 1.	Images of test patterns obtained using 30 µm-thick GdOx scintillator. (a): line pattern [2], (b) Siemens star pattern [3].

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Figure 2.	Photographs of the new phase imaging apparatus. Left: neutron Talbot-Lau interferometer installed at RADEN.
Right: newly fabricated gratings.

studies using a permanent magnet sample and additively manufactured metallic samples were conducted. In
the study, using a permanent magnet, partially demagnetized by local heating treatment, the magnetization
direction and the diminishment of magnetic domain
size could be analyzed by the directional analysis of thecorrelation length dependence of the visibility.
3. Application studies
Recently, neutron imaging studies on the distinction of the water and the ice have been conductedusing energy selection of the pulsed neutron beam.
Because the total neutron cross section of water in the
low neutron energy region differs between liquid andiced state, it is possible to identify the water and theice from the energy-dependent neutron transmission
measurements. This technique has already been applied
to the fuel cell study [4], but by using pulsed neutrons,
scanning broad energy range can compensate for thedifference of molecular density between water andice using the neutron transmission at the high-energy
region, where their cross sections are similar, and candistinguish the state of water using that at a low-energy
region, where their cross sections are different. Hence, it
is possible to recognize their states accurately free fromthe influence of the density change. With this technique,we succeeded in visualizing the thawing process of ice

in a metallic narrow capillary [5].
As another application of neutron imaging, the demands for visualizing spatial distribution of large-neutron absorbing elements like Boron are increasing. The
epithermal neutron radiography and tomography aresuitable technique for this, but we are also developing
a technique combining the epithermal neutron imaging
and the prompt gamma-ray analysis, which enables us
to conduct quantitative analysis of such elements in thesample with spatial resolution.
4. Summary and future plans
Now, RADEN is under user operation and its application spreads widely in various fields, both scientific andindustrial. In addition to the user programs, RADEN’s improvement as an instrument and the development of
neutron imaging techniques continue.
References[1] T. Shinohara et al., Rev. Sci. Instrum., 91, 043302(2020).
[2] M. Segawa, et al., JPS Conf. Proc. 22, 011028 (2018).
[3] C. Grünzweig, et al., Rev. Sci. Instrum. 78, 053708(2007).
[4] M. Siegwart, et al., Rev. Sci. Instrum., 90, 103705(2019).
[5] Y. Higuchi, et al., Phys. Chem. Chem. Phys. (accepted).

T. Shinohara1, T. Kai1, K. Oikawa1, Y. Tsuchikawa1, K. Isegawa1, K. Hiroi1, T. Nakatani2, Y. Su2, H. Hayashida3, J. D. Parker3, Y. Matsumoto3,
and Y. Kiyanagi4
1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Technology Development Section, Materials and Life Science
Division, J-PARC Center; 3Neutron Science and Technology Center, CROSS; 4Graduate School of Engineering, Nagoya University

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Polarized Neutron Spectrometer POLANO
1. Introduction
POLANO is a direct geometry spectrometer withmiddle energy and spatial resolution. In combination
with the SEOP 3He gas spin filter and the 5.5 Qc bending mirror analyzer, the POLANO makes it possible thehigher-energy polarization analysis [1–3]. The construction of the spectrometer started in 2012 and was mostly
completed by 2016. Following beam commissioning
and many mechanical tests, a part of the user programwith an unpolarized neutron beam has finally started.
The neutron polarization technique with the time-offlight (tof ) method was introduced in recent years, andthe devices had to be re-designed to conform to the tof
method. Many of technical or mechanical restrictions
and difficulties arising out of a new concept of newtechnique, have been kept making much effort to overcome and to realize better polarization analysis in the
tof method in the world neutron facilities.
By 2019, some of those neutron facilities put into
practice the tof polarization technique, but all of them
are focusing on polarization analysis with low-energy
region of the transfer energy up to several tens of meV.
However, these energy ranges of polarization analysis
have been actually done so far with reactor-based neutrons. In the research of the dynamical properties of atoms, spins, charges, orbitals, and so on, the energy scale
could reach over 100 meV. The POLANO was designed
to realize much higher-energy polarization analysis
through the combination of a SEOP 3He spin filter andan analyzer mirror as the first step. This enables us toreach higher transfer energy (Ef ~ 42 meV). As the second step, we plan to use the wide angle SEOP/MEOP
system as an analyzer. In this second step, we are targeting polarization analysis with neutron energy (transfer
energy) of up to 100 meV, covering an absolutely wide
momentum and energy region in the reciprocal space.
2. Polarization devices
As we reported in the last year’s annual report, a setof a SEOP polarization system, Helmholtz coils for applying both vertical and horizontal magnetic fields onthe measurement sample, and a guide field to maintainthe neutron spin polarization including a supermirror
analyzer will be stationed in the beamline as depicted inFig. 1. This magnetic system is indispensable to control
the spin direction, to apply the appropriate magnetic
fields, and to maintain the neutron spin direction. The
system is composed of several magnetic devices, namely,
114

Figure 1.	The suite of magnets including SEOP 3He polarizer,
Helmholtz coils, analyzer mirror, and guide fields.

Figure 2.	Asymmetric Helmholtz coils applying flexible magnetic fields on the sample.

guide field systems that combine permanent magnets, apair of SEOP solenoid coils, asymmetric Helmholtz coils
at the sample position, and a magnetic analyzer mirror.
Other magnetic devices, such as spin flippers or a field
controlling system at the sample position, will be developed in the future. We made much effort to research,
design, and manufacture the above magnetic devices,in particular the Helmholtz coil, which was one of themost significant but also complicated devices (Fig. 2).
There are three coils for applying horizontal fields toany 360° direction in the scattering plane. And there is apair of coils for the vertical field. All these four coils needabout 10 Amps each, yielding almost 200°C of high temperature in specific part of the coils. So, we developed ahighly efficient water-cooling system for this Helmholtz
coil keeping the magnet temperature below 100°C.

MLF Annual Report 2019

The cooling system can be effective even in the vacuum
using high performance “heat pipes” for heat removal.
The heat test was very successful, we got up to 80°C at
maximum.
The SEOP polarizer system is almost ready to debut [4]. We are now trying to assemble glass cell witha much more efficient gas mixture. Also, the laser anddevice safety assessment has been done before installing it in the beam line.
3. New sample environment
As mentioned in the introduction, POLANO started
user experiments with an unpolarized neutron beam.
For those users, low-temperature experiments are themain subject of research. We equipped a new refrigerator (cryostat) to cool down the sample. The cryostat is a
top-loading (TL) 4K type, with sample rotating (w-rotation) capability. It is mounted on the vacuum chamber
flange directory as shown in Fig. 3. All this saves time inthe experimental preparation process, such as sample
set-up, evacuation of the vacuum chamber, and temperature control, which is particularly important for longcounting experiments. We are going to provide muchconvenient experiment for the best sciences.

Neutron Science

4. Outcomes of the unpolarized experiment
POLANO finally started user experiments in addition to on-beam commissioning. As shown in Fig. 4, theneutron inelastic signals of the dynamical atom and spin
motions were clearly observed. These data were someof the references measured on 1-dimensional quantum
spin chain material with the new TL refrigerator mentioned above. At the same time, we had some amountof noise that did not originate from the sample. These
were possibly consequences from placing several devices in the vacuum chamber. A much higher signal tonoise ratio is crucial to detect a weak signal of inelastic,
particularly polarized signals. We may need to figure out
where those unwilling noise signals are coming from.

Figure 4.	Energy spectra measured at POLANO with unpolarized neutrons.

Figure 3.	Newly manufactured top-loading type refrigerator.

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).
[4] T. Ino, et al., ibid.

T. Yokoo1,2, N. Kaneko1,2, S. Itoh1,2, K. Hayashi1, M. Ohkawara3, Y. Ikeda3, 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

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AFP NMR Amplifier for 3He Neutron Spin Filter
1. Introduction
Adiabatic fast passage (AFP) is a technique of nuclear magnetic resonance (NMR) that manipulates
magnetic moments to rotate by 180 degrees, or in other words, it reverses the nuclear spin direction [1]. AFP
NMR is often used in 3He neutron spin filters (NSF) toflip 3He nuclear spins, and accordingly the neutron spin
direction [2–7].
Polarized 3He nuclear spins are maintained in astatic magnetic field. By applying an oscillating field
perpendicular to the static field and sweeping thefrequency so that it passes through the Larmor resonance, the 3He spins are adiabatically reversed. The
oscillating field strength B1 should meet the so-called
adiabatic condition dω ⁄dt ≪ |γB1/2|2 to minimize thepolarization loss during the spin flip. Here, γ is the gyromagnetic ratio of the magnetic moment, and ω represents the angular frequency of the oscillating field. The
frequency sweep speed dω⁄dt is limited by another factor, the transverse relaxation rate of the spins under theoscillating magnetic field [8]. Generally, in 3He AFP NMR
with the frequency sweep, dω ⁄dt > 106 rad/s and B1 >0.01 mT. To generate an oscillating magnetic field withthis strength, a radio frequency (RF) amplifier is usuallyused to provide sufficient oscillating current to the B1
coil. Such RF amplifiers are commercially available, butalmost all of them are large and heavy, as well as expensive, since they are made for a wide use, covering
a wide frequency range, capable of a continuous operation, etc. However, for AFP NMR of 3He NSF, the frequency range is limited, and the continuous operation
is not necessary, since 3He spins are only flipped oncein several to tens of minutes. Moreover, the sweep time,
which corresponds to the duration of the RF amplifier
operation, is usually far less than one second, and thecorresponding duty cycle becomes virtually zero.
We have developed several types of compact andlow-cost RF amplifiers specifically for AFP NMR of 3He
NSF, and one of them, with a very simple design, is presented in the next section.
2. RF amplifiers for AFP NMR of 3He NSF
An important requirement for the RF amplifier isthe linearity. Any spurious emissions including noises
may cause unwanted polarization loss [3], and thus aclass A or AB amplifier is ideal for the purpose. Other
requirements, such as the output power, voltage,
116

current, and frequency range, depend on B1 coils andresonance circuits. In our AFP NMR systems, however,no resonance circuits are used as they interfere with
the AFP NMR measurement or the phase-sensitive detection of the AFP NMR signal [2]. For this reason, ourRF amplifiers are designed to drive B 1 coils without
resonance circuits. Typical sweep frequency ranges, impedances, voltage, and current values of our B1 coils are
60–90 kHz, 100–500 W, 70–180 V, and 0.3–0.5 A in amplitude, respectively.
RF amplifiers can be built using discrete transistors,
but the circuit will be much simpler and more stable if
operational amplifiers (op-amps) are used instead. We
used power op-amps PA96 [9] for RF amplifiers. Somerelevant parameters of PA96 are listed in Table 1, andthe RF amplifier circuit is presented in Fig. 1. The power
supply circuit can provide positive and negative DC
voltages whose absolute values are over 135 V for theamplifier part with a limited power consumption. Twosingle-stage amplifiers with normal (non-inverting) andinverting outputs are as simple as Electronics 101. The
amplifier gains are both set to twenty assuming thatthe input signal is fed from a common function generator. The maximum output voltage of each amplifier is> 250 VPP (peek-to-peek), and it can be doubled by thebridge-tied load (BTL) connection, where a B 1 coil isconnected between the normal and inverted outputs.
Pictures of the RF amplifier are shown in Fig. 2.
The power supply circuit occupies more than half ofthe space. The op-amps are attached to heat sinks forconvection cooling as the self-heating of an op-amp is~ 8 W due to the PA96 quiescent current of 30 mA andthe supply voltage of ~ 280 V. The heating during thesignal amplification is negligible as the duty cycle is essentially zero.
Table 1. Some relevant specifications of PA96.
Supply voltage (maximum)

300 V (±150 V)

Output voltage swing (typical)-Vs + 10 V to +Vs - 5.6 V

Output current (minimum)

1.5 A

Slew rate (typical)

250 V/ms

Gain band product (typical)

175 MHz

Quiescent current (typical)

30 mA

MLF Annual Report 2019

Figure 1.	Circuit diagram of an RF amplifier. The power supply part(top) and the amplifier part (bottom). Normal (non-inverting) and inverting amplifiers are configured to enable the
BTL connection.

3. Conclusions
We have developed compact, lightweight, and lowcost RF amplifiers for AFP NMR of 3He NSF. Examples arepresented in Figs. 1 and 2. The instantaneous output
power of this RF amplifier can be > 150 W using the BLT
connection. Despite the high output power, the dimensions, weight, and cost are all far less than those of acommercial RF amplifier with similar specifications dueto the limited band width and low duty cycle.
References[1] A. Abragam, The Principles of Nuclear Magnetism,
Clarendon, Oxford, 1961.
[2] T. Ino, JPS Conf. Proc. 22, 011016 (2018).

Neutron Science

Figure 2.	An RF amplifier developed for AFP NMR
of 3He NSF.

[3] E. Babcock et al., Physica B 397, 172 (2007).
[4] A. K. Petoukhov et al., Physica B 385–386, 1146
(2006).
[5] T. J. McKetterick et al., Physica B 406, 2436 (2011).
[6] W. C. Chen, et al., J. Phys. Conf. Ser. 528, 012014 (2014).
[7] J. Baer, “SEE YOU ON THE FLIPPED SIDE – The
construction and testing of RF Coils used to flip 3Hepolarization,” https://www.ncnr.nist.gov/programs/
CHRNS/pdf/SURF/2014_Baer.pdf[8] C. L. Bohler and D. D. McGregor, Phys. Rev. A 49,
2755 (1994).
[9] PA96U data sheet, rev J, Apex Microtechnology, Inc.,
2017, https://www.apexanalog.com/resources/
products/pa96u.pdf

T. Ino1,2, M. Ohkawara3, N. Kaneko1,2, T. Yokoo1,2, S. Itoh1,2, Y. Ikeda3, and M. Fujita3
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3Institute forMaterials Research, Tohoku University

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Sample Environment at MLF
1. Introduction
The MLF sample environment (SE) team provides the
sample environment equipment commonly used among
several beamlines, and is also responsible for upgradingthat equipment. The MLF SE team develops “cuttingedge” equipment that can function even under extreme
sample conditions and also fulfills the growing users’
needs. Our activities in JFY2019 are described below.
2. Cryogenics and magnets
We have supported users’ experiments using several
devices. In JFY2019, the superconducting magnet was
operated for 10 experiments, the 4He cryostat for 9 experiments, the 3He cryostat for 5 experiments, the dilution refrigerator insert for 9 experiments, the Gifford-McMahon(GM) cryostat for 4 experiments and the GM cryofurnace
for 1 experiment, including instrument proposals.
As the number of devices to handle increases, ourload of user support is also growing. Specially, the superconducting magnet and the 4He cryostat are wet-type
cryostats, which need liquid cryogens for operation, andusers have to refill them once a day or every two days. In
order to reduce the load and improve the efficiency ofthe experiments, we are considering introducing closedcycle cryostats, which are cryogen-free.
3. High temperature equipment
We have two furnaces as the BL-common equipment: a niobium furnace for inelastic and quasi-elastic
neutron scattering measurements, and a furnace forsmall-angle neutron scattering (SANS) measurements.
In JFY2019, the niobium furnace was used for three users’ experiments on BL18. We prepare the SANS furnace
to connect with the common monitoring system at the
MLF, which enables users’ unmanned operation of thefurnace; as of now, according to the regulations of the
MLF, the user should be present at all times to monitor the status whenever a high-temperature furnace isin operation. The hardware setup has been completed,and the preparation is in progress for realization ofhigh-temperature experiments without monitoring by
the user.
4. A pulsed magnet system
In JFY2018, we had already developed a new pulsed
magnet system including a solenoid coil within the insert and a cryostat, using GM refrigerator to cool samples down to 3 K. In this system, even users who are not118

Figure 1. Diffraction spot of 29.2 T accumulating 40 shots.

accustomed to LHe can use this system with convenience and practicality.
In JFY2019, neutron scattering experiments using
this system were performed at NOBORU (BL10) to study
multiferroics TbMnO3. This time, pulsed magnetic fields
up to approximately 30 T were applied to the sample.
Figure 1 shows the diffraction spot. This spot data was
obtained by accumulating 40 shots of applied 29.2 T atneutron beam power of 500 kW. The data were reduced
and visualized by the UTSUSEMI package [1]. Since thepulse interval length was 7 minutes, it took approximately 5 hours to accumulate the data. It was also confirmedthat the pulsed magnet system operated properly.
5. High pressure
The control program of the automatic pressure
pump has been modified. Now, it can refill the hydraulic oil while holding the load of the cell. The strain
measurement system has been upgraded. Currently, it
is possible to observe the ram’s movement at low temperatures during off-line pressurization testing using astrain gauge attached to the test piece.
6. Light irradiation
In the light irradiation experiment, it is important toexamine the light energy dependence on the photo-induced effect because it directly demonstrates the originof the photo-induced change. To allow the experiment
to examine such light energy dependence, we installed
four high-power light emitting diode (LED) modules
with different peak energies (3.38, 3.04, 2.81, 2.38 eV) [2].

MLF Annual Report 2019

Neutron Science

Figure 2.	LED light source system with four modules with different peak energies used on SHARAKU (BL17)

Figure 3.	Photo-induced changes of the small-angle neutron
scattering, suggesting the changes in the micellar
shape of the light-sensitive surfactants [2].

The LED modules were used on SHARAKU (BL17) to observe the light energy dependence of the neutron reflectivity profiles of the light-sensitive films [3].
So far, the light sources of the MLF SE team has beenused only on SHARAKU (BL17). In JFY 2019, the light irradiation experiment was performed on TAIKAN (BL15) using the Hg lamp of the MLF SE team to observe changes
in the micellar shape of the light-sensitive surfactants,
whose change appears at the small-angle region, collaborating with Dr. H. Iwase (CROSS), Dr. Y. Inamura (JAEA),
Mr. S. Kasai (CROSS), Prof. H. Sakai and Dr. M. Akamatsu(Tokyo Univ. of Science) [2]. The experiment clearly demonstrates that the light irradiation system is available on
TAIKAN (BL15) and applicable to many other light-sensitive surfactant systems.

Environment (ISSE) Training School held at HelmholtzZentrum Berlin (HZB) in Berlin, Germany, from October
27 to November 1, 2019. The sophisticated lectures andhands-on training on the sample environment’s techniques were impressive and helpful for the future user
support at the MLF.
Our SE team members, the SE staffs in JAEA, andthe Institute for Solid State Physics, the Universityof Tokyo held the domestic meeting on SE at the“Quantum beam facilities” for the first time as the 23rd
CROSSroads Workshop in Tokai on January 8 and 9,
2020. There were 75 participants who openly discussed
various problems of SE, such as technical and financial
issues, and human resources.

7. SE training school and the domestic meeting on SE
Two of the SE team members (M. I. and H. A.)
took part in the 3rd International Society for Sample

References[1] Y. Inamura et al., J. Phys. Soc. Jpn., 82 SA031 (2013).
[2] Y. Sakaguchi et al., JPS Conf. Ser., to be published.
[3] Y. Sakaguchi et al., Eur. Phys. J AP, 90 30101 (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, T. Oku1, and K. Aizawa1
1
Technology Development Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS;
3
Nippon Advanced Technology Co.; 4Neutron Science Section, Materials and Life Science Division, J-PARC Center

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MLF Annual Report 2019

Development and Application of 3He Spin Filter
1. Introduction
The development of a 3He spin filter, a neutron polarization device which can polarize a neutron beam ina broad energy range and analyze neutron spins witha large solid angle, has been conducted at J-PARC. The
fabrication of the 3He spin filter and its utilization havestarted recently.
2. Development of the 3He spin filter
A gas filling system for fabricating 3He spin filters
was completed in 2018, and 5 high quality 3He spin filters using potassium and rubidium with a long relaxation time of 3He polarization were fabricated in 2019
(Fig. 1). Also, a new 3He pumping system using a 110-W
fiber laser has been constructed at the J-PARC researchbuilding. The 3He spin filter polarized by the new laser
system at the J-PARC research building was installedon neutron beam line BL10, and a demonstration

Figure 1. 3He spin filter fabricated at J-PARC.

Figure 2.	Neutron wavelength dependence of neutron polarization and neutron transmission using the 3He
spin filter at BL10.

experiment was carried out. In the experiment, weachieved a long relaxation time of 170 h at the beamline
and a high 3He polarization of 85%, which was accomplished by using the high quality 3He spin filter made in
J-PARC and the new laser system. The neutron polarization and transmission passing through the 3He spin filter
is shown in Fig. 2. We can see that high neutron polarization is obtained for a broad energy range.
3. Utilization of the 3He spin filter
The utilization of the 3He spin filters has also started
at the MLF. In 2017, a 3He spin filter was supplied for the
first time to a user experiment. No user experiments wereconducted in 2018, but four user experiments were performed in 2019 at BL04 and BL10. The 3He spin filter wasused as a neutron polarizer for those experiments to study
nuclear reactions at BL04 and neutron holography at BL10.
Furthermore, our 3He spin filter was applied to the
MIEZE-type neutron spin echo experiment experiment
as a spin analyzer to study ferrofluid at BL06 (Fig. 3). In
this experiment, high 3He polarization of 75% and a longrelaxation time of 130 h was achieved at the beamline.
Experiments with the 3He spin filter at BL15 andBL21 are also planned for isolating the incoherent scattering from hydrogen atoms and the magnetic scattering from a magnetic sample. A Helmholtz coil equippedwith a sample changer to keep the 3He polarization at
the neutron beam lines has been prepared for BL15.
Also, a coil, which can be installed at the vacuum changer at BL21, is now under construction. The experiments
will be carried out in the next year.

Figure 3.	Experiment at BL06 using a 3He spin filter. The 3He
spin filter was installed behind the sample, and thescattered neutron spins were analyzed by it.

T. Okudaira1, T. Oku1,2, S. Takahashi2, T. Ino3, K. Sakai1, H. Hayashida4, K. Hiroi1, K. Kakurai4, T. Oda5, H. Endo3, M. Hino5, and K. Aizawa1
1
Technology Development Section, Materials and Life Science Division, J-PARC Center; 2Graduate School of Science and Engineering,
Ibaraki University; 3Neutron Science Section, Materials and Life Science Division, J-PARC Center, Institute of Materials Structure Science,
KEK; 4Neutron Science and Technology Center, CROSS; 5Institute for Integrated Radiation and Nuclear Science, Kyoto University

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Statistically Optimal Bin-widths Prediction to Histogram
Experimental 4D Inelastic Neutron Scattering Intensity
Distributions
1. Introduction
Although optimal bin-widths for a histogram of an
INS (Inelastic Neutron Scattering) spectrum are usually
intuitively set by each researcher, they can be determined objectively from the data’s statistics.
In the field of neurophysiology, a method to estimate an optimal bin-width was developed based on the
Poisson statistics of the number of the events recordedin equal intervals [1]. An extrapolation method was also
reported, which estimated the optimal bin-width of the
hypothetical data of m total count from the statistics on
the actual data of n total count.
For the neutron data, Ref. [2] extended the optimization method to the simulated data sets of INS intensity distributions in a (q, E) space. However, thus far, theoptimization method has not been applied to the actual
neutron experimental data. Moreover, the extrapolation method has not been examined on any INS data.
The extrapolation method may be used to terminate ameasurement with necessary and sufficient resolutions.
Alternatively, if we see a faint unknown spectral feature
in a measured intensity distribution, the optimization
method may be used to determine whether the feature
is statistically significant. Thus, we work to introduce thebin-width optimization/extrapolation method to the INS
experiment in the MLF.
2. Methodology
Optimal bin-widths minimizing MISE (mean integrated squared errors) between the histogram and theunderlying probability density function are calculated
as follows [1, 2]:∆*n,qa, ∆*n,qb, ∆*n,qc, ∆*n,E = argminCn⟨k ⟩ − ⟨(kn − ⟨kn⟩)2⟩ ,
Cn = 2nn (∆qa ∆qb ∆qc ∆E)2

(1)

where ∆*n,x is the optimal bin-width along the x axis fordata with a total neutron count n, kn represents a neutron
count in a bin, 〈∙〉 shows an average of ∙ over the bins. FromCn and kn, the cost function is extrapolated to the hypothetical data with a total neutron count m ≠ n as follows:
1 1
1
(2)
Cm|n =  m − n  ∆qa ∆qb ∆qc ∆E ⟨kn⟩ − Cn

Extrapolated optimal bin-widths to the data with m is
as follows:∆*m|n,qa, ∆*m|n,qb, ∆*m|n,qc, ∆*m|n,E = argminCm|n(3)Hereafter, we refer to quantities on the actual data andthe hypothetical data by n and m, respectively.
In experimental INS with pulsed neutron source, theINS data array in a (q, E) coordinate space contains some“masked” spaces where a neutron cannot be detected
due to the measurement geometry. In order to reduce
the effect of these masked spaces on the optimization
results, we made an option to choose whether the statistic procedure eliminates bins containing the masked
spaces. Once this option is turned on, only the bins
which satisfy the following condition are taken into account in the statistics:∑h∈Ai mh > α ∑h∈Ai(4)where h is an index of the data array element, mh = 0 if
the element h is masked and otherwise mh = 1, Ai denotes the 4D space within a bin i, and a is a constantparameter in [0,1]. We prepared phantom data with aknown probability density function and compared theresults with the option on and off. The results with theoption on and appropriate a were closer to the optimization results on the phantom data without the masked
spaces. For a large a, anomalously large bin-widths had
the minimum of the cost function, because the 4D spaceconsidered in the statistics depended on the bin-widths
through Eq. (4). We heuristically increased a as much as
possible before the minimum of the cost function located at anomalously large bin-widths.
3. Application to INS data in the MLF
The method was applied to the INS data acquired
from an fcc single crystal Cu, with three different measurement conditions. The optimal bin-widths on eachdata set are summarized in each columns of Fig. 1.
Firstly, to validate the overall behavior of the optimal
bin-widths, we plot the inverse of the optimal binwidths products (∆*n or ∆*m) with the inverse of the total
neutron counts (n or m). In the horizontal axis regionof large 1/m, 1/∆*m slightly increases as 1/m decreases.
On the other hand, in the region of small 1/m, 1/∆*m
121

optimized
1 / total counts (10-5)

1 / total counts (10-6)(ii) qb // <110>(i) qa // <001>

Bin-width (rlu)

Bin-width (rlu)(i) qa // <001>(iv) energy(iii) qc // <110>

Bin-width (meV)

Bin-width (meV)(iii) qc // <110>(ii) qb // <110>(iv) energy(c) Results on data #3(o) inverse of bin-widths product1 / total counts (10-4)(i) qa // <001>

Bin-width (rlu)extrapolated(b) Results on data #2(o) inverse of bin-widths product(ii) qb // <110>(iii) qc // <110>

Bin-width (meV)(a) Results on data #1(o) inverse of bin-widths product1 / * (rlu-3 meV-1)

MLF Annual Report 20191 / * (rlu-3 meV-1)

1 / * (rlu-3 meV-1)

Neutron Science(iv) energy

Figure 1.	The inverses of the optimal bin-widths product and the total neutron count in the analyzed data arrays (o), and the optimal
bin-widths with respect to the measurement time (i, ii, iii, iv): The data arrays were cumulatively obtained in a measurement session for each data of #1, #2, and #3. In (o) ((i, ii, iii, iv)), the extrapolation results from a data array with a specific total
count (measurement time) are shown by dots, the optimization result on the data with this specific total count (measurement time) is shown by a star, and the optimization results on the data arrays with the other total counts (measurement
times) are shown by squares.

increases noticeably with decreasing 1/m. This behavior
is qualitatively consistent with the following relationshipapproximately deduced on a 1D data set with a specificnature of a probability density function [1],1
1 − 1∆*m ∝ -  m n =+0		

for m > nc
otherwise(5)with a positive constant nc. Secondly, in the second to
fifth rows in Fig. 1 are shown the behaviors of the optimal bin-widths along the respective axes with respect
to the measurement time. The extrapolated optimal
bin-widths are consistent with the optimal bin-widthsof the actual data. Therefore, the extrapolation method
predicts well the optimal bin-widths at different times.
The analyzed data arrays contain the masked spaces. We present the results with a = 0.9 for data #1 and122#2, a = 0.7 for data #3. For data with large measurement
times, for example, 9 and 10 h for data #1 and 24 and29 h for data #2, we confirmed that the optimal binwidths were identical whether the mask option was
turned on or not. Conversely, the results with and without the mask option are useful to see the robustness of
the results.
The optimal energy bin-widths at the total measurement time are 1.5, 0.8 and 0.32 meV for data #1, #2
and #3, respectively. The energy resolutions were estimated from FWHM of a peak in an energy profile at a q
where phonon branches are expected to have energy
extrema: these FWHM values were 3 ± 0.4, 3 ± 0.2 and 0.5± 0.08 meV for data #2 and #3, respectively. The fact thatthe optimal energy bin-widths were not much larger
than the FWHM values supports for the estimate of theenergy resolution as FWHM values.

MLF Annual Report 2019

4. Outlook
The optimization/extrapolation method worked
well on the three kinds of experimental INS data. By
saving redundant preprocesses on the data arrays andpreparing adequate computers with a fast network, we
believe this method can be used during the experiment.

Neutron Science

References[1] H . S h i m a z a k i a n d S . S h i n o m o t o, N e u r a lComputation, 19 1503 (2007).
[2] K. Muto, H. Sakamoto, K. Matsuura, T. Arima, and M.
Okada, J. Phys. Soc. Jpn., 88 044002 (2019).

K. Tatsumi1, Y. Inamura2, M. Kofu2, R. Kajimoto2, and R. Kiyanagi2
Technology Development Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science Section, Materials and Life Science
Division, J-PARC Center

1

123

Neutron Science

MLF Annual Report 2019

Real-Time Data Display and Storage Device with Simple
Functions for Easy Adjustments of a Two-Dimensional
Detector
1. Introduction
We have developed a two-dimensional gaseous
neutron detector system for the Materials and Life
Science Experimental Facility (MLF) at the Japan Proton
Accelerator Research Complex (J-PARC) [1, 2]. The developed system can output time-resolved neutron position
data with a time resolution of less than 1 ms. The experimental data are typically measured using a commercially available multipurpose data acquisition equipment.
However, it is necessary to develop an alternative dataacquisition device because the versatility of the commercially available equipment reduces the processing
speed due to high-load multifunction processes, andthe counting rate is less than a few hundred kilo counts
per second (cps) when the two-dimensional neutron
measurement is performed. Furthermore, a multipurpose equipment requires complex operations and is
not user friendly to a researcher unfamiliar with neutron
scattering experiments. Therefore, we developed a newdata acquisition device with characteristics of real-timedata display and storage for use at the MLF and used
it subsequently to perform operation tests with signalsthat simulate the detector output signals.

Front-end electronics

Signal lines for Y-axis

2. Device design
The schematic diagram of the two-dimensional detector system and developed data acquisition device isshown in Fig. 1. The detector element contains 128 signal lines each for the X- and Y-axes. Charge signals from

Signal lines for X-axis
Front-end electronics

PosionencoderTwo-dimensional detector system

MonitorStoragedeviceHDMIUSB

Developed module
16-bitposion dataT0 signal fromexperimental facility

Figure 1.	Schematic view of the neutron detector systemand data acquisition device.

124

neutrons are collected by the lines and processed by the
amplifier-shaper-discriminator electronics in each axis.
The incident position of the neutrons is determined in
the position encoder using a field programmable gatearray (FPGA). The position encoder transfers the neutron
position data as 16-bit low voltage differential signals
to the developed data acquisition device. In the pulsed
neutron irradiation facility, T0 signals that indicate thetime when the pulsed neutron is generated are always
generated and distributed to all experimental beamlines
for the TOF experiments. The 25-Hz TTL signals with atime interval of 40 ms are used in the MLF.
The photograph of the developed data acquisition
device is shown in Fig. 2. The developed device is fabricated as a one-unit VME module to operate in VME crates
that are widely used at the MLF. A high-definition multimedia interface (HDMI) is adopted as a display connector
to use a commercially available monitor. The developed
device can display two-dimensional neutron images on
the monitor through the HDMI connector with an update
time of 800 ms. The experimental data are saved in thestorage device that has a universal serial bus (USB) connector. The device has a 68-pin connector and ERA00type connectors for receiving the position data from theposition encoder and the T0 signal from the experimental facility, respectively. T0 signals and position data areentered into the FPGA in the developed device, and theTOF, i.e., the time interval between T0 and the following
position data, is calculated in the FPGA. The calculated

USB storage device
HDMI display

T0
68-pin connector
for posion data

Figure 2.	Photograph of developed real-time data display andstorage device fabricated as a one-unit VME module.

MLF Annual Report 2019

Pulse pair tesolution test using double pulses

Counting loss (%)

25
20
15
10
0.97

5

1
1.5
Time interval (s)

25

1

20
Measured signal

15
10

0.5
Counting loss
1.02

0
0.4

0.6

0.8
1
1.2
Frequency (MHz)

5
0
1.4

Figure 4.	Measured signals of the developed device as afunction of the frequency of the continuous test
pulse, and calculated counting losses.

the frequency of the continuous pulse, and the signals
were saturated beyond 1 MHz. The calculated counting
loss and a fitting line with a single linear function areplotted in Fig. 4. The fitting equation of counting lossof the continuous pulse was expressed as Lc = -102
+ 100 f, where Lc represents the counting loss (%); f isfrequency of the continuous pulse (MHz). It was foundfrom the equation that the counting loss was zero until
the frequency reached 1.02 MHz. We obtained a linear
response over 1 MHz using the developed device, andthe maximum counting rate was approximately 1 Mcps.
4. Summary
A real-time data display and storage device wasdeveloped for neutron scattering experiments using
the TOF method. The developed device can determine
the time-of-flight and time-resolved neutron position
data with a time range from 0 to 40 ms using a beam ofpulsed neutrons at 25 Hz. It was confirmed by an operation test using burst and continuous test pulses that thedevice exhibited a pulse pair resolution of less than 1 ms
and a counting rate capability of more than 1 Mcps.

30

0
0.5

30
Counting rate capability test
using continuous pulses

Measured signal (Mcps)

3. Operation test
Performance tests for the developed device were
performed using test signals that simulated the detector output signals. Double pulses of position signals
with various time intervals were entered to evaluate
the time response. Figure 3 shows the dependence ofthe counting loss of the measured signals on the timeinterval of the double pulse. The counting loss is zero
when the time interval was more than 1 ms, and the loss
became larger with decreasing the interval time. It was
confirmed that the developed device could separate thesignal pulses with a time interval of 1 ms. The counting
loss of the double pulse was fitted based on the following single linear equation, Ld = 54.6 - 56.5 t, where Ld
represents the counting loss (%); t is the time interval(ms). It was found from the equation that the counting
loss was zero until the time interval reached 0.97 ms.
The counting rate capability was evaluated using
continuous test pulses. Figure 4 shows the measured
signals plotted as functions of the frequency of the continuous test pulse. The measured signals increased with

1.5

Counting loss (%)

TOF, and position data are saved in the USB storage device. Simple functions and operations are necessary forthe device to demonstrate long-time stability, robustness, and a user-friendly interface. The device contains a
thumbwheel switch for measuring the time and an on/
off switch to start/stop the measurement.

Neutron Science2

Figure 3.	Counting losses of the developed device as a function of the time interval of double pulses.

References[1] K. Toh et al., Nucl. Inst. and Meth. Phys. Res. A, 726
169 (2013).
[2] K. Toh et al., J. Instrum., 9 C11019 (2014).

K. Toh1, T. Nakamura1, K. Sakasai1, and H. Yamagishi2
Neutron Instrumentation Section, Materials and Life Science Division, J-PARC Center; 2Nippon Advanced Technology Co.

1125

Muon ScienceMuon Science

MLF Annual Report 2019

MUSE Facility Overview
1. Electric power substation for the H-line completed
Among the muon beamlines envisioned in theoriginal plan of the MLF, the H-line in experimental hall
No.1 has been expecting funding from MEXT for years.
Considering the situation, the J-PARC headquarters decided to provide partial support for realization of theplan. The support was primarily for the construction ofa new electric power substation to cover the huge demand for electricity expected when the H-line becomesfully operational. Following the installation of cableracks, pitting of the MLF building wall, and outdoor
structures in FY2017, the major civil engineering workfor the substation site near the MLF building was completed by the end of March 2019 (see Fig. 1). Meanwhile,
the work continued to ensure access to electricity at thesubstation site. During the last summer shutdown, apower panel was installed in hall No.1 at the MLF. The
scaffoldings around the main carry-in door (where power cables pass through) was removed after the completion of cabling work from the new power substation to
the interior of the MLF. Those who plan experiments on
the H-line are now hoping to have electricity available
sometime in FY2020.

of a joint breakdown, a multitude of safety measures
were imposed to allow for a restricted operation of thetarget until the next summer shutdown. Fortunately,
the target served for muon production without trouble for about seven months, and was finally replacedwith a brand-new spare during the last summer shutdown. Actually, this was an unprecedented occasion
for the muon target team to replace the whole systemafter a high-proton power operation, and utmost care
was taken to minimize the risk of radiation hazard during the replacement work (Fig. 2). Now, the new target
seems ready to be exposed to a 1-MW proton beam in
the years to come.

Figure 2.	A snapshot of the MUSE target team working on thetarget replacement assembly, where the radiation
workers wearing airtight suites are in a temporary
greenhouse to contain radioactive contaminants.

Figure 1.	Electric power substation constructed on the eastside of the MLF building (left). The white wall in theback is that of the NU2 building (Photo taken in
May 2019).

2. Muon rotating target replaced
As reported a year ago, potential damage of a flexible joint within the muon rotating target system wassuspected during the summer maintenance in FY2018.
After careful assessment of the risk expected in case
128

3. Updates from the S & U-lines
The Okayama University group received a JSPS
Kakenhi grant for their research project “Precision test ofelectroweak theory and search for new physics beyond
the Standard Model by laser spectroscopy of purely leptonic atoms”. This led to the application of a new S1-typeresearch proposal to use a high-flux surface muon beamprovided by MUSE, which was approved at the recent
PAC meeting. As a result of discussion with the MUSE
staff on how to complete this project within the limited
term of the grant, it was agreed that Okayama University
group was going to assume full support for the construction of a new experimental area S2 in FY2020, sothat they can secure a major portion of the beamtime
without affecting other user programs.

MLF Annual Report 2019

At the U-Line, continued efforts for increasing ultraslow muon intensity were in progress. For a muonium
ionization laser system, a new crystal (YSAG) for amplification of 212 nm light was successfully fabricatedand its implementation in the existing system started.

Muon Science

At U1B, a dedicated interference experimental setup
was prepared as a part of the S1-type research project“Transmission Muon Microscopy” to verify the waveparticle duality of the muon.

R. Kadono1,2, Y. Miyake1,2, K. Shimomura1,2, A. Koda1,2, P. Strasser1,2, T. Yamazaki1,2, S. Kanda1,2, H. Fujimori1,2, Y. Ikedo1,2,
Y. Kobayashi1,2, J. Nakamura1,2, N. Kawamura1,2, Y. Oishi1,2, Y. Nagatani1,2, S. Matoba1,2, S. Takeshita1,2, S. Nishimura1,2, S. K. Dey1,2,
W. Higemoto2,3, and T. U. Ito2,3
1
Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science Division, J-PARC Center; 3Advanced
Science Research Center, JAEA

129

Muon Science

MLF Annual Report 2019

Present Status of the Muon-Beam Source, M2 Tunnel
1. Introduction
The muon production target and the front-end partof each muon beamline are located in the M2 tunnel
as well as the primary beamline, as shown in Fig. 1. This
area is crucial for the stable and safe operation of thewhole MLF facility containing not only MUSE but also
JSNS. All the potential issues in this area are linked to
the radiation generated by the muon production target
and related devices like the beam scrapers, and thus themuon science section has a responsibility to deal with allaccidents that may happen in this area in cooperation
with the 3NBT group of the neutron source section. This
engagement has been executed since the construction
period of the MLF facility. We report the present status,
selecting a few topics which was appeared in stepwise
power upgrade of proton beam.

Exp. Hall #1
SH

Muon target
U

D
Exp. Hall #2

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

2. Muon production target
In the last fiscal year, we found a defect in the target
assembly. The coupling made of aluminum alloy connecting the rotating shaft of the target with the rotation
motion feedthrough was damaged [1]. This was considered to be due to embrittlement caused by cyclic stressof the rotating motion, resulting in the breakage of oneof two couplings during the periodical maintenance inthe last fiscal year. The broken one was successfully replaced with a new one made of stainless steel. However,130

it turned out that the other coupling was impossible toreplace manually, and even a visual inspection was difficult. Although there was no obvious evidence that theremaining coupling was damaged, this situation should
not be left unresolved. However, the problem was foundjust a few weeks before resuming the facility operation
and we did not have enough time to perform the replacement work that had to be well planned. Thus, we decided
to continue to use the assembly. Before the operation,
the rotational motion of the target wheel was confirmed
visually from 10-m upstream of the primary beamline.
The worst conceivable trouble of the target is the
sublimation of graphite in the case when the target
rotation is stopped but the proton beam is still injecting into the same position of the target. To avoid sucha problem, any abnormal situations in the target must
be detected with monitors like thermometers, torquesensors, and so on. In addition, we introduced the quadrupole mass spectrometer (QMS) to monitor residual gas
atoms/molecules. Especially tritium, which originatesfrom the spallation process in the target, is expected
to increase if the target temperature rises. It is hard to
distinguish tritium from the other mass-number-3 particles like (HD), and thus basic data are accumulated to
implement QMS into the interlock system. To establish
layered safety, we introduced the buffer tank system [2].
Even in the worst case, the buffer tank stores the evaporated gas, and prevents the release of a huge numberof radio-isotopes contained in the gas to the outside of
the facility.
In this fiscal year, we decided to replace the wholetarget assembly rather than the remaining coupling. The
new rotating target assembly, the 2nd target, has been
operated since November 2019. Details are reported
separately [3].
3. Buffer tank system
The buffer tank system, connected to the downstream of the existing vacuum exhaust line, was installed in the last fiscal year [2]. The system has two
100-liter tanks to be used exclusively by it. One of themstores the exhaust gas, while the gas stored in the othertank is evacuated after the radiation survey. This year,
some of the valves were replaced, and remote-control
capability was introduced. In the case of an emergency,
the tank in use can be swapped without stopping thebeam operation due to local valve operation. This gives
redundancy to the buffer tank operation.

MLF Annual Report 2019

Muon Science

Table 1.	
Tritium release rate to the beamline vacuum stored in the buffer tank system. The amount of tritium is measured
by the liquid scintillation counter (LSC *1) and ionization chamber (IC *2). LSC distinguishes between HTO and HT
with pre-treatment. Because the differences between the values of LSC and IC are a few times, we adopted IC for
the operation hereafter due to its quick response. The grey hatched line shows the off-beam data, and the values
subtracting the off-beam component are also shown *3.
Start

End

Date

Date

2019/5/22

Tritium Release Rate [Bq/day]
LSC

Tritium Release Rate
subtracting off-beam data

*1

IC

*3

*2

[kW]

HT

SUM

2019/5/29

6.2E+05

5.2E+075.2E+07500

2019/5/29

2019/6/26

9.2E+05

2.9E+073.0E+07500

2019/6/26

2019/7/8

9.0E+05

8.4E+078.5E+07500/1000

2019/10/16 2019/11/20

7.1E+04

1.6E+06

1.7E+06

4.9E+050

2019/12/6 2019/12/11

2.0E+05

1.0E+07

1.0E+07

5.3E+06

8.1E+06

4.6E+06500



2019/12/11 2019/12/24

5.3E+04

1.3E+06

1.3E+06

4.6E+06-1.4E+06

3.8E+06500

2020/1/7

2020/2/12

5.4E+04

2.4E+06

2.4E+06

8.1E+06

1.2E+05

7.4E+06500

2020/2/12

2020/4/15

1.3E+07500

The operation data have been accumulated. They
are summarized in Table 1. Before starting the beam
operation, the un-irradiated 2nd target’s data were obtained. Even in the case of an un-irradiated target, therate of tritium in the exhaust gas reaches around 1 MBq/
day. This could be explained by the tritium release fromthe copper scrapers adjacent to the target.
The diffusivity of tritium in copper is evaluated to
be D = 2 × 10-13 m2/s at room temperature [4]. Thus, assuming tritium diffusion generated uniformly in a copper block, about 12% of the tritium in the 1-mm layerfrom the surface has a possibility to be released fromthe block per week, although in reality, the chemical
reaction on the surface may decrease the release rate
to the vacuum. The tritium yield is estimated to be
0.11 and 0.02 MBq/cc/week in the 1st and the 2nd scrapers, respectively, under the 1-MW beam operation,and the surface area of each scraper is 1.2 × 104 cm2.
Therefore, 9 MBq of tritium generated under the 500kW operation is expected to be released to the beamline
vacuum per week even during the off-beam periods.
This rough estimation explains the observed value
rather well.

IC

TargetHTO

1.4E+07

LSC

Beam
Power

Figure 2.	The control panel for the buffer tank system on the
J-PARC control LAN.

References[1] S. Makimura et al., KEK-MSL report 2018.
[2] N. Kawamura et al., KEK-MSL report 2018; proceedingsof J-PARC2019 symposium.
[3] S. Matoba et al., ibid.
[4] F. Reiter et al., “A Compilation of Tritium-MeaterialInteraction Parameters in Fusion Reactor Materials”
Commission of the European Communities (1993).
The diffusivity used in the context is extrapolated to
the room temperature in Fig. A.1

N. Kawamura1,2, S. Matoba1,2, Y. Kobayashi1,2, and A. Koda1,2Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science Division, J-PARC Center

1131Muon Science

MLF Annual Report 2019

Report of Rotating Target at MLF

132

The fixed target was replaced with a rotating target
in September 2014 to extend the lifetime of the muontarget. The rotating target has been successfully used forfive years without replacement. Since 2018, a continuousand stable 500-kW proton beam operation has been successfully conducted. The accumulated operational period
and the number of revolutions have reached 17000 hours
and 16 million, respectively, in July 2019. Furthermore,on July 3, 2019, a 1-MW beam operation (Beam power,
935 kW: 1 MW equivalent to one pulse) was successfully
conducted for 11 hours. Because the rotation axis andthe graphite of the rotating target are moving, it is difficult to directly attach thermocouples for measurement.
Therefore, the temperature variation of the thermocouples that are placed beside the axis and the graphite
through the thermal radiation from the axis and thegraphite is measured. Because the heat is not so strong,
the temperature does not respond quickly. Nevertheless,it was confirmed that the temperature reached a thermal equilibrium state in the 1-MW beam operation for 11hours. The maximum temperatures, to some extent, werein good agreement with the prediction. Figure 1 shows
the temperature variation of the thermocouples.
Meanwhile, damage on the flexible coupling in therotation system was found during the long shutdown
in September 2018. It was decided to repair the target
assembly by replacing only the damaged coupling in
the long-term shutdown in 2019. If the replacement had
been successfully completed, the target assembly would
have been reused. As a backup plan, the replacement of
the entire target assembly was planned. The used target assembly was transported from the beam line to a
storage pod. For the replacement, it was necessary toassemble the greenhouse so as not to spread the pollution and to wear an air line suit to avoid internal radiation exposure.

A large amount of tritium is released from muonproducing targets and scrapers by proton beam irradiation. Tritium deposited on the inner wall of the proton
beamline duct and on the surface of the muon target
assembly is converted to HTO by substitution with H2O
molecules in the atmosphere when exposed to air.
When the muon target assembly is pulled out into theair, HTO diffuses in the air. The concentration of HTO in
the air causes the spread of radioactive contaminationand internal exposure. We carried out decontaminationof tritium in the proton beamline ducts before the replacement work. The beam duct was filled with nitrogenand about 5% air, and tritium-containing gas, which wastransferred from the wall to the water in the air by theisotope reaction, was exhausted. Figure 2 shows thetritium concentration in the beam duct. The first purge(4.7 kPa, 25˚C, 70% humidity) took place on July 16, andthe tritium concentration was 50 Bq/cc on the next day.
The total amount of tritium in the air in the beam duct
was estimated to be about 350 MBq. The contaminated air was exhausted on July 15 and a second purge(5.0 kPa, 25˚C, 67% humidity) was performed on July
16. The tritium concentration on July 22 was 26 Bq/cc,
although the retention period was longer than the firsttime, the tritium concentration decreased, and the decontamination by this method was confirmed. The removal of the vacuum flange was carried out under thecondition that the tritium concentration was reduced
to about 1 Bq/cc by purging with pure nitrogen before
the target extraction operation. The tritium concentration increased to a maximum of 26 Bq/cc after thevacuum flanges were removed, but it has been gradually decreasing as it continues to be released into thestack by the green house exhaust. As a result of thedecontamination, the maximum concentration of tritiated water vapor was about 0.2 Bq/cc, which was lower

Figure 1. The temperature variation of the thermocouples.

Figure 2.	Daily trend of tritium contamination in the beam duct.

MLF Annual Report 2019

Muon Science

Figure 3. The cask with an exhaust fan.

than 0.8 Bq/cc, the concentration limit of tritiated water vapor in the working area of the green house. The
first rotational target was moved with a shielded cask
as shown in Fig. 3.
The cask was maintained at a constant negative
pressure by a blower connected to the stack to prevent the spread of tritium contaminations. The target
assembly was inserted into the vertical hole in thestorage pod because the rotating target was highly radioactive. Since it was necessary to access the screws ina narrow space of the target assembly for the replacement, the workers had to get close to the position of thecoupling. So, the target assembly was placed at the position where the coupling was accessible. It was necessary to place a local shield to reduce external radiation
exposure. Replacement jigs were carefully designed
and manufactured. It had been confirmed that the coupling was successfully replaced using a mock assembly.
Figure 4 showed the pictures of the target assembly,
the conceptual design, and the commissioning test by
a mock assembly. In the summer of 2019, the used target assembly was transported, and the radiation dose
was measured. The radiation dose of the used rotatingtarget at a distance of 10 cm was 500 mSv/h. Though
the radiation dose at the working space was anticipated to be 50 µSv/h, the measured one was 500 µSv/h,therefore, it was decided to give up the replacement of
the coupling. Finally, we decided to replace the entire
target assembly.
The temperatures for the beam power of the second

Figure 4.	The pictures of the target assembly (left), the conceptual design of replacement jigs (right up), and thecommissioning test by the spare target (right down).

Figure 5.	Beam power dependence of the temperatures of
the rotating target system.

and first rotating targets are shown in Fig. 5. Although
there is a slight difference in the axial temperature, there
is almost no difference in the temperature during operation at the same beam power. Therefore, the second rotational target is working properly. The slight differencein the axial temperature is not due to the change in the
beam orbit, but to the different heat transfer due to thedifference in the thermocouple contact.
Since the second rotating target was installed, weare now forced to operate the beam without a sparetarget. We are planning to build a spare target as soon
as possible.

S. Makimura1,2, S. Matoba1,2, and N. Kawamura1,2
Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science Division, J-PARC Center

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Monitoring System for the Muon Rotating Target
It is important to measure the temperature of themuon-production rotating target (hereinafter referred
to as “rotating target”) in order to detect quickly its problems. The temperature of the rotating target cannot bemeasured by direct contact because it is not possible
for thermometers to be attached to the rotating body.
Thermocouples are attached to the cooling jacket tomeasure the temperature due to the thermal radiationfrom the rotating target. However, in the case of a significant temperature rise, this monitoring system cannot
quickly stop the proton beam.
We are developing a real-time two-dimensional radiation thermometer to monitor the temperature of therotating target. We installed a new proton beam duct
for mounting an infrared camera. Figure 1 shows theinfrared camera and a mirror attached to the duct port.
The infrared camera (ULVVIPS-04171SL made by VisionSensing Co., Ltd.) is installed perpendicular to the beamaxis at the bottom of the proton beam duct. Radiationfrom the muon target is reflected by a gold-deposited
mirror placed at 45° in the proton beam duct and observed by a camera through a ZnSe infrared vacuum
window. The infrared camera was installed 11 meters
upstream from the rotating target for radiation protection. The focal length of the lens of the infrared camera was 150 mm and the target can be observed with aspatial resolution of about 2 mm. The infrared camera
is expected to have resistance against 5 Gy or more irradiation that corresponds to more than a one-year operation under 1-MW beam power.
The temperature of the muon target during beam
operation was successfully measured using the infrared
camera as shown in Fig. 2. At the center, a high-temperature part, which is likely to be a beam spot with a diameter of about 1.5 cm, was observed. The temperature of
the part of the target ring was observed to be high dueto the radiation from the face. We are now analyzing theconversion from infrared radiance to absolute temperature and will analyze the change of thermal conductivity
by proton beam irradiation.

Figure 1. Infrared camera on the proton beam duct (upper)
and a shielding made of polyethylene blocks containing lead and boron (lower).

Figure 2.	Infrared camera image of the rotating target during
a beam operation.

S. Matoba1,2, N. Kawamura1,2, and S. Makimura1,2
1
Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science Division, J-PARC Center

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Current Status of µSR Experiment at D1
1. Introduction
At the D-line, muons are delivered to D1 and/or D2.
At the D1-area, a µSR spectrometer is installed as a mainand fixed instrument. Since high-momentum muons, surface muons, and negatively charged muons are available
at D1, all type of µSR measurement, except for ultra-slowµSR, can be carried out. In particular, unique sample environments, such as very low temperature by using thedilution refrigerator, high pressure, etc., were possible tocarry out only at the D1. Recently, negative muon spinrotation/relaxation (µ-SR) is also frequently performed.
Figure 1 shows the µSR spectrometer with the dilution
refrigerator and the fly-past chamber. Here, we report the
recent development of D1.

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

2. Origin of distortion of the µSR spectra
Often, the time dependence of a µSR spectrum is
distorted for some reasons. One of the main reasons is“pile up” of µ-e decay positrons. The counters have finite
dead time and if more than two positrons pass a counter within very short time, the counting system cannot
distinguish the first and second positron, which causes a
finite counting loss of µ-e decay positrons. This counting
loss has been already adjusted and usually the corrected
data are used for analysis. Another reason is due to contamination of positrons (or electrons) in the muon beam.
In particular, a time-dependent positron is one of theissues for distortion of the spectra. To remove positrons
from the muon beam, we use a “particle separator” whichis installed at the upstream part of the septum magnet.
This is a kind of “Wien filter” that can separate muons andpositrons by applying electric field and magnetic field at
the same time. However, if the muons stopped at the ductwall of downstream part of the beam line, the µ-e decay
positrons of the same momentum as the muons could

not be removed by using a positron separator and a finite
amount of positrons with the decay time of 2.2 µs could
reach the sample position. Such positrons could be scattered at the sample and hit the positron counters, whichcauses additional events. Usually, these additional eventsare contributed as a constant µSR signal. However, when
we use a kicker to obtain a single pulse, beam trajectory
depends on time dependence of the kicker operation andµSR spectra could be distorted.
Figure 2 shows the µSR spectra in several Cu plateswith different thickness. When the thickness is less than
~1 mm, the spectra shows almost no distortion. However,significant distortions were seen in the time range of
0–1.5 µs in a thicker sample. Since the thickness of a Cu
plate is enough to stop all surface muons, it is obvious that
this distortion is due to scattered positrons. In addition,
the distortion does not depend on the condition of theseparator, it is clear that the positrons are coming from thedownstream part of the beam line. The shape of the distortion is similar to the magnetic field profile of the kicker
and we conclude that the distortion is owing to positrons
whose trajectory is modified only when the kicker is working. Indeed, no distortion was found in the double pulseµSR spectra, in which the kicker was not working. We also
tried to change the kicker operation mode to kick a second
pulse to D1, however, the distortion still occurred. We notethat the kicker at S1 is not magnetic but electric one andno distortion of the µSR spectra due to positrons is seen.
Unfortunately, we have not solved the distortion but
we are working continuously to improve the situation.

Figure 2.	µSR spectra in several Cu plates with different thickness (~50 mm × 50 mm, room temperature) from
0.3 to 2.7 mm, which were obtained at D1. A surface
muon beam was used. Kicker was used to remove
the 2nd pulse. The Cu plates were placed in the air
without any chamber or sample holder.

W. Higemoto1,2,4 and A. Kota1,3Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Advanced Science Research Center, JAEA; 3Institute of Materials
Structure Science, KEK; 4Department of Physics, Tokyo Institute of Technology

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Negative Muon Commissioning at D1/D2 Areas
1. Introduction
The D-line, which is a beamline located at MUSE,
MLF, has a long superconducting solenoid and, therefore, can supply positive and negative decay muons
from several MeV/c to ~100 MeV/c in addition to surface
muons. Since the energy of the primary proton beam of
the MLF is as high as 3 GeV, the yield of negative muons is higher than at other muon facilities. In particular,
because of the increment of power in recent years, theworld’s highest intensity negative muon beam is supplied. Using the high-intensity negative muons, applications for various experiments such as non-destructive
elementary analysis using muonic X-rays, and negative
muon spin relaxation, are being developed. In this report, we describe the current status of commissioningof the negative muon beam at the D-line.
In the D1 area, negative muon spin relaxation measurements can be performed using polarized high-intensity negative muons. Recently, some results have beenobtained with negative muon spin relaxation methods [1]. However, further commissioning is required toperform experiments on a variety of samples. Here, wereport recent commissioning results on spectral distortion reduction and momentum measurements.
2.	D istortion in asymmetry and backgroundcomponent in μ−-decay spectra
Due to the low intensity of the beam, negative muon
spin relaxation measurements have not been commissioned in the past. However, with the recent increase in
the intensity of proton power at J-PARC, μ-SR has become
familiar to us, and simultaneously some problems havebeen found. One of them is spectral distortion. For example, as shown in Fig. 1, the asymmetry is distorted in thetime domain, especially in the long-time region (t > 10 μs,
in RUN 4554 (Red) in Fig. 1). As a result of the commissioning to improve this, the spectral distortion was significantly improved, as shown in RUN 6633 (Blue) in Fig. 1.
In order to investigate the cause of the distortion, we
first investigated the muon decay spectrum (Fig. 2) andfound that in addition to the muon-derived component
with a lifetime of about two μs for graphite, there is along-lived component with a lifetime of several tens of
μs, which can be confirmed from the Fig. 2. Considering
the muon lifetime, this is unlikely to originate from negative muon decay electrons. Compared with the asymmetry calculated from the histogram (red curve in Fig. 1),
it was found that the asymmetry was distorted in the
136

Figure 1.	Time dependence of the asymmetry in a Graphite
sample before and after beamline tuning.

Figure 2.	μ-e decay histograms before and after beamline
tuning and some other conditions.

region of 15–20 μs, where the muon decay events arealmost impossible to observe. These results suggest that
this background component is responsible for the distortion of the spectra. This background component appears
after the pulse timing of the muon, which is considered
to be caused by neutrons, β- or γ-rays associated with thenegative muon nuclear absorption. In particular, the contribution to the muon absorption rate is thought to besignificant because of the use of large Z elements such as
Pb and W in the collimator at the beam exit.
Therefore, beam tuning was performed in orderto reduce this long-lived background component. The
tuning was carried out under the condition that a 60 x
60 mm slit aperture restricted the beam path. As a result,the long-lived background component was reduced by
one order of magnitude (Fig. 2). The resulting asymmetry is shown in Fig. 1 (blue curve). The spectral distortion
after 10 μs was reduced. By optimizing the beamline slit
aperture, the beam size at the collimator position was
reduced, and the number of negative muons stopped at
the collimator was decreased. As a result, the long lifetime component was also reduced significantly.

MLF Annual Report 2019

3. Beam momentum measurement at D1
The momentum value of the beam is an important
information to determine the volume of the sample forthe negative muon spin relaxation measurement. For thispurpose, the actual momentum value of the beam and its
distribution width were measured. By changing the thickness of the target, we measured how much of the negative
muon beam passed through a target plate (the so-called
range measurement). The central momentum and the distribution width of the beam were calculated by comparing
them with a simulation. As a result, the central momentum
was found to be a little higher than the nominal momentum, and the distribution width was very narrow.
Figure 3 shows a schematic diagram of the target
used for the momentum measurement. The target wasan Al target with a graphite plate overlaid on its downstream surface. Since the graphite plate was sufficiently
thick, all the negative muons that passed through the
Al plate stopped in the graphite plate. And because thenuclear absorption rate of negative muons differs depending on the atomic number Z of the material where
the muons stopped, the number of total decay electron
events observed depends on which side of each plate
the negative muons stopped (the lifetime of negative
muons in Al is about half of that in graphite). Therefore,
the number of negative muon decay electron events
counted by the detector was used as an indicator of how
many muons passed through the Al plate.
The measurements were performed in the μSR experimental apparatus located in the D1 area. The target
was placed in the center of the apparatus. A counter(Kalliope) installed in the apparatus was used to measure the number of decay electrons. The number ofnegative muon decay electron events was evaluated by
calculating the number of decay electrons per unit oftime after integrating the measured number of decay
electrons. The beam condition was the same as that of
RUN 6633 (slit aperture of 60 x 60 mm) in Fig. 2.
The number of decay electron events as a function of the aluminum thickness measured at 30 MeV/cis shown in Fig. 4. The decay electron rate decreases
sharply with increasing thickness, indicating that withthis method, the range measurement can be performed
without any problem.
The fitting result of these data by an error function isshown as a blue line. From this fit, the central thickness

Muon Science

Figure 3.	Schematic view of the beam momentum measurement. The more muons stop at the graphite, thelonger the apparent muon lifetime is.

Figure 4.	Aluminum thickness dependence of muon decay
event rate under a nominal muon momentum of
30 MeV/c.

and its width were obtained. By comparing with simulations using SRIM/TRIM [2, 3], the central beam momentum and distribution width were deduced. The obtained
values were estimated to be 32.8 MeV/c (nominal value+9.3%) for the center and +1.1/-1.2 MeV/c (+3.2/-3.5%)
for the stopping spread.
For the condition of 60 × 60 mm slit aperture, themomentum width was about 3%, which indicated thata very narrow momentum distribution was obtained.
The actual momentum value was slightly higher than
the nominal value. We will investigate the cause in detailand resolve this discrepancy in the future.
References[1] J. Sugiyama et al., Phys. Rev. Lett. 121 (2018) 087202.
[2] J. P. Biersack and L. Haggmark, Nucl. Instr. and Meth.,
174 (1980) 257.
[3] The Stopping and Range of Ions in Solids, Pergamon
Press, New York, USA (1985).

S. Takeshita1,2, P. Strasser1,2, M. Tampo1, S. Doiuchi1, A. Hashimoto1, I. Umegaki3, N. Kawamura1,2, K. Shimomura1,2, and Y. Miyake1,2Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science Division, J-PARC Center; 3Toyota Central
Research & Development Laboratories, Inc.

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Development of Sample Environment at the S1 Area
A light-irradiating setup is required for the µSR sample environment. The light and the muon should irradiate the sample at the same area and time. At the S1and D1 areas, a xenon flash lamp in a short-arc stroboscope package is used as a light source. Typical values
in the manufacturer’s data sheets of the lamp (SAX-100
lamp with SA-130A power supply, Nissin Electronic.
Co., Ltd. [1]) show that the light power is 130 W and thepulse width is 18 µs (FWHM). The light power at the µSR
sample does not only depend on the combination ofa lamp and a power supply but also on repetition frequency and experimental setup. The pulse width also
depends on the frequency. At the MLF, the muon beam
is a 25-Hz pulsed beam, so synchronized 12.5 Hz lightpulses can be used to conduct SR experiments in redgreen mode, showing 12.5-Hz alternative data with lighton and off. As of the setup, the vacuum chamber, flypast
chamber for example, is used for the experiments. A 10cm distance from the sample is a suitable position forthe lamp housing, which is outside of the chamber. We
report the results of the experimental examination of
the light power and the pulse width within the conditions of the µSR experiments.
Firstly, we measured the precise pulse shape, using
a slightly light-leaking scintillator of the µSR detector.
Figure 1 shows the single histogram of the scintillator. An
exponential curve shows a signal of decay positrons, anda gaussian curve shows a light pulse. This results clearlyshow that the pulse width (FWHM) was exactly 18 µs at
our µSR experiments. Note that the light-leaked signal ina single histogram was eliminated in a coincided histogram and conventional experimental data, asymmetry.

Next, we examined the pulse energy of the lightsource. Figure 2(a) shows the setup for the measurements. The energy was measured by a pyroelectric power meter PE50-DEF-C (Ophir Optronics Solutions, Inc.),
which can detect the light pulse thermally. The size of its
light receiving surface is close to that of the SR sample(ϕ35 mm). The measured pulse energy was 7 mJ (=90 W,
Table 1), which was consistent with the typical value.
Although the lamp housing has been replaced to
non-magnetic materials, the longitude field (LF) prevents the lamp from lighting near the magnet. To conduct LF-µSR experiments with light source, we prepareda fiber light guide. The new light source can introduce
light to a direction transverse to the muon beam direction (Fig. 3). In this setup, the same sample surface isirradiated by the muon and light pulse. This allows us
to conduct LF-µSR experiments with side-windowed
vacuum chamber, flypast chamber at the S1 area. The
light is collimated to ϕ20 mm beam and the pulse energy is also examined to be 0.15 mJ (=2 W, Fig. 2(b)). As
shown in Table 1, the light transmission caused the energy loss, which was larger than the value estimated by
the technical data of the light guide. (Typical transmission rate shows 95% for white light and, < 90% for blue
light (< 480 nm) [1].) Therefore, the energy loss shouldhave been caused at the end of the light guide, which
may be improved by further alignment or using anothercollimator lens.

Figure 2.	Setup for examining the pulse energy of the lightsource.

Table 1. Pulse energy of the light source.

Figure 1. Histogram of the light-leaking scintillator.

138(a) Light source(b) With light guide transmission

Pulse energy
7 mJ (90 W)
0.15 mJ (2 W)

MLF Annual Report 2019

Muon Science

In addition, we report on the 3He cryostat, Heliox
AC-V, which was installed to the ARTEMIS spectrometer in the S1 area. Its performance was examined in
our previous report [2]. Next, we prepared temperature
control of the cryostat from the IROHA sequence. The
temperature-controlling sequence was safely operated
at user experiments of 2019B and in the beamtime of
the following 2020A.

Figure 3. LF-µSR setup with light source.

References[1] https://www.nissin-ele.co.jp/[2] J. Nakamura et. al., KEK Progress Report 2019-3(2019) 23.

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

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USM Commissioning at the U1B area
1. Introduction
We are developing a 5-MeV transmission muon microscopy at the U1B area. The goal of the microscopy isvisualizing a thick object (> 10 µm) in nanometer resolution. The ultra-slow muon beam has quantum coherence,and its acceleration over 5 MeV energy gives it deeppenetration capability for thick specimens. A speciallydesigned cyclotron is employed for the acceleration.
2. Diffraction Experiments of muons
We started an experiment of muon diffraction as
the first demonstration of the transmission muon microscopy without reacceleration. The aim is to obtain adirect proof of the quantum interference of muons, bydetecting diffraction patterns of the ultra-slow muon
beam. The experiment will be the first direct proof of thewave-particle duality beyond the second generation of
the Standard Model. The experiment uses the first prototype of the transmission muon microscopy constructedin the U1B area.

the accelerated beam should be in the order of 10-5 for
reducing effects of the chromatic aberration. We adopt
a flat-top RF acceleration for the cyclotron to realize sucha small energy dispersion. This year, we have designed
the cyclotron in detail, and constructed a magnet for it.

Figure 2.	Beam trajectory at the center of the cyclotron andevolution of the energy dispersion.

Figure 3.	Sector pole (left) of the magnet, and the magnet(right) of the cyclotron.

Figure 1.	The prototype of the transmission muon microscopy for the diffraction experiment.

We have also developed a 3-dimensional measurement device of the magnetic field of the cyclotron,
which uses a search coil (see Fig. 4). To reduce the energy dispersion, precise (~10-5) measurement of themagnet is required.

The prototype consists of an object lens, including
a specimen-stage, and a camera-chamber, including
a 2-dimensional image sensor. The object lens makes
a small spot of the muon-beam on the image-sensor
and forms a diffraction pattern of a specimen installed
into the center of the object lens. A multi-channel plate(MCP) with a phosphor plate is employed as the imagesensor for ultra-slow muons. The image on the phosphor
is taken by a CCD camera. We are using a single-layer
graphene as the specimen. We have already taken data
and are analyzing them.

Figure 5.	3-dimensional magnetic field measurement device(left), and core part of the search-coil (right).

3. Cyclotron for muons
We are constructing a 5-MeV cyclotron for muon with
Sumitomo Heavy Industry Inc. The energy dispersion of

Next year, we will tune up the magnet by using thismeasurement device, install the RF-system into the cyclotron, and start beam tests of the cyclotron.

Figure 4.	Concept of the search coil.

Y. Nagatani1,2, T. Adachi1,2, T. Yamazaki1,2, S. K. Dey1,2, Y. Ikedo1,2, and Y. Miyake1,2Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science Division, J-PARC Center

1

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Muon Science

H-Line Construction – Recent Progress
A new beamline named H-line is under construction in the east #1 experimental hall of the MLF. Figure 1
is a layout drawing of the H-line. The H-line is a generalpurpose beamline [1], which can generate both decay
and surface muons, and has two branches named H1and H2-area. Its large acceptance (108 mSr) capturesolenoid and following beamline magnets with large
apertures enable us to use high intensity muons for precise measurements, such as the MuSEUM experiment tomeasure the hyperfine splitting of muonium [2] and themuon g-2/EDM experiment [3]. The intense muon beamof the H-line is also suited to search for rare processes
forbidden in the framework of the Standard Model ofparticle physics (DeeMe experiment [4]). In addition, atransmission muon microscope (TμM), which enables
us to observe thick samples, such as living tissue, nondestructively, is planned to be installed at the H2 area.

H-line consumes a lot of electricity which cannot beprovided by surplus electricity of the MLF. One of thereasons is that the capture solenoid of the H-line is anormal conducting magnet since it is located only
600 mm apart from the muon production target and iswound with radiation-resistant mineral insulation cables(MIC) [5].
The building work of the platform of the new electric sub-station was almost completed in FY2018, andthen, in FY2019, the electrical construction was executed. High voltage receiving cubicles and voltage transformers from 6.6 kV to 400/200 V were installed. The
cabling work from the new electric sub-station to the
new experimental panelboards in the MLF was also finished, and the construction of the sub-station was finallycompleted in FY2019 (Fig. 2).

Figure 2.	The construction of the new electric sub-station
was completed in FY2019.

Figure 1.	A layout drawing of the east #1 experimental hall of
the MLF in the 1st phase of the H-line.

The H-line has been constructed step by step. First,
its frontend devices, such as the capture solenoid andthe first bending magnet, were installed during thesummer shutdowns in FY2012 and FY2014. Then radiation shields and beam blockers were installed in
FY2016.
Since FY2017, the construction of a new electric
sub-station for the H-line started. This is because the

In FY2020, we plan to carry out installation of beamline apparatuses, electrical cabling and cooling water
piping of some magnets, as well as an update of thesafety interlock system to release the first beam in the
H1 area.
Other important progress is made on an extension building for the H2 area. We have to build a newbuilding for the H2 area in the east side of the MLF,
currently occupied by a parking lot. This is because
the muon g-2/EDM experiment planned at the H2 area
needs very low emittance muon beam re-accelerated
up to 212 MeV by linear accelerators of about 50 m. In
FY2019, a J-PARC center task force was organized toconsider many issues concerning the extension building, such as its exterior design, relocation of equipment, radiation control, utilities, and so on. Figure 3
shows one of its results, exterior design endorsed by
the J-PARC center task force.
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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).
[5] H. Fujimori, et al., Nucl. Instrum. Methods Phys. Res.
Sect. A 600, 170 (2009).
Figure 3.	Exterior design of the extension building for the H2area endorsed by the J-PARC center task force.

T. Yamazaki1,2 and N. Nakamura1,2
Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science Division, J-PARC Center

1

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MLF Annual Report 2019

Research Safety
1. Radiation safety
Radiation safety for users
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.
The monitors for take-out articles allow to bring anarticle out from the controlled area without significant
trouble. However, the troubles with hand-foot-clothemonitors (such as damage of the light shielding sheets),
which check the radiation contamination in workers,
have not decreased.
The MLF radiation team, in cooperation with CROSS,
supports user experiments by measuring activated samples and devices with Ge detectors, and also supports
rad-work, contamination and dose-rate surveys in eachof the experiment devices, radiation safety checks forexperiments, and so on. All monitors and all survey meters prepared by the MLF radiation team are inspected
and calibrated annually.
Survey of the MLF facility for the 1-MW operation
On July 3, 2019, a 1-MW proton beam operation
at the MLF was conducted for 10.5 hours. In the 1-MW
operation, the MLF division and the Radiation Control
section cooperatively measured the dose rates at all
evaluation points inside and outside the MLF to checkthe shielding performance. The dose rate limitations
specified in the law are 1 mSv/week (25 μSv/hour with
40 hours/week) at the controlled area, where persons
can always enter and 1.3 μSv/3month (2.6 mSv/hour
with 500 hours/3month) at the non-controlled area.
The results confirmed that the dose rates measured at
all evaluation points were below those allowed in theradiation license application.

of their actual physical state – powder, solid, liquid orgas, were performed successfully by the chemical-safety
team, along with the approval of the actual materials
for use by individual beamline staffs. As a result, theexperiments were conducted without serious chemical problems. Figure 1 shows a trend for the amount ofchemical materials subjected to safety checks over thelast 10 years. The saturation of amount of user-broughtchemical materials for chemical safety is seen from Fig. 1
under the stable 500-kW class operation.

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

Therefore, we can evaluate the amount of userbrought chemical materials at a 1-MW stable operation. It is expected to be around 15,000. Because of theenormously large number of chemical materials, we introduced online monitors for displaying a “sample risk
assessment sheet” of chemical materials for individual
proposals for that day in experimental halls to confirm
them quickly and prepare them in advance.

Radiological license upgrade
The specified radiological license upgrades for the
MLF in FY2019 were not done.
2. Chemical safety
As an annual task, the usual chemical safety checksof user-brought chemical materials, such as specimen
and reagents, to evaluate their toxicity and the stability
144

Figure 2.	Online monitor for displaying a “sample risk assessment sheet”.

MLF Annual Report 2019

Table 1. Statistics of the common sample environment.

Equipment
7T magnet
2K cryostat
3He cryostat
Dilution cryostat
Cryostat for residual stressmeasurement
GM cryo-furnace
Nb furnace
SANS furnace
Xenon lamp
Mercury lamp
LED light source
Total

Times
10
9
5
9

Total days
47
29
20
48

4

9

1
3
1
1
3
1
47

2.5
11.5
4
4
6
2.5
183.5

4. Crane safety
Throughout the year, we use cranes to change sample environment equipment for experiments and to
perform various kinds of maintenance of the neutron
instruments. There are 50 t and 7.5 t cranes in experimental-hall No.1 and there are 50 t, 7.5 t and 15 t cranes
in experimental-hall No.2 and its extension building. The
operations of those cranes are limited to crane operators
licensed by the government who were also trained byour crane safety staff and passed our skill check. In addition, before each individual crane operation, the craneworking group must submit a dedicated usage sheet andits content, which includes information of suspendedload, weight, total number and method of slinging by thecrane staff, must be approved. As a result, last year, there
were no problems with the crane operations. Figure 3
shows last year’s statistics of crane use. All cranes in theexperimental halls were used 244 times in total. The usage number increased by about 20% compared with theprevious year. As usual, from June to October, which isthe period of maintenance of the neutron instruments,
the trend of crane usage was high. In addition, the highest crane usage number was recorded in March of thisfiscal year. It was because the beam operation was performed in the end of March when the fabricated apparatus was delivered and tested in the experimental halls.
䢶䢲䣐䣷䣯䣤䣧䣴䢢䣱䣨䢢䣥䣴䣣䣰䣧䢢䣷䣵䣣䣩䣧

3. Sample environment safety
Table 1 shows the statistics of the common sample
environment for experiments, such as a magnetic fieldapparatus and various kinds of cryostats and furnaces
in the last year. The items with red letters are the new
apparatus introduced in the MLF in the last year. They
provide various kinds of external light field. The common sample environment equipment was used 50 times
within 256 days in total. The common sample environment is maintained by a sample environment team,whose members include JAEA, KEK and CROSS staffs.
The technology development section of the MLF must
perform safety check of each common sample environment before it is approved for regular operation. For
example, the maximum controllable value, the temperature of the equipment, the interlock system, andthe electrical and structural integrity are examined in
the safety check. If the specifications of each common
sample environment have changed, it is necessary to doa new safety check. As a result, all common sample environment equipment operated well, and there were nosafety problems, including with the newly introduced
apparatus.

MLF Safety䢢䣫䣰䢯䣪䣱䣷䣵䣧䢢䣵䣶䣣䣨䣨䢢䣥䣱䣰䣵䣶䣴䣷䣥䣶䣱䣴

䢵䢲

䢴䢲

䢳䢲

䢲

䢶

䢷

䢸

䢹

䢺

䢻 䢳䢲 䢳䢳 䢳䢴 䢳

䢴

䢵

䣏䣱䣰䣶䣪

Figure 3.	Trend of the total crane usage in one year.

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, M. Ishikado5, 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

145

MLF Operations in 2019

MLF Operations in 2019

MLF Annual Report 2019

Beam Operation Status at the MLF
1. Overall
In Japanese Fiscal Year (JFY) 2019, the beam operation at the MLF started on April 2, 2019, with a beam
power of 500 kW and ended on March 27, 2020. Table 1
shows the scheduled time and availability in JFY2019.
In the schedule, the beam period of 2019A switched to
2019B on November 17. Since neutron Target #9, which
was replaced in the summer of 2019 with Target #11, had
the helium bubbler to mitigate cavitation erosion at thetarget vessel, the beam power was increased beyond
500 kW. The records of the beam power and the availability are shown in Fig. 1. In JFY2019, the beam operation started with a power of 500 kW with a double-bunch
beam in the period from April 3 and to the end of March.
As shown in Table 1, a very stable beam operation

with a 95.9% availability was maintained from April 3
to June 28, just before the summer outage period. R&D
for a high-intensity beam operation were carried out.
To minimize the negative influence on the users’ work
caused by potential target failure, we made a demonstration of the high-intensity beam operation after theuser beam delivery. A successful beam operational demonstration with 1-MW power was carried out for 10.3
hours on July 3 with a remarkably high beam availabilityof 98.6%. For measurement for the emergency call in thecase of failure, the demonstration had been limited by
10 PM, which was required by radiation safety group toachieve effeicency emergency call. Since the operation
with 1 MW was proven to be safe, next year, the demonstration with the same power will not have a time limit.

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

Run

Duration

Scheduled time (h)Beam time (h)Availability (%)

82
83
84

Apr 2 – Jul 2
Nov 5– Dec 19
Jan 13 – Mar 31

1840
936
1647

1763.2141.7
1522.5

95.9
15.1
94.3

2019A
2019B

Apr 2 – Nov 16
Nov 17 – Mar 31

2071
2352

1763.21694.2

85.2
72.0

4423

3457.4

78.2

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

148

MLF Operations in 2019

MLF Annual Report 2019

Table 2. Events that stopped the beam and reduced the daily availability to less than 80%.

Stop date
4/18

Cause of beam stop

Stop durationfor each event [h]

LINAC ion source failure and replacement

16.8

RCS shift bump failure and MLF fire alarm malfunction

6.7

MLF gas handling system for target replacement

768

12/12

LINAC timing module failure

7.0

12/18

MR beam transport (3–50BT) water flow shortage

6.0

3NBT vacuum failure

11.6

2/3

MR beam transport (3–50BT) water flow shortage

7.0

3/8

LINAC klystron failure and recovery

8.0

6/18 and 6/19
From 11/5 to 12/11

1/26 and 1/27

After the summer outage period, the beam operation was planned to be resumed on November 5. Due tothe failure of the gas handling system for the mercury
target, the restart date was significantly postponed until
the replacement of the mercury target was completed.
The work to fix the system was the main reason for the
beam stop. After the outage, the beam operation was
resumed on December 6. Eventually, the overall availability in JFY2019 was 78.2%.
In the past, a relatively long beam shutdown period
was required to complete the purification of the cryogenic system for the neutron moderator. In the summerof 2016, the impurities in the loop of the cryogenic system were removed completely; after that, the periodical
purification was not required. Thus, a long uninterrupted work period of 3,459 h was attained in JFY2019.
The beam operation was stopped on several occasions due to minor failures. Typical causes of the beamstops with daily availability of less than 80% are summarized in Table 2 and described below.
2. Causes of the beam stop
LINAC:
During JFY2019, there were no shortages of waterflow for the magnet at LINAC, which had been the main
reason for beam stops in the last fiscal year. On April
18, the ion source stopped due to the failure of its RF
antenna. It took 14 hours to replace it with a new ion

source. After the replacement, the tuning of the accelerator tookr 4 hours.
3-GeV Rapid Cycling Synchrotron (RCS):The power supply to the shift bump magnet at RCS
failed in the early morning of June 18 due to the failure of
the charger of the power supply. Following this event, afire alarm malfunction happened at the MLF late at night.
Beam transport from RCS to the MLF (3NBT)
A malfunction of the vacuum system happened on
January 16 at 3NBT due to the crack of a chain clamp used
as a coupler at the vacuumed beam duct. With the helpof the auxiliary vacuum pumps, the vacuum pressure recovered quickly. Due to the electrical noise of the auxiliary pump, malfunctions of the vacuum pressure gauge
for fast closing value occurred several times while thecracked chain clamp was being changed. Next summer,
all chain clamps vulnerable to cracking will be exchanged.
30-GeV Synchrotron (MR)
After fixing the failure of the beam-bending magnet at the 3–50 BT, which delivers the beam from the
RCS to MR, the MR operation was resumed last summer.
In JFY2019, the beam operation to MR started in beam
sharing mode at RCS. Due to insufficient water flow to
the magnet, the beam operation to the MLF was interrupted twice on December 18 and February 3.

S. Meigo
Neutron Source Section, Materials and Life Science Division, J-PARC Center149

MLF Operations in 2019

MLF Annual Report 2019

Users at the MLF
In fiscal year (FY) 2019, the MLF was running stably
with a beam power of 500 kW throughout the year. Dueto the delay caused by restoring of the gas handling system, the overall availability in JFY2019 was decreased
to 78.2%. In addition, before the summer maintenanceperiod, the 1-MW beam test was successfully operated
on July 3, 2019, for 10.5 hours with a remarkably highbeam delivery. The total number of users of the neutron and muon experimental facilities in FY2019 was
1,078, a slight decrease compared with FY2018, 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.
FY2008Domestic
Users
NeutronMuon

FY2009Foreign
Users

Domestic
Users

12

303

0

38

Foreign
Users

Domestic
Users

107
18

Muon

432

2

42

Foreign
Users

Domestic
Users

113

476

Domestic
Users

44

238

8

21

Foreign
Users

Domestic
Users

Foreign
Users

Domestic
Users

21

628

2

46

Foreign
Users

DomesticUsers

FY2017

108

742

99
16

789

Neutron (Foreigners)

Muon (Japanese)

Muon (Foreigners)
30

1050

10
46

750

8
42
44

450
2
38
14

300

432

0

18
12
95

303

108

185

Foreign
Users

Domestic
Users

61
11
FY2019

744

711

628
399

742

Foreign
Users

940
827

113
138

15

15
146

127

11
127

176

113

789

827

83

50
50

476

238

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

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

150

50

50

10
59
11

2
21
21

149

83

113

80

600

150

16

78

10

Foreign
Users

449

176

146

Neutron (Japanese)

900

399

161
30

13

80

965
185

149

DomesticUsers

FY2018179

83

Foreign
Users

56

927

744

FY2013

708

23

852

10

FY2012259

FY20168359

Foreign
Users

50

69
13

FY2011

476

559

91
78

14

FY2015824
711

Domestic
Users

40

18
FY2014

NeutronForeign
Users

317

95

DomesticUsers

FY201011

MLF Annual Report 2019

MLF Operations in 2019

MLF Proposals Summary – FY2019
Table 1. Breakdown of Proposals Numbers for the 2019 Rounds.
2019A

Beamline

Instrument

2019B

Full Year

Submitted Approved Submitted Approved Submitted Approved
GU

GU

BL01 4D-Space Access Neutron Spectrometer - 4SEASONS

16(0)

13(0)

26(1)

12(1)

1

1

1

1

BL02 Biomolecular Dynamics Spectrometer - DNA

12(0)

8(0)

29(3)

10(3)

2

2

2

2

1

0

1

1

0

0

0

0

0

43

10

4

11

4

5

5

5

5

BL03 Ibaraki Biological Crystal Diffractometer - iBIX
BL04(100-b)(b)‡†

Accurate Neutron-Nucleus Reaction Measurement Instrument ANNRI

BL05 Neutron Optics and Physics - NOP

GU

GU

PU/S

IU

PU/S

IU

0

0

0

43

1

1

1

1

1

0

1

0

※

0
※

0

BL06 Neutron Resonance Spin Echo Spectrometers - VIN ROSE

4

3

4

2

1

0

1

0

BL08 Super High Resolution Powder Diffractometer - S-HRPD

14

10

17

12

1

0

1

0

BL09 Special Environment Neutron Power Diffractometer - SPICA

6

3

4

4

1

0

1

0

BL10 Neutron Beamline for Observation and Research Use - NOBORU

8

8

13

7

3

1

3

1

BL11 High-Pressure Neutron Diffractometer - PLANET

9(0)

9(0)

15(0)

10(0)

0

1

0

1

BL12 High Resolution Chopper Spectrometer - HRC

5

5

10

5

1

0

1

0

BL14 Cold-neutron Disk-chopper Spectrometer - AMATERAS

27

11

37

10

3

1

3

1

BL15 Small and Wide Angle Neutron Scattering Instrument - TAIKAN

36(2)

14(2)

59(0)

13(0)

3

3

3

3

21

18

21

20

0

1

0

1

19(2)

16(2)

27(2)

13(2)

1

3

1

3

13(0)

8(0)

25(1)

5(1)

1

1

1

1

16

12

24

14

1

1

1

1

10

5

14

8

0

0

0

0

42

42

25

25

25

0

25

0

BL21 High Intensity Total Diffractometer - NOVA

22

20

25

19

1

0

1

0

BL22 Energy Resolved Neutron Imaging System - RADEN

17(0)

13(0)

21(0)

11(0)

1

2

1

2

BL23 Polarization Analysis Neutron Spectrometer - POLANO

2

2

2

2

1

0

1

0

17(0)

8(0)

18(1)

8(1)

0

1

0

1

BL16

High-Performance Neutron Reflectometer with a horizontal
Sample Geometry - SOFIA

BL17 Polarized Neutron Reflectometer - SHARAKU
BL18

Extreme Environment Single Crystal Neutron Diffractometer SENJUBL19 Engineering Diffractometer - TAKUMIBL20 Ibaraki Materials Design Diffractometer - iMATERIA

D1(100-b)(b)‡†

Muon Spectrometer for Materials and Life Science Experiments D1

D2

Muon Spectrometer for Basic Science Experiments - D2

8(1)

4(0)

12(4)

6(2)

0

1

0

1

S1

General purpose µSR spectrometer - ARTEMIS

30(2)

25(1)

29(3)

23(3)

1

1

1

1

UA

Muon UTotal
GU : General Use

PU : Project Use or Ibaraki Pref. Project Use

0

0

0

0

0

1

0

1

369

265

473

253

86

22

86

22

S : S-type Proposals

IU : Instrument Group Use† : Ibaraki Pref. Exclusive Use Beamtime (β = 80% in FY2019)‡ : J-PARC Center General Use Beamtime (100-β = 20% in FY2019)( ) : 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 2019 Rounds.
Application FY

Submitted

Approved

2017

24

8

2018

9

5

2019

9

4

151

MLF Operations in 2019

MLF Annual Report 2019

Not Approved

Approved

1200

Proposals

1000
800
600

142

400
200
0

34
67

20
214

278

293

395

231

126

42

45

309

255

460

422

469

321

353

507

199

607

329

630

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

Proposal Round
Figure 1. MLF Proposal Numbers over Time.

KEK
48
JAEA 5%
80
8%

CROSS
24
2%
Universies (Japan)
Companies (Japan)

Foreign
Organizaons
216
23%

Universies (Japan)
412
43%

Research Instutes (Japan)
Foreign Organizaons
JAEA
KEK
CROSS

Research Instutes (Japan)
49
Companies (Japan)
5%
130
14%

Figure 2. Origin of Submitted Proposals by affiliation - FY2019.

P9
11
2%
P7
59
8%
P6
64
8%

Q1
50
7%

P1:Materials Science and Engineering

Q2
62
8%

P2:Energy Science and High-Pressure Science

P1
153
20%

P3:So Maer, Biomaterials and Liquids
P4:Magnesm and Strongly Correlated Electron Systems (Elasc Scaering)
P2
76
10%

P5
94
12%

P4
64
8%

P3
126
17%

P5:Magnesm and Strongly Correlated Electron Systems (Inelasc Scaering)
P6:Fundamental and Nuclear Physics, Instrumentaon, Imaging
P7:Industrial Applicaons
P8:(Reserved)
P9:Trial Use Access Program
Q1:Electronic Properes of Maer & Hydrogen in Maer
Q2:Hydrogen in Maer & General Applicaons

Figure 3. Submitted Proposals by Sub-committee/Expert Panel - FY2019.

152

MLF Operations in 2019

MLF Annual Report 2019

MLF Division Staff 2019
Toshiji Kanaya (Head)

Kazuya Aizawa (Deputy Head)

Kazuhiko Soyama (Deputy Head)

Eiichi Wakai

Toshiya Otomo (Deputy Head)

Izumi Kuwahara

Yasuhiro Miyake (Deputy Head)

Neutron Source Section

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

Hideyuki Nemoto

Shigeto Tanaka

Kenji Sakai (Sub-Leader)

Akihiko Watanabe

Shizuka Yoshinari

Masahide Harada

Hideki Muto

Kyoko Takahashi

Makoto Teshigawara

Kouhei Hanano

Hiroshi Takada *Hiroyuki Kogawa

Mitsuaki Sekijima

Shoichi Hasegawa *Tomokazu Aso

Yoshinori Kikuchi

Eiichi Wakai *Motoki Ooi

Masakazu Nakamura

Shin-ichiro Meigo *Takashi Naoe

Hidemitsu Hosokawa

Hidetaka Kinoshita *Takashi Wakui

Atsushi Akutsu

Kenichi Oikawa *Masakazu Seki

Toshiyuki Yasuhara

Tetsuya Kai *Shiho Masuda

Hiromi Inoue

Hiroyuki Uehara *Akira Shibata

Noriyuki Morikawa

Neutron Science Section

*: additional duties<JAEA>
Kenji Nakajima (Leader)

Yasuhiro Inamura

Misono Fujii

Yukinobu Kawakita (Sub-Leader)

Hiroyuki Aoki

Naoko Shimizu

Kentaro Suzuya

Takuro Kawasaki

Toshiko Goto

Ryoichi Kajimoto

Kousuke Hiroi

Itaru Tamura *Takanori Hattori

Maiko Kofu

Kouji Kaneko *Mitsutaka Nakamura

Naoki Murai

Hiroshi Nakagawa *Stefanus Harjo

Yoshichika Seki

Hideo Harada *Kenichi Oikawa

Takayuki Yamashita

Atsushi Kimura *Takashi Ohhara

Yusuke Tsuchikawa

Shoji Nakamura *Takenao Shinohara

Kanae Ito

Yosuke Toh *Tetsuya Kai

Tatsuya Kikuchi

Mariko Segawa *Seiko Kawamura

Masashi Harada

Masahide Harada *Shinichi Takata

Daigo Setoyama

Kazuya Aizawa *Ryoji Kiyanagi

Takeshi Harada

Masao Watanabe *Kaoru Shibata

Hideaki Isozaki

Dai Yamazaki *Asami Sano

Keiichi Inoue

Hiroshi Suzuki *153

MLF Operations in 2019

MLF Annual Report 2019

Satoshi Morooka *Kazuo Kurihara *Atsushi Moriai *Tarou Tamada *Shunsuke Endo *Yuu Hirano *Takeshi Hiromoto *<KEK>
Shinichi Ito (Sub-Leader)

Norifumi Yamada

Hiroyuki Aoki *Hideki Seto

Takashi Honda

Asami Sano *Toshiya Otomo *Naokatsu Kaneko

Kazutaka Ikeda

Takashi Kamiyama

Shuki Torii

Masato Hagihala

Hitoshi Endo

Hidetoshi Oshita

Hiraku Saito

Testuya Yokoo

Kaoru Taketani

Takashi Saito

Takashi Ino

Kenji Mishima

Cho Kwanghee

Technology Development Section

*: additional duties<JAEA>
Kazuya Aizawa * (Leader)

Wu Gong

Tatsuya Nakamura *Takayuki Oku (Sub-Leader)

Kazuhiro Kawakami

Yasuhiro Inamura *Kazuyoshi Tatsumi

Hiromichi Tanaka

Masahide Harada *Takeshi Nakatani

Hiroyuki Asai

Tomokazu Aso *Masao Watanabe

Yukiko Nagai

Seiko Kawamura *Yuhua Su

Kenji Sakai *Fumiaki Kono *Ryota Komine

Tetsuya Kai *Rumi Shimizu *Takuya Okudaira

Hiroyuki Kogawa *Tatsuhito Matsuo *The Dang Vu

Motoki Ooi *Satoru Fujiwara *Wataru Kambara

Kentaro Suzuya *Motoyasu Adachi *Akihiro Hori

Mitsutaka Nakamura *Shigeki Arai *Hideaki Takahashi

Shinichi Takata *Chie Shibazaki *Ryuta Takahashi

Kaoru Sakasai *<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>

154

Kaoru Sakasai (Leader)

Tatsuya Nakamura

Masashi Suzuki

Dai Yamazaki

Ryuji Maruyama *Yukiko Uno

Kentaro Toh

Tomokatsu Koizumi

Masumi Ebine *MLF Operations in 2019

MLF Annual Report 2019

Muon Science Section

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

Junpei Nakamura

Hirotaka Okabe

Naritoshi Kawamura (Sub-Leader)Takashiro Yuasa

Motonobu Tanpo

Yasuhiro Miyake *Yu OishiTaihei Adachi

Koichiro Shimomura

Yukinori Nagatani

Tatsuhiko Tachibana

Akihiro Koda

Shiro Matoba

Hua LiPatrick Strasser

Soshi Takeshita

Shogo Doiuchi

Takayuki Yamazaki

Hiroaki Natori

Akiko Hashimoto

Hiroshi Fujimori

Dey Sourav Kumar

Yoshinori Ito

Yutaka Ikedo

Shoichiro Nisimura

Izumi Umegaki

Yasuo Kobayashi

Masatoshi Hiraishi<JAEA>
Wataru Higemoto *Takashi Ito *155

MLF Operations in 2019

MLF Annual Report 2019

CROSS Staff 2019
Director

Hideaki Yokomizo

Science Coordinators
Kazuhisa Kakurai

Jun Sugiyama

Takashi Noma

Research & Development Division*: additional duties

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

Kenichi Funakoshi (Deputy Head)

Kazuki Ohishi (Leader)

Koji Kiriyama (Leader)

Tsukasa Miyazaki * (Deputy Head)

Jun-ichi Suzuki *Takayoshi Ito (Sub-Leader)

Sayaka Suzuki *Hiroki Iwase

Yoshifumi Sakaguchi

Yukihiko Kawamura

Hiroshi Kira

<BL01 Group>

Motoyuki Ishikado

Kazuya Kamazawa (Leader)<BL17 Group>

Nobuo Okazaki

Kazuhiko Ikeuchi

Noboru Miyata (Leader)

Shuoyuan Zhang

Kazuki Iida

Kazuhiro Akutsu

Makoto Kobayashi

Takayasu Hanashima

Satoshi Kasai<BL02 Group>

Toshiaki Morikawa

Masato Matsuura (Leader)<BL18 Group>

Hideyuki Hiramatsu

Takeshi Yamada

Akiko Nakao (Leader)

Kentaro Moriyama

Taiki Tominaga

Koji Munakata

Hiroshi Arima

Yoshihisa Ishikawa

Keiichi Ohuchi<BL11 Group>

Masae Sahara

Kenichi Funakoshi * (Leader)<BL22 Group>

Jun AbeHirotoshi Hayashida (Leader)

Shinichi Machida

Joseph Don Parker
Yoshihiro Matsumoto

Safety Division

156*: additional duties

Yasuhiro Yamaguchi (Head)

Tazuko Mizusawa *Koji Kiriyama *Masae Sahara *MLF Annual Report 2019

Utilization Promotion Division

MLF Operations in 2019*: additional duties

Junichi Sato (Head)

Tazuko Mizusawa

Sayaka Suzuki

Tsukasa Miyazaki * (Deputy Head)

Taeko Ishikawa

Yutaka Ebara

Atsuko IrieMaya Endo

Takayoshi Ito *Miho Igarashi

Toshiki Asai (Leader)

Nobuo Okazaki *Seiya Konishi (Leader)

Emi Goto

Administration Division
Michihiko Murasawa (Head)

Rei Ohuchi

Mutsumi Shiraishi

Takashi Hikita (Leader)

Tomoko Sakuma

Shinobu Matsumoto

Industrial Collaboration Promotion Division*: additional duties

Tsukasa Miyazaki (Head)

Seiya Konishi *Jun Abe *Takashi Noma *Noboru Miyata *Takeshi Yamada *157

MLF Operations in 2019

MLF Annual Report 2019

Ibaraki Neutron Beamline Staff in 2019

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

Akinori Hoshikawa

Tomoyuki Nakazawa

Naomine Yano

Takeshi Matsukawa

Mitsuyuki Fujii

Ichiro Tanaka

Yusuke Onuki

Shinju Shibata

Takaaki Hosoya

Satoshi Koizumi

Takumi Inada

Yohei Noda
Tomoki Maeda

158

MLF Annual Report 2019

MLF Operations in 2019

Proposals Review System, Committees and Meetings

Proposal Review System
The JAEA-KEK-CROSS Agreement of Cooperaon on the Promoon of Public Ulizaonof the Specific Neutron Beam Facilies at J-PARC (Enacted on 1 April 2011)
President
CROSS

President
JAEA

Director General
KEK

J-PARC
CenterCollaboraonCommieeDirector
J-PARC(JAEA/KEK)

RegisteredInstuon

Director
CROSS

All except Public Beamlines

Public Beamlines Only

MLF Advisory
Board

SeleconCommiee

(CROSS)

Task Forces

Joint MeengMuon Instrument
Proposal Rev. Comm.

Muon Science
Proposal Rev. Comm.

All except Contract
Beamlines

Contract Beamlines
Only

All except Public
Beamlines

Public Beamlines Only

Neutron Instrument
Proposal Rev. Comm.

Contract Beamline
Evaluaon Comm.

Neutron Science
Proposal Rev. Comm.

Proposal
Evaluaon Comm.

Joint Meeng

Muon
Instrument
Proposals

Joint Meeng

Neutron Instrument
Proposals
Muon Program
Advisory Comm.

Muon Scienfic Proposals

Repor he 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 Evaluaon
CommieeCommiee
Panel
Joint Meeng

Neutron Scienfic Proposals

Unified
Access Point

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

159

MLF Operations in 2019

MLF Annual Report 2019

Materials and Life Science Facility Advisory Board

Kenji Nakajima

Japan Atomic Energy Agency

Kazuya Aizawa

Japan Atomic Energy Agency

Toshiya Otomo

Hiroshi Amitsuka

Hokkaido University

High Energy Accelerator Research
Organization

Taka-hisa Arima

The University of Tokyo

Yoshiharu Sakurai

Japan Synchrotron Radiation
Research Institute

Ryosuke KadonoHigh Energy Accelerator Research
Organization

Taku Sato

Tohoku University

Kazuhisa Kakurai

Comprehensive Research
Organization for Science and Society

Hideki Seto

High Energy Accelerator Research
Organization

Takashi Kamiyama

High Energy Accelerator Research
Organization

Takashi Kamiyama

Hokkaido University

Toshiji Kanaya

High Energy Accelerator Research
Organization

Yukinobu Kawakita

Japan Atomic Energy Agency

Takamitsu Kohzuma

Ibaraki University

Yoji Koike

Tohoku University

Kenya Kubo

International Christian University

Yasuhiro Miyake

High Energy Accelerator Research
Organization

Neutron Science Proposal Review Committee

160

Hiroyuki Kagi

The University of Tokyo

Ryosuke KadonoHigh Energy Accelerator Research
Organization

Toshiji Kanaya

High Energy Accelerator Research
Organization

Yoshiaki Kiyanagi

Nagoya University

Tsukasa Miyazaki

Comprehensive Research
Organization for Science and Society

Kenji Nakajima

Japan Atomic Energy Agency

Kenji Ohoyama

Ibaraki University

Mitsuhiro Shibayama The University of Tokyo
Kazuhiko Soyama

Japan Atomic Energy Agency

Masaaki Sugiyama(chair)

Kyoto University

Jun-ichi Suzuki

Comprehensive Research
Organization for Science and Society

Atsushi Takahara

Kyushu University

Masayasu Takeda

Japan Atomic Energy Agency

Toshio Yamaguchi

Fukuoka University

Term: through March 31, 2021

Hideki Seto

High Energy Accelerator Research
Organization

Shinichi Shamoto

Japan Atomic Energy Agency

Yuichi Shimakawa

Kyoto University

Hirohiko Shimizu

Nagoya University

Masaaki Sugiyama(chair)

Kyoto University

Masayasu Takeda

Japan Atomic Energy Agency

Ichiro Tanaka

Ibaraki University

Term: through September 30, 2019

Muon Science Proposal Review Committee

Wataru Higemoto

Japan Atomic Energy Agency

Tadashi Adachi

Sophia University

Adrian Hillier

Rutherford Appleton Laboratory

Kenta Amemiya

High Energy Accelerator Research
Organization

Ryosuke KadonoHigh Energy Accelerator Research
Organization

Hiroshi Amitsuka

Hokkaido University

Toshiji Kanaya

Hidehito Asaoka

Japan Atomic Energy Agency

High Energy Accelerator Research
Organization

Toshiyuki Azuma

Institute of Physical and Chemical
Research

Naritoshi Kawamura

High Energy Accelerator Research
Organization

Katsuyuki Fukutani

The University of Tokyo

Yasushi Kino

Tohoku University

MLF Annual Report 2019

MLF Operations in 2019

Akihiro Koda

High Energy Accelerator Research
Organization

Toshiya Otomo

High Energy Accelerator Research
Organization

Kenya Kubo (chair)International Christian University

Hideki Seto

Roderick Macrae

Marian University

High Energy Accelerator Research
Organization

Yasuyuki Matsuda

The University of Tokyo

Tatsushi Shima

Osaka University

Tsutomu Mibe

High Energy Accelerator Research
Organization

Koichiro Shimomura

High Energy Accelerator Research
Organization

Yasuhiro Miyake

High Energy Accelerator Research
Organization

Jun Sugiyama

Toyota Central R&D Labs.

Masaaki Sugiyama

Kyoto University

Kenji Nakajima

Japan Atomic Energy Agency

Toshiyuki Takayanagi Saitama University

Chihiro OhmoriHigh Energy Accelerator Research
Organization

Hideki Tou

Kobe University

Term: through March 31, 2019

Proposal Evaluation Committee

Shinichi Shamoto

Japan Atomic Energy Agency

Hiroyuki Kagi

The University of Tokyo

Yuichi Shimakawa

Kyoto University

Toshiji Kanaya

High Energy Accelerator Research
Organization

Hirohiko Shimizu

Nagoya University

Nagoya University

Masaaki Sugiyama(chair)

Kyoto University

Yoshiaki Kiyanagi
Tsukasa Miyazaki

Comprehensive Research
Organization for Science and Society

Ichiro Tanaka

Ibaraki University

Kenji Ohoyama

Ibaraki University

Selection Committee

Term: through September 30, 2019

Yoshiharu Sakurai

Japan Synchrotron Radiation
Research InstituteTaku Sato

Tohoku University

Taka-hisa Arima

The University of Tokyo

Yasuhiro Iye (chair)Japan Society for Promotion of
Science

Takashi Kamiyama

Hokkaido University

Masaaki Sugiyama

Kyoto University

Hiroyuki Kishimoto

Sumitomo Rubber Industries, LTD.

Atsushi Takahara

Kyushu University

Hideaki Kitazawa

Research Center for Strategic
Materials

Shinji Tsuneyuki

The University of Tokyo

Toshio Yamaguchi

Fukuoka University

Yoji Koike

Tohoku University

Takamitsu Kohzuma

Ibaraki University

Mitsuhiro Shibayama The University of Tokyo

Term: through March 31, 2021

161

MLF Operations in 2019

MLF Annual Report 2019

Neutron Advisory Committee (NAC)
NAC convened on 17–18 February, 2020 at the J-PARC site, TokaiGroup photo of NAC

Neutron Advisory Committee (17–18 Feb. 2020)

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

Institute of Physical and Chemical Research

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 on 25–26 February, 2020 at the KEK Tokai Campus, TokaiGroup photo of MAC

162

Muon Advisory Committee (25–26 Feb. 2020)

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 2019

MLF Operations in 2019

Workshops, Conferences, Seminars and Schools in 2019
Conferences held jointly by J-PARC MLF and CROSS

Workshops held by KEK

2019 Meeting on J-PARC MLF Industrial Use
18–19 Jul. 2019, Akihabara Convention Hall, Tokyo

Fundamental Physics with Pulsed Cold Neutrons(BL05)
20–21 Dec. 2019, Nagoya Univ., Aichi
High-Resolution Neutron Powder Diffraction
Method using SuperHRPD (BL08)
11 Dec. 2019, KEK Tokai Campus, Tokai
Dynamics using High Resolution Chopper
Spectrometer (BL12)16 Dec. 2019, KEK Tokai Campus, Tokai

Photo of the 2019 Meeting on J-PARC MLF Industrial Use(photo courtesy of J-PARC Center)

The 3rd J-PARC Symposium (the 10th Anniversary)
23–26 Oct. 2019, Epochal Tsukuba, Ibaraki

Order-disorder structural analysis of functional
materials using high-intensity neutron total
scattering method (BL21)
29 Nov. 2019, KEK Tokai Campus, Tokai
Elucidation of cross-correlation physics using thePolarized Neutron Spectrometer, POLANO (BL23)
5 Dec. 2019, KEK Tokai Campus, Tokai
1st Symposium on Integration of Humanities andScience
27–28 Jul. 2019, National Museum of Nature andScience, Tokyord

Photo of The 3 J-PARC Symposium (the 10th Anniversary)(photo courtesy of J-PARC Center)

AOCNS 2019 & 19th JSNS meeting
16–21 Nov. 2019, Kenting, Taiwan
MRM2019
10–14 Dec. 2019, Yokohama Symposia, Kanagawa
2019 Z-Code Beginner Level Training Course
7–8 Nov. 2019, Essam Kanda Hall, Tokyo

2nd Symposium on Integration of Humanities andScience
25–26 Dec. 2019, Osaka University, Osaka

Workshops and Seminars held by CROSS andother organizations
1st Meeting on evaluation method of reinforced
concrete using neutron
10 Apr. 2019, IBARAKI Quantum Beam Research Center,
Tokai
Explanatory meeting on evaluation method of
reinforced concrete using neutron
18 Apr. 2019, J-PARC Research Building, Tokai

163

MLF Operations in 2019

MLF Annual Report 2019

1st Meeting on materials research using neutron
under high pressure
15 Aug. 2019, TKP Tokyo
The 22nd CROSSroads Workshop“Neutron Scattering for the Material Science ofWater, Ice and Hydrides”
15 May 2019, IBARAKI Quantum Beam Research Center,
Tokai

Workshop of Tohoku Univ. & CROSS“Development of new science by complemental useof polarized neutrons at J-PARC and JRR-3”
22–23 Aug. 2019, Tohoku Univ., Miyagi
6th Symposium on the Collaborative Use of Large
Research Institutions and the KEI Super Computer2019
17 Sep. 2019, Akihabara UDX, Tokyo
2nd Meeting on materials research using neutron
under high pressure
28 Oct. 2019, TKP Tokyo station conference center, Tokyo

Group photo of the CROSSroads 22 (photo courtesy of CROSS)

2nd Meeting on evaluation method of reinforced
concrete using neutron
20 Jun. 2019, Hazama Ando Corp., Tokyord

3 Meeting on evaluation method of reinforced
concrete using neutron
19 Aug. 2019, Tokyo University of Science, Noda campus,
Chiba
st

2019 1 Workshop on Structural Biology
28 Nov. 2019, Essam Kanda Hall, Tokyo
2019 Workshop on Materials Science &2019 2nd Workshop on iMATERIA“Forefront of solar cell research”
20 Aug. 2019, Essam Kanda Hall, Tokyo
2019 Workshop on Soft Matter Neutron Scattering &2019 2nd Workshop on iMATERIACurrent status and development of dynamic
spin-polarized neutron small-angle scattering(DNP-SANS)
21 Aug. 2019, Essam Kanda Hall, Tokyo164

4th Meeting on evaluation method of reinforced
concrete using neutron
31 Oct. 2019, Tokyo University of Science, Noda campus,
Chiba2019 Neutron experiment technique training
course29 Nov. 2019, Essam Kanda Hall, Tokyo
1st Joint Workshop for Complementary Use of
Synchrotron Radiation and Neutrons“Small-angle X-ray scattering measurement”
28 Nov. 2019, SPring-8, Hyogo
2nd Joint Workshop for Complementary Use of
Synchrotron Radiation and Neutrons“Toward mutual use of X-rays and neutron inelastic
scattering”
9 Dec. 2019, SPring-8, Hyogo
2019 Workshop on Non-destructive Visualization
and Analysis Methods
20 Dec. 2019, Essam Kanda Hall, Tokyo
23rd CROSSroads Workshop“Sample Environment at Quantum Beam
Experimental Facilities”
8 Jan. 2020, IBARAKI Quantum Beam Research Center,
Tokai

MLF Annual Report 2019

MLF Operations in 20192019 Workshop on Metallographic Structure
14 Jan. 2020, Essam Kanda Hall, Tokyo
2019 Workshop on Magnetic Materials
17 Jan. 2020, Essam Kanda Hall, Tokyo
2019 Workshop on Battery Materials &2019 Workshop on Surfaces and Interfaces
29 Jan. 2020, Essam Kanda Hall, Tokyo

Schools in 2019
Hello Science from J-PARC: Exploring materials
with muon
31 May 2019, iVil, Tokai
Hello Science from J-PARC: Identifying Energy
Related Materials with Muon Particles
20 Sep. 2019, iVil, Tokai
Hello Science from J-PARC: Using Neutrons to
Capture the Fleeting Moments of Bubbles
25 Oct. 2019, iVil, Tokai
The 4th Neutron and Muon School and MIRAI PhD
School 201928 Oct. – 2 Nov. 2019, J-PARC Center and IBARAKI
Quantum Beam Research Center, TokaithGroup photo of the 4 Neutron and Muon School(photo courtesy of J-PARC Center)165

MLF Operations in 2019

MLF Annual Report 2019Award List
The Sawamura Award of the Iron and Steel Instituteof JapanIn situ Neutron Diffraction Study on Ferrite and Pearlite
Transformations for a 1.5Mn-1.5Si-0.2C SteelY. Tomota, Y. Wang, T. Ohmura, N. Sekido, S. Harjo,
T. Kawasaki, W. Gong, A. Taniyama (2020-03-17)
Encouragement Award for Graduate Student,
Department of Architecture Graduate School of
Science, Tokyo University of Science
Research on deformation analysis of reinforced concrete
using neutron imaging technology
K. Ueno (2020-03-17)
Japan Building Materials Association Outstanding
Student Award
Research on deformation analysis of reinforced concrete
using neutron imaging technology
K. Ueno (2020-03-05)
The Atomic Energy Society of Japan Kyushu Office
Young Researcher Award
Measurement of SEU rates for SRAMs under Irradiation of
Spallation Neutrons
J. Kuroda (2019-12-07)

166

The JSNS Achievement Prize
Pioneering research and leading role in the use of pulsed
neutrons
M. Arai (2019-11-20)
The JSNS Technology Prize
Development of the neutron flatpanel detector
H. Takahashi, T. Fujiwara (2019-11-20)
The JSNS Young Researcher Prize
Investigations on low-dimensional and frustrated
magnets
K. Nawa (2019-11-20)
The JSNS Young Researcher Prize
Microstructual characterizaton in steel using small-angle
neutron scattering
Y. Oba (2019-11-20)
The Japan Society of Applied Physics Young Scientist
Presentation Award
Synthesis and fast H- conduction of new lanthanum
oxyhydride LaH3-2xOx
K. Fukui (2019-11-13)

3rd Asia-Oceanian Conference on Neutron
Scattering Best Poster Award
Crystal structure of organic conductor l-(BETS)2FeCl4
studied by SENJU J-PARC
Y. Noda (2019-11-21)

Japan Association of Mineralogical Science Young
Researcher Award
Elucidation of the behavior of carbon, hydrogen, andnitrogen-related substances in the interior of the Earthand icy celestial bodies.
A. Shinozaki (2019-09-22)

3rd Asia-Oceanian Conference on Neutron
Scattering Best Poster Award
Structures of mixed surfactants in solution for industrial
application
M. Ohno (2019-11-20)

The 58th Annual Meeting of the Japan Oil Chemists’Society, Oral, Student Presentation Award
Rapid Control of Interfacial Property with Light Irradiation
by Using Amphiphilic Lophine Dimers
K. Kobayashi (2019-09)

Best Poster Award (Second Place Award) -Session 1:
Condensed Matter Physics- at the 3rd Asia-Oceanian
Conference on Neutron Scattering
Localized magnetic excitations in the fully frustrated
dimerized magnets
N. Kurita (2019)

CerSJ Award for Advancements in Ceramic Scienceand Technology
Research of oxide type solid-state electrolytes andelectrode activation materials
K. Kataoka (2019-06-07)

MLF Annual Report 2019

MLF Operations in 2019

The Award from the Society of Rubber Science andTechnology, Japan
Thermal property of bound rubber at interface withcarbonK. Hori (2019-05-23)
CerSJ Poster Award
Evaluation of magnetic anisotropy and magnetic structureof X-type hexaferrite crystal
M. Komabuchi (2019-05-15)
CerSJ Electronics Division Young Researchrs Award
Development of all-solid-state secondary lithium battery
using garnett-type solid-state single-crystal electrolyte
K. Kataoka (2018-11-16)

JSNS: The Japanese Society for Neutron Science
CerSJ: The Ceramic Society of Japan167

MLF Operations in 2019

MLF Annual Report 2019

MLF Publication 2019
1

2

S. Goto, H. Kura, H. Yanagihara, E. Kita, M. Tsujikawa, R. Sasaki, M.
Shirai, Y. Kobayashi, T. Honda, and K. Ono,
Positive Weiss Temperature in Layered Antiferromagnetic FeNiN for
High-Performance Permanent Magnets
ACS Appl. Nano Mater., 2 6909–6917 (2019).

3

M. Inutsuka, M. Haraguchi, M. Ozawa, N.L. Yamada, and K. Tanaka,
Adhesion Control of Elastomer Sheet on the Basis of Interfacial
Segregation of Hyperbranched Polymer
ACS Macro Letters, 8 267–271 (2019).

4

Y. Sawama, K. Ban, K. Akutsu-Suyama, H. Nakata, M. Mori, T.
Yamada, T. Kawajiri, N. Yasukawa, K. Park, Y. Monguchi, Y. Takagi,
M. Yoshimura, and H. Sajiki,
Birch-Type Reduction of Arenes in 2‑Propanol Catalyzed by ZeroValent Iron and Platinum on Carbon
ACS Omega, 4 11522–11531 (2019).

5

Y. Shibuya, K. Katayama, K. Akutsu-Suyama, and A. Yamaguchi,
Continuous mesoporous aluminum oxide film with perpendicularly
oriented mesopore channels
ACS Omega, 4 17890–17893 (2019).

6

H. Fukui, M. Fujimoto, Y. Akahama, A. Sano-Furukawa, and T. Hattori,
Structure change of monoclinic ZrO2 baddeleyite involving softeningsof bulk modulus and atom vibrations
Acta Crystallogr. B, 75 742–749 (2019).

7

K. Yamashita, K. Komatsu, T. Hattor, S. Machida, and H. Kagi,
Crystal structure of a high-pressure phase of magnesium chloridehexa­hydrate determined by in-situ X-ray and neutron diffraction
methods
Acta Crystallogr. C Struct. Chem., C75 1605–1612 (2019).

8

9

168

K. Mukai, M. Yashima, K. Hibino, and T. Terai,
Experimental Visualization of Interstitialcy Diffusion of Li Ion in
β-Li2TiO3
ACS Appl. Energy Mater., 2 5481–5489 (2019).

A. Ahadi, T. Kawasaki, S. Harjo, W.-S. Ko, Q.P. Sun, and K. Tsuchiya,
Reversible elastocaloric effect at ultra-low temperatures innanocrystalline shape memory alloys
Acta Mater., 165 109–117 (2019).
A. Ahadi, R. Khaledialidusti, T. Kawasaki, S. Harjo, A. Barnoush, and
K. Tsuchiya,
Neutron diffraction study of temperature-dependent elasticity of B19’
NiTi---Elinvar effect and elastic softening
Acta Mater., 173 281–291 (2019).

analysis
AIP Adv., 10 015323 (2019).
13

Y. Wang, X. Dong, X. Tang, H. Zheng, K. Li, X. Lin, L. Fang, G. Sun, X.
Chen, L. Xie, C.L. Bull, N.P. Funnell, T. Hattori, A. Sano-Furukawa, J.
Chen, D.K. Hensley, G. Cody, Y. Ren, H.H. Lee, and H. Mao,
Pressure-Induced Diels-Alder Reactions in C6H6-C6F6 Cocrystal towards
Graphane Structure
Angew. Chem. Int. Ed. Engl., 58 1468–1473 (2019).

14

P. Miao, R. Wang, W. Zhu, J. Liu, T. Liu, J. Hu, S. Li, Z. Tan, A. Koda, F.
Zhu, E. Feng, Y. Su, T. Kamiyama, Y. Xiao, and F. Pan,
Revealing magnetic ground state of a layered cathode material bymuon spin relaxation and neutron scattering experiments
Appl. Phys. Lett., 114 203901 (2019).

15

K.M. Kojima, M. Hiraishi, H. Okabe, A. Koda, R. Kadono, K. Ide, S.
Matsuishi, H. Kumomi, T. Kamiya, and H. Hosono,
Electronic structure of interstitial hydrogen in In-Ga-Zn-O
semiconductor simulated by muon
Appl. Phys. Lett., 115 122104 (2019).

16

T. Sugiura, C. Takahashi, Y. Chuma, M. Fukuda, M. Yamada, U.
Yoshida, H. Nakao, K. Ikeda, D. Khan, A.H. Nile, V.A. Bankaitis, and
M. Nakano,
Biophysical parameters of the Sec14 phospholipid exchange cycle
Biophys. J., 116 92–103 (2019).

17

Y. Kameda, Y. Amo, T. Usuki, Y. Umebayashi, K. Ikeda, and T. Otomo,
Origin of the Difference in Ion-Water Distances Determined by X-ray
and Neutron Diffraction Measurements for Aqueous NaCl and KCl
Solutions
Bull. Chem. Soc. Jpn., 92 754–767 (2019).

18

M. Toshiyuki, S. Takagi, K. Shimoda, K. Okazaki, Y. Ishikawa, M.
Yonemura, Y. Ukyo, T. Fukunaga, and E. Matsubara,Comprehensive elucidation of crystal structures of lithiumintercalated graphite
Carbon, 142 513–517 (2019).

19

N. Kitamura, Y. Tanabe, N. Ishida, and Y. Idemoto,
The atomic structure of a MgCo2O4 nanoparticle for a positiveelectrode of a Mg rechargeable battery
Chem. Commun., 55 2517–2520 (2019).

20

M. Harada, K. Kudo, and N.L. Yamada,Compositional Segregation in Cross Section of Wet Nafion Thin Filmon Platinum Surface
Chem. Lett., 48 51–54 (2019).

10

K. Osamura, S. Machiya, K. Kajiwara, T. Kawasaki, S. Harjo, Y. Zhang,
S. Fujita, Y. Iijima, and D.P. Hampshire,
Inverted-parabolic and weak strain dependencies on the criticalcurrent in practical<110> and<100> oriented REBCO tapes
AIP Adv., 9 75216 (2019).

21

T. Sugahara, M. Akamatsu, H. Iwase, Y. Takamatsu, K. Sakai, and H.
Sakai,
Small-angle neutron scattering study of micelle structure andhydration behavior of oleic acid-based gemini surfactant
Chem. Lett., 48 1050–1053 (2019).

11

H. Kawasoko, K. Ohoyama, R. Sei, K. Matsumoto, D. Oka, A.
Hoshikawa, T. Ishigaki, and T. Fukumura,
Investigation of magnetism and magnetic structure of anti-ThCr2Si2type Tb2O2Bi by magnetization and neutron diffraction measurements
AIP Adv., 9 115301 (2019).

22

M. Nakano,
Evaluation of interbilayer and transbilayer transfer dynamics ofphospholipids using time-resolved small-angle neutron scattering
Chem. Pharm. Bull., 67 316–320 (2019).

23
12

Y. Zhong, Y. Kurokawa, G. Nagashima, S. Horiike, T. Hanashima, D.
Schönke, P. Krautscheid, R.M. Reeve, M. Kläui, and H. Yuasa,
Determination of fine magnetic structure of magnetic multilayer withquasi antiferromagnetic layer by using polarized neutron reflectivity

S. Benz, R. Missong, G. Ogutu, R. Stoffel, U. Englert, S. Torii, P. Miao,
T. Kamiyama, and R. Dronskowski,
Ammonothermal Synthesis, X-Ray and Time-of-Flight Neutron
Crystal-Structure Determination, and Vibrational Properties of Barium
Guanidinate, Ba(CN3H4)2

MLF Annual Report 2019

ChemistryOpen, 8 327–332 (2019).
24

25

26

27

28

29

T. Sato, L.L. Daemen, Y. Cheng, A.J. Ramirez-Cuesta, K. Ikeda, T. Aoki,
T. Otomo, and S. Orimo,
Hydrogen‐Release Reaction of a Complex Transition Metal Hydridewith Covalently Bound Hydrogen and Hydride Ions
Chemphyschem, 20 1392–1397 (2019).

New precise measurements of muonium hyperfine structure at J-PARC
MUSE
EPJ Web Conf., 198 3 (2019).
35

N.V. Mdlovu, F.A. Mavuso, K.-S. Lin, T.-W. Chang, Y. Chen, Y.-H. Tsai,
S.S.-S. Wang, C.-M. Wu, N.B. Mdlovu, and Y.-S. Lin,
Iron oxide-pluronic F127 polymer nanocomposites as carriers for
doxorubicin drug delivery system
Colloids Surf. A Physicochem. Eng. Asp., 562 361–369 (2019).

N. Nagakura, K. Hirota, S. Ieki, T. Ino, Y. Iwashita, M. Kitaguchi, R.
Kitahara, J. Koga, K. Mishima, A. Morishita, Y. Nakano, H. Oide, H.
Okabe, H. Otono, Y. Seki, D. Sekiba, T. Shima, H. Shimizu, N. Sumi, H.
Sumino, K. Taketani, T. Tomita, H. Uehara, T. Yamada, S. Yamashita,
M. Yokohashi, and T. Yoshioka,
New project for precise neutron lifetime measurement at J-PARC
EPJ Web Conf. (PPNS2018), 219 03003 (2019).

36

M. Ishikado, K. Kodama, R. Kajimoto, M. Nakamura, Y. Inamura, K.
Ikeuchi, S. Ji, M. Arai, and S. Shamoto,Q Dependence of Magnetic Resonance Mode on FeTe0.5Se0.5 Studied
by Inelastic Neutron Scattering
Condens. Matter., 4 69 (2019).

C. Haddock, K. Hirota, T. Ino, M. Kitaguchi, K. Mishima, N. Oi, T.
Shima, H. Shimizu, W.M. Snow, and T. Yoshioka,
A search for deviations from the inverse square law of gravity at nm
range using a pulsed neutron beam
EPJ Web Conf. (PPNS2018), 219 05002 (2019).

37

R. Maruyama, T. Bigault, T. Saerbeck, D. Honecker, K. Soyama, and
P. Courtois,
Coherent magnetization rotation of a layered system observed bypolarized neutron scattering under grazing incidence geometry
Crystals, 9 383 (2019).

K. Mishima, T. Otomo, K. Ikeda, and H. Ohshita,
Neutron scattering cross section of diamond nanoparticle
EPJ Web Conf. (PPNS2018), 219 10005 (2019).

38

T.-N. Lam, Y.-S. Chou, Y.-J. Chang, T.-R. Sui, A.-F. Yeh, S. Harjo, S.Y. Lee,J. Jain, B.-H. Lai, and E.-W. Huang,Comparing Cyclic Tension-Compression Effects on CoCrFeMnNi HighEntropy Alloy and Ni-Based Superalloy
Crystals, 9 420 (2019).

T. Yamaguchi, M. Nishino, K. Yoshida, M. Takumi, K. Nagata, andT. Hattori,
Ion hydration and association in an aqueous calcium chloride solution
in the GPa range
Eur. J. Inorg. Chem., 2019 1170–1177 (2019).

39

K. Máthis, D. Drozdenko, G. Németh, S. Harjo, W. Gong, K. Aizawa,
M. Yamasaki, and Y. Kawamura,In-situ investigation of the microstructure evolution in long-periodstacking-ordered (LPSO) magnesium alloys as a function of thetemperature
Front. Mater., 6 270 (2019).

40

T. Hattori, A. Sano-Furukawa, S. Machida, J. Abe, K. Funakoshi, H.
Arima, and N. Okazaki,
Development of a technique for high pressure neutron diffraction at
40 GPa with a Paris-Edinburgh press
High Press. Res., 39 417–425 (2019).

41

J. Sugiyama,Spin polarized beam for battery materials research: μ±SR and β-NMR
Hyperfine Interact., 240 17 (2019).

42

W. Liao, M. Hashimoto1, S. Manabe, Y. Watanabe, S. Abe, K. Nakano,
H. Takeshita, M. Tampo, S. Takeshita, and Y. Miyake,
Negative and Positive Muon-Induced SEU Cross Sections in 28-nm and
65-nm Planar Bulk CMOS SRAMs
IEEE International Reliability Physics Symposium Proceedings,
2019 8720568 (2019).

43

H. Yamaguchi, K. Sasaki, T. Tanaka, M. Abe, D. Flay, D. Kawall,
Tsutomu Mibe, S. Seo, K. Shimomura, Y. Ueno, and P. Winter,
Development of a CW-NMR Probe for Precise Measurement ofAbsolute Magnetic Field
IEEE Trans. Appl. Supercond., 29 9000904 (2019).

44

S. Hashimoto, K. Kurozono, K. Yano, T. Yamauchi, K. Shibata, T.
Yamada, K. Nakajima, T. Kikuchi, and K. Kamazawa,
Analysis on Enhancement of Thermal Conductivity in Nanofluids
Innovative Materials for Processes in Energy Systems (IMPRES2019), D309 (2019).

45

Y. Yasui, E. Niwa, M. Matsui, K. Fujii, and M. Yashima,
Discovery of a Rare-Earth-Free Oxide-Ion Conductor Ca3Ga4O9
by Screening through Bond Valence-Based Energy Calculations,
Synthesis, and Characterization of Structural and Transport Properties
Inorg. Chem., 58 9460–9468 (2019).

46

R. Kataoka, T. Kimura, K. Sakaki, M. Nozaki, T. Kojima, K. Ikeda, T.
Otomo, N. Takeichi, and A. Kamegawa,

T. Matsukawa, T. Honda, H. Ohshita, T. Otomo, and T. Ishigaki,
Average and local structures of κ-phase CeZrO4 crystals by neutron
powder diffraction
CrystEngComm, 21 6335–6339 (2019).

30

M. Sugishima, K. Wada, M. Unno, and K. Fukuyama,
Bilin-metabolizing enzymes: site-specific reductions catalyzed by two
different type of enzymes
Curr. Opin. Struct. Biol., 59 73–80 (2019).

31

T. Nakane, S. Yoneyama, T. Kodama, K. Kikuchi, A. Nakao, T. Ohhara,
R. Higashinaka, T.D. Matsuda, Y. Aoki, and W. Fujita,
Magnetic, thermal, and neutron diffraction studies of a coordination
polymer: bis(glycolato)cobalt(II)Dalton Trans., 48 333 (2019).

32

Y. Idemoto, Y. Mizutani, C. Ishibashi, N. Ishida, and N. Kitamura,
Synthesis, crystal structure and electrode properties of spinel-type
MgCo2−xMnxO4
Electrochemistry, 87 220–228 (2019).

33

T. Kawamoto, M. Aoki, T. Kimura, P. Chinapang, T. Mizusawa, N.L.
Yamada, F. Nemoto, T. Watanabe, H. Tanida, M. Matsumoto, H. Imai,
J. Miyake, K. Miyatake, and J. Inukai,
Sublayered Structures of Hydrated Nafion® Thin Film Formed by
Casting on Pt Substrate Analyzed by X-ray Absorption Spectroscopy
under Ambient Conditions and Neutron Reflectometry at Temperatureof 80°C and Relative Humidity of 30–80%
Electrochemistry, 87 270–275 (2019).

34

MLF Operations in 2019

P. Strasser, M. Abe, M. Aoki, S. Choi, Y. Fukao, Y. Higashi, T. Higuchi,
H. Iinuma, Y. Ikedo, K. Ishida, T. Ito, T.U. Ito, M. Iwasaki, R. Kadono,
O. Kamigaito, S. Kanda, K. Kawagoe, D. Kawall, N. Kawamura, M.
Kitaguchi, A. Koda, K.M. Kojima, K. Kubo, M. Matama, Y. Matsuda,
Y. Matsudate, T. Mibe, Y. Miyake, T. Mizutani, K. Nagamine, S.
Nishimura, T. Ogitsu, N. Saito, K. Sasaki, S. Seo, H.M. Shimizu, K.
Shimomura, T. Suehara, M. Tajima, K.S. Tanaka, T. Tanaka, J. Tojo,
D. Tomono, H.A. Torii, E. Torikai, A. Toyoda, Y. Tsutsumi, K. Ueno, Y.
Ueno, D. Yagi, A. Yamamoto, T. Yamanaka, T. Yamazaki, H. Yasuda,
M. Yoshida, and T. Yoshioka,

169

MLF Operations in 2019

MLF Annual Report 2019

Facile Synthesis of LiH-Stabilized Face-Centered-Cubic YH3 HighPressure Phase by Ball Milling Process
Inorg. Chem., 58 13102−13107 (2019).
47

48

A. Lavakumar, M.H. Park, S. Gao, A. Shibata, Y. Okitsu, W. Gong, S.
Harjo, and N. Tsuji,
In-situ neutron diffraction study on the deformation of a TRIP-assisted
multi-phase steel composed of ferrite, austenite and martensite
IOP Conf. Ser. Mater. Sci. Eng., 580 012036 (2019).

49

H. Mizoguchi, S.-W. Park, K. Kishida, M. Kitano, J. Kim, M. Sasase, T.
Honda, K. Ikeda, T. Otomo, and H. Hosono,
Zeolitic Intermetallics: LnNiSi (Ln = La–Nd)
J. Am. Chem. Soc., 141 3376–3379 (2019).

50

Y. Yasuda, Y. Hidaka, K. Mayumi, T. Yamada, K. Fujimoto, S. Okazaki,
H. Yokoyama, and K. Ito,
Molecular Dynamics of Polyrotaxane in Solution Investigated by
Quasi-Elastic Neutron Scattering and Molecular Dynamics Simulation:
Sliding Motion of Rings on Polymer
J. Am. Chem. Soc., 141 9655–9663 (2019).

51

S. Koizumi, S. Ueda, T. Inada, Y. Noda, and R.A. Robinson,
Microstructure and water distribution in catalysts for polymer
electrolyte fuel cells, elucidated by contrast variation small-angle
neutron scattering
J. Appl. Crystallogr., 52 791–799 (2019).

52

T. Yamada, N. Yano, T. Hosoya, and K. Kusaka,
Single-crystal time-of-flight neutron Laue methods: application to
manganese catalase from Thermus thermophilus HB27
J. Appl. Crystallogr., 52 972–983 (2019).

53

T. Kumada, K. Akutsu, K. Ohishi, T. Morikawa, Y. Kawamura, M.
Sahara, J. Suzuki, and N. Torikai,
Development of spin-contrast-variation neutron reflectometry for the
structural analysis of multilayer films
J. Appl. Crystallogr., 52 1054–1060 (2019).

54

T. Fukuda, T. Yamaguchi, T. Kakeshita, S. Harjo, and T. Nakamoto,
Neutron diffraction study on martensitic transformation undercompressive stress in an ordered Fe3Pt
J. Appl. Phys., 126 25107 (2019).

55

T. Komori, T. Hirose, T. Gushi, K. Toko, T. Hanashima, L. Vila, J.-P.
Attanè, K. Amemiya, and T. Suemasu,
Magnetic reversal in rare-earth free Mn4−xNixN epitaxial films below
and above Ni composition needed for magnetic compensation
around room temperature
J. Appl. Phys., 127 043903 (2019).

56

57

58

170

J. Hu, K. Lin, Y. Cao, R. Huang, T. Matsukawa, T. Ishigaki, H. Fischer,
K. Kato, T. Honda, K. Ikeda, T. Otomo, K. Ohoyama, J. Deng, J. Chen,
and X. Xing,
A case of multifunctional intermetallic compounds: negative thermal
expansion coupling with magnetocaloric effect in (Gd,Ho)(Co,Fe)2Inorg. Chem. Front., 6 3146–3151 (2019).

M. Ooe, K. Miyata, J. Yoshioka, K. Fukao, F. Nemoto, and N.L. Yamada,
Direct observation of mobility of thin polymer layers via asymmetricinterdiffusion using neutron reflectivity measurements
J. Chem. Phys., 151 244905 (2019).
H. Iwase, R. Kawai, K. Morishima, S. Takata, T. Yoshimura, and M.
Shibayama,
Rheo-SANS study on relationship between micellar structures andrheological behavior of cationic gemini surfactants in solution
J. Colloid Interface Sci., 538 357–366 (2019).
H. Frielinghaus, K. Koch, V.P. Antonio, Y. Noda, and S. Koizumi,
The locally columnar model for clay/polymer systems: Connections
to scattering experiments

J. Colloid Interface Sci., 544 172–177 (2019).
59

K. Shimizu, H. Hayashida, H. Toda, T. Kai, Y. Matsumoto, and Y.
Matsumoto,
Neutron Imaging Analysis of Hydrogen Content in Pure Palladium andAluminum Alloys
J. Japan Inst. Met. Mater, 83 434–440 (2019).

60

T. Matsushita, V. Sonnenschein, W. Guo, H. Hayashida, K. Hiroi, K.
Hirota, T. Iguchi, D. Ito, M. Kitaguchi, Y. Kiyanagi, S. Kokuryu, W.
Kubo, Y. Saito, H.M. Shimizu, T. Shinohara, S. Suzuki, H. Tomita, Y.
Tsuji, and N. Wada,
Generation of 4He*2 Clusters via Neutron-3He Absorption Reaction
towards Visualization of Full Velocity Field in Quantum Turbulence
J. Low Temp. Phys., 196 275–282 (2019).

61

K. Asami, M. Shiraiwa, J. Ueda, K. Fujii, K. Hongo, R. Maezono, M.G.
Brik, M. Yashima, and S. Tanabe,
Crystal structure analysis and evidence of mixed anion coordination at
the Ce3+ site in Y3Al2(Al,Si)3(O,N)12 oxynitride garnet phosphor
J. Mater. Chem. C Mater., 7 1330–1336 (2019).

62

S. Fujiwara, F. Kono, T. Matsuo, Y. Sugimoto, T. Matsumoto, A. Narita,
and K. Shibata,
Dynamic properties of human-synuclein related to propensity toamyloid fibril formation
J. Mol. Biol., 431 3229–3245 (2019).

63

A. Hyde, M. Ohshio, C.V. Nguyen, S. Yusa, N.L. Yamada, and C.M.
Phan,
Surface Properties of the Ethanol/Water Mixture: Thickness andComposition
J. Mol. Liq., 290 111005 (2019).

64

H. Abe, T. Takekiyo, Y. Yoshimura, and A. Shimizu,
Static and dynamic properties of nano-confined water in roomtemperature ionic liquids
J. Mol. Liq., 290 111216 (2019).

65

K. Yoshida, T. Zenin, A. Fujiyoshi, Y. Sanada, T. Yamaguchi, K. Murata,
S. Takata, K. Hiroi, T. Takekiyo, and Y. Yoshimura,
The effect of alkyl ammonium ionic liquids on thermal denaturation
aggregation of β-lactoglobulin
J. Mol. Liq., 293 111477 (2019).

66

S. Ohira-Kawamura, R. Takahashi, M. Ishikado, Y. Yamauchi, M.
Nakamura, K. Ohuchi, H. Kira, W. Kambara, K. Aoyama, Y. Sakaguchi,
M. Watanabe, and T. Oku,
Cryogenic sample environments shared at the MLF, J-PARC
J. Neutron Res., 21 17–22 (2019).

67

Y. Sakaguchi, R. Takahashi, S. Kasai, K. Ohuchi, and T. Morikawa,
Sample environment equipment for light irradiation experiments at
J-PARCJ. Neutron Res., 21 23–28 (2019).

68

Y. Sakaguchi, S. Takata, H. Arima, and R. Takahashi,High temperature furnace for small-angle neutron scattering
instrument at J-PARC
J. Neutron Res., 21 29–38 (2019).

69

M. Watanabea and H. Nojiri,
Pulsed magnet system at MLF in J-PARC
J. Neutron Res., 21 39–45 (2019).

70

H. Ishikawa, T. Kai, H. Sato, and T. Kamiyama,
Neutron spectrum change with thermal moderator temperature in acompact electron accelerator-driven neutron source and its effects onspectroscopic neutron transmission imaging
J. Nucl. Sci. Technol., 56 221 (2019).

71

A. Kimura, S. Nakamura, K. Terada, T. Nakao, K. Mizuyama, N.

MLF Annual Report 2019

Iwamoto, O. Iwamoto, H. Harada, T. Katabuchi, M. Igashira, T. Sano,
Y. Takahashi, C.H. Pyeon, S. Fukutani, T. Fujii, T. Yagi, K. Takamiya,and J. Hori,
Measurements of the 243Am neutron capture and total cross sections
with ANNRI at J-PARC
J. Nucl. Sci. Technol., 56 479–492 (2019).
72

73

74

75

76

77

78

79

80

MLF Operations in 2019

Hybridization and Decay of Magnetic Excitations in Two-Dimensional
Triangular Lattice Antiferromagnets
J. Physical Soc. Japan, 88 081003 (2019).
83

S. Itoh and Y. Endoh,
Neutron Brillouin Scattering and Low-Q Dynamics in Condensed
MatterJ. Physical Soc. Japan, 88 081004 (2019).

84

K. Iwasa,
Neutron Scattering Studies on 4f 2-Electron Multipoles in Pr-based
Systems
J. Physical Soc. Japan, 88 081005 (2019).

85

T. Nakajima and T. Arima,
Observation of magnetic skyrmions by neutron scattering
J. Physical Soc. Japan, 88 081006 (2019).

86

N. Nishi, J. Uchiyashiki, Y. Ikeda, S. Katakura, T. Oda, M. Hino, and
N.L. Yamada,Potential-Dependent Structure of the Ionic Layer at the Electrode
Interface of an Ionic Liquid Probed Using Neutron Reflectometry
J. Phys. Chem. C, 123 9223–9230 (2019).

S. Asano, K.M. Suzuki, K. Kudo, I. Watanabe, A. Koda, R. Kadono,
T. Noji, Y. Koike, T. Taniguchi, S. Kitagawa, K. Ishida, and M. Fujita,
Oxidation Annealing Effects on the Spin-Glass-Like Magnetism andAppearance of Superconductivity in T*-type La1−x/2Eu1−x/2SrxCuO4 (0.14≤ x ≤ 0.28)
J. Physical Soc. Japan, 88 84709 (2019).

87

H. Akiba, H. Kobayashi, H. Kitagawa, K. Ikeda, T. Otomo, T.
Yamamoto, S. Matsumura, and O. Yamamuro,
Structural and Thermodynamic Studies of Hydrogen Absorption/
Desorption Processes on PdPt Nanoparticles
J. Phys. Chem. C, 123 9471–9478 (2019).

R. Kajimoto, K. Nakajima, M. Fujita, M. Ishikado, S. Torii, Y. Ishikawa,
P. Miao, and T. Kamiyama,
Crystal Structures of Highly Hole-Doped Layered Perovskite Nickelate
Pr2−xSrxNiO4 Studied by Neutron Diffraction
J. Physical Soc. Japan, 88 114602 (2019).

88

Y. Idemoto, F. Tejima, N. Ishida, and N. Kitamura,
Average, electronic, and local structures of LiMn2-xAlxO4 in chargedischarge process by neutron and synchrotron X-ray
J. Power Sources, 410-411 38–44 (2019).

89

N. Kitamura, Y. Kubo, N. Ishida, and Y. Idemoto,
Study of atomic ordering across the layer in lithium-rich layered
positive electrode material towards preparation process optimization
J. Power Sources, 437 226905 (2019).

90

K. Ninomiya, T.U. Ito, W. Higemoto, N. Kawamura, P. Strasser, T.
Nagatomo, K. Shimomura, Y. Miyake, M. Kita, A. Shinohara, K.M.
Kubo, and T. Miura,
Negative muon capture ratios for nitrogen oxide molecules
J. Radioanal. Nucl. Chem., 319 767 (2019).

91

G. Yoshida, K. Ninomiya, M. Inagaki, W. Higemoto, P. Strasser, N.
Kawamura, K. Shimomura, Y. Miyake, T. Miura, K.M. Kubo, and A.
Shinohara,
Initial quantum levels of captured muons in CO, CO2, and COS
J. Radioanal. Nucl. Chem., 320 283 (2019).

92

K. Ninomiya, T. Kudo, P. Strasser K. Terada, Y. Kawai, M. Tampo, Y.
Miyake, A. Shinohara, and K.M. Kubo,
Development of non-destructive isotopic analysis methods using
muon beams and their application to the analysis of lead
J. Radioanal. Nucl. Chem., 320 801 (2019).

93

W. Huang, K. Yoshino, S. Hori, K. Suzukia, M. Yonemura, M. Hirayama,
and R. Kanno,
Superionic lithium conductor with a cubic argyrodite-type structurein the Li–Al–Si–S system
J. Solid State Chem., 270 487–492 (2019).

94

T. Kawamoto, M. Aoki, T. Kimura, T. Mizusawa, N.L. Yamada, J.
Miyake, K. Miyatake, and J. Inukai,
In-Plane Distribution of Water inside Nafion Thin Film Analyzed by
Neutron Reflectivity at Temperature of 80°C and Relative Humidity of
30-80% Based on 4-Layered Structural Model
Jpn. J. Appl. Phys., 58 SIID01 (2019).

M. Hirai, S. Ajito, S. Arai, M. Adachi, R. Shimizu, K. Wakamatsu, S.
Takata, and H. Iwase,
Observation of protein and lipid membrane structures in a model
mimicking the molecular-crowding environment of cells using
neutron scattering and cell debris
J. Phys. Chem. B, 123 3189–3198 (2019).
Y. Kameda, K. Sato, R. Hasebe, Y. Amo, T. Usuki, Y. Umebayashi, K.
Ikeda, and T. Otomo,
Solvation Structure of Li+ in Methanol and 2‑Propanol Solutions
Studied by ATR-IR and Neutron Diffraction with 6Li/7Li Isotopic
Substitution Methods
J. Phys. Chem. B, 123 4967–4975 (2019).

M. Russina, G. Gunther, V. Grzimek, M.C. Schlegel, C.M. Veziri, G.N.
Karanikolos, T. Yamada, and F. Mezei,
Nanoscale Dynamics and Transport in Highly Ordered LowDimensional Water
J. Phys. Chem. Lett., 10 6339−6344 (2019).
S. Fujiwara, T. Matsuo, Y. Sugimoto, and K. Shibata,
Segment Motions of Proteins under Non-native States Evaluated Using
Quasielastic Neutron Scatering
J. Phys. Chem. Lett., 10 7505–7509 (2019).
R.Y. Umetsu, M. Tsujikawa, K. Saito, K. Ono, T. Ishigaki, R. Kainuma,
and M. Shirai,
Atomic ordering, magnetic properties, and electronic structure of
Mn2CoGa Heusler alloy
J. Phys. Condens. Matter., 31 65801 (2019).
Y. Nakazawa, H. Iinuma, Y. Iwata, Y. Iwashita, M. Otani, N. Kawamura,T. Mibe, T. Yamazaki, M. Yoshida, R. Kitamura, Y. Kondo, K. Hasegawa,T. Morishita, N. Saito, Y. Sue, N. Hayashizaki, and H. Yasuda,
Development of Inter-Digital H-Mode Drift-Tube Linac Prototype with
Alternative Phase Focusing for a Muon Linac in the J-PARC Muon G-2/
EDM Experiment
J. Phys. Conf. Ser., 1350 012054 (2019).
M. Otani, Y. Fukao, K. Futatsukawa, N. Kawamura, S. Matoba, T. Mibe,
Y. Miyake, K. Shimomura, T. Yamazaki, K. Hasegawa, R. Kitamura,
Y. Kondo, T. Morishita, T. Iijima, K. Inami, Y. Sue, M. Yotsuzuka, H.
Iinuma, Y. Nakazawa, K. Ishida, N. Saito, and H. Yasuda,
Negative Muonium Ion Production With a C12A7 Electride Film
J. Phys. Conf. Ser., 1350 012067 (2019).

81

K. Kaneko, M.D. Frontzek, M. Matsuda, A. Nakao, K. Munakata, T.
Ohhara, M. Kakihana, Y. Haga, M. Hedo, T. Nakama, and Y. Onuki,
Unique Helical Magnetic Order and Field-Induced Phase in Trillium
Lattice Antiferromagnet EuPtSi
J. Physical Soc. Japan, 88 013702 (2019).

82

T. Kim, K. Park, J.C. Leiner, and J.-G. Park,

171

MLF Operations in 2019

95

96

MLF Annual Report 2019

Y. Kitanaka, K. Makisumi, Y. Noguchi, M. Miyayama, A. Hoshikawa,and T. Ishigaki,
Composition-driven structural variation in ferrielectric phase of(Bi1/2Na1/2)TiO3-Ba(Mg1/3Nb2/3)O3
Jpn. J. Appl. Phys., 58 SLLA04 (2019).
S. Koizumi and Y. Noda,
A Variety of Small-angle Neutron Scattering Instruments Available
in Tokyo Area, Japan —Complimentary Use of Accelerator andReactor—JPS Conf. Proc., 25 11004 (2019).

108 F. Kaneko, A. Radulescu, H. Iwase, S. Takata, M. Nishiura, and Z. Hou,
Complexation of syndiotactic polystyrene with branched molecules
Macromol. Symp., 386 1900008 (2019).
109 S. Lee, W. Lee, N.L. Yamada, K. Tanaka, J.H. Kim, H. Lee, and D.Y. Ryu,
Instability of Polystyrene Film and Thermal Behaviors Mediated by
Unfavorable Silicon Oxide Inter-layer
Macromolecules, 52 7524–7530 (2019).

97

K. Kusaka, T. Yamada, N. Yano, T. Hosoya, T. Ohhara, and I. Tanaka,
Current Status and Future Prospects of Single Crystal Neutron
Diffractometer iBIXJPS Conf. Proc., 25 11005 (2019).

98

I. Tanaka,
Necessity and Effectiveness of a Biological Diffractometer for
Installation in Second Target Station as a New Neutron Pulsed Source
in Japan
JPS Conf. Proc., 25 11015 (2019).

111 Y. Tomota, M. Ojima, S. Harjo, W. Gong, S. Sato, and T. Ungár,
Dislocation densities and intergranular stresses of plastically
deformed austenitic steels
Mater. Sci. Eng. A Struct. Mater., 743 32–39 (2019).

K. Akutsu-Suyama, Y. Hasegawa, T. Niizeki, S. Suzuki, H. Aoki, and
F. Nemoto,
Neutron Reflectometry Study of Penetration of Protective Coating
Material by Deuterated Sodium Pyruvate
JPS Conf. Proc., 25 11018 (2019).

112 H. Chae, E.-W. Huang, J. Jain, H. Wang, W. Woo, S.-W. Chen, S. Harjo,
T. Kawasaki, and S.Y. Lee,
Plastic anisotropy and deformation-induced phase transformation of
additive manufactured stainless steel
Mater. Sci. Eng. A Struct. Mater., 762 138065 (2019).

100 T. Inada, S. Ueda, Y. Noda, T. Maeda, K. Kanie, and S. Koizumi,
Micellar Structure of Perfluorooctanesulfonic Acid in Water
Investigated by Combination of SAXS and SANSJPS Conf. Proc., 25 11019 (2019).

113 Y. Koyanagi, S. Ueta, T. Kawasaki, S. Harjo, K. Cho, and H.Y. Yasuda,
Investigation of strengthening mechanism in Ni–38Cr-3.8 Al alloy withfine lamellar structure by in situ neutron diffraction analysis
Mater. Sci. Eng. A Struct. Mater., 773 138822 (2019).

101 M. Watanabe, H. Nojiri, S. Itoh, S. Ohira-Kawamura, T. Kihara, T.
Masuda, T. Sahara, M. Soda, and R. Takahashi,
Development of Compact High Field Pulsed Magnet System for New
Sample Environment Equipment at MLF in J-PARC
JPS Conf. Proc., 25 11024 (2019).

114 M.-M. Schiavone, H. Iwase, S. Takata, and A. Radulescu,
The multilevel structure of sulfonated syndiotactic-polystyrene model
polyelectrolyte membranes resolved by extended Q-range contrast
variation SANS
Membranes, 9 136 (2019).

102 Y. Onuki and S. Sato,
Anomalous Twinning as the Macroscopic Deformation Mechanism
for AZ31 Magnesium Alloy
Key Eng. Mater., 810 95–100 (2019).

115 Y. Onuki, T. Hirano, A. Hoshikawa, S. Sato, and T. Tomida,
In Situ Observation of Bainite Transformation and Simultaneous
Carbon Enrichment in Austenite in Low-Alloyed TRIP Steel Using Timeof-Flight Neutron Diffraction Techniques
Metall. Mater. Trans. A Phys. Metall. Mater. Sci., 50 4977–4986(2019).

99

103 T. Sakamaki, Y. Inutsuka, K. Igata, K. Higaki, N.L. Yamada, Y. Higaki,
and A. Takahara,
Ion-Specific Hydration States of Zwitterionic Poly (sulfobetaine
methacrylate) Brushes in Aqueous Solutions
Langmuir, 35 1583–1589 (2019).
104 T. Miyazaki, N. Miyata, M. Asada, Y. Tsumura, N. Torikai, H. Aoki, K.
Yamamoto, T. Kanaya, D. Kawaguchi, and K. Tanaka,
Elucidation of a Heterogeneous Layered Structure in the Thickness
Direction of Poly(vinyl alcohol) Films with Solvent Vapor-Induced
Swelling
Langmuir, 35 11099–11107 (2019).
105 K. Imwiset, T. Hayakawa, Y. Fukushima, T. Yamada, and M. Ogawa,
Novel flexible supramolecular assembly of dioleyldimethylammonium
ion in a two-dimensional nanospace studied by neutron scattering
Langmuir, 35 13977–13982 (2019).
106 M. Shibayama, Y. Shudo, and A. Izumi,
Phenolic Resins - Recent Progress of Structure and Properties
Investigations
Macromol. Symp., 385 1800156 (2019).
107 K. Yamamoto, E. Ito, and Y. Mori,
SAXS and SANS studies on the phase‐separated network structureof amphiphilic copolymer composed of poly(dimethyl siloxane) andpoly(N,N‐dimethyl acrylamide) gels swollen in water and a water/172

methanol mixture
Macromol. Symp., 385 1800181 (2019).

110 N. Itagaki, D. Kawaguchi, Y. Oda, N.L. Yamada, T. Yamaguchi, andK. Tanaka,
A Surface Effect on Frictional Properties for Thin Hydrogel Films ofPoly(vinyl ether)
Macromolecules, 52 9632 (2019).

116 K. Kiriyama, S. Zhang, H. Hayashida, J. Suzuki, and T. Kuwabara,
Development of a biaxial tensile testing machine for pulsed neutron
experiments
MethodsX, 6 2166–2175 (2019).
117 K. Nagura, A. Bogdanov, N. Chumakova, A.K. Vorobiev, S. Moronaga,
H. Imai, T. Matsuda, Y. Noda, T. Maeda, S. Koizumi, K. Sakamoto, T.
Amano, F. Yoshino, T. Kato, N. Komatsu, and R. Tamura,Size-tunable MRI-visible nitroxide-based magnetic mixed micelles:
preparation, stability, and theranostic application
Nanotechnology, 30 224002 (2019).
118 Y. Fujishiro, N. Kanazawa, T. Nakajima, X.Z. Yu, K. Ohishi, Y.
Kawamura, K. Kakurai, T. Arima, H. Mitamura, A. Miyake, K. Akiba, M.
Tokunaga, A. Matsuo, K. Kindo, T. Koretsune, R. Arita, and Y. Tokura,
Topological transitions among skyrmion- and hedgehog-lattice states
in cubic chiral magnets
Nat. Commun., 10 1059 (2019).
119 K. Nawa, K. Tanaka, N. Kurita, T.J. Sato, H. Sugiyama, H. Uekusa, S.
Ohira-Kawamura, K. Nakajima, and H. Tanaka,
Triplon band splitting and topologically protected edge states in the
dimerized antiferromagnet
Nat. Commun., 10 2096 (2019).

MLF Annual Report 2019

120 K. Fukui, S. Iimura, T. Tada, S. Fujitsu, M. Sasase, H. Tamatsukuri, T.
Honda, K. Ikeda, T. Otomo, and H. Hosono,
Characteristic fast H− ion conduction in oxygen-substituted
lanthanum hydrideNat. Commun., 10 2578(1–7) (2019).
121 J. Wang, K. Ran, S. Li, Z. Ma, S. Bao, Z. Cai, Y. Zhang, K. Nakajima,
S. Ohira-Kawamura, P. Cermak, A. Schneidewind, S. Savrasov, X.
Wan, and J. Wen,
Evidence for singular-phonon-induced nematic superconductivity ina topological superconductor candidate Sr0.1Bi2Se3
Nat. Commun., 10 2802 (2019).
122 M. Hirschberger, T. Nakajima, S. Gao, L. Peng, A. Kikkawa, T.
Kurumaji, M. Kriener, Y. Yamasaki, H. Sagayama, H. Nakao, K. Ohishi,
K. Kakurai, Y. Taguchi, X. Yu, T. Arima, and Y. Tokura,
Skyrmion phase and competing magnetic orders on a breathing
Kagome latticeNat. Commun., 10 5831 (2019).
123 B. Li, Y. Kawakita, S. Ohira-Kawamura, T. Sugahara, H. Wang, J. Wang,
Y. Chen, S.I. Kawaguchi, K. Ohara, S. Kawaguchi, K. Li, D. Yu, R. Mole,
T. Hattori, T. Kikuchi, S. Yano, Z. Zhang, Z. Zhang, W. Ren, S. Lin, O.
Sakata, K. Nakajima, and Z. Zhang,Colossal barocaloric effects in plastic crystals
Nature, 567 506–510 (2019).
124 Y. Onodera, Y. Takimoto, H. Hijiya, T. Taniguchi, S. Urata, S. Inaba, S.
Fujita, I. Obayashi, Y. Hiraoka, and S. Kohara,
Origin of the mixed alkali effect in silicate glass
NPG Asia Mater., 11 75 (2019).
125 M. Hagihala, S. Hayashida, M. Avdeev, H. Manaka, H. Kikuchi, andT. Masuda,
Magnetic states of coupled spin tubes with frustrated geometry in
CsCrF4
NPJ Quantum Mater., 4 14 (2019).
126 Y. Noda, and S. Koizumi,
Dynamic nuclear polarization apparatus for contrast variation
neutron scattering experiments on iMATERIA spectrometer at J-PARC
Nucl. Instrum. Methods Phys. Res. A, 923 127–133 (2019).
127 A.S. Tremsin, T. Shinohara, K. Oikawa, Jiaqi Li, and P.J.M. Monteiro,
Non-destructive mapping of water distribution through white-beamand energy-resolved neutron imaging
Nucl. Instrum. Methods Phys. Res. A, 927 174–183 (2019).
128 M. Teshigawara, Y. Tsuchikawa, G. Ichikawa, S. Takata, K. Mishima,
M. Harada, M. Ooi, Y. Kawamura, T. Kai, S. Ohira-Kawamura, K.
Nakajima, Y. Ikeda, and Y. Kiyanagi,
Measurement of neutron scattering cross section of nano-diamondwith particle diameter of approximately 5 nm in energy range of 0.2
meV to 100 meV
Nucl. Instrum. Methods Phys. Res. A, 929 113–120 (2019).
129 A.D. Pant, T. Adachi, P. Strasser, Y. Ikedo, Y. Oishi, J. Nakamura, W.
Higemoto, K. Shimomura, R. Kadono, Y. Miyake, and E. Torikai,
Characterization and optimization of ultra slow muon beam at
J-PARC/MUSE: A simulation study
Nucl. Instrum. Methods Phys. Res. A, 929 129–133 (2019).
130 Y. Nakazawa, S. Baeb, H. Choib, S. Choib, T. Iijimad, H. Iinuma, N.
Kawamura, R. Kitamura, B. Kim, H.S. Ko, Y. Kondo, T. Mibe, M. Otani,
G.P. Razuvaev, N. Saito, Y. Sue, E. Won, T. Yamazaki, and H. Yasuda,
Beam commissioning of muon beamline using negative hydrogenions generated by ultraviolet light
Nucl. Instrum. Methods Phys. Res. A, 937 164 (2019).
131 M. Otani, R. Kitamura, Y. Fukao, K. Hasegawa, K. Ishida, N. Kawamura,
Y. Kondo, Y. Miyake, N. Saito, K. Shimomura, and P. Strasser,
Response of microchannel plates to positrons from muon-decays

MLF Operations in 2019

Nucl. Instrum. Methods Phys. Res. A, 943 162475 (2019).
132 S. Shimizu, K. Horie, Y. Igarashi, H. Ito, K. Kamada, S. Kimura, A.
Kobayashi, M. Mihara, A. Yamaji, and A. Yoshikawa,A new experimental method to search for T-violation using asequential CeF3 scintillating calorimeter
Nucl. Instrum. Methods Phys. Res. A, 945 162587 (2019).
133 M. Otani, Y. Sue, K. Futatsukawa, T. Iijima, H. Iinuma, N. Kawamura,
R. Kitamura, Y. Kondo, T. Morishita, Y. Nakazawa, H. Yasuda, M.
Yotsuzuka, N. Saito, and T. Yamazaki,
Compact buncher cavity for muons accelerated by a radio-frequency
quadrupole
Nucl. Instrum. Methods Phys. Res. A, 946 162693 (2019).
134 T. Hosobata, N.L. Yamada, M. Hino, H. Yoshinaga, F. Nemoto, K. Hori,
T. Kawai, Y. Yamagata, M. Takeda, and S. Takeda,
Elliptic neutron-focusing supermirror for illuminating small samples
in neutron reflectometry
Opt. Express, 27 26807 (2019).
135 S. Kobayashi, R. Kawagoe, H. Murakami, K. Ohishi, Y. Kawamura,and J. Suzuki,
Thermal aging effects on magnetisation reversals in a predeformed
Fe-1wt%Cu alloy studied via first-order reversal curves
Philos. Mag. Lett., 99 217–225 (2019).
136 K. Akutsu-Suyama, S. Mori, and T. Hanashima,
Design and Characterization of a 2-(2’-Hydroxyphenyl)benzimidazoleBased Sr 2+-Selective Fluorescent Probe in Organic and Micellar
Solution Systems
Photochem. Photobiol. Sci., 18 2531–2538 (2019).
137 K.L. Browning, J.F. Browning, M. Doucet, N.L. Yamada, G. Liu, andG.M. Veith,
Role of conductive binder to direct solid-electrolyte interphaseformation over silicon anodes
Phys. Chem. Chem. Phys., 21 17356 (2019).
138 K. Akutsu-Suyama, M. Cagnes, K. Tamura, T. Kanaya, and T.A.
Darwish,Controlled deuterium labelling of imidazolium ionic liquids toprobe the fine structure of the electrical double layer using neutronreflectometry
Phys. Chem. Chem. Phys., 21 17512–17516 (2019).
139 T. Takamuku, H. Sakurai, A. Ogawa, A. Tashiro, M. Kawano, Y.
Kawazu, K. Sadakane, H. Iwase, and K. Ozutsumi,
Effects of the long octyl chain on complex formation of nickel(II)with dimethyl sulfoxide, methanol, and acetonitrile in Ionic liquid of[C8mim][TFSA]
Phys. Chem. Chem. Phys., 21 3154–3163 (2019).
140 A. Kyono, M. Kato, A. Sano-Furukawa, S. Machida, and T. Hattori,
Crystal structure change of katoite, Ca3Al2(O4D4)3, with temperature
at high pressure
Phys. Chem. Miner., 46 459–469 (2019).
141 H. Kadowaki, M. Wakita, B. Fåk, J. Ollivier, S. Ohira-Kawamura, K.
Nakajima, and J.W. Lynn,
Spin correlations of quantum-spin-liquid and quadrupole-orderedstates of Tb2+xTi2-xO7+yPhys. Rev. B, 99 014406 (2019).
142 J. Yamaura, H. Hiraka, S. Iimura, Y. Muraba, J. Bang, K. Ikeuchi, M.
Nakamura, Y. Inamura, T. Honda, M. Hiraishi, K.M. Kojima, R. Kadono,
Y. Kuramoto, Y. Murakami, S. Matsuishi, and H. Hosono,
Quantum dynamics of hydrogen in the iron-based superconductor
LaFeAsO0.9D0.1 measured with inelastic neutron spectroscopy
Phys. Rev. B, 99 220505(R) (2019).
143 K. Matan, T. Ono, G. Gitgeatpong, K. de Roos, M. Ping, S. Torii, T.

173

MLF Operations in 2019

MLF Annual Report 2019

Kamiyama, A. Miyata, A. Matsuo, K. Kindo, S. Takeyama, Y. Nambu,
P. Piyawongwatthana, T.J. Sato, and H. Tanaka,
Magnetic structure and high-field magnetization of the distorted
kagome lattice antiferromagnet Cs2Cu3SnF12
Phys. Rev. B, 99 224404 (2019).
144 K.P. Kramer, M. Horio, S.S. Tsirkin, Y. Sassa, K. Hauser, C.E. Matt,
D. Sutter, A. Chikina, N.B.M. Schröter, J.A. Krieger, T. Schmitt, V.N.
Strocov, N.C. Plumb, M. Shi, S. Pyon, T. Takayama, H. Takagi, T.
Adachi, T. Ohgi, T. Kawamata, Y. Koike, and T. Kondo,
Band structure of overdoped cuprate superconductors: Density
functional theory matching experiments
Phys. Rev. B, 99 224509 (2019).
145 K. Iida, Y. Nagai, S. Ishida, M. Ishikado, N. Murai, A.D. Christianson,
H. Yoshida, Y. Inamura, H. Nakamura, A. Nakao, K. Munakata, D.
Kagerbauer, M. Eisterer, K. Kawashima, Y. Yoshida, H. Eisaki, andA. Iyo,Coexisting spin resonance and long-range magnetic order of Eu in
EuRbFe4As4
Phys. Rev. B, 100 014506 (2019).
146 S. Klotz, M. Casula, K. Komatsu, S. Machida, and T. Hattori,
High-pressure structure and electronic properties of YbD2 to 34 GPa
Phys. Rev. B, 100 0210101(R) (2019).
147 H. Suzuki, A. Nambu, and M. Okamoto,
X-ray magnetic circular dichroism and neutron diffraction
measurements of the magnetic moment of titanium in
Sm(Fe0.8Co0.2)11Ti
Phys. Rev. B, 100 144443 (2019).

155 N. Kurita, D. Yamamoto, T. Kanesaka, N. Furukawa, S. OhiraKawamura, K. Nakajima, and H. Tanaka,
Localized magnetic excitations in the fully frustrated dimerizedmagnet Ba2CoSi2O6Cl2
Phys. Rev. Lett., 123 027206 (2019).
156 M. Matsuura, T. Sasaki, S. Iguchi, E. Gati, J. Müller, O. Stockert, A.
Piovano, M. Böhm, J.T. Park, S. Biswas, S.M. Winter, R. Valentí, A.
Nakao, and M. Lang,
Lattice Dynamics Coupled to Charge and Spin Degrees of Freedom
in the Molecular Dimer-Mott Insulator κ−(BEDT−TTF)2Cu[N(CN)2]Cl
Phys. Rev. Lett., 123 027601 (2019).
157 Y. Sakaguchi, T. Hanashima, A.-A.A. Simon, and M. Mitkova,
Structural transformation in GexS100-x (10≤x≤40) network glasses:
Structural varieties in short-range, medium-range, and nanoscopic
scale
Phys. Rev. Mater., 3 35601 (2019).
158 J.N. Hendriks, A.W.T. Gregg, R.R. Jackson, C.M. Wensrich, A. Wills,
A.S. Tremsin, T. Shinohara, V. Luzin, and O. Kirstein,
Tomographic reconstruction of triaxial strain fields from Bragg-edge
neutron imaging
Phys. Rev. Mater., 3 113803 (2019).

148 H. Tamatsukuri, S. Mitsuda, T. Shimizu, M. Fujihala, H. Yokota, K.
Takehana, Y. Imanaka, A. Nakao, and K. Munakata,
Nonlinear piezomagnetoelectric effect in CuFeO2
Phys. Rev. B, 100 201105 (2019).

159 R. Kajimoto, M. Ishikado, H. Kira, K. Kaneko, M. Nakamura, K.
Kamazawa, Y. Inamura, K. Ikeuchi, K. Iida, N. Murai, S. OhiraKawamura, R. Takahashi, K. Aoyama, and W. Kambara,
Study on use of superconducting magnet and first inelastic
neutron scattering experiment under magnetic field at 4SEASONS
spectrometerPhysica B Condens. Matter., 556 26–30 (2019).

149 S. Ideta, N. Murai, M. Nakajima, R. Kajimoto, and K. Tanaka,
Experimental investigation of the suppressed superconducting gap
and double-resonance mode in Ba1−xKxFe2As2
Phys. Rev. B, 100 235135 (2019).

160 R. Kajimoto, T. Yokoo, M. Nakamura, Y. Kawakita, M. Matsuura, H.
Endo, H. Seto, S. Itoh, K. Nakajima, and S. Ohira-Kawamura,
Status of neutron spectrometers at J-PARC
Physica B Condens. Matter., 562 148–154 (2019).

150 A. Koda, H.T. Hirose, M. Miyazaki, H. Okabe, M. Hiraishi, I. Yamauchi,
K.M. Kojima, I. Nagashima, J. Yamaura, Z. Hiroi, and R. Kadono,
Coupled spin-charge-phonon fluctuation in the all-in/all-out
antiferromagnet Cd2Os2O7
Phys. Rev. B, 100 245113(1–6) (2019).

161 T. Kikuchi, K. Nakajima, S. Ohira-Kawamura, Y. Inamura, M.
Nakamura, D. Wakai, K. Aoyama, T. Iwahashi, and W. Kambara,
Background issues encountered by cold-neutron chopper
spectrometer AMATERAS
Physica B Condens. Matter., 564 45–53 (2019).

151 C.C. Haddock, M. Hiromoto, K. Hirota, T. Ino, M. Kitaguchi, K.
Mishima, N. Oi, T. Shima, H.M. Shimizu, W.M. Snow, and T. Yoshioka,
Measurement of the total neutron-scattering cross-section ratios ofnoble gases of natural isotopic composition using a pulsed neutron
beam
Phys. Rev. C, 100 64002 (2019).

162 M. Nakamura, T. Kikuchi, and Y. Kawakita,
Applicability and limitations of G(r, E) analysis transformed from theinelastic neutron scattering data
Physica B Condens. Matter., 567 61–64 (2019).

152 J. Guo, L. Yue, K. Iida, K. Kamazawa, L. Chen, T. Han, Y. Zhang, and
Y. Li,
Preferred magnetic excitations in the iron-based Sr1-xNaxFe2As2
superconductor
Phys. Rev. Lett., 122 017001 (2019).
153 H. Wo, Q. Wang, Y. Shen, X. Zhang, Y. Hao, Y. Feng, S. Shen, Z. He, B.
Pan, W. Wang, K. Nakajima, S.O. -Kawamura, P. Steffens, M. Boehm,
K. Schmalzl, J.T. Park, T.R. Forrest, M. Matsuda, Y. Zhao, J.W. Lynn,
Z. Yin, and J. Zhao,
Coexistence of ferromagnetic and stripe-type antiferromagnetic spin
fluctuations in YFe2Ge2
Phys. Rev. Lett., 122 217003 (2019).
154 M. Mogi, T. Nakajima, V. Ukleev, A. Tsukazaki, R. Yoshimi, M.
Kawamura, K.S. Takahashi, T. Hanashima, K. Kakurai, T. Arima, M.
Kawasaki, and Y. Tokura,

174

Large Anomalous Hall Effect in Topological Insulators with
Proximitized Ferromagnetic Insulators
Phys. Rev. Lett., 123 016804 (2019).

163 S. Itoh, T. Yokoo, T. Masuda, S. Asai, H. Saito, D. Kawana, R. Sugiura,
T. Asami, and Y. Ihata,
Progress in High Resolution Chopper Spectrometer HRC by improving
collimator and Fermi chopper
Physica B Condens. Matter., 568 76–80 (2019).
164 M. Sakurai, G. Matsuba, K. Sotoyama, K. Nishida, T. Kanaya, and
S. Takata,
Molecular weight component dependence of shish-kebab structure ofpolyethylene blends with X-ray and neutron scattering measurements
covering a wide spatial scale
Polym. Cryst., 2 e10034 (2019).
165 H. Aoki,
Chain dynamics in spin-coated films of poly(methyl methacrylate) ina solvent annealing process
Polym. J., 51 611–616 (2019).
166 T. Maeda, M. Kitagawa, A. Hotta, and S. Koizumi,MLF Annual Report 2019

Thermo-Responsive Nanocomposite Hydrogels Based on PEG-b-PLGA
Diblock Copolymer and Laponite
Polymers, 11 250 (2019).
167 Y. Ueno, Y. Matsuda, S. Seo, T. Tanaka, H.A. Torii, D. Yagi, H. Yasuda,
S. Nishimura, K.I. Sasaki, Y. Sato, K. Shimomura, P. Strasser, H.
Yamaguchi, S. Kanda, K.S. Tanaka, T. Yamanaka on behalf of the
MuSEUM collaboration,
New Precision Measurement of Muonium Hyperfine Structure
PoS (ICHEP2018), 340 466 (2019).
168 S. Kanda, K. Ishida, and K. Shimomura,
Precision spectroscopy of exotic atoms involving muons
PoS (ICHEP2018), 341 138 (2019).
169 M. Abe, S. Bae, G. Beer, G. Bunce, H. Choi, S. Choi, M. Chung, W. da
Silva, S. Eidelman, M. Finger, Y. Fukao, T. Fukuyama, S. Haciomeroglu,
K. Hasegawa, K. Hayasaka, N. Hayashizaki, H. Hisamatsu, T. Iijima, H.
Iinuma, K. Inami, H. Ikeda, M. Ikeno, and K. Ishid,
A New Approach for Measuring the Muon Anomalous Magnetic
Moment and Electric Dipole Moment
Prog. Theor. Exp. Phys., 2019 053C02 (2019).
170 R. Kitahara, K. Hirota, S. Ieki, T. Ino, Y. Iwashita, M. Kitaguchi, J. Koga,
K. Mishima, A. Morishita, N. Nagakura, H. Oide, H. Otono, Y. Seki, D.
Sekiba, T. Shima, H.M. Shimizu, N. Sumi, H. Sumino, K. Taketani, T.
Tomita, T. Yamada, S. Yamashita, and M. Yok,
Improved determination of thermal cross section of 14N(n,p)14C for theneutron lifetime measurement
Prog. Theor. Exp. Phys., 2019 093C01 (2019).
171 Y. Sakaguchi, H. Asaoka, and M. Mitkova,
Kinetics of silver photodiffusion into amorphous S-rich germanium
sulphide – neutron and optical reflectivity
Pure Appl. Chem., 91 1821–1835 (2019).
172 F. Kaneko, T. Kawaguchi, A. Radulescu, H. Iwase, T. Morikawa, S.
Takata, M. Nishiura, and Z. Hou,A new simultaneous measurement system of wide Q-range small
angle neutron scattering combined with polarized Fouier transform
infrared spectroscopy
Rev. Sci. Instrum., 90 093906 (2019).
173 T. Wu, A. Ishikawa, T. Honda, H. Tamatsukuri, K. Ikeda, T. Otomo,
and S. Matsuishi,
Nephelauxetic effect of the hydride ligand in Sr2LiSiO4H as a hostmaterial for rare-earth-activated phosphors
RSC Adv., 9 5282–5287 (2019).
174 S. Hayashida, M. Matsumoto, M. Hagihala, N. Kurita, H. Tanaka, S.
Itoh, T. Hong, M. Soda, Y. Uwatoko, and T. Masuda,
Novel Excitations near Quantum Criticality in Geometrically Frustrated
Antiferromagnet CsFeCl3
Sci. Adv., 5 eaaw5639 (2019).
175 K. Sakurai, J. Jiang, M. Mizusawa, T. Ito, K. Akutsu, and N. Miyata,
Neutron visualization of inhomogeneous buried interfaces in thinfilms
Sci. Rep., 9 571 (2019).
176 K. Iida, H. Yoshida, H. Okabe, N. Katayama, Y. Ishii, A. Koda, Y.
Inamura, N. Murai, M. Ishikado, R. Kadono, and R. Kajimoto,
Quantum magnetisms in uniform triangular lattices Li2AMo3O8 (A =In, Sc)Sci. Rep., 9 1826 (2019).
177 Y. Kitanaka, M. Miyayama, and Y. Noguchi,
Ferrielectric-mediated morphotropic phase boundaries in Bi-basedpolar perovskites
Sci. Rep., 9 4087 (2019).

MLF Operations in 2019

Yuan, and T. Hattori,Interstitial hydrogen atoms in face-centered cubic iron in the Earth’s
core
Sci. Rep., 9 7108 (2019).
179 A. Machida, H. Saitoh, T. Hattori, A. Sano-Furukawa, K. Funakoshi,
T. Sato, S. Orimo, and K. Aoki,
Hexagonal closed packed iron hydride behind the conventional phase
diagramSci. Rep., 9 12290 (2019).
180 Y. Kitanaka, Y. Noguchi, and M. Miyayama,
Uncovering ferroelectric polarization in tetragonal (Bi1/2K1/2)TiO3–(Bi1/2Na1/2)TiO3 single crystals
Sci. Rep., 9 19275 (2019).
181 J.G. Kim, J.W. Bae, J.M. Park, W. Woo, S. Harjo, K.-G. Chin, S. Lee, H.S.
Kim Hyoung,
Synergetic strengthening of layered steel sheet investigated using anin situ neutron diffraction tensile test
Sci. Rep., 9 43837 (2019).
182 A. Shibata, Y. Takeda, N. Park, L. Zhao, S. Harjo, T. Kawasaki, W. Gong,
and N. Tsuji,
Nature of dynamic ferrite transformation revealed by in-situ neutron
diffraction analysis during thermomechanical processing
Scr. Mater., 165 44–49 (2019).
183 J.W. Bae, J.G. Kim, J.M. Park, W. Woo, S. Harjo, and H.S. Kim,
In situ neutron diffraction study of phase stress evolution in a ferrous
medium-entropy alloy under low-temperature tensile loading
Scr. Mater., 165 60–63 (2019).
184 F. Endo, N. Kurokawa, K. Tanimoto, H. Iwase, T. Maeda, and A. Hotta,
SANS study on the nano-crystalline network structure of quenchedsyndiotactic polypropylene gels
Soft Matter, 15 5521–5528 (2019).
185 N. Ishida, S. Ando, N. Kitamura, and Y. Idemoto,
Crystal structure and cathode properties of delithiated Li1xMn1/3Ni1/3Co1/3O2 for Mg rechargeable batteries
Solid State Ion., 343 115080 (2019).
186 K. Mori, K. Iwase, Y. Oba, K. Ikeda, T. Otomo, and T. Fukunaga,
Structural and electrochemical features of (Li2S)x(SiS2)100–x superionicglasses
Solid State Ion., 344 115141 (2019).
187 Y. Iizawa, H. Shishido, K. Nishimura, T.D. Vu, K.M. Kojima, T. Koyama,
K. Oikawa, M. Harada, S. Miyajima, M. Hidaka, T. Oku, K. Soyama, K.
Aizawa, S.Y. Suzuki, and T. Ishida,
Energy-resolved neutron imaging with high spatial resolution using a
superconducting delay-line kinetic inductance detector
Supercond. Sci. Technol., 32 125009 (2019).
188 J. Sugiyama, I. Umegaki, M. Matsumoto, K. Miwa, H. Nozaki, Y.
Higuchi, T. Noritake, O.K. Forslund, M. Månsson, S.P. Cottrell, A.
Koda, E.J. Ansaldo, and J.H. Brewer,
Desorption reaction in MgH2 studied with in situ μ+SR
Sustain. Energy Fuels, 3 956–964 (2019).
189 K. Hanawa, Y. Onuki, Y. Uemura, A. Hoshikawa, S. Suzuki, H. Otsuka,
Y. Chiba, and S. Sato,
Analysis of Reverse Transformation Behavior in Iron-based Alloys
Based on Quantitative Microstructure Information by Neutron
Diffraction
Tetsu to Hagane, 105 998–1007 (2019).

178 D. Ikuta, E. Ohtani, A. Sano-Furukawa, Y. Shibazaki, H. Terasaki, L.

175

Editorial Board

MLF Annual Report 2019

Editorial Board - MLF Annual Report 2019

Chief Editor

Kazuhiro Akutsu

Takashi Naoe
Neutron Source Section

CROSS

Miho Igarashi

Yukinori Nagatani

CROSS

Muon Science Section

Kazutaka Ikeda

Tazuko Mizusawa

Neutron Science Section

CROSS

Yoshihisa Ishikawa

Dai Yamazaki

CROSS

Neutron Instrumentation Section

Kenichi Oikawa

Taro Yamada

Neutron Science Section

Ibaraki University

Yuhua SuTechnology Development Section

176

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

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