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

MLF
ANNUALREPORTCover photographs
1 : The SEM image of a nanosized graphene flower produced by
the hot isostatic pressing treatment. Development of this new
material is in progress to enhance neutron intensity below
cold neutrons.
2 : The 6th Neutron and Muon School.

1

3 : MLF Experimental Hall-1 in October 2022.
4

2

3

5

4 : An interdigital H-mode drift tube linear accelerator (IH-DTL)
for the J-PARC muon g−2/EDM experiment. Drift tubes madeof oxygen-free copper are monolithically machined.
5 : Plasma fluorescence produced by laser.
This is the plasma fluorescence produced when the Kr gas
used as a wavelength conversion medium is ionized in theprocess of generating intense vacuum ultraviolet coherent
light for Ultra-slow Muon generation.
6 : The 6th Neutron and Muon School.

6

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

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

J-PARC 23-02

MLF Annual Report 2022

Preface

PrefaceToshiya Otomo

Division Head of Materials and Life Science Division, MLF
In 2022, beam power of 830 kW with high operational efficiency of over 90% was reached for the first time in theuser program. 21 neutron beamlines and 7 muon areas were operated. Despite that, the soaring electricity costs affected the beam time, J-PARC reviewed the operation schedule upon the approval of a supplementary budget anddecided to elongate the MLF user operation until March 14. The user program was operated for a total of 146 days,
although 159 days were originally planned, and 418 general user proposals were conducted.
Over 250 papers were published, such as a structural study of new flexible and tough super elastic alloy withpromising use in Biomedical Applications, asteroid explorer Hayabusa2, initial analysis revealing the formation andevolution of the carbonaceous asteroid Ryugu, nondestructive two-dimensional quantitative analysis of degradationof the charging capacity of Lithium-ion secondary batteries and discovering the hidden order of the Mo and Nb atoms
in disordered Ba7Nb4MoO20 crystals.
As part of the process to establish a stable operation, the target vessel replacement process was re-examined, andthe tritium release was successfully reduced. Also, the preparation of the spare muon target (the third muon rotatingtarget) advanced and will be completed in 2023.
The SEOP system as a spin polarizer on BL23 has been set and finally the on-beam commissioning with a polarized
neutron beam has begun. Constructing the world’s first muon accelerator on the H2 area of the H-line was approvedby the Nuclear Regulatory Authority (“GENSHIRYOKU-KISEI-CHOU”). The RFQ and IH-DTL, by which ultra-slow muons
are accelerated to 4.3 MeV, will be installed in the H2 area. They act as the front stage of the 212 MeV linear accelerators.
Events in 2022 were held in a hybrid mode of in-person and internet meetings: one of them was the annual meeting of neutron industrial application at Akihabara with 300 participants. This annual meeting was held to merge theoutcomes from the MLF and Japan Research Reactor - 3 (JRR-3) of JAEA. The 11th International Workshop on Sample
Environment at Scattering Facilities (ISSE) was held at Nasu and the 6th Neutron and Muon School (NM-school) was held
as KEK-IINAS (Inter-Institution Network for Accelerator Science) School at Tokai (https://mlfinfo.jp/sp/school/6th-nms/).
Workshops were held for neutron sources with ESS (online capability), for commissioning with the ESS & J-PARC collaboration, for the accelerator system and neutron/muon target system with ISIS and for the neutron source systemwith SNS.
In November 2022, the border control of Japan restored almost completely the rules from the time before COVID-19.
The number of foreign users is gradually reaching the previous level and various activities now take place as before. We
will continue to improve the environment so that more and more excellent results will be produced in the MLF.

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

MLF Annual Report 2022

Preface

Mitsuhiro Shibayama

Director, CROSSThe Comprehensive Research Organization of Science and Society (CROSS), a partner institution of the Materials
and Life Science Experimental Facility (MLF), is honored to release the J-PARC MLF ANNUAL REPORT 2022 (MLFAR2022), which includes sections on R&D Highlights, Neutron Sources, Neutron Science, Muon Science and more. The
Neutron Science Center of the CROSS is a registered organization of the J-PARC's Specific Neutron Beamline Facility,
appointed by the Japanese government in 2011. It supports the activities of the 7 public beamlines of the MLF (BL01
4SEASONS, BL02 DNA, BL11 PLANET, BL15 TAIKAN, BL17 SHARAKU, BL18 SENJU, and BL22 RADEN), and provides highquality user support to the MLF users, both academic and industrial researchers, and promotes the use of the facility.
In FY2022, the neutron beam at the MLF was stably operated, which ensured highly reliable machine operation.
The total numbers of short term neutron proposals submitted and accepted in the two proposal rounds in FY2022
were 614 and 286, respectively, and those for the Public Beamlines were 285 and 123, respectively. As of the outcome,200 scientific papers (excluding proceedings) were published from the MLF in 2022, 74 of which were from the Public
Beamlines. The details are included in the Research and Development Highlights collected in this volume. The numbers of press releases were 20 from the MLF and 5 from the Public Beamlines. These numbers illustrate the high activities of the Public Beamlines as well as the MLF, which have been used by a wide range of users from the academia andvarious industries. The special program for new users “New User Promotion (NUP)”, which started in 2016, was also
operated in 2022, and 9 NUP neutron users conducted experiments at the MLF.
Regarding public relations, in FY2020, a unified consultation service named “J-JOIN”, operated by the J-PARC MLF,
Ibaraki Pref., JRR-3 (JAEA and the University of Tokyo), and the CROSS, welcomed potential users. (https://jrr3ring.jaea.
go.jp/jjoin/index_en.php).
I hope that this Annual Report would provide useful information about the current status of the MLF operations
and recent scientific achievements, the technical R&D reports, and so on. On behalf of the CROSS, I sincerely welcome
your visit to the MLF.

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

Contents
PrefaceOrganization Chart
J-PARC Map
Muon and Neutron Instruments

Research and Development Highlights
Atomic Distribution and Local Structure in Ice VII from in situ Neutron Diffraction··································································

2

Study on Large Elastic Deformation in Bulk Metal by In Situ Neutron Diffraction·······································································

4

Effect of Hydrogen on Evolution of Deformation Microstructure in 2Mn-0.1C Ferritic Steel··················································

7

High-Pressure Synthesis of Transition-Metal Oxyhydrides with Double Perovskite Structures············································· 10
The Ion Dynamics in Li10GeP2S12 Investigated by Quasi-Elastic Neutron Scattering Measurements···································· 13
Impact of Na Concentration on the Phase Transition Behavior and H− Conductivities in the Ba-Li-Na-H-O
Oxyhydride System······················································································································································································ 16
Tracer diffusion coefficient measurements in solid-state electrolytes through neutron radiography································ 18
Ionomer Distribution of N-Doped Carbon Surfaces······························································································································· 22Interfacial Structure and Tribological Property of Adsorbed Layer Formed by Organic Friction Modifier························· 24
Mobile Water Near Poly(ethylene oxide) at Physiological Temperature························································································· 26
Monitoring of Rapid Morphological Changes by Photo-Irradiation in Micelles by in situ SANS············································ 28
High-resolution Neutron Structure Reveals the Non-planarity of Peptide bonds······································································ 31
Excitations in the Ordered and Paramagnetic States of Honeycomb Magnet Na2Co2TeO6····················································· 34
Crystal Electric Field Level Scheme Behind Giant Magnetocaloric Effect for Hydrogen Liquefaction································· 37
Relief of Spin Frustration through Magnetic Anisotropy in the Quasi-one-dimensional S = 1/2
Antiferromagnet Na2CuSO4Cl2································································································································································· 39
Zigzag Antiferromagnetic Order in the Kitaev Spin-liquid Candidate RuBr3 with a Honeycomb Lattice··························· 42
Square and Rhombic Lattice States of Magnetic Skyrmions in a Centrosymmetric Magnet EuAl4······································· 44
Evolution of Magnetism and Superconductivity Toward the Quantum Critical Point in the Heavy Fermion System········ 46
Ambipolarity of Dilute Hydrogen in Power Semiconductor β-Ga2O3 Revealed by μSR···························································· 48
Determination of Light Element Composition for Asteroid Ryugu Using Muon Beam···························································· 50
Energy-resolved Neutron-induced Soft-error Cross Section from 10 meV to 800 MeV Measured byTime-of-flight Method················································································································································································ 52
Breakthrough of Neutron Interferometer·················································································································································· 55
Measurement of the 241Am Neutron Capture Cross Section with Fe and Si-filtered Neutron Beam Using
the NaI(Tl) Spectrometer of the ANNRI Beamline····························································································································· 57
Development of Pulsed Magnet System for Sample Environment equipment··········································································· 60
New Material Exploration to Enhance Neutron Intensity Below Cold Neutrons········································································· 62

Neutron Source
Neutron Source Section···················································································································································································· 66
Transportation of Used Mercury Target Vessel #3··································································································································· 68
Preparation of the Proton Beam Window in 2022··································································································································· 70

Neutron Science
Neutron Science Section·················································································································································································· 74
BL01: 4D-Space Access Neutron Spectrometer 4SEASONS················································································································· 77
Current Status of BL02 DNA in 2022····························································································································································· 79
IBARAKI Biological Crystal Diffractometer iBIX········································································································································· 81
Resonance Parameter Analysis in Double-bunch mode at MLF (BL04 ANNRI)············································································ 83
Status of Fundamental Physics Beamline BL05 (NOP) in 2022··········································································································· 85
BL06: Commissioning Status of Village of Neutron Resonance Spin Echo Spectrometers (VIN ROSE)······························· 87
BL08: Maintaining the Aluminum Window of the SuperHRPD Sample Vacuum Chamber····················································· 89
Current Situation of BL09 in FY2022···························································································································································· 91
BL10: NOBORU····································································································································································································· 93
Developments at BL11 PLANET····································································································································································· 95
High Resolution Chopper Spectrometer HRC·········································································································································· 97
BL14 AMATERAS·································································································································································································· 99
Upgrading TAIKAN······························································································································································································ 101
Developments of Multi Incident-angle Neutron Reflectometry········································································································ 103
Online Data Processing Application Suite for Polarized Neutron Reflectometer SHARAKU··················································· 106
Status of SENJU 2022························································································································································································· 108
Recent Research and Advancements in BL19 TAKUMI·························································································································· 110
The Current Status of the Versatile Neutron Diffractometer, iMATERIA·························································································· 112
Status of the High Intensity Total Diffractometer (BL21, NOVA)········································································································ 114
Current Status of the Energy-Resolved Neutron Imaging System RADEN····················································································· 116
Polarized Neutron Spectrometer POLANO················································································································································ 118
Sample Environment at the MLF··································································································································································· 120
Evaluation with Geant4 for Neutron Detector Performance··············································································································· 122
KENS Computing································································································································································································· 124Muon Science
Muon Section······································································································································································································· 128
Muon Rotating Target························································································································································································ 130
Beam Commissioning at D1/2 Areas···························································································································································· 131
Development of D2 (Muonic X-ray Element Analysis) Instrument and Sample Environment ·············································· 134
Muon Beamline Magnets and Power Supplies Update − Upgrade of D1-triplet and Power Supply −······························· 136
Muon H-Line PPS Interlock System Update··············································································································································· 138
Commissioning of the Ultra-slow Muon Beamline in FY2022············································································································ 140
Commissioning of the U1A Spectrometer in FY2022···························································································································· 142
USM Commissioning at the U1B area·························································································································································· 144
The Progress of Laser System for Ultra-slow Muon Generation········································································································· 146
Present Status of the S-line·············································································································································································· 148
Present Status of the H-line············································································································································································· 150

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

MLF Operations in 2022
Beam Operation Status at the MLF······························································································································································· 156
Users at the MLF·································································································································································································· 158
MLF Proposals Summary – FY2022······························································································································································· 159
MLF Division Staff 2022····················································································································································································· 161
CROSS Staff 2022································································································································································································· 164
Ibaraki Neutron Beamline Staff in 2022······················································································································································ 166
Proposals Review System, Committees and Meetings·························································································································· 167
Workshops, Conferences, Seminars and Schools in 2022···················································································································· 171
Award List·············································································································································································································· 175
MLF Publication 2022························································································································································································ 177
Editorial Board - MLF Annual Report 2022················································································································································· 187

Organization Chart

MLF Annual Report 2022

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

Organization Chart of
CROSS

CROSS is “Registered Institution for facility Use
Promotion” for the public-access neutron
beam facilities 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 Section
Neutron Science Section
Neutron Instrumentation
SectionMuon Science Section
Technology Development
SectionParticle & Nuclear Physics Division
Nuclear Transmutation Division
Cryogenics Section
Information System Section
Public Relations Section
Facility Engineering Section
Administration and Operations
Support Division
Users OfficeDirector, Neutron Scienceand Technology Center
Science Coordinators
R&D Division
Utilization Promotion
Division
Industrial Collaboration
Promotion Division
Safety Division
Administration Division
New Business Creation
Division

The Role of CROSS

Under the terms of the legislation that supports
the Public Neutron Beam Facility, CROSS is
entrusted with specific responsibilities. In
practical terms, the core functions of CROSS canbe summarized as follows:Proposal Selection and Beamtime Allocationon 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 2022

J-PARC Map

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

J-PARC Center Users Office

R245

(

KEK Tokai Campus

Main Gate
R245
Linac

HENDEL R&D Building

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MLF Annual Report 2022

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Research and Development
Highlights

Research and Development Highlights

MLF Annual Report 2022

Atomic Distribution and Local Structure in Ice VII fromin situ Neutron Diffraction
1. Introduction
Water (H2O or D2O) is one of the simplest molecules
but is also known for the anomalous diversity in crystalline polymorphs, which number 20 to date. Ice VII is oneof the high-pressure phases, which is stable at temperatures higher than 273 K at 3 GPa. Ice VII is a hydrogendisordered phase in which water molecules randomly
orient. It transforms to ice VIII below 273 K [1]. Ice VIII isan ordered counterpart which has an oxygen sublatticeidentical to ice VII, but the orientations of water molecules align in a certain manner.
In ice structures, each water molecule is connected
to four neighbouring water molecules via hydrogenbonds in tetrahedral geometry. Hence, the structure of
ice VII is often described by a cubic model in which oxygen forms BCC sublattice and hydrogens are located on
the vertices of oxygen-centred tetrahedra. This simple“single-site model” reproduces the diffraction patterns
well and is widely adopted. On the other hand, it is also
known to result in physically unreasonable water geometry such as too short covalently-bonded OD (0.89 Å [2])compared to those in ice VIII (0.97 Å [2, 3]). This discrepancy comes from the too-simplified description withtetrahedral symmetry.
More reasonable “multi-site models” have been
proposed to describe the structure of ice VII. In thesemodels, the hydrogens are located away from a straightline between adjacent oxygens [4, 5]. Oxygen positions
were modelled mainly in two ways: displacements towards <111> [5] or <100> [2]. Displacements along<100> imply that ice VII favours local structures similar
to ice VIII, while displacements along <111> imply the
opposite. A computational study supported the <100>model but also claimed the insufficiency of the simple
models with discrete atom sites [6]. In the present study,
we investigated the disordered structure of ice VII fromin-situ neutron diffraction combined with the maximum
entropy method (MEM) and pair distribution function(PDF) analyses [7].
2. Experimental
The powder diffraction experiments were performed at the BL11 (PLANET) beamline [8] using the
MITO system [9] for pT control. Powder samples of deuterated ice VII were obtained via solid-solid phase transitions, which provide fine powder samples suitable for2structure analyses. Deuterated samples (D) are used to
avoid the incoherent scattering from light hydrogen (H).
Diffraction patterns of ice VII were collected at 2.2 GPaand temperatures of 298 K and 274 K. A powder diffraction pattern of ice VIII was also collected at 2.2 GPa and274 K for comparison in PDF analysis. The sample pressures were estimated from the equation of state of ice
VII and VIII themselves [10].
3. Atomic distribution from MEM analysis
Based on the principle of maximum entropy, theMEM analysis derives the most probable distribution
ρ(r) by maximising the information entropy under constraints on the observed structure factors Fo(k) and theiruncertainties σFo(k). The MEM analysis is often called“model-free” analysis in comparison to the conventionalparameter refinements of presumed structure models
such as the Rietveld analysis.
The obtained MEM result (Fig. 1) shows the elongated feature of oxygen distribution along <111> direction,
consistent with Nelmes’ work [5]. At the same time, thedistribution has a tetrahedral shape rather than a tetrapodal one, which suggests that the oxygen distribution

Figure 1.	Distribution of scattering-length density in ice VII
derived at 298 K and 2.2 GPa. (b) indicates the crosssections of (a) on the (110) plane. The oxygens anddeuteriums are illustrated as those in the single-site
model with O-D = 0.97 Å, as in the water molecule,and DOD = 109.47° for comparison. Density decreases from red to blue colour.

MLF Annual Report 2022

also includes the components along <100>.
The deuterium has density maxima aside from the<111> axis, as reported in the previous studies [4, 5].
On the other hand, the distribution is not localised at
discrete points but has a ring-like feature. Moreover, thedistribution is elongated along <111>. These features
cannot be described in the conventional models withellipsoidal atom sites, but their physicochemical origin
is not clear yet.
4. Local structure from PDF analysis
We also derived local structure information from
PDF analysis. The MEM analysis only deals with Bragg
peaks assuming a periodic structure, resulting in an averaged structure within the unit cell. In the PDF analysis, the interatomic correlation is obtained from the backFourier transformation of the structure factor S(Q) without the assumption of the periodicity.
The obtained PDF G(r) shows the consistency of intramolecular structures between ice VII and VIII (Fig. 2).
The covalently-bonded OD bond distances are estimated to have similar values: 0.9662 (5) for ice VII and
0.9658 (5) Å for ice VIII. These findings are in contrast to
the Rietveld result with OD = 0.9163 (5) Å for ice VII and
0.9681 (8) Å for ice VIII. On the other hand, ice VII and VIII
differ in the intermolecular region. This is consistent with
the MEM result and a computational study suggestingthat the ice-VII-like is no longer dominant at the temperature close to the phase boundary [11].

Research and Development Highlights

5. Future plans
Various experiments suggested the crossover indominant dynamic processes in ice VII at approximately
10 GPa from molecular rotation to proton translation([12] and references therein). Such cross-over would be
related to the structural changes upon compression,
such as the shortening of intermolecular distances andaccompanying steric hindrance. High-pressure in-situ
diffraction techniques will lead to comprehensive pictures of the anomalous physical properties of ice VII.
References[1] E. Whalley et al., J. Chem. Phys. 45, 3976 (1966).
[2] W. F. Kuhs et al., J. Chem. Phys. 81, 3612 (1984).
[3] J. D. Jorgensen et al., J. Chem. Phys. 81, 3211 (1984).
[4] J. D. Jorgensen and T. G. Worlton, J. Chem. Phys. 83,
329 (1985).
[5] R. J. Nelmes et al., Phys. Rev. Lett. 81, 2719 (1998).
[6] C. Knight and S. J. Singer, J. Phys. Chem. A 113,
12433 (2009).
[7] K. Yamashita, et al., Proc. Natl. Acad. Sci. 119, 1(2022).
[8] T. Hattori et al., Nucl. Instruments Methods Phys. Res.
780, 55 (2015).
[9] K. Komatsu et al., High Press. Res. 33, 208 (2013).
[10] S. Klotz et al., Phys. Rev. B 95, 174111 (2017).
[11] K. Umemoto et al., Chem. Phys. Lett. 499, 236 (2010).
[12] R. Yamane et al., Phys. Rev. B 104, 214304 (2021).

Figure 2.	Pair distribution functions G(r) of ice VII and VIII obtained at
274 K and 2.2 GPa. The abscissa on top is normalised interatomic distance by lattice parameter a0 = 3.346632 (13) Å ofice VII, determined from the Rietveld analysis.

K. Yamashita1,#, K. Komatsu1, S. Klotz2, O. Fabelo3, M. T. Fernández-Díaz3, J. Abe4, S. Machida4, T. Hattori5, T. Irifune6, T. Shinmei6,
K. Sugiyama7, T. Kawamata7, and H. Kagi1
1
Geochemical Research Center, Graduate School of Science, The University of Tokyo; 2Institut de Minéralogie, de Physique des Matériaux etde Cosmochimie, Sorbonne Université; 3Institut Laue-Langevin; 4Neutron Science and Technology Center, CROSS; 5Neutron Science Section,
Materials and Life Science Division, J-PARC Center; 6Geodynamics Research Center, Ehime University; 7Institute for Materials Research,
Tohoku University #Present address: Institute of Physical Chemistry, University of Innsbruck3

Research and Development Highlights

MLF Annual Report 2022

Study on Large Elastic Deformation in Bulk Metal by
In Situ Neutron Diffraction
1. Introduction
The metals and alloys used in our everyday life aremostly crystalline, capable of elastic deformation as thebonds between atoms can be temporarily expanded orcontracted by external forces. Theoretically, a maximum
elastic strain in the order of 10% is predicted for mostmetal crystals under a uniaxial stress, but in practicalbulk metallic materials, the elastic strain is usually below 0.5% due to defects. The stress-strain relationshipof bulk metals in this small elastic deformation region is
generally linear and follows the well-known Hooke’s law.
Metals with a large capacity for elastic deformation
can store mechanical energy due to their ability to undergo substantial reversible strain, making them goodcandidates for applications in mechanical vibration systems, sports equipment, medical devices, and more. It is
known that downscaling is effective in achieving large
elastic strains in metal crystals. For instance, when metal
samples are reduced to microscale or nanoscale, as in
the case of whiskers or nanowires, the generation of
dislocations is suppressed, and they are known to exhibit ultra-high yield strengths and elastic strains up to
4%~7%, close to the theoretical values. However, scaling
up metals to bulk dimensions, such as exceeding 1 mm³,
has proven difficult to achieve large elastic strains. Until
now, only a few titanium-based alloys known as gum
metals [1] and certain high-entropy alloys [2] have beenreported to have large elastic strains, but these strains
are only about 2%. In a recent study, we have discoveredthat a BCC-structured Heusler-type bulk copper alloy exhibits a substantial giant elastic strain exceeding 4.3% atroom temperature [3]. This paper introduces the investigation of its origins through in situ neutron diffraction
experiments.
2. Experimental
The alloy with a chemical composition of
Cu69Al17Mn14 (at%) was prepared by induction melting
from pure elements. The ingot was then hot rolled andsubjected to cyclic heat treatment [4], by which singlecrystal sheets with length over several centimeters
could be obtained. Tensile tests on the single crystals
at room temperature were conducted in conjunction
with neutron diffraction measurements. The neutron
diffraction experiments were carried out using theEngineering Materials Diffractometer BL19 “TAKUMI”
4

installed at the Materials and Life Science Experimental
Facility (MLF) of the J-PARC (Japan Proton Accelerator
Research Complex). This instrument is a time-of-flight(TOF) neutron diffraction diffractometer using powerfulpulsed neutrons, capable of simultaneously measuring
diffraction profiles existing over a wide range of latticeplane spacings. In situ neutron diffraction experiments
during uniaxial deformation can simultaneously measure the lattice plane spacings in the loading direction(LD) and the transverse direction (TD) by positioning thedetectors at ±90° to the incident beam and setting up
the testing machine so that the load axis is horizontal
at 45° [5].
3. Results and discussion
The alloy shows a giant elastic anisotropy [6], asshown in Fig. 1a. The Zener ratio is very large at 11.1, andthe Young’s modulus along <100> direction is very small
at 23.2 GPa based on the calculation results from elastic
constants. Figure 1b shows the stress-strain curve for asingle-crystal sample stretched along <100> direction atroom temperature. Upon unloading the applied stress,
it was found that the sample fully recovered its original shape. The reversible strain in this process reached4.31%, which is about an order of magnitude larger thanthe elastic strain values of most practical bulk metallic
materials, including steels. The initial Young’s modulus
along the <100> direction was found to be approximately 24 GPa. Additionally, the stress hysteresis in theloading-unloading loop is zero, indicating that essentially no work is dissipated. Moreover, with the increaseof applied stress, the slope of the stress-strain curve becomes smaller, indicating a significant elastic softening
phenomenon.
When the phenomenon of large reversible strain
without stress hysteresis was initially discovered, it was
assumed to be due to the contribution of local stressinduced martensitic transformation. To investigate thenature of this phenomenon, in situ neutron diffraction
measurement was conducted. The changes in the twodimensional diffraction profiles of LD and TD accompanying the load-unloading tensile deformation are
shown in Figs. 2a and 2b, respectively. The maximum
applied stress was set at 580 MPa to prevent damage
to the sample. The diffraction profiles were demonstrated to change continuously and reversibly with theMLF Annual Report 2022

Research and Development Highlights

Figure 1.	(a) The crystal orientation dependence of Young’s modulus, where a giant elastic anisotropy can be referred; (b) The loading-unloading tensile stress-strain curve for a <100> single crystal obtained at room temperature.

Figure 2.	(a) Two-dimensional neutron diffraction patterns in the LD; (b) Two-dimensional diffraction patterns in the TD; (c) Latticestrain as a function of engineering stress.

application and release of stress in both LD and TD. In
the wide range of interplanar spacing d-spacing from0.67 Å to 3.33 Å, no other diffraction patterns were detected during the measurement, revealing that neither
phase transformation nor phase decomposition occurred during the reversible deformation.
To quantitatively evaluate the atomic-level structural changes during reversible deformation, one-dimensional diffraction patterns corresponding to the (400)plane in LD and the (004) plane in TD were extracted,
and the lattice strains were then obtained. Figure 2cplots the lattice strain, which is the rate of change ofinterplanar spacing relative to the initial value before
loading, against the applied stress. The engineering
stress-lattice strain curve for LD shows a shape similar to
the macroscopic stress-strain curve shown in Fig. 1b. The
maximum reversible lattice strain in LD at 580 MPa stressis large at 3.81%, which closely matches the strain of

3.83% macroscopically measured with an extensometer.
The results of the neutron diffraction experiments
reveal that the nature of the large reversible strain in
the Cu-Al-Mn alloy is a true elastic deformation, wherereversible lattice strains occur while maintaining theparent phase. This is independent of the “pseudoelastic deformation” caused by martensitic transformation,
which is characteristic of the shape memory alloys.
4. Summary and future perspectives
This paper presented results from in situ neutron
diffraction experiments applied to the study of the
dynamic deformation behavior of metallic materials,
using the Cu-Al-Mn alloy as an example of a material
exhibiting significant elastic strain. Bulk Cu-Al-Mn alloy,
which shows large elastic strain, possesses superior elastic properties in terms of elastic deformation capacity
and Young’s modulus compared to conventional bulk
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MLF Annual Report 2022

metallic materials. This suggests a wide range of potential applications for high-performance springs, sealingmaterials, and precision machinery. We hope that theseresults will encourage the development of new materials capable of large elastic strain and the invigoration ofresearch using in situ neutron diffraction experimentsfrom both fundamental and practical perspectives.

References[1] T. Saito et al., Science, 300 464 (2003).
[2] Q. F. He et al., Nature, 602 251 (2022).
[3] S. Xu et al., Nat. Commun., 13 5307 (2022).
[4] T. Omori et al., Science, 341 1500 (2013).
[5] https://mlfinfo.jp/en/bl19/[6] S. Xu, Ph.D. thesis, Tohoku University (2020).

S. Xu1, T. Odaira1, X. Xu1, T. Omori1, T. Kawasaki2, S. Harjo2, and R. Kainuma1
Department of Materials Science, Tohoku University; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center

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Research and Development Highlights

Effect of Hydrogen on Evolution of Deformation
Microstructure in 2Mn-0.1C Ferritic Steel
1. Introduction
Deterioration of the mechanical properties ofmetals and alloys by hydrogen is known as hydrogen
embrittlement. Hydrogen-related quasi-cleavage (QC)
fracture, one of the typical fracture modes of hydrogen
embrittlement, occurs along a non-cleavage plane in atransgranular manner. We previously found that the QC
fracture propagated parallel to {011} planes both in martensitic steel and ferritic steel [1, 2]. These results suggested that the mechanism of the QC fracture is closely
related to plastic deformation because {011} plane corresponds to the slip plane in body-centered cubic (BCC)
crystals. Therefore, further study on the effect of hydrogen on plastic deformation is needed to understand themechanism of the QC fracture.
In this study, we characterized the evolution of thedeformation microstructure in a hydrogen-charged
steel with ferrite microstructure [3].
2. Experimental
A 2Mn-0.1C (mass%) steel with ferrite (87%) andpearlite (13%) phases was used in this study. Sheet-type
tensile test specimens with a gauge length of 10 mm, awidth of 5 mm, and a thickness of 1 mm were cathodically pre-charged with hydrogen in an aqueous solution (3% NaCl + 3 g L–1 NH4SCN) at a current density of
5 A m–2. Uniaxial tensile tests were performed at a strain
rate of 8.3 × 10–6 s–1, at ambient temperature under hydrogen concurrent-charging condition (same as the
pre-charging condition). Some of the tensile tests were
stopped and the specimens were unloaded at strain
amounts of 3%, 11.5%, 20%, and 24% corresponding to

the end of the Lüders deformation, the middle point ofwork hardening, the ultimate tensile strength, and prior
to the final rupture, respectively.
The tensile-tested and unloaded specimens at strain
amounts of 3%–20% were analyzed by neutron diffraction using BL19 “TAKUMI” in J-PARC. From the obtained
neutron diffraction profiles, the dislocation densities
and the fractions of screw/edge dislocations were evaluated by a convolutional multiple whole profile (CMWP)
fitting proposed by Ungar [4]. The microstructures of
the tensile-tested and neutron-diffraction-measured
specimens were characterized by scanning transmission electron microscopy (STEM). TEM is very useful incharacterizing the dislocation morphology, character,and density. However, the disadvantage of TEM is thelimited observation area. In contrast, we can obtain bulk
average information from neutron diffraction. Using
TEM and neutron diffraction together, we characterized
the deformation microstructure from bulk to nanoscale.
3. Results and discussion
Figure 1(a) shows the nominal stress–nominal strain
curves and dislocation densities. Although the total
elongation of the hydrogen-charged specimen (red,27%) is much smaller than that of the uncharged specimen (black, 48%), the dislocation densities are hardly
affected by the presence of hydrogen at the corresponding strain amounts. We note that a certain amount of dislocation that forms cell boundaries is excluded in Fig. 1
because their elastic strain fields mutually cancel eachother. Figure 1(b) shows the fractions of screw/edge
dislocations estimated from the neutron diffraction

Figure 1.	(a) Nominal stress–nominal strain curves and dislocation densities, (b) fractions of screw and edge dislocations, (c) screw
dislocation densities of the uncharged specimens (black, circle marks) and the hydrogen-charged specimens (red, triangle
marks) [3].

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MLF Annual Report 2022

analysis. The left and right axes indicate the fractionsof the edge and screw components, respectively. In theuncharged specimens (black circle marks), almost all of
the dislocations were screw-type at the initial stage of
deformation (e = 3%), and the fraction of the edge component increased monotonically with increasing strain.
In contrast, in the hydrogen-charged specimens (redtriangle marks), almost equal fractions of screw/edge
components were present and did not vary greatly withthe strain amount. From the dislocation density data
(Fig. 1(a)) and the fractions of the dislocations (Fig. 1(b)),
we calculated the individual densities of each type of
dislocations. Figure 1(c) shows the changes in the screw
dislocation density with strain amount. We found thatthe screw dislocation density in the hydrogen-charged
specimen was much higher than that of the uncharged
specimen at the later stage of deformation (e = 20%).
Figures 2(a, d) show low-magnification STEM images of the dislocation morphologies in the uncharged
and hydrogen-charged specimens, respectively, at
e = 3%. The dislocations are linear in the uncharged
specimen, while they are curved and tangled in thehydrogen-charged specimen. To further investigate thedeformation microstructure, the nature of the dislocations was characterized. Figures 2(b, e) show high-magnification STEM images of the deformed microstructurein the uncharged and hydrogen-charged specimens,
respectively, at e = 3%. Figures 2(c, f ) are the schematic
illustrations of the dislocation configurations in (b, e),respectively, where the Burgers vectors of the dislocations determined by the g · b = 0 invisibility criterion are
represented by different colors. In the uncharged specimen, almost all the observed dislocation loops elongated parallel to their Burgers vectors, suggesting thatthey have a large screw component. On the other hand,in the hydrogen-charged specimen, many dislocations
have a large edge component as indicated by arrows
in Fig. 2(f ). Accordingly, the results demonstrated thatthe fractions of screw/edge dislocations estimated fromthe neutron diffraction analysis (Fig. 1(b)) were consistent with the real dislocation nature observed by STEM.
We also confirmed that the fraction of each dislocation
component was consistent between neutron diffractionand STEM at e = 20%.
It is widely accepted that in BCC transition metals,edge dislocations have greater mobility than screw dislocations because of the higher Peierls potential of screw
dislocations, leading to screw-segment-elongateddislocation loops at the initial stage of deformation [5].
This is consistent with the present microstructure in
the uncharged specimen. On the other hand, in thehydrogen-charged specimen, many edge-segmentelongated dislocation loops were observed. Thus, theresults strongly suggest that the relative velocity ofscrew dislocation to edge dislocation was increased byhydrogen. Itakura et al. [6] performed first-principles
calculations and reported that hydrogen reduced theactivation energy for kink-pair nucleation, which led to a

Figure 2.	(a, d) low-magnification and (b, e) high-magnification STEM images of the dislocation morphologies under two-beamconditions (g = 011) at a strain amount of 3%. (c, f ) Schematic illustrations of the dislocation configurations corresponding (b, e), respectively, where the Burgers vectors of the dislocations determined by contrast analysis are represented by different colors [3]. (a–c) and (d–f ) show the uncharged and hydrogen-charged specimens, respectively.

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decrease in the critical shear stress for screw dislocation
motion. In addition, using molecular dynamics simulations, Matsumoto et al. [7] reported that the motion ofedge dislocations was significantly damped by hydrogen. Therefore, we can consider that the tangled dislocation morphology in the hydrogen-charged specimen
resulted from the frequent cutting of screw dislocations
due to the increase in their relative velocity.
At a strain amount of 24%, well-developed dislocation cell structures, the so-called low energy dislocation
structures (LEDS), were observed both in the uncharged
and hydrogen-charged specimens. The statistical distributions of LEDS size (dLEDS) and misorientation of
LEDS boundaries (θLEDS) are summarized in Fig. 3(a, b),
respectively. The dLEDS was smaller and θLEDS was larger
in the hydrogen-charged specimen than those in theuncharged specimen, suggesting that the amount of
dislocation constituting LEDS boundaries was larger inthe hydrogen-charged specimen. As explained previously, a certain amount of dislocation constituting the
LEDS boundaries was not involved in the dislocation
densities derived from the neutron diffraction analysis(Fig. 1(a)). Therefore, the amount of excluded dislocation in the neutron diffraction analysis should be larger
in the hydrogen-charged specimen and the density of
total dislocations (existing outside the LEDS boundaries
and constituting LEDS boundaries) was higher in thehydrogen-charged specimen.

Research and Development Highlights

4. Conclusions
In this study, the effect of hydrogen on the evolution of the deformation microstructure in 2Mn-0.1C
steel mainly composed of ferrite microstructure wassystematically investigated. We found that the densities of the total dislocations (existing outside the LEDS
boundaries and constituting LEDS boundaries) werehigher in the hydrogen-charged specimens. In addition,
we conclude that hydrogen increases the relative mobility of screw dislocations to edge dislocation, leading to
the frequent cutting of screw dislocations and tangled
dislocation morphology.
5. Acknowledgements
This study was financially supported by JSPS
KAKENHI (JP19J21267, JP15H04158, JP19H02459, andJP20K21083) and the Elements Strategy Initiative for
Structural Materials (ESISM). The neutron diffraction
experiment at the J-PARC was performed under a user
program (Proposal No. 2018A0051).
References[1] A. Shibata et al., Mater. Sci. and Technol., 33 1524 (2017).
[2] K. Okada et al., Int. J Hydro. Ener., 43 11298 (2018).
[3] K. Okada et al., Acta Mater., 225 117549 (2022).
[4] T. Ungar et al., J Appl. Cryst., 32 992 (1999).
[5] D. Caillard, Acta Mater., 58 3439 (2010).
[6] M. Itakura et al., Acta Mater., 61 6857 (2013).
[7] R. Matsumoto et al, Int. ISIJ, 62 2402 (2022).

Figure 3.	Statistical distribution of (a) LEDS size (dLEDS) and (b) misorientation of LEDS boundaries (θLEDS) of
the microstructures at a strain amount of 24% [3]. The red, green, and black bars indicate areas
1 mm from the crack tip in the hydrogen-charged specimen, just beneath the quasi-cleavage
surface in the hydrogen-charged specimen, and the uncharged specimen, respectively.

K. Okada1,2, A. Shibata1,3, W. Gong3,4, and N. Tsuji2,3Research Center for Structural Materials, NIMS; 2Department of Materials Science and Engineering, Kyoto University; 3Elements Strategy
Initiative for Structural Materials (ESISM), Kyoto University; 4Neutron Science Section, Materials and Life Science Division, J-PARC Center

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MLF Annual Report 2022

High-Pressure Synthesis of Transition-Metal Oxyhydrides
with Double Perovskite Structures
1. Introduction
Transition-metal Oxyhydrides crystallizing in perovskite-type and related structures often exhibit highperformances regarding ionic conductivity and catalyzing ammonia synthesis owing to the low valence andlarge negative redox potential of H– (–2.25 eV) [1–4].
Because such performances are improved with increasing H– content, the development of oxyhydrides containing large amounts of H– is crucial.
Known perovskite transition-metal oxyhydrides are
represented by the general formula ABO3–xHx , where
A is an alkaline earth metal and B is an early transition
metal such as Ti, V, and Cr. To ensure charge neutrality,
the number of hydride ions can be increased by decreasing the valency of the transition-metal ions at the B site,
as observed for BaTiO3–xHx [5]. However, it is difficult toincrease x to values above 1 when using early transition
metals because they are mostly stable in trivalent andtetravalent states.
To explore a transition-metal oxyhydride withhigh H– content, the reduction of the total cation valence would be helpful. Thus, we focused on doubleperovskite-type structures (A2B’ B” X6), which comprisecorner-sharing octahedra as in the ABO3 perovskite, butwith two types of B cations arranged in two distinct octahedral sites (rock-salt-type order). Various combinations of B’ and B” metals are allowed within a range oftolerance factors [7]. For instance, the tolerance factorof Ba2NaM(O,H)6 (M = an early transition metal) is approximately 1 owing to the ionic radii of its constituent
ions. In this study, we successfully synthesized four new
oxyhydrides with double perovskite structures with different B” atoms, namely Ba2NaVO3H3, Ba2NaVO2.4H3.6,
Ba2NaCrO2.2H3.8, and Ba2NaTiO3H3 [7].
2. Experimental
Polycrystalline samples of Ba2NaVO3H3, Ba2NaVO2.4H3.6,
Ba2NaCrO3H3, and Ba2NaTiO3H3 were synthesized by asolid-state reaction under high pressure. The molar ratio of these starting materials was stoichiometric, except
for the 2 molar excess of NaH. A mixture of these reagents was ground thoroughly in an Ar-filled glovebox
and placed in a NaCl capsule, which was placed in a pyrophyllite cell with a graphite heater. The cell was compressed to a pressure of 4 GPa using a cubic anvil press,
heated for 1 h at 825°C, and then quenched to room
10

temperature before releasing the pressure. The obtained
sample was washed with 0.1 molar NH4Cl/MeOH to remove residual NaH. Powder XRD measurements were
performed using a SmartLab (Rigaku) with CuKα1 radiation selected by a Johansson-type monochromatorwith a Ge(111) crystal. Time-of-flight powder ND measurements were performed using a neutron total scattering spectrometer (NOVA) installed in the Japan Proton
Accelerator Research Complex (MLF J-PARC). Powder
diffraction data were collected at room temperature using a vanadium holder with a diameter of 3 mm. The
crystal structure was determined by the simultaneousrefinement of the XRD and ND data by the Rietveld
method using the Jana2006 program [8]. The chemicalcompositions of the products were examined by EDX
analysis (JSM-IT100). Thermogravimetric measurements
were carried out by heating powder samples at a rateof 10 K min–1 under flowing oxygen atmosphere using
Bruker TG-DTA 2020SA. The electronic charge densities
of Ba2NaTiO3H3 and BaTiO2.5H0.5 were obtained using
first-principles DFT calculations implemented in the
WIEN2k code [9].
3. Results and discussion
First, we will discuss Ba2NaVO3H3. Elemental analysis
by EDX for the obtained sample reveals that the molar
ratio of Ba:Na:V was 2:1:1. To determine the precise crystal structure and chemical composition of the product,
we carried out structural analyses using XRD and neutron diffraction (ND) data based on a structural modelof the double-perovskite structure (Fig. 1). Two assumptions were made: (1) the anion sites are randomly occupied by O2– and H–, and (2) V and Na are ordered in arock-salt-type manner at the octahedral sites. As shownin Fig. 2, fittings of both data were satisfactory and converged with reasonably small R factors (Rwp = 7.47% and
Rp = 5.52% for XRD; Rwp = 1.05% and Rp = 0.83% for ND).
We examined the possibility of site mixing among the
Na and V sites and found that both atoms are highly ordered with a mixing of less than 1%. This is likely due tothe large differences between the ionic radii and valences of Na+ (1.02 Å) and V4+ (0.58 Å). The refined chemicalcomposition is Ba2NaVO2.996(4)H3.004(4); this gives a tetravalent state for V, which agrees with the average valenceof V in the starting materials. Thermogravimetric analysis of the sample under oxygen flow shows a weightMLF Annual Report 2022

Research and Development Highlights

Figure 1. Crystal structure of double-perovskite oxyhydrides
A2B’ B”(O, H)6.

Figure 2.	Powder XRD pattern (upper) and powder neutron diffraction (ND)
pattern (lower) of Ba2NaVO3H3 analyzed by the Rietveld method.
The observed (red marks), calculated (black line), and difference(blue line) profiles are shown, together with the positions of the
Bragg reflections represented by the green ticks.

increase of 7.36%, which is consistent with this chemicalcomposition.
We also attempted to synthesize vanadium oxyhydrides with higher hydride contents. The synthesis yielded a double-perovskite phase. Our structural analyses of
the XRD and ND data revealed the formation of a double
perovskite oxyhydride with a chemical composition of
Ba2NaVO2.400(5)H3.600(5). Furthermore, we found that not
only vanadium but also chromium and titanium formed
oxyhydrides with double-perovskite structures. The syntheses yielded double-perovskite phases with chemicalcompositions of Ba2NaCrO2.238(9)H3.762(9) and Ba2NaTiO3H3.
For the latter compound, our structural refinements

revealed nearly 7% anti-site mixing between Na and Ti.
Owing to the high hydride contents, newly discovered Ba2NaM(O,H)6 have a covalent bonding nature of
the M–H bonds. To compare that of Ba2NaM(O,H)6 andknown perovskite oxyhydrides BaM(O,H)3, two-dimensional electronic charge densities for Ba2NaTiO3H3 andBaTiO2.5H0.5 were visualized by DFT calculations using
atomic positions obtained from structural analyses.
Figures 3 represent the contour plots of the electronic
charge densities around the Ti, O, and H sites, in which
the semi-core states, such as Ti-3s and -3p, were removed to obtain a meaningful picture of the chemicalbonds. In each compound, there is a certain electron
11Research and Development Highlights

MLF Annual Report 2022

Figure 3.	Two-dimensional contour plots of the electronic
charge densities of (a) Ba2NaTiO3H3 and (b) BaTiO2.5H0.5
in the (100) plane.

charge density around H, which is indicative of a hydride
anion. The non-spherical charge distribution around Ti
in Ba2NaTiO3H3 clearly shows the noticeable covalentnature of the Ti–H and Ti–O bonds in the double-perovskite oxyhydride. This covalent nature of the Ti–H
bonds is reduced in BaTiO2.5H0.5, with fewer hydrides,
as evidenced by the almost spherical charge density
around Ti.
4. Conclusion
We synthesized successfully four new oxyhydrides,
Ba2NaM(O,H)6 (M = Ti, V, Cr) with double-perovskite
structures via high-pressure synthesis. Structural analyses of the XRD and ND data showed that Na and M arehighly ordered in a rock-salt-type structure. The hydride
species occupy a maximum of 63% of the anion sites
in Ba 2NaCrO 2.2H 3.8, which is the highest amount reported thus far for known transition-metal oxyhydrides
with perovskite-related structures. Owing to this highhydride content, the M–(O,H) bonds have significant covalent nature confirmed by DFT calculations. We believethat these oxyhydrides could provide a new platform for
hydride chemistry.
References[1] T. Yajima et al., J. Am. Chem. Soc., 134, 8782-8785(2012).
[2] G. Kobayashi et al., Science, 351, 1314-1317 (2016).
[3] T. Yajima et al., Nat. Chem., 7, 1017 (2015).
[4] Y. Tang et al., Adv. Ener. Mater., 8, 1801772 (2018).
[5] Y. Kobayashi et al., Nat. Mater., 11, 507-511 (2012).
[6] S. Vasala et al., Prog. Solid State Ch., 43, 1-36 (2015).
[7] T. Yajima et al., Inorg. Chem. 61, 2010-2016 (2022).
[8] V. Petricek et al., Z. Kristallogr. -Cryst. Mater. 229, 345(2014).
[9] P. Blaha et al., Technische Universität Wien: Vienna,
Austria, (2001).

T. Yajima1,2, K. Takahashi2, H. Nakajima2, T. Honda3,4, K. Ikeda3,4, T. Otomo3,4, and Z. Hiroi2
Graduate School of Engineering, Nagoya University; 2Institute for Solid State Physics, University of Tokyo; 3Neutron Science Section,
Materials and Life Science Division, J-PARC Center; 4Institute of Materials Structure Science, KEK

1

12

MLF Annual Report 2022

Research and Development Highlights

The Ion Dynamics in Li10GeP2S12 Investigated by
Quasi-Elastic Neutron Scattering Measurements
1. Introduction
The performances of current Li-ion batteries could
potentially be enhanced through the developmentof all-solid-state Li batteries, where Li+ conductors areused as solid electrolytes to replace conventional organic liquid electrolytes [1]. For the ideal design of Li+
conductors, it is important to understand the correlation
between microscopic and macroscopic motions (e.g.,
microscopic = Li+ jumping between neighboring sites;
macroscopic = long-range Li+ migration). This study [2]reports the application of the quasi-elastic neutron scattering (QENS) measurement to characterize the lithium
diffusive behavior in a well-known superionic conductor, Li10+xGe1+xP2−xS12 (LGPS) [3]. The microscopic diffusivity obtained by analysis of the QENS spectra is comparedwith reported values [4, 5] measured by pulse-field
gradient nuclear magnetic resonance (PFG-NMR) for
relatively long-range Li+ migration, to highlight the factthat QENS provides the local dynamic behavior for the
Li+ species present in bulk crystals. In addition, QENS is
used to measure the Li9P3S9O3 (LiPSO) phase [6], which
is a structural derivative of LGPS, but exhibits an ionic
conductivity two orders of magnitude lower than thatof LGPS. As a result, the dynamic parameters of the twophases can be compared, and any differences in theirconductivities can be rationalized.

A

2. Description of materials and methods
Figure 1A shows the crystal structure frameworksof LGPS and LiPSO [7, 8]. For LGPS, the structure consists of a scaffold composed of PS4 and [P/Ge]S4 tetrahedral units. Through these tetrahedral units Li sites arewidely distributed forming connected sites along thec-axis, which is considered as a Li migration pathway.
The LiPSO crystal possesses similar structural features,
except that its tetrahedral units are PS4 and P[S/O]4, andits unit cell volume is smaller than that of LGPS.
The phase-pure LGPS and LiPSO samples weresynthesized according to previous reports [3, 8]. In
synthesis, Li was substituted into 7Li to avoid neutron
absorption. The sample compositions and the reported
ionic conductivity at room temperature are summarizedin Table 1, together with the physical values determinedby the present QENS study. The QENS spectra were recorded at the BL02 beamline (DNA at MLF/J-PARC),
which is a TOF-type near-backscattering spectrometerequipped with a high-resolution Si crystal analyzer.
Measurements were performed with an energy resolution of 3.6 eV in the temperature (T ) range between
150 and 614 K, and the instrument resolution function
was measured at 150 K, where no QENS signal was observed. Data were collected within an energy transfer
range from −40 to 100 μeV and a Q range of 0.1–1.9 Å−1.

B

8.188 ÅC

12.34 Å[P2](S/O) 4[P2]S 4

S(Q,E) / arb. units

0.7
0.6

[P1]S 4

614 K

0.4

0.02

150 K

0.3
0.2

0
-20

0.1
0
-40

[Ge/P1]S4

0.04

0.5

0

40
ΔE / µeV

0

20

80

c
b

a

Figure 1.	QENS study of LGPS and LiPSO. (A) Tetrahedral structural units and lithium site distributions along the c-axis for LGPS (left)and LiPSO (right). For the lithium sites, only those located along the c-axis are displayed for clarity. The black rectangle
indicated for each phase represents the scale of the unit cell. The lattice parameters for LiPSO at 473 K are indicated. (B)Normalized scattering spectra S(Q, E) for LGPS. The inset shows an amplification of the quasi-elastic region. (C) Arrhenius
plots of the diffusivities measured using the QENS and PFG-NMR techniques [4, 5] for LGPS and LiPSO. Reproduced withpermission [2]. Copyright 2022, the American Chemical Society.

13Research and Development Highlights

MLF Annual Report 2022

Table 1. S ample information, dynamic parameters for Li+ diffusion, and details for the mobile Li+ fractions for LGPS and LiPSO at different measurement temperatures.
τQENS
DQENS
T
LQENS or rQENS
Mobile fraction
a
−6
2 −1
b
/Å
/ps
/10 cm s/K
1− EISF338
2.4 ± 0.13
117 ± 5.8
0.8 ± 0.09
0.14 ± 0.020376
2.6 ± 0.50
111 ± 29.1
1.0 ± 0.43
0.29 ± 0.056
LGPS
12
7
( Li10.05Ge1.05P1.95S12)473
2.8 ± 0.08
62 ± 2.3
2.1 ± 0.13
0.40 ± 0.031614
3.3 ± 0.10
31 ± 1.5
5.8 ± 0.41
0.48 ± 0.004373
4.5 ± 0.31–
1.3 ± 0.38
0.12 ± 0.005
LiPSO
<0.1
7
( Li9P3S9O3)473
4.9 ± 0.22–
2.3 ± 0.35
0.25 ± 0.004
a+
LQENS represents the jump distance for LGPS, and rQENS indicates the radius of the sphere for Li diffusion in LiPSO.
b
The mobile fraction was obtained from the elastic incoherent structure factor (: EISF).
Sample(composition)

σ RT−1/mS cmHere, Q represents the magnitude of the scattering vector expressed by Q = ki − kf, where ki and kf denote the
wavevector of the incident and the scattered neutrons,
respectively. The intensity of the spectra was integrated
over a separate Q step. The step size ranged from 0.1 to
0.15 Å−1, depending on the Q range.
3. Analysis of QENS spectra
Figure 1B shows the normalized scattering spectra S(Q, E) of LGPS at 150 and 614 K as a function of theenergy transfer ΔE μeV between the incident and scattered neutrons at a representative scattering vector
Q = 0.33 Å−1. Compared with the resolution function
observed at 150 K, clear quasi-elastic broadening was
detected at 614 K with a sufficiently low background.
This result implies that the recorded QENS signal, whichis due to the relaxation process of the Li ion, is statistically relevant and worthy of further analysis.
The QENS spectra were fitted with a combinationof a delta function, a Lorentz function, and a constantbackground, which were convoluted with the resolution function, in order to obtain an elastic incoherent
structure factor (EISF), and half width at half maximum(Γ ) of the Lorentz function. The former was calculated
from coefficients of the delta and Lorentz function to estimate the immobile species ratio for all Li ions present
in the compound.
For LGPS, the obtained Q-dependences of Γ were
found to fit well using the Chudley–Elliott model [9],which is a diffusion model that assumes a jump-diffusion
process. The fitting analysis provided the jump distance
LQENS and the residence time τ QENS. From these parameters the diffusion coefficient (DQENS) was calculated.
For LiPSO, the Chudley-Elliott model was not applicable to the Q dependence of Γ. Thus, the obtained
EISF was analyzed using an alternative model in which
the mobile species diffuse in a restricted space of a14

characteristic radius rQENS. The rQENS value (2rQENS ~10 Å)
obtained from Q-dependence of EISF was used to derive
DQENS from the Γ –Q dependence [10–12].
4. Discussion
The physical values determined by the present QENS
analysis are summarized in Table 1. Figure 1C compares
the DQENS (/10−6 cm2 s−1) values with those measured by
PFG-NMR (DPFG-NMR /10−6 cm2 s−1) techniques in previous
studies [4, 5].
Herein, the difference in the reported conductivity between LGPS (>10 mS cm−1) and LiPSO (<0.1 mS cm−1)[3, 8]
can be rationalized by two factors indicated by QENS:(1) an impediment that blocks Li ion migration at a spatial scale below 10 Å, and (2) the number of Li ions participating in the conduction process. More specifically,
the first factor was indicated by the Γ –Q relationships
obtained for LGPS and LiPSO. The former was well described by the translational motion of Li+ without restriction over the Q/Å−1 range of 0–2, corresponding toa value of d > 3.1 Å. In contrast, the translational motion model was applicable to the latter only in the cases
where 1 < Q/Å−1 < 2 (i.e., 3.1 < d/Å < 6.3), while outside
this range, the inside sphere diffusion model was moresuitable with a sphere diameter 2rQENS of ~10 Å (corresponding to the size of single unit cell of LiPSO with a =8.1876 Å and c = 12.3415 Å at 473 K). These differencesin the Γ –Q relationships for the two materials indicatethat the migration of Li ions in LiPSO is more impeded
at certain unit cell sizes (~10 Å) than in the case of LGPS.
This was considered partly due to the crystal structure
difference between LGPS and LiPSO, the anion distribution (Fig. 1A). The anion site is evenly occupied by sulfur
in LGPS, but is unevenly occupied in LiPSO due to theoxygen partially occupying the anion sites. In the unit
cell for LiPSO there is one pair of PO4 and PS2O2 tetrahedral units or two PSO3 units, potentially attracting Li

MLF Annual Report 2022

ions [8], and thereby trapping mobile ions around thetetrahedral unit, and eventually impeding Li migration
across several unit cells. The oxygen distribution in the
LiPSO may be the reason for the fact that Li+ diffusion
over a range longer than the unit cell size was more
restricted for LiPSO than for LGPS, as indicated by our
QENS analysis. This finding is consistent with the diffusivity evaluated by PFG-NMR, which represents the macroscopic diffusivity to a greater extent than the QENS
technique [13]. More specifically, the DPFG-NMR value for
LiPSO (i.e., 6.4 × 10−2 at 353 K) was found to be lower
than that of LGPS (i.e., 15 × 10−2 at 353 K), while the DQENS
value for LiPSO (i.e., 1.3 ± 0.38 at 373 K for d < 10 Å) was
determined to be slightly larger than that of LGPS (1.0 ±0.43 at 376 K for d > 3.1 Å).
The second factor responsible for the conductivity
difference between LiPSO and LGPS involves the number of Li ions contributing to the conduction process.
More specifically, the mobile lithium fraction estimatedfor LiPSO was lower than that for LGPS; in the estimation
based on EISF, the mobile fractions of the Li ions at 473 K
were 0.40 ± 0.03 for LGPS and 0.25 ± 0.004 for LiPSO (seeTable 1). Based on these values, the volumetric concentrations of mobile Li ions were calculated to be 13.4 and9.04 mol L−1 for LGPS and LiPSO at 473 K, respectively. It
was therefore apparent that a larger number of mobile
Li ions were present in LGPS, and so in combination with
its higher macroscopic diffusivity over the micrometerscale, this factor contributes to its higher conductivity
when compared to that of LiPSO.

Research and Development Highlights

5. Conclusions
In this study, we successfully observed short-lengthionic motion in lithium-ion systems and established therelationship between such motion and ionic conduction for both LGPS and LiPSO. The diffusivity obtained
by PFG-NMR was smaller than that obtained by QENS
measurements, indicating that any factors acting to impede the diffusivity only become evident during longerscale ionic migration, especially for the case of LiPSO.
Moreover, the mobile fraction of Li ions also influenced
the conductivity. Thus, the present study demonstrates
that QENS measurements on sulfide fast ionic conductors can allow elucidation of the dynamic behavior ofions, which is linked to the conductivity of the material.
References[1] K. Takada, Acta Mater., 61, (2013) 759.
[2] S. Hori, et al., J. Phys. Chem. C, 126, (2022) 9518.
[3] N. Kamaya, et al., Nat. Mater., 10, (2011) 682.
[4] A. Kuhn, et al., Energy Environ. Sci., 6, (2013) 3548.
[5] A. Kurima, et al., Abstract of the 55th Battery
Symposium in Japan, (2014).
[6] K. Takada, et al., Solid State Ionics, 176, (2005) 2355.
[7] T. Yajima, et al., J. Mater. Chem. A, 9, (2021) 11278.
[8] M. Xu, et al., Inorg Chem, 61, (2022) 52.
[9] C. T. Chudley, et al., Proc. Phys. Soc., 77, (1961) 353.
[10] F. Volino, et al., Mol. Phys., 41, (1980) 271.
[11] K. Ito, et al., J. Phys. Chem. C, 125, (2021) 21645.
[12] V. Kuznetsov, et al., Phys Chem Chem Phys, 23,(2021) 7961.
[13] M. J. Klenk, et al., Solid State Ionics, 312, (2017) 1.

S. Hori1, R. Kanno1, O. Kwon2, Y. Kato3, T. Yamada4, M. Matsuura4, M. Yonemura5, T. Kamiyama5, K. Shibata6, and Y. Kawakita6
Institute of Innovative Research, Tokyo Institute of Technology; 2Interdisciplinary Graduate School of Science and Engineering, Tokyo
Institute of Technology; 3Toyota Motor Europe; 4Neutron Science and Technology Center, CROSS; 5Neutron Science Division (KENS), Instituteof Materials Structure Science, KEK; 6J-PARC Center, Japan Atomic Energy Agency

115

Research and Development Highlights

MLF Annual Report 2022

Impact of Na Concentration on the Phase Transition
Behavior and H− Conductivities in the Ba-Li-Na-H-O
Oxyhydride System
1. Introduction
Hydrogen transport in solids has received muchattention due to expectation for electrochemical applications, including fuel cells and batteries. In the field,
proton (H+) conduction has been almost the only choice,but recently, the use of hydride ion (H−) is becoming a
new trend. Owing to its basic characteristics, such as
mono-valence and large polarizability, H – could beconsidered a promising charged carrier for fast conduction. We especially focus on K2NiF4-type oxyhydride as aplatform of H– conducting materials and have reported
La2–x–ySrx+yLiH1–x+yO3–y in 2016 [1], followed by Ln2LiHO3(Ln = La, Pr, Nd) [2], and Ba2MHO3 (M = Sc, Y) [3].
Recently, we found a new member, Ba1.75LiH2.7O0.9,
hereafter called BLHO [4], wherein a sizable number ofvacancies in Ba-, H-, and O-sites form a long-range ordering at room temperature (β-BLHO, space group Pnm21).
Upon heating, a successive order-disorder phase transition to γ -BLHO (space group Pnma) at 300°C, followed
by to δ -BLHO (space group I4/mmm) at 360°C, triggereda drastic increase in ionic conductivity reaching over
10–2 S/cm without being influenced by the temperature.
Such a non-trivial, so-called “superionic conduction”
state was firstly observed in the H– conduction.
In this study, we attempted to stabilize the superionic phase by partial Na substitution for Li (Na-BLHO).
By using high-intensity and high-resolution neutron diffraction experiments, the impact of the chemical substitution on the phase transition behavior and the ionic
conducting property were investigated.
2. Experiment
Powder samples of nominal composition
Ba2Li1−xNaxH3O (x = 0.2, 0.4, and 0.6) were synthesized by
the high-pressure method, and post annealing process
in an H2 gas-filled SUS container (0.42 MPa) provided ahighly vacant compositions.
Temperature-controlled powder synchrotron X-ray
diffraction measurements were performed at BL02B2 at
SPring-8 [5]. Powder neutron diffraction data at room
temperature and 427°C for samples loaded into a cylindrical vanadium cell (radius = 6 mm, height = 55 mm)
were collected using time-of-flight (TOF) diffractometers (SPICA(BL09) and NOVA(BL21)) at J-PARC. The
16

collected profiles were analyzed by the Rietveld method
using the RIETAN-FP program [6] for the X-ray diffraction data and the Z-Rietveld program [7] for the neutron
diffraction data. Ionic conductivity of the Na-BLHO wasmeasured by electrochemical impedance spectroscopy(EIS) under H2 gas flow at 200–350°C, with an appliedfrequency range from 0.1 Hz to 35 MHz. The obtained
impedance spectra were fitted with electrical equivalentcircuits using the EC-Lab software.
3. Results and discussion
SXRD profiles revealed that, with increasing Na
content x, the points of phase transitions were lowered. In response to that trend, the high conductivity
region (≥10–2 S/cm) was expanded to lower temperatures, as shown in the Arrhenius plot, Fig. 1. In addition,
the x ≥ 0.4 samples showed an increase in conductivity

Figure 1.	Temperature dependencies of the total (bulk andgrain boundary contributions) conductivity foreach composition in Na-BLHO, together with thatof BLHO [4]. The unfilled circles show the inflection points of the Arrhenius plots, the β -γ transition
temperature estimated from the temperature-controlled synchrotron X-ray diffraction.

MLF Annual Report 2022

more than 100 times also at low temperature region(< 300°C), compared to the pristine BLHO. The slopeon the Arrhenius plots of discontinuous transitions to
the high conductivity region became shallower withincreasing x, implying that the transition nature waschanged by Na doping.
To investigate the impact of Na on the phase transition, the crystal structures for x = 0.2, and 0.4 were
evaluated using neutron diffraction. Figure 2a shows
the fitting profile of Rietveld refinement for the data ofx = 0.4 collected using SPICA at room temperature. The
refinement result converges using a structure model
based on the β -BLHO [4], indicating that the similar superlattice structure is maintained (Fig. 2b). The refinedcomposition of Ba1.60(3)Li0.6Na0.4H2.25(3)O0.959(8) has more

Figure 2.	a) Rietveld refinement profile of neutron diffraction data collected at RT for Na-BLHO (x = 0.4) using SPICA. b) Refined crystal structure of x = 0.4.
c) Comparison in vacancy distributions of equatorial
H–sites between BLHO (x = 0) and x = 0.4 projectedalong the [001] direction. The crystal structures
were drawn using VESTA software [9].

Research and Development Highlights

vacancies than that of Ba1.75LiH2.7O0.9 (x = 0), especiallyin the occupancies of Ba and H eq sites. Furthermore,as shown in Fig. 2c, a contrast in the occupancy(g(Ba) = 0.74-0.85, and g(Heq) = 0.65-0.76) weakens,meaning that the crystal structure at room temperature
is closer to the high conductive γ -phase [4] in which H–
and vacancies are disordered. This is consistent with theresults of enhanced conductivity for x ≥ 0.4 at < 300°C.
On the other hand, x = 0.2 has almost the same ordering manner with β -BLHO. Such a trend in vacancy ordering could result in a difference in conductivity at low
temperatures.
4. Conclusion
We succeeded in expanding the “superionic conduction” state appeared by order/disorder transition in
BLHO to lower temperatures by Na doping [8]. With theincrease of the Na content x, the phase transition points
were lowered and high conductivity over 10−2 S/cm wasachieved at 300°C. Furthermore, for x ≥ 0.4, the conductivity below 300°C was also enhanced more than
100 times compared to the pristine BLHO, that is attributed to a decrease in the degree of vacancy orderings
in Ba/VBa and Heq/VH at even the orthorhombic phase atroom temperature.
References[1] G. Kobayashi et al. Science, 351 1314 (2016).
[2] Y. Iwasaki et al. J. Mater. Chem. A, 6 23457 (2018).
[3] F. Takeiri et al. Inorg. Chem., 58 4431 (2019);
H. Nawaz et al. Chem. Commun., 56 10373 (2020).
[4] F. Takeiri et al. Nat. Mater., 21 325 (2022).
[5] S. Kawaguchi et al. Rev. Sci. Instrum., 88 085111(2017).
[6] F. Izumi et al. Solid State Phenom., 130 15 (2007).
[7] R. Oishi et al. Nucl. Instrum. Methods Phys. Res. Sect.
A, 600 94 (2009).
[8] K. Okamoto et al. Adv. Sci., 10 2203541 (2022).
[9] K. Momma et al. J. Appl. Cystallogr., 44 1272 (2009).

K. Okamoto1, F. Takeiri2, and G. Kobayashi2,31Institute for Materials Research, Tohoku University; 2Cluster for Pioneering Research (CPR), RIKEN; 3Department of Electrical Engineeringand Bioscience, Waseda University

17

Research and Development Highlights

MLF Annual Report 2022

Tracer diffusion coefficient measurements in solid-stateelectrolytes through neutron radiography
1. Introduction
All-solid-state batteries (ASSBs) have been an attractive technology for higher reliability and higher
energy density in comparison to ordinary Li-ion batteries. However, due to the low ionic conductivity of solidstate electrolytes (SSEs) which is a key component to the
ASSBs, the performance of ASSBs is less than ideal. One
way to mitigate such problem is to heterogeneously
dope the SSEs with dielectric particles (i.e., composite
SSEs) [1].
Originally discovered in halide-based SSEs, it was
believed that space charge layers facilitating ionic conduction can be formed at particle/SSE interfaces, leading to significant increase in overall ionic conductivity
once an optimum particle/SSE interface distribution isachieved [1]. Although researchers have been focusedon halide-based SSEs during early stage, this strategy
has been successfully applied to the oxide-based SSEs
by Onishi et. al., where a 2-fold enhancement in roomtemperature conductivity has been observed when
LaPO4 particles were added to Li1.7Al0.3Ti1.7(PO4)3 (LATP)
SSEs [2, 3].
Due to the different defect chemistries inherent to
LATP-based SSEs in comparison to the halides, the ionic
conductivity enhancement mechanism might be different from our previous understanding. Therefore, it isquintessential to measure the Li diffusion coefficient of
LATP-based composite SSEs from multiple scales in order to understand how the dielectric particle dispersion
technique enhances the mass transport behavior.
By utilizing the significant difference in neutron
cross sections between 7Li and 6Li, neutron radiography
has been proven a viable technique in measuring the
diffusion coefficients of Li-ion-conductive materials onmacroscopic scale [4]. In this study, tracer diffusion experiments at 300 to 500°C were conducted on 7Li LATP
and composite SSEs with 6Li as tracer species. The diffusion of 6Li was observed through neutron radiography at
RADEN BL22 at J-PARC MLF. This allows calculation of thesample tracer diffusion coefficients, the results of whichwere then compared with conclusions from other works.
2. Material and methods
The 7Li LATP and LATP-LaPO4 composite samples
were synthesized through ordinary solid-state reaction
method [2]. The sintered samples were in cuboid shape18(approx. 6 × 6 × 8 mm) and polished until mirror finish
was obtained on a 6 mm × 6 mm face. In tracer diffusion experiment, saturated 6LiNO3 aqueous solution wasapplied to the polished surface. The samples were thenannealed at 300 to 500°C for 20 to 30 min (in a tubular
furnace within the beamline), after which the samples
were cooled to room temperature and subjected to neutron radiography observation. The annealing + neutron
radiography process was repeated 4-6 times until the
total annealing time (i.e., diffusion time) reached 80 to
180 min.
During the experiment at RADEN BL22 at J-PARC
MLF, the sample was configured 18 m away from thebeam source, accepting a white beam (with fast neutrons removed by a T0 chopper). The samples wereplaced on an aluminum sample holder which is directly
attached onto the protective aluminum plate of thescintillator to maximize resolution. A 50 μm 6LiF/ZnS
scintillator was employed to capture the transmitted
neutrons. The converted photons were then sampled
by a water-cooled CCD camera (Andor Technology Ltd.).
During each neutron radiography, 5 consecutive images
were taken with 3 min exposure time for each image.
For each measurement, an average intensity image ofthe 5 images were calculated to mitigate the gamma
noise and beam intensity fluctuation. The ‘averaged’ image was then divided by the open beam image to obtainthe spatially resolved transmission of the samples.
3. Result and discussion
Typical neutron radiographs (transmission) before
and after the diffusion experiment are shown in Fig. 1.
Since the LATP and LATP-LaPO4 composite samples
consist of species with relatively small neutron crosssections (7Li, Al, Ti, P, O, and La), the presence of 6Li cancontribute to a significant drop in transmitted neutron
flux, thereby producing a dark contrast on the neutron
radiographs. At locations further away from the surface
where 6Li was applied (x = 0 plane), the contrast from6
Li becomes weaker. The length of the diffusion (diffusion distance) also increases as the diffusion time isincreased. It is therefore assumed that the diffusion is asemi-finite 1-dimensional diffusion. The result also demonstrates a straightforward way of visualizing Li masstransportation at macroscopic scale.
Quantitatively, the Beer-Lamberts law can beMLF Annual Report 2022

Research and Development Highlights

along y direction. By assuming M and D are constant,equation 1 describes the neutron transmission as afunction of position. Since t is a known quantity, equation 1 allows calculation of tracer diffusion coefficientsfrom the intensity profiles of the neutron radiographs
through non-linear fitting, as demonstrated by Fig. 2.
The measured tracer diffusion coefficients areTransmission / A.U.

combined with the semi-finite solution to the Fick’s second law (fixed amount of 6Li at surface), which gives:(1)-ln(I/I0) = M·(4πDt)–1/2·exp(–x2/4Dt)
where M is the total amount of diffusing species, D is
the tracer diffusion coefficient, t is diffusion time, x is
the position where the specific I/I0 is observed, I/I0 is theneutron transmission at local that is spatially averaged

Figure 1.	Typical transmitted neutron images of LATP – LaPO4 composite (left) and pristine LATP (right) samples (a) before application of 6LiNO3, (b) applied with 6LiNO3 followed by annealing at 300°C for 30 min, and (c) annealing at 300°C for 150 min.
Plots (d)–(f ) are intensity profiles corresponding to the selected rectangle areas in (a)–(c). Used with authors’ permission
from ref. [5].

a 0.20LATP

30 min63 min90 min
120 min
150 min180 min

LATP-LaPO430 min63 min90 min
120 min
150 min180 min-ln(I / I0)

0.15
0.10
0.05
0

b 0.20-ln(I / I0)

0.15
0.10
0.05
0
0

0.2

0.4

0.6

0.8

1.0

x / cmFigure 2.	Diffusion profile of (a) pristine LATP and (b) LATP – LaPO4 composite samples after diffusion at 300°C. Fit results basing on
the Fick’s second law are also given by blue curves. Used with authors’ permission from ref. [5].

19Research and Development Highlights

MLF Annual Report 2022

summarized in Table 1 and are compared with chemical diffusion coefficients from other works in Fig. 3 (converted from ionic conductivities through Nernst-Einstein
relation). The diffusion coefficient of LATP – LiPO4 measured through neutron radiography is comparable tothe chemical diffusion coefficient calculated from theresult of Onishi’s work [2], but that of the pristine LATP

measured in this work as well as by other works show alower consistency. This might be due to different sample
preparation methods employed in different works whichleads to various impurity content or humidity at LATP
grain boundaries that affects the overall Li mobility.
The activation energy measured in this work also
falls within the reported range (0.15 – 0.3 eV) [7-9]. It

Table 1 T racer diffusion coefficient of lithium ion in LATP and LATP – LaPO4 composite obtained bytracer diffusion - neutron radiography experiments
−6

2

−1

Diffusion coefficient, D* / 10 cm ∙spristine LATP
LATP – LaPO4 composite
1.71 (20)
2.95 (14)2.60 (12)3.22 (19)2.88 (16)3.53 (53)4.97 (27)4.48 (37)7.63 (25)Temperaturet / °C
300
350
400
450
500

Temperature / C-3

500 400 300

200 150-4

Log(D / cm2 s-1)

-4.5

-5.5
-6

50

25

D*composite, total
D*LATP, total
D , composite, total (Onishi et al. [2])D , LATP, total (Song et al. [6])D*LATP, bulk (Case et al. [7])D , LATP, total (Kosova et al. [8])D , LATP, bulk (Arbi et al. [9])

-3.5

-5

100

0.172 eV

0.18 eV
0.176 eV

-6.5

0.28 eV0.22 eV0.25 eV

-7
-7.5

0.3eV

-8
-8.5
-9
1.2

0.4 eV

1.6

2

2.4

2.8

3.2

1000 T 1 / K 1
Figure 3.	Arrhenius plots of the tracer diffusion coefficients of pristine LATP (▼) and LATP – LaPO4 composite (▲). The conductivity
diffusion coefficients for LATP – LaPO4 composite (△) and pristine LATP (▽) are obtained from conductivities measured inprevious works using Nernst-Einstein equation [2, 6]. The blue dash line is the bulk tracer diffusion coefficient in pristine
LATP simulated by Case et al. [7], the dark cyan and purple solid lines are total and bulk conductivity diffusion coefficients,
respectively in pristine LATP, which are converted from the conductivity measured by Kosova et al. and Arbi et al. throughNernst-Einstein equation [8, 9]. Adapted with authors’ permission from ref. [5].

20MLF Annual Report 2022

is also worth noting that the activation energy for the
LATP – LaPO4 composite at 300 – 500°C is relatively close
to that of the pristine sample, which indicates that thebulk diffusion is the dominant mechanism in both samples at 300 – 500°C, coinciding with the observation in
Kosova’s work [8]. This also explains the similar diffusion coefficients for LATP and LATP – LaPO4 composite
measured in this work: as the bulk diffusion becomes
the dominant mechanism at high temperatures, contribution from grain boundary and LaPO4 / LATP interface
become much less obvious. The results confirms the
speculation that dielectric particle dispersion enhancement for SSEs is more suitable at room temperatures
rather than high temperatures [10].
4. Perspectives
This work demonstrated that the neutron radiography is an effective and non-destructive way of diffusion
coefficient measurement for Li-ion conductors. It also
shows a possibility for in-situ visualizations of Li masstransport within ASSBs with thick electrolytes. In thiscase, the oxide-based solid-state electrolyte samples
were annealed at 300 to 500°C in order to accelerate the
Li diffusion and thereby reduce the time cost. Since the
ASSBs are mostly operating at room temperature where
the Li mobility is significantly lower, conducting such
experiment under room temperature will take much
longer times. Nevertheless, this method is proven to bean effective way of characterizing overall diffusion coefficients in SSEs with engineered microstructures.
However, the limitation of the diffusion experimentResearch and Development Highlights

should also be addressed. The presented work modeled
the 6Li diffusion with the semi-finite solution of the Fick’s
second law, where the 6Li is assumed to be a dimensionless thin film with finite concentration and diffuses toward the other end of the sample. However, in cases
where an excessive amount of 6Li was applied to thesample surface, redistribution of 6Li within the thick 6Li
layer can disrupt the diffusion behavior of the 6Li diffusion in the sample, since the excessive 6Li that are not initially available can migrate to the sample surface duringlater process, contributing to an underestimation of the
Li diffusion coefficient. On the other hand, if the samples
are porous, permeation of LiNO3 solution can contributeto a significant overestimation of diffusion coefficient at
early stages of the diffusion. Such complication should
be fully considered and controlled through modificationof experiment and sample preparation such that macroscopic diffusion coefficients can be measured withhigher accuracies.
References[1] J. Maier, Chem. Mater., 26 (2014) 348-360.
[2] H. Onishi, et. al., Electrochemistry. 84 (2016) 967-970.
[3] F. Song, et. al., J. Alloy Compd., 853 (2021) 157089.
[4] S. Takai, et. al, Solid State Ionics, 256 (2014) 93-96.
[5] F. Song, et. al., Solid State Ionics, 377 (2022) 115873.
[6] F. Song, et. al., Materials, 14 (2021) 3502.
[7] D. Case, et. al., Solid State Ionics, 346 (2020) 115192.
[8] N.V. Kosova, et. al., Ionics, 14 (2008) 303-311.
[9] K. Arbi, et. al., Inorg. Chem., 52 (2013) 9290-9296.
[10] J. Maier, Prog. Solid State Chem., 13 (1995) 171-263.

F. Song1, H. Hayashida2, T. Kai1, T. Shinohara1, T. Yabutsuka3, T. Yao4, and S. Takai3
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS; 3Graduate
School of Energy Science, Kyoto University; 4Kyoto University
121Research and Development Highlights

MLF Annual Report 2022

Ionomer Distribution of N-Doped Carbon Surfaces
1. Introduction
To meet the demand for more affordable fuel cellelectric vehicles, it is necessary to reduce the Pt loading in the catalyst layer of polymer electrolyte fuel cells(PEFCs). Ott et al. [1] proposed a method involving NH3
treatment to modify the carbon support used in the
catalyst layer of PEFCs. They demonstrated that themodified N-doped carbon resulted in a more uniform
ionomer distribution in the catalyst layer and improved
the PEFC performance. Therefore, to understand the influence of ionomers on the PEFC performance, it would
be interesting to explore the effect of the surface modification on the ionomer adsorption behavior. We evaluated the interfacial structure of ionomers on N-dopedcarbon surfaces using the neutron reflectivity (NR) technique and discussed the influence of surface properties
on the ionomer adsorption [2].
2. Experiment
The deposition of carbon thin films (50 nm) on Si
wafers was performed by magnetron sputtering. The asdeposited carbon films (Film C) were first treated withconcentrated HNO3 at 70°C for 2 h, and then rinsed threetimes with ultrapure water. The oxidized carbon films(Film O) were then heated in a tube furnace with NH3/Ar
gas at 200°C, 400°C and 600°C, for 2 h. The obtainedcarbon films were designated as Film N200, N400, andN600 at the respective treatment temperatures. On the
top of the carbon films, ionomer thin films (30 nm) wereprepared by spin-coating a Nafion ionomer dispersion
at 2000 rpm for 30 s. The Nafion ionomer dispersion was

diluted to 1 wt% with 1-propanol. The thin films wereannealed at 120°C for 1 h in a vacuum oven. NR measurements were performed at BL17 SHARAKU in J-PARC
MLF (Japan Proton Accelerator Research Complex,
Material and Life Science Experimental Facility). Neutron
pulses of 25 Hz were generated with a wavelength bandof 0.2 nm < λ < 0.88 nm. NR profiles were obtained atreflection angles of 0.3, 0.7, 1.6, and 3.5°, covering aq-range of 0.07–3.0 nm–1. The magnitude of the scattering vector q was defined as 4πsinθ/λ, where θ is the incident angle. All measurements were performed at room
temperature (22°C) with two scattering contrasts on thesame system using H2O/D2O vapor for double contrast
measurements. A saturated KCl in H2O/D2O was used tomaintain the vapor condition.
3. Results and discussion
Figure 1 shows NR curves of the ionomer thin films
obtained at H2O/D2O vapor. The observed fringes in the
NR curves arise from the interference of reflections at
the interfaces within the thin films. The shape of thefringes at q = 0.55 nm–1 exhibited variations between
Films C–O and Films N200–N600, indicating changes in
the interfacial structures associated with the ionomer on
the N-doped carbon surfaces. First, the NR curves of thethin films obtained under H2O vapor were analyzed todetermine the structural parameters of the carbon andionomer layers, including thickness, scattering lengthdensity (SLD), and interfacial roughness. Subsequently,
the NR curves collected under D2O vapor were fitted using the parameters determined from the H2O vapor fits.

Figure 1.	Experimental NR data and the corresponding fits (solid lines) of Nafion ionomer thin films obtained under (a) H2O and (b) D2O vapors. The NR curves
have been vertically offset (×10–1, ×10–2, ×10–3, and ×10–4 for Films O, N200,
N400, and N600, respectively) to aid visualization. Copyright 2022, American
Chemical Society.

22

MLF Annual Report 2022

In the fits, only the SLDs of the ionomer layers were fitted as variables, while the other parameters were fixed.
Figures 2a–e show the SLD profiles of the ionomer
thin films under H2O/D2O vapor as a function of verticaldistance from the carbon surfaces. These SLD profiles
showed a SLD variation with the vertical distance, indicating fluctuations in the density and/or compositionof the ionomers and water in the thin films. The SLD
profiles under D2O vapor were subtracted from thoseunder H2O vapor to determine the water volume fraction in the thin films (Figs. 2f–j). Based on the obtainedwater volume fraction, the ionomer volume fraction
was evaluated under certain constraints [2]. The NR
analysis revealed an “ionomer adsorption layer” at the
carbon-ionomer interface. The hydrophobic carbon surface (Film C) had a higher volume fraction of ionomer
adsorption layer than the hydrophilic carbon surface(Film O). The difference may be due to the breakdownof ionomer aggregates and the adsorption of the ionomer backbone onto the hydrophobic carbon surface by
the hydrophobic interaction [3]. Moreover, the thickness
and volume fraction of the ionomers in the adsorption
layer increased after NH3 treatment (Films N200–N600).
The wettability of N-doped carbon surfaces exhibitedhydrophilic nature as well as Film O. It is worth notingthat the ionomer adsorption behavior was different in

Research and Development Highlightshydrophilic oxidized and N-doped carbon thin films
in wet conditions. Yang et al. [4] reported that theζ-potential of carbon black was changed from –1.28 to+74.2 mV after introducing nitrogen functional groups
into the carbon. The positive charge derived from theionization of the N-doped carbon surface is sufficient to
attract the negatively charged SO3– groups in the side
chains of the ionomers via the Coulombic interaction.
The strong electrostatic interaction induces a thick anddense ionomer adsorption layer form at the ionomercarbon interface.
4. Conclusion
We conducted modification on a carbon surface by
NH3 treatment to investigate the ionomer distribution
on these modified surfaces using the NR technique. The
results support the idea that introducing nitrogen into
carbon supports can promote the formation of a dense
ionomer layer at the ionomer-carbon interface.
References[1] S. Ott et al., Nat. Mater. 19 77 (2020).
[2] W. Yoshimune, et al., ACS Appl. Mater. Interfaces 1453744 (2022).
[3] T. Mashio, et al., J. Phys. Chem. C 114 13739 (2010).
[4] F. Yang, et al., ACS Appl. Mater. Interfaces 9 6530 (2017).

Figure 2.	(a–e) SLD profiles of Nafion ionomer thin films as a function of vertical distance fromthe carbon surfaces z obtained under H2O (blue) and D2O vapors (red). (f–j) Volume fractions of the components of the ionomer thin films. Gray, red, blue, and light blue lines
represent carbon, the ionomer, water, and air, respectively. Copyright 2022, American
Chemical Society.

W. Yoshimune1, N. Kikkawa1, H. Yoneyama1, N. Takahashi1, S. Minami1, Y. Akimoto1, T. Mitsuoka1, H. Kawaura1, M. Harada1,
N. L. Yamada2,3, and H. Aoki2,3
1
Toyota Central R&D Labs., Inc.; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center; 3Institute of Materials
Structure Science, KEK

23

Research and Development Highlights

MLF Annual Report 2022

Interfacial Structure and Tribological Property ofAdsorbed Layer Formed by Organic Friction Modifier
1. Introduction
In recent years, engine oil has been increasingly
low-viscosity in order to achieve further fuel efficiency
in automobiles. However, low viscosity engine oil tends
to cause oil film breakage, which increases the risk ofseizure in addition to increased friction and wear in thesliding parts. Molybdenum dithiocarbamate (MoDTC)
and Zinc Dialkyldithiophosphate (ZnDTP) are generally
used as lubricating additives to engine oils to reduce
friction by forming a ‘tribofilm’ on the sliding surfaces
under high temperature and high pressure, thereby
reducing friction and wear [1, 2]. However, MoDTC and
ZnDTP cause problems, such as additive-derived metal
sludge, clogging of oil filters, and catalyst poisoning forexhaust gas treatment due to the presence of phosphorus and sulfur. Therefore, development of organic
friction modifiers that do not contain metal, such as
phosphorus and sulfur, is underway [3–5].
In this study, we focus on dibasic acid ester derivatives, which are one of the organic friction modifiers.
In a high-speed reciprocating friction and wear test
conducted in a previous study, these dibasic acid ester
derivatives were reported to have the same friction reduction effect as glycerol monooleate (GMO) at room
temperature and the same wear durability as ZnDTP
and phosphate ester amine salts even at high temperature [6]. On the other hand, there has been no sufficientstudy on how these additives form adsorption layers on
metal surfaces and contribute to the improvement offriction and wear properties. In this study, the interfacial
structure of the adsorbed molecular film formed on theiron surface by dibasic acid ester derivatives was evaluated by neutron reflectometry, and the macrotribological properties of each additive comprising the derivative
were evaluated [7]. The relationship between the structure and tribological properties of adsorbed molecular
films was finally discussed.
2. Samples
The dibasic acid ester derivative, succinic acid monooleyl dimethyl laurylamine salt (SA-DA, Fig. 1(a)),
was the target of this study. The constituent acid wasmonooleoyl succinate (C18: 1SA) and the amine was dimethyl laurylamine (C12DA). In the neutron reflectometry study, SA-DA with all hydrogen atoms deuterated
should ideally be used, but since it was difficult to obtain
24(a) SA-DA(b) dC8SA-DA

Figure 1.	The chemical structures of the dibasic acid ester derivatives prepared for the study.

deuterated molecules of both C18: 1SA and C12DA, theoleyl chain of C18: 1SA was substituted with a deuterated octane chain in the present study. Therefore, we
prepared a derivative (dC8SA-DA, Fig. 1(b)) by combining the deuterated monooctane succinate (dC8SA) with
deuterated octane (C12DA). Polyalphaolefin (PAO) wasused as the base oil, and the sample oil was a mixtureof the dibasic acid ester derivative at a concentration of
0.1 mass%.
3. Neutron reflectometry
The neutron reflectometry experiments were conducted using the BL16 SOFIA, a time-of-flight neutronreflectometer installed at the MLF J-PARC. An ironcoated silicon block was set in a holder, and reflectivity
profiles were obtained from the interface of iron andsample oil. First, the sample oil was put in a liquid cell in
the holder and the reflectivity profiles were measured.
In addition, the reflectivity profiles were measured after
heating at 50°C for 30 minutes, and again after heating
at 100°C for 30 minutes. The obtained reflectivity profiles
and the scattering length density profiles estimated by
the optimum fitting on the Parratt’s theory are shownin Fig. 2 [7]. In this measurement, the C12DA, which is
a component of dC8SA-DA, is not deuterated as is thecase with PAO. Therefore, the thickness and density of
the adsorbed layer formed by dC8SA-DA were estimated from the thickness and film density of the adsorbed
layer formed by dC8SA, which constitutes the derivative. Figure 2 shows that the thickness of the adsorbed
layer formed by dC8SA-DA on the iron surface at room
temperature was about 2.0 nm, with a graft density ofMLF Annual Report 2022(a)

Research and Development Highlights

(b(b

a)a)
PAO
PAO
+ C12DA+ C12DA + C16FA+ C16FA+ C18:1SA+ C18:1SA+ SA-DA+ SA-DA(a) Reflectivity profiles
(a)

b)b)

Fe

(a)
(a)AtAt25°C
25°C
PAO
PAO
+ C16FA+ C16FA+ C12DA+ C12DA

Fe2O3
SiO2
Si

+ dC8SA-DA+ dC8SA-DA (100ºC)(25ºC, 50ºC)+ C18:1SA+ C18:1SA+ SA-DA+ SA-DA

PAO(b) SLD profiles estimated by fitting procedure(b)(b)AtAt150°C
150°C

Figure 2.	Neutron reflectometry results for the interface between iron surface and sample oil [7].

Figure 3.	Typical friction behaviours of sample oils containing each additive [7].

26%. The thickness and graft density remained almost
unchanged when the temperature was increased to
50°C, but the graft density increased to 47% when thetemperature was increased to 100°C. This indicates thatthe dibasic acid ester derivatives form dense adsorption
layers, especially at high temperatures.

additive, but that additional friction also produces succinate-derived metallic soap, which in turn produces asustained low-friction effect. These results provide useful guidelines for the development of effective additives
in the future, and in particular, the combination with theneutron reflectometry was shown to be extremely effective in elucidating the mechanism.

4. Friction tests
To evaluate the macrotribological properties of theadsorbed layers formed by the various additives, friction tests were conducted using balls and discs made ofbearing steel (AISI 52100). Typical friction behaviours ofsample oils containing each additive are shown in Fig. 3.
Palmitic acid, a common type of oiliness additive, wasalso added as a reference OFM here (shown as C16FA).
When SA-DA was used, the behavior of the coefficientof friction was stable and smaller than that of the otheradditives. In addition, the wear amount was also significantly lower than that of the other additives. Combinedwith the results of neutron reflectometry, SA-DA formed
a dense adsorption layer on the iron surface, which suppressed friction and wear. Furthermore, not only does
the coefficient of friction decrease rapidly with the number of friction cycles due to the properties of the amine

References[1] J. Zhang and H. A. Spikes, Tribology Letters, 63 2 1(2016).
[2] W. Shen, T. Hirayama, N. Yamashita et al., Tribology
International, 167 107365 (2022).
[3] M. Desaker, X. He et al., ACS Applied Materials &Interfaces, 9 10 9118 (2017).
[4] B. M. Fry, M. Y. Chui et al., Tribology International,
151 106438 (2020).
[5] Y. Song, K . Fukuzawa, T. H irayama et al.,Macromolecules, 56 5 1954 (2023).
[6] Y.Shimizu, Tribology Monthly Magazine, 400 22(2020) (in Japanese).
[7] N. Yamashita, T. Hirayama, N. L. Yamada et al.,Tribology Online, 17 4 246 (2022).

T. Hirayama1, N. Yamashita1, and N. L. Yamada2
1
Dept. of Mechanical Engineering and Science, Kyoto University; 2Institute of Materials Structure Science, KEK

25

Research and Development Highlights

MLF Annual Report 2022

Mobile Water Near Poly(ethylene oxide) at PhysiologicalTemperature
1. Introduction
The macroscopic properties of synthetic polymers
are greatly varied by the choice of functional groups in
the main and side chains. Appropriate placement of hydrophilic and hydrophobic functional groups can control the position of water molecules around the polymer
chain and the state of hydrogen bonding. These properties allow findings from basic science research to be
applied and used as advanced functional materials in avariety of medical applications.
Poly(2-methoxyethyl acrylate) (PMEA)[1] (Fig. 1a)
is utilized in the inner wall coating of the circuit of theextracorporeal membrane oxygenation (ECMO), known
as Covit-19 medical devices. The full picture of themechanism of its superiority over other materials is not
yet clear, and research is underway by various methodologies as a major topic of a research grant (Aquatic
Functional Materials [2]). The research outcomes will
advance the fundamental science of water on material
surfaces and design greater materials.
We are studying water dynamics in the vicinity ofmatter via incoherent neutron quasi-elastic scattering(QENS) using BL02 at the J-PARC MLF. BL02 provides abroad energy range of dynamics and a high signal-tonoise ratio, enabling us to obtain even a tiny amountof dynamics information. By replacing H in substances
other than water with deuterium (D), which has a low incoherent scattering capability, the motion of substanceswith high incoherent scattering capability of light hydrogen (H) can be evaluated. Therefore, the combination of fully deuterated polymer and light water canselectively extract information on the motion of waterin the material. Conversely, the combination of a polymer with regular hydrogen and heavy water can provide
information on the polymer chain dynamics.
The side chains of PMEA have hydrophilic structures
such as poly(ethylene oxide) (PEO). Here, we focused on
the dynamics of water near the polymer chains at 37°C
using PEO (Fig. 1b). PEO is known to form eutectic with

Figure 1. Chemical structure of (a) PMEA, and (b) PEO.

26

water at lower water content or lower temperature. In
this study, we evaluated the dynamics properties of mobile water interacting with PEO chains at 37°C.
2. Experimental procedures
Perdeuterated PEO (dPEO, Polymer Source Inc.,
Mn: 17000 g/mol, Mw/Mn: 1.07), protiated PEO (hPEO,
Polymer Source Inc., Mn: 16000 g/mol, Mw/Mn: 1.05)
were used as received. Milli-Q water (H 2O) and D 2O
(deuteration ≥ 99.96%, Aldrich) were added to thedried dPEO and hPEO. The ratios of water molecules toethylene oxide, nwater/nEO was prepared to be 0, 0.3, 0.5,
1.1, 2.2, and 4.0 for the hPEO + D2O samples, and 0, 0.3,
0.4, 0.9, 1.8, and 3.2 for the hPEO + D2O samples.
The samples were cast on a Nb foil [3], were folded
then shaped into cylinders and set in an Al cell. The
QENS measurements were performed with BL02 [4] at
500 kW beam power operation. The scattering vector,
Q [Å–1] range was 0.125 < Q < 1.875. The energy resolutions were 3.6 and 12 µeV in the energy transfer E [µeV]
ranges of –20 < E < 50 and –40 < E < 1000 respectively.
The exposure time was approximately 3 h. The sample
temperature was 37°C [5].
3. Results and discussion
The dynamic structure factor S(Q, E) of the dPEO +H2O sample exhibited an increase in H2O mobility withincreasing water content [5]. We could fit the QENS profiles by the sum of three terms, a delta function and two
Lorentz functions (eq. 1).
S(Q, E) = R(Q, E) ⊗ [Aimmobile(Q) δ(Q, E) + Aslow(Q)(1)
Lslow(Γslow, E ) + Afast(Q) Lfast(Γfast, E )] + Bg,
where L, R, δ, A(Q), Γ, and Bg are the Lorentz function,
the instrumental resolution function, the delta function, a coefficient of the delta or the Lorentz function,
HWHM of the Lorentz function, and a constant background, respectively. The delta function represents
the immobile component in BL02 that is longer than
the sub-nanosecond order. The Q2 dependence of Dslow
and Dfast was followed by the jump diffusion model [6]:Γ = DQ2/(1 + DQ2τ0), where D and τ0 are the diffusion
coefficient and mean residence time, respectively.
The D of the fast mode water were of the same orderof magnitude as that of the bulk water [7], and those of

MLF Annual Report 2022

Research and Development Highlights

the slow mode water were an order of magnitude smaller than those of the fast mode water (Fig. 2a). Comparedto the dynamics of PEO obtained from the experiments
by hPEO+D2O samples, the mobility of the polymer
chains increased abruptly with the addition of water tothe dried polymer and increased with the increase ofwater content and was equivalent in order to Dslow. This
provides evidence of an interaction between the PEO
chains and the hydration water molecules.
Figure 2b shows the nwater /nEO dependence of τ0. The
maximum values of τ0 of the slow mode water were obtained at nwater /nEO ~ 1. These behaviors may be attributed to the length of the hydrogen bonding in the water
network, which is close to the O–O distance in the PEO
chain [8].
In the nwater/nEO range of 0.3 to 4.0, the ratios of Aimmobile,
Aslow, and Afast did not change significantly, approximately
in the order of 5, 65, and 30%. ‘Immobile water’ corresponds to water that interacts strongly with PEO, ‘slow
water’ interacts moderately well with PEO, and ‘fast water’ is free water that interacts with PEO but is closest tobulk water. Thus, a large amount of mobile water exists
around PEO, interacting with the polymer chain. The terahertz time-domain spectroscopy results also revealed
that in the nwater /nEO range of 1–2, the ratio of water tototal water interacting with PEO is approximately 60%,
which is comparable to the QENS analysis results [5].
4. Summary
QENS revealed that at physiological temperatures,
under low water content, significant amounts of mobile
water are interacting with PEO. Although PEO has noside chains, polymer chains with side chains, such as
PMEA, deuteration of the main chain or part of the side
chains can be approached into a detailed depiction.
Acknowledgements
The neutron experiments were conducted by proposal Nos. 2018B0235 and 2020A0221. This work was
supported by Grants-in-Aid for Scientific Research on
Innovative Areas Nos. JP19H05717 and JP19H05720.

Figure 2. T he nwater /nEO dependence of D for slow mode water(square), fast mode water (triangle), and PEO chain(circle). (b) The nwater /nEO dependence of τ0 for slow
mode water (squares) and fast mode water (triangles) [5].

References[1] M. Tanaka et al., Biomaterials, 21 1471 (2000).
[2] https://www.aquatic-functional-materials.org[3] T. Tominaga et al., J. Appl. Cryst., 54 1631 (2021).
[4] K. Shibata et al., JPS Conf. Proc., B 036022 (2015).
[5] T. Tominaga et al., J. Phys. Chem. B, 126, 1758 (2022).
[6] M. Bée, Quasielastic Neutron Scattering (Adam
Hilger: Bristol, England, 1988).
[7] T. Yamada et al., J. Phys. Chem. B, 115 13563 (2011).
[8] A. Maconnachie et al., Polymer 19 33 (1978).

T. Tominaga1, M. Hishida2, D. Murakami3, Y. Fujii4, M. Tanaka5, and H. Seto6
Neutron Science and Technology Center, CROSS; 2Department of Chemistry, Faculty of Science, Tokyo University of Science; 3Faculty of
Humanity-Oriented Science and Engineering, Kindai University; 4Graduate School of Engineering, Mie University; 5Institute for Materials
Chemistry and Engineering, Kyushu University; 6Neutron Science Section, Materials and Life Science Division, J-PARC Center, Institute ofMaterials Structure Science, KEK
1

27

Research and Development Highlights

MLF Annual Report 2022

Monitoring of Rapid Morphological Changes by
Photo-Irradiation in Micelles by in situ SANS
1. Introduction
Photo-induced rapid control of molecular assemblies formed by surfactants, such as micelles and vesicles can be applied in the controlled release and deliveryof drugs or active components (Fig. 1(a)) [1]. A varietyof photoresponsive surfactants based on photochromic compounds (e.g., azobenzene and spiropyran) havebeen synthesized and characterized. However, conventional photoresponsive molecular assemblies require
minutes to hours of photo-irradiation for significant
changes in the properties. For promising applications,the response by light irradiation needs to be fast and tooccur at an arbitrary moment.
To achieve rapid control of surfactant self-assembly,
we focused on the lophine dimer (LPD) as a photochromic moiety. The LPD molecules quickly dissociate into
two lophyl radicals and are recovered by a thermal recombination reaction (Fig. 1(b)). However, this recombination is extremely slow due to the free diffusion of
the radical species. Abe et al. reported that the reaction
rate is significantly enhanced by inhibiting diffusion of
the radicals when two lophine moieties are connected
through a linker [2]. Our group also reported the rapid

Figure 1.	Schematic image of controlled release with a photoresponsive molecular assembly (a) and photochromism of the lophine dimer derivatives (b).

28

recombination in micelles formed by surfactants as
a confined space to inhibit free diffusion of the radicals [3–5].
In this study, we investigated the effects of micellevolumes as a reaction site on the recombination rate of
the lophyl radicals by using small-angle neutron scattering (SANS) measurements. Furthermore, we examined
the morphological changes in the micelles, formed byamphiphilic LPD derivatives by using an in situ SANS
system.
2. Effects of the micelle volumes on recombination
reaction of the lophyl radicals
The recombination reaction of lophyl radicals
produced from LPD by ultraviolet (UV) light irradiation is significantly enhanced when LPD molecules aresolubilized and incorporated in the micelle formed bysurfactants. It is expected that the inner space of themicelle confines the radicals in the nano space and enhances the recombination of the radicals. In this study,
we examined the relationship between the micelle volumes and the recombination rates (Fig. 2) [6].
For this, an LPD derivative with triethylene glycol

Figure 2.	Schematic of micellar structures formed between
TEG-LPD and cationic surfactants and apparent reaction rates of recombination of the lophyl radicals(k’) vs. the volume of the micelle with different alkyl
chain length of cationic surfactants.

MLF Annual Report 2022

monomethyl ether groups (TEG) (TEG-LPD, Fig. 1(b))
was solubilized into micelle solutions prepared using cationic surfactants bearing alkyl chains of various
lengths (C12TAB, C14TAB, or C16TAB). To reveal the morphology and size of the micelles, we performed SANS
measurements (0.5 mM TEG-LPD/50 mM surfactant
in D2O) with the small and wide angle neutron scattering instrument TAIKAN (BL-15) installed at the MLF
in J-PARC. The SANS data could be well fitted using auniform prolate ellipsoid model interacting through ascreened Coulomb potential. With increasing alkyl chain
length, both the long radius (Ra) and short radius (Rb) increased, and so did the volume of the individual micelles(Vm). From these results, the inner volumes of micelles asa reaction space of the recombination can be tuned by
selection of the surfactants.
Next, we examined the apparent recombination
rates (k’) of the lophyl radicals in these micelles as a UV/
vis absorption spectroscopy and plotted the k’ against
micelle volume Vm according obtained by SANS analysis (Fig. 2). The recombination was enhanced in micelles
with smaller inner volumes. To see a clear trend for thisassumption, we calculated the free volume per lophyl
radical in the micelle (Vf ) according to Vm. This value indicates that the C12TAB micelle has the smallest volume for
diffusion of the lophyl radicals, which is consistent withthis trend. From these results, it becomes clear that theconfined space of micelles is useful for enhancing andtuning of the photochromic reaction of LPD.
3. in situ SANS measurement for photo-induced rapid
morphological changes in the micelle
Next, we examined the morphological changes
in micelles formed by an amphiphilic LPD derivative(3TEG-LPD) upon UV light irradiation. However, conventional lab-scale analytical techniques for colloidal
particles (e.g., light scattering and laser diffraction) haveproblems with obtaining precise information about thestructures of molecular assemblies by high time resolution and overlapping optical systems for photochromic
reactions and analysis. To overcome the problems, wedeveloped an in situ SANS system (TAIKAN, MLF, J-PARC)
by installing a lamp and a UV/Vis absorption spectrometer to monitor the morphology of the micelles andthe photochromic reaction of the LPD moiety of 3TEGLD (Fig. 3) [7,8]. Figure 4(a) shows the SANS profiles of
3TEG-LPD in D2O. The experimental data were well fitted using a uniform prolate ellipsoid model with a longradius (ra) of ~47 Å and a short radius (rb) of ~28 Å [9].
After UV irradiation, the long radius increased to ~70 Å.

Research and Development Highlights

Figure 3. Picture of in-situ SANS system.

This indicated that UV irradiation induced elongationof the longer axis of the micelles because of photo-induced morphological changes in the molecular structures between the dimer and monomer forms.
To see the time course of morphological changes in
the SANS profile, the integrated scattering intensity inthe q-region of 0.01–0.05 Å−1 during cycles of 2 min UV
irradiation followed by 4 min standing in the dark wasplotted against the time, as shown in Fig. 4(b). This revealed that the elongation of the elliptical micelles wascompleted after 60 s of irradiation and reversed after
60 s of standing in the dark. UV/Vis absorption spectra
were collected simultaneously during the SANS measurements. As shown in Fig. 4(c), a new absorption band
deriving from the lophyl radical was observed at 580 nm
during UV irradiation. The change in the absorption at
580 nm during the irradiation cycle revealed that morphological changes in the micelles and photochromismof LPD occurred without a time lag within the analyticaltime resolution (Fig. 4(b) and 4(c)). From these results,
we have successfully observed rapid morphologicalchanges in the LPD micelles by the developed in-situ
SANS system.
4. Conclusion
Recombination of lophyl radicals produced froma lophine dimer with UV light irradiation was significantly enhanced in the surfactant micelle as a confinednano space. SANS measurements revealed the detailed
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because in a smaller space, the lophyl radicals easily collide and rapidly recombine themselves. Furthermore, we
examined the photo-induced morphological changes in
the micelle, formed by an amphiphilic LPD derivative. An
in-situ SANS system, developed at the small and wide
angle neutron scattering instrument TAIKAN at the MLF
in J-PARC revealed that the LPD micelle is rapidly andreversibly elongated during UV light irradiation in theorder of seconds and the speed of the morphologicalchanges exceeds the conventional photoresponsive
molecular assemblies. From these results, the SNAS
technique (particularly, in situ set-up) is suitable forstimuli-responsive materials.
5. Future plans
We enabled the observation of photo-induced
rapid morphological changes in the micelles by the developed in-situ SANS systems. Recently, the structural
analysis of the LPD micelles with a time scale of 500 ms
was realized by stroboscopic SANS [10]. In the future,
we will change the time resolution to ~10 ms and enable the understating of the dynamics of morphologicalchanges in the properties of photoresponsive molecularassemblies.

Figure 4.	(a) SANS profiles of 10 mM 3TEG-LPD in D2O before
and after 2 min UV irradiation and 4 min standing
in the dark. (b) The integrated scattering intensityof the SANS profiles of 3TEG-LPD in the q-regionof 0.01–0.05 Å−1 during cycles of UV irradiation andstanding in the dark. (c) UV/Vis absorption spectra
before and after UV irradiation and standing in thedark (left), and the temporal changes in absorption
at 580 nm during the cycle using an in-situ UV/Vis
absorption spectrometer (right).

micelle structures as a reaction site and their effect on
the recombination rate. With the decrease in the micelle volume, the recombination rate increased. This isReferences[1] M. Akamatsu et al., Chem. Lett., 52, 573 (2023).
[2] Y. Kishimoto et al., J. Am. Chem. Soc., 131, 4227
(2009).
[3] M. Akamatsu et al., Chem. Lett., 47, 113 (2018).
[4] M. Akamatsu et al., J. Oleo. Sci., 68, 659 (2019).
[5] M. Akamatsu et al., Chem. Commun., 55, 9769
(2019).
[6] M. Akamatsu et al., Colloids Surfaces A Physicochem.
Eng. Asp., 638, 128319 (2022).
[7] Y. Sakaguchi et al., JPS Conf. Proc. JPS Conf. Proc., 33,
011100 (2021).
[8] H. Iwase et al., J. Appl. Cryst., 56, 110 (2023).
[9] M. Akamatsu et al., Sci. Rep., 11, 10754 (2021).
[10] H. Iwase et al., Langmuir, 39, 12357 (2023).

M. Akamatsu1,2, H. Iwase3, K. Kobayashi2, T. Morita2, R. Tanaka2, Y. Sakaguchi3, K. Sakai2, and H. Sakai2
Faculty of Engineering, Tottori University; 2Faculty of Science and Technology, Tokyo University of Science; 3Neutron Science and Technology
Center, CROSS

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Research and Development Highlights

High-resolution Neutron Structure Reveals
the Non-planarity of Peptide bonds
1. Introduction
Proteins are polymers composed of α-amino acids,interconnected through peptide bonds. The dihedral
angles of main chain, known as ϕ and ψ, are restricted
to energetically favorable regions, serving as parameters in Ramachandran plots for assessing the accuracy of structure refinement. Due to the double-bondcharacter of the peptide bond, the dihedral angle, ω,
between the C-N bond is typically 180° in its trans formor 0° in its cis form. Traditional understanding dictatesthat the six atoms involved in the peptide bond lie on
the same plane. However, high-resolution X-ray crystallography has revealed inconsistencies in the distortionof peptide bonds, dependent on the values of ϕ andψ [1­­–3]. Despite the advancements in high-resolution
X-ray structural determination, refining the coordinatesof amide protons remains a significant challenge. In protein structure refinement, the coordinates of hydrogenatoms are constrained using a riding model, which assumes that hydrogen atoms ride on their parent atoms.
This means that the position of a hydrogen atom is determined based on the knowledge about the chemicalbond between the hydrogen and its attached heavier
atoms. Neutron crystallography is highly effective fordirect observation of the hydrogen atoms. Through ourefforts, we were able to obtain neutron data with animpressive resolution of 1.2 Å for the oxidized structureof the high-potential iron-sulfur protein (HiPIP) from
Thermochromatium tepidum. This resolution allowed
for the refinement of the coordinates of amide protons
without the geometric constraints [4].

2. Experiments
We carried out the crystallization of HiPIP employing a solution prepared from deuterated reagents andheavy water, yielding deuterium-substituted crystals.
Neutron diffraction data were collected utilizing the
IBARAKI Biological Crystal Diffractometer (iBIX) at BL03
in J-PARC MLF. X-ray diffraction data were collected at
the Photon Factory BL5A using ADSC Q315r detector.
For the structural refinement, we used neutron (1.2 Å
resolution) and X-ray data (0.66 Å resolution). The datato-parameter ratio in the neutron data was adequate tomodify the crystallographic parameters for amide protons, prompting us to refine their coordinates withoutgeometric constraints. This was appropriated for deuterium atoms with occupancies exceeding 0.60, andfor protium atoms with occupancies exceeding 0.75.
The final Rwork and Rfree values were 7.41% and 8.15%,
respectively, for the X-ray data, and 15.4% and 16.8%,
respectively, for the neutron data.
3. Results and Discussion
As a result of X/N refinement, electron density andneutron scattering length density can be observed
independently for each atom, and a density map thatclearly shows the polarization of hydrogen atoms canbe obtained (Fig. 1). The neutron data is of sufficientquality to determine the accurate positions of hydrogen atoms. In the case of typical hydrogen bond, theinteraction is often characterized by an acceptor-donor
dyad. Nonetheless, alternative configurations of hydrogen bond exist, which consists of multiple donors or

Figure 1.	(A) Density map between Pro12 and Thr13 and Asn70 and Val71. (B) Difference between the electron and neutron scattering length density map of indole ring of Trp78. (C) Close-up view of Nε1– Hε1 and Cη2– Hη2 of Trp78 [4].

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acceptors, and it is called a bifurcated hydrogen bond. In
single-acceptor hydrogen bonds, the angular relationships among the donor, hydrogen, and acceptor (denoted as ∠DH…A) frequently deviate from the riding
models, often displaying increased angles (Fig. 2A). The
nuclei of amide protons have a pronounced propensity
to orient themselves toward acceptor atoms. In contrast, the bifurcated bond paradigm reveals a distinct
pattern: certain amide protons are conspicuously displaced from proximate acceptor atoms (Fig. 2B). This observation underscores the significance of bidirectional
electrostatic forces in influencing the spatial positioningof atoms involved in hydrogen bonding, a compellingdemonstration.
Historically, affirmations of the planarity of peptide
bonds have relied on non-hydrogen atoms, due to a
deficit of structural insights for the amide proton. Here,
we focus on the dihedral angle of the H i – N i –C i -1 = O i -1
plane (where “i ” denotes residue number) as ω’. The planarity associated with a double bond, which implies adominance of sp2 hybrid orbitals, can be evaluated using
the pyramidalization angle, denoted as θ [5]. For carbon(θC), these angles range between –5° and 5°, reflecting
the consistent maintenance of the sp2 orbital arrangement in the C = O double bond (Fig. 3A). On the other
hand, the pyramidalization angle of amide nitrogen (θN)

Figure 2.	(A) Deviation of the amide proton from peptide plane in single-acceptor hydrogen bond (left) and bifurcated hydrogenbond (right). (B) Histogram of the frequency of differences in donor-hydrogen acceptor angles in single-acceptor hydrogen bonds between the experimentally refined model and the riding model. (This figure is modified from reference [4].)Figure 3.	(A) Scatter plot of θC against ω’ angle. (B) Scatter plot of θN against the ω’ angle. Linear regression is shown as a solidline. (C) Side-view schematic of the peptide bond. The attraction of the amide proton by the acceptor atom shifts the
H i – N i – C i -1 = O i -1 plane [4].

32MLF Annual Report 2022

spans a broad range from –25° to 20° (Fig. 3B). Suchdata clearly suggest that the tendency of amide nitrogens to assume a pyramidal shape is triggered whenamide protons are drawn to acceptors due to electrostatic forces. This disrupts the inherent planarity of the
H i – Ni – C i -1 = O i -1 (Fig. 3C). These insights suggest that
this plane is susceptible to alterations by electronic influences, potentially causing deviations from the peptide bond planarity.

Research and Development Highlights

References[1] D. S. Berkholz et al., Proc. Natl. Acad. Sci. USA, 109,449 (2012).
[2] R. Improta et al., PLOS ONE, 6, e24533 (2011).
[3] L. Esposite et al., J. Mol. Biol., 347, 483 (2005).
[4] Y. Hanazono et al., Sci. Adv., 8, eabn2276 (2022).
[5] G. N. Ramachandran and A. S. Kolaskar, Biochim.
Biophys. Acta, 303, 385 (1973).

Y. Hanazono1, Y. Hirano2,3, K. Takeda4, K. Kusaka5, T. Tamada2,3, and K. Miki4
Medical Research Institutes, Tokyo Medical and Dental University; 2Institute for Quantum Life Science, National Institutes for Quantum
Science and Technology; 3Graduate School of Science, Chiba University; 4Graduate School of Science, Kyoto University; 5Neutron Scienceand Technology Center, CROSS

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Excitations in the Ordered and Paramagnetic States of
Honeycomb Magnet Na2Co2TeO6
1. Introduction
The spin-1/2 Kitaev honeycomb model is a booming direction to search for quantum spin liquids, wherespins are highly frustrated due to bond-directional Isinginteractions [1]. In the past decade, the materializationof this model has been focused on iridium and ruthenium compounds [2], with Na2IrO3 and α-RuCl3 being two
most promising candidates [3, 4]. Recently, cobalt-based
honeycomb materials were proposed to be anothercategory of compounds for the realization of Kitaev
model [5, 6]. Among a series of candidates, Na2Co2TeO6shows intriguing magnetism and similar thermodynamic properties with α-RuCl3 [7, 8], which therefore has attracted a lot of attention. However, its leading exchangeinteractions remain elusive due to a lack of knowledge on
the full excitation spectrum. For example, previous inelastic neutron scattering (INS) studies on powder samples
have pointed to diversifying sets of parameters [8-11],
which puts its relevance to the Kitaev physics under hot
debate. To resolve this problem, we performed an INS

experiment on high-quality Na2Co2TeO6 single crystals
with the 4SEASONS spectrometer.
2. Spin waves in the ordered state
In the magnetically ordered state, sharp spin waves
can be clearly resolved. Figure 1(a) presents the lowestenergy spin wave branch at 5 K along high-symmetriclines in the two-dimensional Brillouin zone. This branchreaches the same energy minimum (∼1 meV) at both
the M (0.5, 0) and Γ (0, 0) points. There are two possible
magnetic ground states of Na2Co2TeO6: one is a zigzag
structure [Fig. 1(d)] [9, 12, 13], which has C3-related domains in a macroscopic sample; another is a triple-q
structure [Fig. 1(e)] [14] formed by the vector sum of all
C3-related zigzag structures. However, if the zigzag state
were driven by Kitaev interactions, the spin waves would
reach their band minimum at the M point, and become
higher-energy flat modes near the Γ point [15, 16],
which is different from different from our observation.
The observation of the same spin wave energy at the M

Figure 1.	(a) Low-energy spin waves along high-symmetric lines of the Brillouin zone at 5 K. The dashed curve is the fitted dispersion.
(b) Calculated spin waves with a J3-Δ model. Inset shows the goodness of fit. (c) Full spin-wave spectrum at 5 K. Data areaveraged over the entire covered L-range and all presented intensities are converted to absolute units with phonon scattering. (d) Zigzag order in the honeycomb lattice (only one zigzag domain is shown). The dashed orange lines show the J3
connection. (e) Triple-q order in the honeycomb lattice. (f ) Highlight of the emerging honeycomb lattice with Néel orderfrom (a) and (b).

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and Γ points therefore supports either a zigzag structure
driven primarily by competing Heisenberg terms or a
triple-q magnetic structure.
Although the powder averaged excitation spectrum has been widely discussed in the context of an exchange Hamiltonian with Kitaev interaction, we find thelowest-energy spin wave can be adequately describedby an effective model with only third-nearest-neighbor
antiferromagnetic (AFM) coupling (J3) and gap-opening(Δ) terms:

The model has an effective Néel order on each of
the four J3-linked (enlarged honeycomb) sublattices
denotes the ordered spin di[Fig. 1(d) and (e)], andrection at site i. We fit the observed dispersion [Fig. 1(a)]with linear spin wave theory. The best-fit parameters
are J3 = 1.896(9) meV and Δ = 0.170(6) meV, which also
reproduce the observed intensities very well [Fig. 1(b)].
Under this J3-Δ model, the two possible magnetic structures (zigzag and triple-q) are completely equivalent[Fig. 1(f )], which accounts for why they cannot be distinguished by most experiments up to date.
At higher energy, we can further identify at least fivespin wave branches [Fig. 1(c)]. The dispersions of the two
branches between 6 meV and 8 meV (#3 and #4) are veryclear, which can also be well captured by respective J3-Δ
models [dashed curves in Fig. 1(c)]. From a structural
point of view, the cobalt hexagons in Na2Co2TeO6 centered around tellurium atoms, whose spatially extendedd orbitals may naturally promote electron hopping andResearch and Development Highlights

further-neighbor coupling.
3. Diffuse scattering in the paramagnetic state
Upon warming above TN ~ 27 K, the spin waves disappear, yet the finite-energy dynamics persist far above
TN [Fig. 2(a)]. These paramagnetic fluctuations are weakly structured in energy but strongly structured in Q: intensities are concentrated around the M points of theBrillouin zone [Fig. 2(b)], indicative of instability towards
the ordering at low temperature. This Q-structure canbe modeled by the equal-time spin correlation function,
which in effect considers scattering interference froma hexagonal unit. There are two kinds of spin arrangements in the hexagonal unit [Fig. 2(c)], in accord with thetwo magnetic structures. The calculated patterns basedon both spin arrangements are consistent with the experiment data [Fig. 2(d) and (e)]. A common characteristic of them is that the AFM J3 coupling always connects
opposite spins, reminding us of J3’s fingerprint on themost pronounced spin waves in the ordered state.
4. Conclusion
We have successfully mapped out the magnetic excitations over the 2D Brillouin zone and studied theirtemperature dependence in conjunction with thermodynamics. In the ordered state, sharp spin waves contribute the most spectrum weight. With linear spin-wave
theory, we find that a third-nearest-neighbor Heisenberg
interaction alone provides a highly accurate effective
description of the low-energy spin waves. Moreover,
we find paramagnetic scattering persists well above
the ordering temperature, which can be accounted for

Figure 2.	(a) Paramagnetic fluctuations at 63 K plotted along (H, 0) direction. (b) Constant energy cut around 4 meV in the (H, K)
plane. (c) Two zigzag-type spin arrangements in a hexagon. (d) and (e) Calculated paramagnetic scattering patterns basedon the spin arrangements in (c).

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MLF Annual Report 2022

by equal-time magnetic structure factors of a hexagonalcluster. Our results shed light on the closely competinginteractions and instabilities in Na2Co2TeO6 and provide
new insights on designing Kitaev materials in general.
This work was published in [17].
References[1] A. Kitaev, Ann. Phys. 321, 2 (2006).
[2] Takagi et al. Nat. Rev. Phys. 1, 264 (2019).
[3] Singh et al. Phys. Rev. B 82, 064412 (2010).
[4] Plumb et al. Phys. Rev. B 90, 041112(R) (2014).
[5] Liu et al. Phys. Rev. B 97, 014407 (2018).

[6] Sano et al. Phys. Rev. B 97, 014408 (2018).
[7] Yao et al. Phys. Rev. B 101, 085120 (2020).
[8] Lin et al. Nat. Commun. 12, 5559 (2021).
[9] Samarakoon et al. Phys. Rev. B 104, 184415 (2021).
[10] Kim et al. J. Phys. Condens. Matter 34, 045802 (2022).
[11] Sanders et al. Phys. Rev. B 106, 014413 (2022).
[12] Lefrançois et al. Phys. Rev. B 94, 214416 (2016).
[13] Bera et al. Phys. Rev. B 95, 094424 (2017).
[14] Chen et al. Phys. Rev. B 103, L180404 (2021).
[15] Banerjee et al. Nat. Mater. 15, 733 (2016).
[16] Chaloupka et al. Phys. Rev. Lett. 110, 097204 (2013).
[17] Yao et al. Phys. Rev. Lett. 129, 147202 (2022).

W. Yao1, K. Iida2, K. Kamazawa2, and Y. Li1
International Center for Quantum Materials, School of Physics, Peking University; 2Neutron Science and Technology Center, CROSS

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Research and Development Highlights

Crystal Electric Field Level Scheme Behind
Giant Magnetocaloric Effect for Hydrogen Liquefaction
1. Introduction
Magnetic refrigeration, which is known as a cooling method using a magnetic field, has been actively
researched so far mainly for application to near room
temperature or extremely low temperatures below
1 K [1]. On the other hand, recently, magnetic refrigeration in the intermediate temperature range (on the order of several tens of K) has been attracting attention
as a new cooling method for efficiently cooling liquidhydrogen [2]. Magnetic refrigeration for the purposeof hydrogen liquefaction requires efficient cooling in
the temperature range from the hydrogen liquefaction
temperature of 20 K to around 77 K (assuming precooling with liquid nitrogen). In magnetic refrigeration, themagnetic entropy change (ΔSM) of a magnetic material
when a magnetic field is excited or demagnetized is an
important factor in developing an efficient magnetic
refrigeration system.
For the purpose of obtaining high performance
MCE materials, heavy rare earth compounds become
the most promising candidates. Because, as a potential maximum magnetic entropy is defined as S M =R ln (2J + 1), where R is the gas constant and J is total angular momentum quantum number. However, in mostof the cases, such potentially large SM does not exist atseveral tens degrees of Kelvin temperature range that
could be useful for hydrogen liquefaction, due to the
crystal electric field reducing the large entropy even inzero magnetic field condition. Such temperature rangeof several tens degrees of Kelvin is generally comparable
to the crystal electric field (CEF) energy levels for heavyrare earth ions (schematic illustration is presented inFig. 1). Magnetic entropy change (ΔSM) strongly depends
on the degeneracy of the CEF ground state, which is lifted by external magnetic field through Zeemann splitting, leading to MCE. In this context, understanding the
CEF level scheme for heavy rare earth compounds isimportant for designing the MR materials for hydrogenliquefaction.

example, we selected the MR material HoB2 with a huge
MCE to evaluate the CEF energy level scheme. HoB2 wasrecently discovered to exhibit a very large |ΔSM | value
near the hydrogen liquefaction temperature [2]. INS experiments were performed using the High-Resolution
Chopper Spectrometer (HRC) beamline. The experimentally determined CEF level scheme shown in Fig. 2(a) was
illustrated, which reproduces the experimental INS spectrum. (Fig. 2(b)). In order to calculate magnetic entropychange with the determined CEF parameters, we conducted the mean-field calculation, which successfully
reproduced the ΔSM, observed in previous magnetization measurement [2] (Fig. 2(c)).
Here, we discuss how the CEF states of the obtained
HoB2 affect the magnetic entropy change ΔSM when amagnetic field is applied. When the temperature of thesystem is assumed to be 20 K, the energy gap between
the ground state (Γ1B) and the excited states Γ6C and Γ6B
can be considered pseudo-degenerated with respect tothe system temperature. When applying magnetic fields
along a principal axis, the pseudo-degeneracy is lifted,
leading to such a large |ΔSM| (Fig. 2(d)).

2. Inelastic neutron scattering of HoB2
In inelastic neutron scattering (INS) experiments,
the energy levels of the CEF can be determined bymeasuring the energy spectrum of the purely paramagnetic phase, because there is no internal magnetic
field induced by ferromagnetic long-range order. As an

Figure 1. Schematic illustration of complicated crystal electricfield (CEF) energy level splitting in heavy rare earth ions(with schematic drawings of electrons wave functions in each energy level), and Zeemann splittingof the CEF levels resulting in a large magnetocaloric effect. For several tens degrees of Kelvins energy
scale, CEF splittings are generally comparable to thesystem temperature in heavy rare earth system.

3.	Mean-field calculation with CEF and exchange
parameters
We also calculated the ideal CEF level scheme forgeneral heavy rare earth ions with site symmetries,
cubic Oh and hexagonal D6h by using mean-field calculations. Figure 3(a) shows one example, crystal fieldparameter dependence of |ΔSM| (5 T, 20 K) for cubic Oh.

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Figure 2. (a) Crystal electric field (CEF) level scheme in HoB2
was determined by the present neutron scatteringexperiment. (b) The neutron intensity (open circle)
was successfully explained by theoretical calculation curve (solid line) with the CEF parameters.
(c) Magnetic field and temperature dependence ofmagnetic entropy change (open circle) is roughly
consistent with those calculated with the meanfield calculation with the determined CEF parameters. (solid line) The data were taken from Ref. [3].
(d) Calculated Zeemann splitting for HoB2 in magnetic field perpendicular to the c-axis.

The |ΔSM| influences significantly the crystal field parameters. It is important to note that this does not necessarily show that |ΔSM| is largest when the crystal field iszero. In this way, in addition to the degree of degeneracyof the pseudo ground state of the crystal field, the degree of how much the ground state is isolated when amagnetic field is also an important factor in producing
a large |ΔSM|.
The calculation results are summarized in Fig. 3(c).
The maximum |ΔSM| for Ho3+ with the hexagonal symmetry for powder case, corresponding to HoB2 case, is10.1 J mol–1 K–1, which is 30% larger than that of HoB2.
We, therefore, found that there is still room to improve|ΔSM | even in one of the largest MCE materials, HoB2.
4. Concluding remarks
The relationship between ΔSM and crystal field parameters derived in this study provides new guidelines
for searching for compounds with larger magnetocaloric effects near the hydrogen liquefaction temperature. Recent advancements in density functional theory

Figure 3. C ontour map of magnetic entropy change of Ho3+
in the cubic Oh symmetry at T = 20 K in magnetic
field change from 0 to 5 T along [100] direction.
(b) Zeemann splitting in magnetic field along [100]direction at T = 25 K for the set of CEF parametersindicated by the star symbol in (a). (c) Heavy rareearth ion dependence of the maximum magnetic
entropy change, predicted by the present meanfield calculations for the cubic Oh and hexagonal
D6h symmetries. The experimental value of HoB2 at
15 K is also plotted [3].

calculations have unlocked the possibility of predicting
CEF parameters for rare-earth systems based on the
crystal information. A combination of DFT calculations
and the relationships between |ΔSM| and the CEF parameters derived in this study would accelerate the searchfor compounds with a large MCE and help to design
more magnetic refrigeration materials.
References[1] T. Numazawa, et. al., Cryogenics 62,185 (2014).
[2] P. Baptista de Castro, et. al., NPG Asia Mater. 12, 35(2020).
[3] N. Terada, et. al., Communications Materials 4 13(2023).

N. Terada1, H. Mamiya1, H. Saito2, T. Nakajima2, 3, T. D. Yamamoto1, K. Terashima1, H. Takeya1, O. Sakai4, S. Itoh5, 6, Y. Takano1, M. Hase1,
and H. Kitazawa1
1
National Institute for Materials Science; 2Institute for Solid State Physics, The University of Tokyo; 3RIKEN Center for Emergent Matter
Science (CEMS); 4Neutron Science and Technology Center, CROSS; 5 Institute of Materials Structure Science, KEK; 6Materials and Life
Science Division, J-PARC Center

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Research and Development Highlights

Relief of Spin Frustration through Magnetic Anisotropy
in the Quasi-one-dimensional S = 1/2 Antiferromagnet
Na2CuSO4Cl2
1. Introduction
Exotic spin states are expected to be observed in
low-dimensional magnets. In most low-dimensional
magnets, however, there is relatively strong threedimensional (3D) magnetic coupling, which induces
magnetic ordering at finite temperatures. More to thepoint, the coexistence of such coupling and magnetic
anisotropy stabilizes the 3D spin structure in low-dimensional magnets. Therefore, to identify quantum phases,
it is usually important to explore a model compoundwith negligibly small interchain or interlayer couplings.
Although it is rare, a moderately strong interchain interaction can play an important role in quasi-onedimensional (quasi-1D) spin systems with a uniform
Dzyaloshinskii-Moriya (DM) interaction in realizing an
exotic spin state.
The S = 1/2 quasi-1D antiferromagnet Na2CuSO4Cl2
exhibits peculiar DM interactions that are uniform along
its spin chains and antiparallel with respect to neighboring chains [1, 2]. Linear spin chains along the a axis areformed by the exchange interaction J = 14.2 K throughthe Cu-Cl-Cl-Cu path, which is much larger than the interchain interaction J’ = 0.18 K estimated from the Néel
temperature TN = 0.54 K. Based on the crystal structure,
Na2CuSO4Cl2 exhibits substantial DM interactions thatare aligned parallel to the b axis [Fig. 1]. However, theDM vector is aligned antiparallel between the adjacent

chains. In this case, helical correlations with opposing
helicity are present when interacting spin chains feature peculiar DM interactions that are uniform along
the chain and antiparallel with respect to neighboring chains, thus resulting in unique spin frustration.
However, the magnitude of DM vector (D) and the magnetic structure, which is required to understand the DMinduced frustration effect, were not determined.
2. Experiments
Large single crystals of Na2CuSO4Cl2 were successfully grown by using a low-temperature molten-salt
reaction process [1]. High-purity CuCl2 and Na2SO4 powders were mixed with the molar ratio of 1 : 1 and vacuum
sealed into a quartz tube. The mixture was heated at
470°C for two days and then slowly cooled. High-field
multifrequency ESR measurements were performed using pulsed magnetic fields up to 13 T in the frequency
range from 70 to 260 GHz at several temperatures. A
standard of 2,2-diphenyl-1-picrylhydrazyl (known as
DPPH) was employed as a g = 2.0036 marker for themagnetic field. Neutron-diffraction measurements ina wide reciprocal space were performed using a timeof-flight (TOF) neutron diffractometer (BL18 SENJU) installed at the MLF of the J-PARC [3]. The collected data
were processed with the software STARGAZER [4].

Figure 1.	The crystal structure of Na2CuSO4Cl2. The Cu2+ ions (black) displayed with nearby oxygen (red), SO4 ions (yellow tetrahedra),and chlorine ions (green). The direction of the Dzyaloshinskii-Moriya vector D, as determined by ESR measurements, isindicated by the orange arrow.

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3. Results and discussion
The direction and magnitude of D in Na2CuSO4Cl2
was determined using ESR. Considering a single
Heisenberg chain with a uniform DM interaction, in thecase of H || D, the ESR doublet M+ and M− appear equidistant to the left and right of the paramagnetic resonance line P* in the temperature range of T << |D| [5].
As shown in Fig. 2(a), two lines (P* and M+) are clearlyobserved for a field along the b axis. The reason why
the M− line is not seen is because it becomes difficult toseparate the P* and M− lines in the temperature regionof T > |D| [6]. The temperature evolution of the 240 GHz
ESR line at H || b is shown in Fig. 2(c), indicating thatM+ develops when the temperature decreases. These
results indicate an antisymmetric exchange with a uniform D pointing along the b axis, as shown in Fig. 1.
The values of the g factors and |D| are estimated to be
ga = 2.07(1), gb = 2.23(2), gc = 1.99(1), and |D| = 1.01(3) K
by fitting the frequency dependencies of the resonancefields of mode P* and M+. The estimated value is larger
than the Néel temperature TN = 0.54 K of Na2CuSO4Cl2.
Below TN, about 100 magnetic reflection peaks wereobserved on the (n/2 k l ) where n is an odd integer. The
presence of the (n/2 k l ) magnetic peaks indicates thatnearest-neighbor Cu atoms within a chain have exactly
antiparallel magnetic moments and the magnetic unit
cell is twice as large as a chemical unit cell along the aaxis. Four magnetic Cu2+ ions are located on the Wyckoff

positions 4c: r1 = (0.636, 0.25, 0.966), r2 = (0.136, 0.25,
0.534), r3 = (0.364, 0.75, 0.034), and r4 = (0.864, 0.75,
0.466) in the orthorhombic unit cell with space group
Pnma. In this case, the possible magnetic structure canbe represented by only four irreducible spin arrangements (↑, ↑, ↑, ↑), (↓, ↑, ↑, ↑), (↑, ↓, ↑, ↑), and (↓, ↓, ↑, ↑),where the parentheses show the relative phase factorsof the spins on the sites (r1, r2, r3, r4). Therefore, in thecase that the spins are pointing along one of the crystal axes, there are only 12 possible magnetic structures.
Mag
Nuc
Figure 3(a) shows the observed intensities obs
and obsMag
Nucplotted against calculated intensities calc
and calc forMag
the nuclear and magnetic peaks. The calc presented
in Fig. 3(a) are calculated for the magnetic structure
shown in Fig. 3(b). Based on how good a fit is, a candidate magnetic structure is obtained, as shown in
Fig. 3(b). There is no large deviation between the calculated magnetic intensities with full Cu2+ moment of
1 µB and the line fitted to the observed nuclear intensity
in the almost extinction-free region [Fig. 3(a)]. The spin
direction is parallel to the D expected from the crystal
structure, indicating that the DM interaction is not thedriving force for the magnetic phase transition.
Most low-dimensional copper salts exhibit longrange magnetic ordering at low temperature, withthe spins pointing in a specific direction in the crystal,suggesting that there is a finite magnetic anisotropy
in these salts. In copper salts, there is no anisotropy

Figure 2. ESR spectra of Na2CuSO4Cl2 at 1.8 K with a magnetic field applied along the a axis and b axis. The red arrows mark mode
M+. The black arrows mark the paramagnetic mode P*. The narrow peaks marked by gray arrows are the mode DPPH.
(b) ESR spectra for a magnetic field parallel to the DM vector (H || b) for various frequencies. (c) Temperature evolution of
the 240 GHz ESR spectra at H || b.

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Research and Development Highlights

Figure 3.	(a) Observed intensities of the nuclear and magnetic scattering plotted against the calculated values for the nuclear andmagnetic peaks. The intensities of the magnetic scattering are calculated for the magnetic structure shown in (b). The
solid gray line is a linear fit to the observed nuclear intensities below 1000 intensity units. The values in the plot show theobtained ordered moment and Pearson’s correlation coefficient R. (b) Possible magnetic structure of Na2CuSO4Cl2 . The
thick black lines show the magnetic unit cell. The Cu2+ positions are labeled 1 – 4 according to their positions r1 – r4.

energy arising from the crystal field because Cu2+ ionshave a spin of 1/2, therefore, the specific spin structurein the magnetic ordered state is a result of the co-influence of the magnetic dipole interaction, symmetricanisotropic exchange interaction, and DM interaction(antisymmetric anisotropic exchange). Unfortunately, it
is not possible to estimate the magnitude of these anisotropies from the present experimental results. The DM
interaction mediates a spin-spin coupling of the form
D · (S1 × S2), which is usually responsible for the helimagnetic spin arrangement in 1D spin chains. In contrast,
a magnetic dipole interaction and symmetric anisotropic exchange interaction require the spins to point
along a specific direction in the crystal, either parallelor antiparallel. The estimated g factors and magnetic
structure of Na2CuSO4Cl2 strongly suggest the presenceof a magnetic dipole interaction and/or symmetric anisotropic exchange interaction. We consider that otherterms in the anisotropic spin Hamiltonian counteract
the effects of the DM interaction and stabilize the Néeltype structure in this system. In addition to Na2CuSO4Cl2,
K2CuSO4X2 (X = Cl, Br) are candidates for DM-induced
frustrated S = 1/2 quasi-1D antiferromagnets [6, 7].

The other anisotropy terms contribute to relieving
the DM-induced frustration, which should also occur in K2CuSO4X2. Both the DM and intrachain interactions depend on the orbital overlap in the chains andare proportional to each other. In addition, the otheranisotropies depend on the crystal structure. The structural similarity between the chains in Na2CuSO4Cl2 andK2CuSO4X2 suggests that the ratio of these effects may
be similar. We believe it is important to find a different
model compound to study the intrinsic magnetism on
the unique frustration induced by the DM interactions.
References[1] M. Fujihala et al., Phys. Rev. B 101, 024410 (2020).
[2] M. Fujihala et al., Phys. Rev. B 105, 144410 (2022).
[3] T. Ohhara et al., J. Appl. Crystallogr. 49, 120 (2016).
[4] T. Ohhara et al., Nucl. Instrum. Methods Phys. Res.,
Sect. A 600, 195 (2009).
[5] K. Y. Povarov et al., Phys. Rev. Lett. 107, 037204(2011).
[6] A. I. Smirnov, et al., Phys. Rev. B 92, 134417 (2015).
[7] M. Hälgi et al., Phys. Rev. B 90, 174413 (2014).

M. Fujihala1,2, Y. Sakuma1, S. Mitsuda1, A. Nakao3, K. Munakata3, R. A. Mole4, S. Yano5, D. H. Yu4, K. Takehana6, Y. Imanaka6, M. Akaki7,
S. Okubo7, and H. Ohta7
1
Department of Physics, Tokyo University of Science; 2Advanced Science Research Center, Japan Atomic Energy Agency; 3Neutron Science andTechnology Center, CROSS; 4Australian Nuclear Science and Technology Organisation; 5National Synchrotron Radiation Research Center;6
National Institute for Materials Science; 7Molecular Photoscience Research Center, Kobe University

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Zigzag Antiferromagnetic Order in the Kitaev Spin-liquid
Candidate RuBr3 with a Honeycomb Lattice
1. Introduction
A search for elementary excitations with the fractional quantum number has been one of the most intriguing topics in condensed matter physics. Recently,
compounds with a honeycomb lattice have attracted attention due to a theoretical breakthrough [1, 2]. Kitaev
has found that a spin liquid state is realized in a spin
1/2 honeycomb lattice magnet with bond-dependent
ferromagnetic Ising interactions as an exactly solvableground state [1].
To reveal the nature of the fractional excitations,the magnetic properties of candidate compounds havebeen investigated. Intensive studies have been made on
α -RuCl3. α -RuCl3 exhibits a zigzag antiferromagnetic order at 8-14 K [3-5]. Earlier works, including inelastic neutron scattering experiments, have revealed that most of
the spin excitations are left even above the transition
temperature [6, 7], indicating that ferromagnetic Kitaev
interactions dominate the magnetism in this compound.
On the other hand, the presence of the zigzag antiferromagnetic order also suggests the sizable contributions of non-Kitaev interactions [8, 9]. Thus, it has
been desired to suppress these magnetic interactions
to tune the system closer to the Kitaev limit. One ofthe promising ways is to replace ligands of candidate
compounds. We have discovered new polymorphs of
RuX3 (X = Br [10], I [11]) by high pressure synthesis, andfound that Ru3+ forms the honeycomb structure in thesecompounds. To reveal the substitution effect in the Ru3+
based honeycomb compounds, we have investigatedthe crystal and magnetic structures of RuBr3 with thehoneycomb structure [10].

2. Experiments
The polycrystalline sample was prepared by highpressure synthesis starting from RuBr3 with the chain
structure (P63/mcm). Powder neutron diffraction experiments were performed using the high-resolution time-of
flight (TOF) neutron powder diffractometer SuperHRPD
installed at the beam line BL08 of J-PARC [12]. The total
amount of 1.4 g of the polycrystalline sample was sealed
in a vanadium-nickel cylindrical can and then set to the4
He closed-cycle refrigerator. SuperHRPD has three setsof detector banks: backscattering (BS), quarter-angle(QA) and low-angle (LA) detector banks. All the threediffraction patterns were simultaneously used with thesame weighting in the crystal-structure refinement,
while the diffraction patterns from QA and LA detectorbanks with the d-range larger than 2.9 Å were used forthe magnetic-structure refinement.
3. Crystal and magnetic structures
The neutron diffraction pattern revealed that thepolymorph of RuBr3 is the same as that of the BiI3 structure, which crystallizes in space group of R-3. The neutron powder diffraction pattern at room temperature isshown in Fig. 1. All the peak positions and intensities
are well fitted by the BiI3 structure. The BiI3 structure isalso referred to as one of the low-temperature structures of α -RuCl3 [5]. The crystal structure refined fromthe neutron diffraction pattern is shown in Fig. 2(e). The
Br atoms form the hexagonal closed-packed structure.
Ru atoms occupy two-thirds of the vacancies for every
two Br layers, resulting in the regular honeycomb lattice. The powder diffraction patterns collected at low

Figure 1.	Neutron diffraction pattern collected at 300 K by the backscattering (BS) bank. The red
dots, black curve, and blue curve represent the observed intensities, calculated intensities, and the difference between them. The difference is shifted for clarity. The vertical
black bars indicate the peak position expected from the space group R-3.

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Research and Development Highlights

Figure 2.	(a-d) Neutron diffraction patterns focused on the magnetic reflections. Intensities at 3 (red dots) and 100 K (black dots) arecompared in (a, c), while the observed intensities (red dots) are plotted with calculated intensities (black curves) and thedifference between them (blue curves, shifted for clarity) in (b, d). The vertical red bars indicate the peak position expectedfrom zigzag antiferromagnetic order. Corresponding indexes of magnetic reflections are shown in (a, c). (e) Schematic viewof crystal and magnetic structures refined from the neutron diffraction pattern.

temperatures indicate that the BiI3 structure is preserved
down to low temperatures.
The magnetic structure is solved from five peaks observed below TN = 34 K. The neutron diffraction patterns
collected at the LA and QA detector banks are shownin Fig. 2(a) and 2(c), respectively. Candidates for initial
magnetic structures were obtained using the magnetic
representation theory [13]. The magnetic representations for the Ru moments are decomposed into two
one-dimensional representations of the k-group withthe magnetic modulation vector of (0, 1/2, 1). The one
representation corresponding to a zigzag antiferromagnetic structure well reproduces the intensities, as shownin Fig. 2(b) and 2(d). The magnetic structure determinedfrom the refinement is given in Fig. 2(e). The magnetic
moment is canted from the ab-plane for 64(12) degrees.
The magnitude of the magnetic moment is estimated as0.74(12) µ B, which is comparable to or larger than thatfor α -RuCl3 [3-5].
4. Discussions
The magnetic structure is characterized by thecanting angle of 64 degrees, which is much larger than
32-48 degrees in RuCl3 [4, 5, 14]. From theoretical viewpoints, this suggests that the non-Kitaev interactions
are much weaker than the Kitaev interactions for thenearest neighbors [8, 9]. In addition, the Weiss temperature of -58 K and the TN higher than RuCl3 suggests thatthe third nearest neighbor interactions J3 (see Fig. 2(e))
are enhanced. These results indicate that tuning of theKitaev and non-Kitaev interactions can be accomplishedby replacing the ligand sites, providing another route for
exploring Kitaev spin liquids.
References[1] A. Kitaev, Ann. Phys. 321, 2 (2006).
[2] G. Jackeli and G. Khaliullin, Phys. Rev. Lett. 102,
017205 (2009).
[3] R. D. Johnson et al., Phys. Rev. B 92, 235119 (2015).
[4] H. B. Cao et al., Phys. Rev. B 93, 134423 (2016).
[5] S.-Y. Park et al., cond-mat arXiv 1609.05690v1. (2016).
[6] A. Banerjee et al., Nat. Mater. 15, 733, (2016).
[7] S. -H. Do et al., Nat. Phys. 13, 1079 (2017).
[8] J. G. Rau et al., Phys. Rev. Lett. 112, 077204 (2014).
[9] J. Chaloupka and G. Khaliullin, Phys. Rev. B 92, 024413(2015).
[10] Y. Imai et al., Phys. Rev. B 105, L041112 (2022).
[11] K. Nawa et al., J. Phys. Soc. Jpn. 90, 123703 (2021).
[12] S. Torii et al., J. Phys. Soc. Jpn. 80, SB020 (2011).
[13] Y. Izyumov and V. Naish, J. Magn. Magn. Mater. 12,
239 (1979).
[14] J. A. Sears et al., Nat. Phys. 16, 837 (2020).

Y. Imai1, K. Nawa2, Y. Shimizu3, W. Yamada1, H. Fujihara1, T. Aoyama1, R. Takahashi2, D. Okuyama2, T. Ohashi3, M. Hagihala4, S. Torii4,
D. Morikawa2, M. Terauchi2, T. Kawamata5, M. Kato5, H. Gotou6, M. Itoh3, T. J Sato2, and K. Ohgushi11
Department of Physics, Graduate School of Science, Tohoku University; 2Institute of Multidisciplinary Research for Advanced Materials,
Tohoku University; 3Department of Physics, Nagoya University; 4Institute of Materials Structure Science, KEK; 5Department of Applied
Physics, Graduate School of Engineering, Tohoku University; 6Institute for Solid State Physics, University of Tokyo

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Square and Rhombic Lattice States of Magnetic Skyrmionsin a Centrosymmetric Magnet EuAl4
1. Introduction
Recently, topological objects in condensed mattershave attracted significant attention as the source of richemergent phenomena and functions. One typical example is the magnetic skyrmion with swirling spin texture,
which is characterized by topologically-stable particlelike nature and now intensively studied as the potential
candidate for high-density information carrier.
Magnetic skyrmions were originally observed in aseries of noncentrosymmetric magnets, where a competition between the Dzyaloshinskii-Moriya and ferromagnetic exchange interactions stabilizes a triangularskyrmion lattice (SkL). On the other hand, the SkL states
were also recently discovered in centrosymmetric compounds, in which extremely small diameter (less than
5 nm) of skyrmions are commonly realized [1–3]. For
such systems, a distinct skyrmion formation mechanism
mediated by itinerant electrons has been proposed. So
far, only few centrosymmetric magnets hosting skyrmions are known, and further search of skyrmion-hostingmaterials is highly desired.
As an ideal candidate material, we focus on a centrosymmetric tetragonal magnet EuAl4, in which themagnetism is governed by the Eu 2+ ions. This compound undergoes multiple-step magnetic transitions
before reaching the forced ferromagnetic (FM) state
for the external magnetic field H || [001]. As seen in the
H-T (temperature) magnetic phase diagram (Fig. 1(a)),
four distinctive magnetic phases (I, II, III, and IV) are
identified at lower temperatures. Although a preceding neutron scattering study revealed incommensurate
magnetic orders at zero field [4], the magnetic structure for each phase in the magnetic fields has not been

experimentally identified. Here, we successfully observed square and rhombic lattice states of nanometricskyrmions in EuAl4 by performing small-angle neutron
scattering (SANS) experiments [5].
2. Experiments
SANS measurements were carried out at BL15(TAIKAN) in Materials and Life Science Experimental
Facility of J-PARC. A thin crystal with a thickness of
0.2 mm having the widest surface of 5 mm by 2.5 mm
parallel to the (001) plane was installed in a cryostat
equipped with a horizontal-field superconducting magnet. An incident neutron beam with a wavelength bandof 0.7-7.7 Å was exposed on the sample. The incident
beam was always directed along the [001] axis within
the accuracy of 2 degrees. The SANS patterns were obtained with rotating and tilting the sample up to 2 degrees. Background data were obtained above Tc in amagnetic field of 0.05 T and subtracted from the dataobtained at low temperature to leave only the magnetic
signal.
In polarized SANS experiments, a polarized incident
neutron beam was obtained by a supermirror polarizer.
The neutron spin polarization at the sample position was
controlled to be parallel to the [001] axis of the sample
by guide fields and the horizontal-field superconducting
magnet. A supermirror spin analyzer was set between
the sample and the detectors and was used to separate
the spin-flip (SF) and non-spin-flip (NSF) scattering signals. The total beam polarization measured using a direct beam was 0.85 for the neutrons with wavelengths
longer than 3.5 Å. The mixing of the SF and NSF signals
was corrected considering the total beam polarization.

Figure 1.	(a) H(magnetic field)-T(temperature) magnetic phase diagram of EuAl4 for H || [001]. (b) Typical SANS patterns for phases
I-IV taken at 5 K for H || [001].

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3. Results and discussion
First, to identify the magnetic modulation vector ineach phase, we performed SANS experiments for the(001) plane at 5.0 K in H || [001]. Figure 1(b) exhibits the
typical SANS patterns for phases I-IV, revealing multiplestep reorientations of the fundamental magnetic modulation vector Q1 as a function of H. Here, the observed
Q1 is always incommensurate in phases I-IV, and themodulation period is 2.2 nm for phase I and 3.5 nm forphases II-IV. Notably, we also identified the clear Q1+Q2
reflections in phases II, III, and IV, proving that thesephases are double-Q states.
Next, to investigate the detailed spin orientations ineach phase, we carried out polarized SANS experimentfor H || [001] and measured the intensities of SF and NSF
scattering (ISF and INSF, respectively) separately for various
temperatures at 1 T. In phases II and III, magnetic reflections are observed for both ISF and INSF channels, provingthat the modulated spin component possesses both inplane and out-of-plane components normal to Q. Thissuggests that phases II and III are characterized by thescrew-type spin modulation. In phase IV, however, themagnetic scattering appears only in the ISF channel,
indicating that only the in-plane component normal
to Q exists. Thus, phase IV can be characterized by thein-plane sinusoidal spin modulation. By considering the
double-Q nature of phases II-IV, the resultant spin textures for each phase are illustrated as shown in Fig. 2,
indicating the rhombic and square lattices of magnetic

Research and Development Highlights

skyrmions with a diameter of 3.5 nm for phases II and III,
respectively, and the rhombic vortex lattice for phase IV.
4. Summary
In this work, the centrosymmetric tetragonal magnet EuAl4 turns out to host square and rhombic latticestates of nanometric skyrmions by means of SANS experiments. Unlike previously reported skyrmion-hostingmaterials, EuAl4 shows two distinctive topological magnetic phases with multiple-step reorientation of fundamental magnetic modulation vector Q as a function of
the magnetic field, which probably reflects the delicate
balance of itinerant-electron-mediated interactions. The
present results demonstrate that rare-earth intermetallics with delicate balance of magnetic interactions canbe a promising platform to realize the competition ofmultiple topological magnetic phases in a single compound, which would be a good guideline for further
search of exotic materials with emergent functional
responses.
References[1] T. Kurumaji et al., Science 365, 914 (2019).
[2] M. Hirschberger et al., Nature Commun. 10, 5831
(2019).
[3] N.D. Khanh et al., Nat. Nanotech. 15, 444 (2020).
[4] K. Kaneko et al., J. Phys. Soc. Jpn. 90, 064704 (2021).
[5] R. Takagi et al., Nature Commun., 13 1472 (2022).

Figure 2. Schematic illustrations of spin textures for phases II, III, and IV, corresponding to
the rhombic skyrmion lattice (SkL), square SkL, and rhombic vortex lattice (VL).

R. Takagi1,2,3,4, N. Matsuyama1, V. Ukleev5, L. Yu5,6,7, J.S. White5, S. Francoual8, J.R.L. Mardegan8, S. Hayami1,3, H. Saito9, K. Kaneko10,11,
K. Ohishi12, Y. Ōnuki4, T. Arima4,13, Y. Tokura1,4,14, T. Nakajima4,9, and S. Seki1,2,3,4
1
Department of Applied Physics, University of Tokyo; 2Institute of Engineering Innovation, University of Tokyo; 3PRESTO, JST; 4RIKEN
Center for Emergent Matter Science (CEMS); 5Laboratory for Neutron Scattering and Imaging (LNS), Paul Scherrer Institute (PSI); 6Instituteof Physics, École Polytechnique Fédérale de Lausanne (EPFL); 7Institute of Materials, EPFL; 8Deutsches Elektronen-Synchrotron DESY;
9
Institute for Solid State Physics, University of Tokyo; 10Materials Sciences Research Center, JAEA; 11J-PARC Center, JAEA; 12Neutron Scienceand Technology Center, CROSS; 13Department of Advanced Materials Science, University of Tokyo; 14Tokyo College, University of Tokyo

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Evolution of Magnetism and Superconductivity Toward
the Quantum Critical Point in the Heavy Fermion System
1. Introduction
Quantum critical phenomena are one of the central issues in condensed matter physics. In the vicinityof the quantum critical point (QCP) where two different
interactions compete at T = 0, the quantum fluctuation
plays a major role to realize unconventional superconductivity as well as other exotic ground states [1-3]. This
could be observed when the phase transition occurs at
T = 0 by tuning parameters rather than temperature,such as magnetic field, pressure, and chemical substitutions. For instance, in a heavy fermion system, magnetic
Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction conflicts with the non-magnetic Kondo effect and the Fermi
liquid, which is a basic concept of interacting fermions,
often fails. Such a “non-Fermi liquid” (NFL) state is observed in thermodynamic and transport quantities. For
thermodynamic properties, -lnT or T -n (n < 1) increase
toward T = 0 is a hallmark of the NFL and is often observed in strongly correlated electron systems.
Furthermore, unconventional superconductivity often appears in a region of the phase diagram enclosed
by a dome-shaped boundary near QCP. The propertiesof the system in the superconducting (SC) dome aredominated by quantum criticality, and the mechanismof the superconductivity is strongly related to the quantum critical spin fluctuations in many cases. However, it
is challenging to reveal the spin state in the SC dome inwhich the strong impact of quantum critical fluctuations
must be turned up. Moreover, in most cases, the quantum phase transitions are identified experimentally as
first-order phase transition.
As an example of the quantum critical compounds
showing superconductivity, tetragonal CeCoIn5 is one of
the extensively investigated heavy fermion compounds
which is believed to show dx 2-y 2 superconductivity atambient pressure (Tc = 2.3 K at B = 0) [5, 6]. CeCoIn5
shows the NFL behaviors in various quantities just above
the SC upper critical field Hc2(= 5 T//c), such as -lnT divergence in the specific heat divided by the temperature
and T-linear dependence in electrical resistivity[7], suggesting that the magnetic field could induce quantum
critical fluctuation[8].
It is known that chemical substitution could inducea magnetic phase transition. Recently, the coexistence ofsuperconductivity and magnetic ordering was also suggested in Zn substitution system CeCo(In1-xZnx)5 [9-11].
46

By substitution of In with a tiny amount of Zn, a small
modification in the system, corresponding to an energy
scale in the order of a few Kelvin, occurs without any
structural phase transition, and it is possible to tune
only magnetism and superconductivity. In this regard,
CeCo(In1-x Znx)5 is one of the ideal systems to investigate
the role of magnetic quantum criticality in the evolutionof the superconductivity. In CeCo(In1-x Znx)5, the SC transition temperature Tc is continuously reduced from 2.3 K(x = 0) to ~1.4 K (x = 0.07) by doping Zn, and then the
AFM order, with a transition temperature of TN ~ 2.2 K,
is found for x larger than 0.05 at B = 0. However, in thedoping range where x < 0.05, TN becomes smaller thanTC, yielding that a significant response due to superconductivity masks weak signal of AFM state and its quantum critical fluctuation in the SC dome. This situation
has also been observed in many quantum critical superconductors; it is unclear whether the quantum phasetransition and its fluctuations exist even deeper inside
the SC phase.
To reveal the possible weak magnetism and quantum criticality both inside and outside the SC dome in
CeCo(In1-x Znx)5, we employed the muon spin rotation/
relaxation technique [12].
2. Experimental
All muon experiments were performed at the D1
spectrometer, Materials and Life Science Facility, J-PARC,
Tokai, Japan. We used 4 MeV positively charged muons.
Conventional µSR in the dilution refrigerator was carried out. Plate-shaped single crystals of CeCo(In1-x Znx)5,
whose basal planes are perpendicular to the tetragonal
c-axis, were grown by the indium-flux method [9].
3. Results and Discussions
Figure 1(a, b) shows the temperature dependenceof the muon spin relaxation spectra under zero-magnetic field (ZF-µSR) in CeCo(In1-x Znx)5(x = 0.0, 0.03). At
x ≤ 0.025, muon spins depolarize only because of thenuclear magnetic fields. This result strongly suggests
non-magnetic ground states for x ≤ 0.025. In contrast,
at x = 0.03, a tiny change was observed in the spectra at
low temperatures and B = 0 as shown in Fig. 1(b), demonstrating the presence of a very weak magneticallyordered state in the SC dome. This slow muon spin relaxation is easily quenched by applying weak magnetic

MLF Annual Report 2022

Research and Development Highlights

Figure 1.	ZF-µSR spectra in CeCo(In1-xZnx)5(a) x = 0.0, (b) x = 0.03.

Figure 2.	x-T phase diagram of magnetically orderedtemperature (■) and superconducting transition
temperature (●) and superconducting penetration
depth (▲) [12].

field along initial muon spin polarization direction, indicating that the internal magnetic field at the muon site
is static or quasistatic.
A more pronounced signature of the coupling between the QCP and the SC state appears in the magnetic penetration depth. The magnetic penetration
depth characterizes the superconducting properties,
because it is related to the superfluid weight. The superfluid weight may be an indicator of QCP, since it is determined by microscopic aspects of electronic states. To
measure the penetration depth using µSR, a magnetic
field was applied along the c-axis or ab-plane.
In Fig. 2, we summarize the x-T phase diagram ofmagnetism and superconductivity from the presentµSR experiments, along with the AFM and SC transition
temperatures for x = 0.07 estimated by the experimentsof the neutron scattering and the specific heat [10].
Since magnetic ordering also appears in the SC phaseof x ≥ 0.03, we plotted the x dependence of the penetration depth at 1.0 K (pure SC phase). It was found that amagnetically ordered state develops at x ≥ 0.03, coexisting with the superconductivity. The magnitude of theordered magnetic moment is continuously reduced withdecreasing x, and it disappears below x ~ 0.03, indicatinga second-order phase transition and the presence of the
QCP at this critical Zn concentration. Furthermore, themagnetic penetration depth diverges toward the QCP.
These facts provide evidence for the intimate coupling
between quantum criticality and Cooper pairing [12].
References[1] J. A. Hertz, Phys. Rev. B 14, 1165-1184 (1976).
[2] H. Löhneysen et al., Rev. Mod. Phys. 79, 1015-1075(2007).
[3] P. Gegenwart, Q. Si, F. Steglich, Nat. Phys.4, 186(2008).
[4] G.R. Stewart, Rev. Mod. Phys. 73, 797 (2001).
[5] C. Petrovic et al., J. Phys.: Cond. Mat. 13, L337 (2001).
[6] K. An et al., Phys. Rev. Lett. 104 037002 (2010).
[7] J. Paglione et al.,Phys. Rev. Lett. 91, 246405 (2003).
[8] A. Bianchi et al., Phys. Rev. Lett. 91, 257001 (2003).
[9] M. Yokoyama et al.,J. Phys. Soc. Jpn. 83, 033706(2014).
[10] M. Yokoyama et al., Phys. Rev. B 92, 184509 (2015).
[11] M. Yokoyama et al.,Phys. Rev. B 105, 054515 (2022).
[12] W. Higemoto, M.Yokoyama et al., PNAS 119,e2209549119 (2022).

W. Higemoto1,2,3, M. Yokoyama4, T. U. Ito1,2, T. Suzuki1,3, S. Raymond5, and Y. Yanase6,7
Advanced Science Research Center, Japan Atomic Energy Agency; 2Muon Science Section, Materials and Life Science Division, J-PARC
Center; 3Department of Physics, Tokyo Institute of Technology; 4Department of Physics, Ibaraki University; 5Universite Grenoble Alpes;
6
Department of Physics, Kyoto University; 7Institute for Molecular Science

147

Research and Development Highlights

MLF Annual Report 2022

Ambipolarity of Dilute Hydrogen in Power Semiconductor
β-Ga2O3 Revealed by μSR
1. Introduction
Power semiconductors are used in a variety of electronic devices as key components for voltage conversion
and AC to DC conversion. Gallium oxide is now being
studied as a candidate material for next-generation
power semi-conductors. Because of its characteristics,
gallium oxide is expected to have higher breakdown
voltage and lower power consumption than silicon,
which is currently the main material used. In order toprecisely control electrical properties such as carrier
density, it is necessary to understand the main factors
affecting electrical properties (impurities, oxygen andgallium defects, etc.) and to investigate in detail theirrelationship with synthesis and device fabrication
methods.
Hydrogen (H) is a ubiquitous impurity in materials.
Since the discovery that H in silicon has a significant
effect on its electrical properties, H has attracted considerable attention in the field of functional materials,
including various semiconductor and solar cell materials. Theoretical studies on gallium oxide also indicatethat H can contribute to n-type conduction. However,experimental knowledge has been very limited due tothe lack of methods to study trace amounts of H.
To clarify the electronic structure of muons as
pseudo-H, muon spin rotation / relaxation (μSR) experiments were performed on β-Ga2O3, the most stable structure among gallium oxides [2]. Hereafter, we
introduce the elemental symbol Mu to denote muon

as pseudo-H. Conventional μSR measurements were
performed using the ARTEMIS spectrometer installed in
the S1 area at the MLF, J-PARC. The high-intensity muon
beam enabled us to observe the time evolution of themuon spin polarization Gz(t) up to ∼25 μs.

2. Results and discussion
The normalized and background-subtracted μSRtime spectra at 300 K are shown in Fig. 1(a). The zero
field (ZF) spectrum clearly consists of two components,
one exhibiting slow Gaussian relaxation with partially
recovered at t ≳ 12 μs (Mu1) and the other exhibiting no
relaxation at all (Mu2). The recovery of Gz(t) at a later time
is a characteristic behavior of the Kubo-Toyabe function
at ZF:
KT (

1
2
2 2)
exp(−Δ2 2 ) ,LF = 0) ≡ 3 + 3 (1 − Δ

where Δ is the linewidth determined by random local
fields from nuclear magnetic moments of Ga, BLF is themagnitude of longitudinal field (LF).
ZF and LF spectra at 300 K were analyzed by global
curve fit using the following function:( )= 1KT (; Δ,

LF ) + 2 ,where fi (i = 1, 2 and f1 + f2 = 1) are the relative yields ofthe Mui components. As shown by solid lines in Fig. 1(a),Δ = 0.140(1) μs–1 and f1 = 0.433(3) well reproduce the experimental data. Comparison of Δ with the predicted Δ
at several candidate Mu as pseudo-H sites, as evaluated(b) Δsim = 0.136 μs-1 (c) Δsim = 0.150 μs-1

(a)

GaII

1.0
Mu1

OIII

OI
GaI

0.6
0.4
Mu2
0.2
0.0

OII

H/Mu1

0.8
Gz(t)

; Δ,

(d) Δsim = 0.161 μs-1 (e) Δsim = 0.345 μs-1

LF-µSR 300 K
LF 1mT
LF 0.5mT
ZF

H-

a

0

5

10
15
Time (µs)

20

25
b

c

Figure 1.	(a) μSR time spectra for single crystalline β-Ga2O3 at 300 K. 4 × 108 positron events were collected for ZF and2 × 108 for LF spectra. (b–e) Local structures H-related defects and predictions of the linewidth Δ corresponding
to (b) H I, (b) H II, (c) H III, and (d) H− state. HI−III are bonded to O as H+, while H− forms bonding with two Ga3+ ions.

48

Research and Development Highlights

MLF Annual Report 2022

electrons, causing unintended n-type conduction.
Furthermore, E 0/– is located close to the CB but on thelower energy side [left side of the Fig. 2(a)] than the
charge neutral level Fint , suggesting that the state corresponding to E 0/– can actually act as an acceptor andexchange electrons with the CB. Considering this andthe fact that the acceptor-like neutral state Mu0 in various materials has been reported to exhibit fast diffusion,
the Mu2 state exhibits fast diffusion motion throughthe neutral state due to the charge exchange reaction
with conduction electron (Mu– ⇆ Mu0 + e –), as shownin Fig. 2(b). This Mu2 state has been overlooked in previous studies because of its indistinguishability frombackground components [4] and was revealed for the
first time using the high-intensity muon beam at the
J-PARC MLF.
The findings revealed in this study are expected toprovide new guidelines for the development for downsizing and performance enhancement of devices.

by first-principles density-functional theory (DFT) calculations, shows good agreement with the structure
shown in Fig. 1(b). As described earlier, this interstitial H
has been reported to act as a donor [1], indicating that it
also corresponds electronically to Mu1 in the dilute limit(~105 cm–3).
Meanwhile, the rapid motion of Mu2 is inferred fromthe fact the absence of interstitial sites free of local magnetic fields from Ga nuclear magnetic moments (with100% natural abundance), which is only compatible
with the situation where the relaxation due to the local
field is suppressed by the motional averaging.
Various instances of experimental evidence indicate that muons injected as ion beams are in a metastable state. The recently established ambipolar model
assumes ambipolarity in the sense that muons can bein the donor and acceptor states simultaneously as
such metastable states (relaxed-excited states) [3].
Specifically, we assume that the two relaxed-excitedstates correspond to the donor level (E +/0), and the acceptor level (E 0/–) in Fig. 2(a). We further assume thatwhich charged state each takes is determined by theband structure and the relationship between E +/0 andE 0/– in the material. The present experimental results arein good agreement with this model, since E +/0 is in the
conduction band (CB), the corresponding H (or Mu) isalways ionized [H → H+ + e –, see Fig. 2(b)] to provide

References[1] H. Li and J. Rovertson, J. Appl. Phys., 115, 203708(2014).
[2] M. Hiraishi, et al., Phys. Rev. B, 107, L041201 (2023).
[3] M. Hiraishi, et al., J. Appl. Phys., 132, 105701 (2022).
[4] P. D. C. King, et al., Appl. Phys. Lett., 96, 062110(2010).

(b)
Energy

(a) 4
Mu−

E0/−

0
-2
-4
-6

0

Mu−

E+/0
CB

E+/0

Mu0

E0/−

↑

Valence band

Formation energy (eV)Band gap

2

Mu+

E+/−
Mu+

1

EFint (charge
neutral level)

Conduction
band

2
3
4
5
Fermi energy (eV)

6

VB

7

Figure 2.	(a) The relationship between the formation energy of Muq (q = 0, ±1) and the Fermi energy
in β-Ga2O3 [1], where the symbols E+/0, E0/−, and E+/− correspond to mutual intersection
points among each formation energy of the charged states. (b) Schematic diagram of theband structure corre-sponding to the donor (Mu+ = Mu1) and acceptor (Mu– = Mu2) levels.

M. Hiraishi1,2, H. Okabe1,3, A. Koda1,4, R. Kadono1,4, T. Ohsawa5, N. Ohashi5, K. Ide6, and T. Kamiya6,7
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Graduate School of Science and Engineering, Ibaraki
University; 3Institute for Materials Research, Tohoku University (IMR); 4Department of Materials Structure Science, The Graduate University
for Advanced Studies (Sokendai); 5National Institute for Materials Science (NIMS); 6Materials and Structures Laboratory, Tokyo Institute ofTechnology; 7Materials Research Center for Element Strategy, Tokyo Institute of Technology (MCES)

1

49

Research and Development Highlights

MLF Annual Report 2022

Determination of Light Element Composition for
Asteroid Ryugu Using Muon Beam
1. Introduction
What was the early solar system like, and why did life
emerge on Earth? The composition of the solid material in
the solar system is one element of the fundamental andessential data to solve these big mysteries. Many pieces
of information related to this issue have previously beenobtained from meteorites: meteorites classified as CI havebeen thought as the most primordial materials we havebeen able to obtain so far. However, it was not known
whether these meteorites were truly primordial and freefrom terrestrial contamination.
The Hayabusa2 project aimed to bring solid material
from C-type asteroid Ryugu directly back to Earth that is
expected to have kept information about the early stateof the solar system. In 2014, the Hayabusa2 spacecraft was
launched from Earth and after its arrival at asteroid Ryugu
in 2018, two sample collection operations were successfully completed. In 2020, the Hayabusa2 provided 5.4 g of
Ryugu material to Earth. As an initial analysis, various studies of Ryugu samples have been conducted [1-8].
The returned samples from Ryugu are precious.
Therefore, although the sample heterogeneity is expected,
it is impractical to use large amount samples for destructive
analysis that is commonly applied for quantification of lightelements, such as C, N and O. To solve this problem, we applied a non-destructive elemental analysis method to the
Ryugu samples using muon beams [1, 9].
Our research group has been developing the muon elemental analysis method at J-PARC for the last 15 years andapplying this method for various sample analyses [10-14].
This method is based on the measurement of characteristic muonic X-rays emitted after muon stop in the sample
having 200 times larger energies compared to fluorescent
X-ray energies. High energy muonic X-rays enable us toquantify the light elements even if these exist inside thematerial.
2. Experimental
The muon experiment was conducted at the D2experimental area in the MUon Science Establishment(MUSE) of J-PARC MLF [15]. To analyze Ryugu samples, a
dedicated experimental setup was developed, as shownin Fig. 1 [16] that can handle the sample and conduct
muon irradiation under the helium atmosphere conditions. That is, the sample is completely free from thecontamination by terrestrial materials during muon
50

irradiation, and the analyzed samples can be applied
to other analyzes involving destructive methods. This
setup allowed us to use large amount of samples (123
mg in total) for muon analysis that allowed us to reduce
the effects of sample heterogeneity. During the muon
experiment, the momentum of the muon was tuned at29.2 MeV/c and the duration of muon irradiation was
116 hours. To obtain calibration data for quantitative
analysis, we also performed muon irradiation for 4 carbonaceous meteorites (Orgueil, Murray, Yamato980115
and Tagish Lake).
3. Results and discussion
Figure. 2 shows a muonic X-ray spectrum for the
Ryugu sample. X-rays originated muon captures on C, N,
O, Na, Mg, Si, S, Fe, and Ni atoms were clearly observed,that is, the main components of the Ryugu sample wereidentified as these elements. X-rays from muonic Be andCu were derived from the muon stop by measuring system. The quantitative analysis was conducted using calibration data obtained from three meteorite samples of
Murray, Yamato980115 and Tagish Lake. The elemental
compositions of these meteorites were determined byenergy dispersive X-ray spectroscopy equipped in scanning electron microscope, prompt gamma-ray analysis
by neutron activation and elemental analysis by combustion. A linear relationship between the elemental
composition and intensity of muonic X-ray for eachelement, and using the calibration data, the elemental
composition of the Ryugu sample was determined frommuonic X-ray intensity.
The elemental composition of Ryugu was similar to

Figure 1.	
Photo of the experimental group’s members andthe muon analysis system for the Ryugu sample.

MLF Annual Report 2022

Research and Development Highlights

Figure 2. Muonic X-ray spectrum obtained from the Ryugu sample with major peak assignments.

that of CI (carbonaceous meteorite of Orgueil), which
was thought to be the most primordial material in thesolar system. This shows that Ryugu is one of the representative materials of solid matter in the solar system.
On the other hand, a clear difference in oxygen concentration between Ryugu and Orgueil was found; the oxygen concentration of Ryugu was 25% lower than thatof Orgueil. One possible reason of such difference is derived from the alteration of Orgueil by water and oxygenin the atmosphere. In fact, it has been reported that theabundance of Fe2+ is higher in Ryugu than in Orgueil,
which indicates that Fe2+ in Orgueil was oxidized to Fe3+
immediately after it fell to Earth [1]. The elemental composition determined by muon analysis method was ingood agreement with these determined by other destructive analysis methods [2, 7, 8].
We concluded that the most predominant and completely unaltered solid material in the solar system was
obtained by the Hayabusa2 project. In the future, theresults of the analysis of the Ryugu sample, including
muon analysis method, may replace the result of CI as
the canonical elemental composition for solid materials
in the solar system.

References[1] T. Nakamura et al., Science, 379, eabn8671 (2022).
[2] H. Naraoka et al., Science, 379, eabn9033 (2022).
[3] T. Noguchi et al., Nature Astronomy, 7, 170 (2022).
[4] R. Okazaki et al., Science, 379, eabo043 (2022).
[5] R. Okazaki et al., Earth Planets Space, 74, 190 (2022).
[6] H. Yabuta et al., Science, 379, eabn9057 (2022).
[7] T. Yokoyama et al., Science, 379, eabn7850 (2022).
[8] E. Nakamura et al., Proc. Jpn. Acad., Ser. B, Phys., 98,
227 (2022)[9] K. Ninomiya et al., submitted to Meteoritics &Planetary Science.
[10] K. Ninomiya et al., J. Phys. Conf. Ser., 225, 012040(2010).
[11] K. Ninomiya et al., Bull. Chem. Soc. Jpn. 85, 228(2012).
[12] K. Terada et al., Sci. Rep., 4, 5072 (2014).
[13] K. Ninomiya et al., Anal. Chem., 87, 4597 (2015).
[14] K. Shimada-Takaura et al., J. Nat. Med. 75, 532 (2021).
[15] K. Shimomura et al., Nucl. Instrum. Methods Phys.
Res. Sect. A, 600, 192 (2008).
[16] T. Osawa et al., ACS Earth Space Chem., 7, 699 (2023).

K. Ninomiya1, I. Chiu1, K. Terada1, T. Osawa2, T. Wada3, T. Nakamura3, S. Nagasawa4, T. Minami4, M. Katsuragawa4, S. Takeda4,
T. Takahashi4, M. K. Kubo5, A. Taniguchi6, S. Watanabe7, T. Azuma8, K. Mizumoto9, S. Takeshita10,11, I. Umegaki10,11, K. Shimomura10,11,
and Y. Miyake10,11
1
Osaka University; 2Japan Atomic Energy Agency; 3Tohoku University; 4The University of Tokyo; 5International Christian University; 6Kyoto
University; 7JAXA; 8RIKEN; 9Tokyo University of the Arts; 10Muon Science Section, Materials and Life Science Division, J-PARC Center;
11
Institute of Materials Structure Science, KEK

51

Research and Development Highlights

MLF Annual Report 2022

Energy-resolved Neutron-induced Soft-error Cross Section
from 10 meV to 800 MeV Measured by Time-of-flight Method
1. Overview
We measured successfully a semiconductor neutron-induced soft-error cross section from 10 meV to
1 MeV by time-of-flight measurement at MLF. The findings reveal, for the first time, a complete picture of theenergy dependence of soft-errors (J-PARC Proposal No.
2022A0249) [1]. As a result, we were able to clearly observe the effect of the cross section of the 10B ( n , α)7 Li
reaction below 0.1 MeV.
2. BackgroundToday, sophisticated electronic devices support ourlives in numerous ways, but they increasingly fall victim
to soft-errors caused by cosmic rays. When cosmic rays,
which pour down from space, collide with oxygen or
nitrogen atoms in the atmosphere, neutrons are emitted. When neutrons collide with a semiconductor in anelectronic device, they can cause “soft-errors”, a phenomenon whereby the data stored in a semiconductor
are changed. Soft-errors have the potential to impact
social infrastructures causing communication failures,and other adverse effects (Fig. 1).
In considering measures against soft-errors inelectronic devices, it is important that the system design considers the frequency of the soft-error-induced
failures of each device. Meanwhile, the frequency ofsoft-error-induced failures varies greatly depending on
the energy of neutrons reaching the device. Therefore,

detailed data on the energy dependence of soft-error
cross section is crucial. The soft-error cross section σ (E)is defined as( )=( )⁄Φ( )which identifies a neutron fluence Φ(E) as the total number of neutrons per unit area impinging on the semiconductor device, and the total number of soft-errors, N(E),generated by these neutrons. In addition, neutrons in
the natural environment and neutrons generated by accelerators have different energy distributions. Therefore,
the soft-error rate (SER), which is the number of softerrors occurring per unit time in a specific neutron irradiation environment can be indicated as∞( ) ( )

= ∫0

Galactic cosmic rays
Solar cosmic rays

(1) Atmospheric reactions
High-energy particle breaks atomic nucleus in
the air

High-energy particle

Atmosphere

ProtonNeutron
Neutron

Neutron

NeutronSemiconductor devices inelectronic equipment

Figure 1. Mechanism of soft-error.

52

Muon

Neutron

Neutron breaks
silicon nucleus

Silicon nucleus

NeutronEquipment

Nucleus(nitrogen or oxygen)
π-meson(2) Reactions in electronic equipment
Soft error

Neutron(2)

using the neutron flux φ(E) at each neutron energy E
and the soft-error cross section σ (E). Thus, the soft-error cross section is the most important basic data that isnecessary for calculating the failure rate of semiconductor devices due to soft-errors.
For this purpose, we measured the soft-error crosssection in the high-energy neutron region (1 MeV
to 800 MeV) at Los Alamos Neutron Science Center(LANSCE) in 2020 [2]. However, it is impossible to measure the neutron energy range below 1 MeV at the
LANSCE radiation effects facilities, because the interval
repetition of the proton beam, which is produced as a

Figure 1. Mechanism of soft-error
Universe(1)

Secondary particle
generation

MLF Annual Report 2022

pulsed neutron beam, is 1.8 μs (1.8 μs corresponds tothe neutron flight time of 0.6 MeV neutrons over a neutron flight path length of 20 m) and the neutron intensity below 1 MeV is very low. Therefore, we decided touse the facility at the MLF to perform a measurementof a continuous energy-dependent neutron-induced
soft-error cross section for an energy range extending
below 1 MeV.

Research and Development Highlights

MLF BL10. The intensity of neutrons used for irradiation
at this facility was evaluated using the gold foil activation method. The soft-error cross section in an FPGA
40 nm was measured for continuously varying energies
with high energy resolution. Figure 2 shows the fitted
curve of the measured time structure of the proton
pulse at an accelerator power of 200 kW [3]. As can beseen, the energy resolution of measurements in the highenergy region above about 0.1 MeV is not very highsince the proton pulse of this facility is double-bunchwith a peak to peak distance of 600 ns.

3. Measurement method and experiment
In this study, we measured soft-errors caused by
low-energy neutrons below 1 MeV using the time-offlight method with a high-speed soft-error detector
reported in 2020. The experiment was conducted bya high-speed soft-error detector at the instrument forneutron source characterization (NOBORU) installed at

4. Results and discussions
The results of time-of-flight spectrum of the softerror counts for the FPGA is shown in Fig. 3 ((a) shows atime resolution of 20 ns and (b) shows a time resolution

Figure 2. Time structure of proton pulse at
J-PARC (200 KW)
80

Intensity [arb. unit]

70
60
50
40
30
20
10

Figure 3. Time-of-flight spectrum of thesoft-error counts
0

0

0.2

0.4

0.6
0.8
Time [μs]11.2Soft error counts / 10μs

Soft error counts / 20ns

Figure 2. Time structure of proton pulse at J-PARC (200 KW).

450
400
350
300
250
200
150
100
50
0

(a)

0

FPGA 40nm

500

1000

1500

2000

Time of flight [ns]

1000

(b)

FPGA 40nm

100

10

1

0

5000

10000

15000

20000

25000

Time of flight[μs]

30000

35000

40000

Figure 3. Time-of-flight spectrum of the soft-error counts.

53

Figure 4. soft-error cross section of the FPGA
40 nm
Research and Development Highlights

MLF Annual Report 2022

Soft-error cross section[cm2/Mbit]

1.0E-0710-7
1.0E-08
10-8

FPGA 40 nm below 1 MeV (Measured at J-PARC)FPGA 40 nm above 1 MeV (Measured at J-PARC)FPGA 40 nm (Measured at LANSCE)

1.0E-09
10-9
1.0E-1010-10
1.0E-1110-11
1.0E-12
10-12

10-13
1.0E-1310-14
1.0E-1410-8 1.0E-07
10-7 1.0E-06
10-6 1.0E-05
10-5 1.0E-04
10-4 1.0E-03
10-3 1.0E-02
10-2 1.0E-01
10-1 1.0E+00
100 1.0E+01
101 1.0E+02
102 1.0E+03
103
1.0E-08

Neutron Energy[MeV]

Figure 4. soft-error cross section of the FPGA 40 nm.

of 10 μs). Figure 3 (a) depicts clearly the double pulse
structure. However, we were not able to deduce thecross section from this since the pulse width of each
proton pulse was about 100 ns and because of that theenergy resolution was very poor. Figure 3 (b) indicatesthat soft-errors occurred even at large flight time values
and low energy. Figure 4 shows the soft-error cross section derived from soft-error counts and neutron energy
spectrum. The data show that the soft-error cross section tends to be lowest around 0.1 MeV but increases
as the energy decreases further. We consider that this isdue to the influence of Boron, which is present in trace
amounts in semiconductors.

5. Conclusion
We measured a neutron-induced soft-error crosssection for FPGAs using the time-of-flight technique foran energy range from 10 meV to 800 MeV at J-PARC andLANSCE. The effect on the cross section of the 10B(n,α)7Li
reaction was clearly observed below 0.1 MeV neutrons.
The findings allow us to calculate more accurately the
failure rate due to soft-errors, a rate which is the key toevaluating soft-errors and planning countermeasures.
References[1] H. Iwashita et al., IEEE Trans. Nucl. Sci.,70, 216 (2023).
[2] H. Iwashita et al., IEEE Trans. Nucl. Sci., 67, 11 (2020).
[3] H. Hasemi et al., Nucl. Instrum. Methods Phys. Res. A
773, 137 (2015).

H. Iwashita1,2, R. Kiuchi1, Y. Hiroshima1, Y. Okugawa1, T. Sebe2, M. Takeda2, H. Sato2, T. Kamiyama2, M. Furusaka2, and Y. Kiyanagi2
Environment and Energy Laboratories, NTT; 2Faculty of Engineering, Hokkaido University

1

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MLF Annual Report 2022

Research and Development Highlights

Breakthrough of Neutron Interferometer
1. Introduction
Neutron interferometer is an apparatus for theultra-high precision measurement of neutron-related
interactions. Numerous experiments for various fields
have been performed since the first successful test ofa single-crystal neutron interferometer. These include
measurements of neutron-nuclear scattering length,
demonstrations of classical physics with elementary particles, validations of quantum mechanics, and investigations of exotic interactions as predicted by new physics
beyond the standard model of elementary particles [1].
The interferometer uses mirrors to split the neutron
wave into two paths and then superpose them again.
The potential difference between the two paths is observed as a phase shift in the interference fringes. The
sensitivity is proportional to the neutron wavelengthand the interaction length, however, the conventional
interferometers that use silicon crystal are limited by thelattice constant in terms of the available neutron wavelengths and are also size constrained by the dimensionsof the ingot [2]. To overcome those limitations, neutroninterferometers using multilayer mirrors were developed [3, 4]. The neutron wavelength to be used can be
freely selected by controlling the structure of the neutron multilayer mirrors.
2. Multilayer interferometer with pulsed neutrons
A novel neutron interferometer integrating unpolarized neutron multilayer mirrors was introduced
at J-PARC. The interferometer concurrently measuresphase shifts at diverse wavelengths by identifying the
wavelength from the time of flight (TOF). This is not only
statistically advantageous, but also allows for tracking
temporal disturbances of the apparatus. This overcomes
the weakness of conventional interferometers.
The experiment was conducted at the low-divergence

branch of BL05 (NOP) within the Materials and Life
Science Experimental Facility [5]. The beam power sustained during the experiments was 620 kW. Pulsed neutron beam was transported through the neutron benderat BL05 to the interferometer. The interferometer comprised two beam-splitting etalons (BSEs) that split neutron waves into two parallel paths and later recombine
them (Fig. 1). The BSEs were designed with half and totalreflection mirrors separated by an air gap of 189 μm. The
mirrors, deposited on a flat SiO2 substrate, were bondedby optical contact to maintain parallelism. The parallelism was preserved at approximately 30 nm. The flat SiO2
substrates with the mirrors were bonded by optical contact to maintain parallelism. The parallelism between
the mirrors was preserved at approximately 30 nm. The
mirrors can reflect momentum transfers in the range of
0.232 < Q < 0.292 nm–1. The BSEs were positioned with
the incident angle of 1.05° and distance of 140 mm. Theinterference fringes as a function of TOF were observedby using two-dimensional position sensitive detector.
A precision stage was developed to insert the device
and/or sample to be measured into the path in the interferometer. To minimize external disturbances, theinterferometer and the sample insertion assembly wereplaced on an active vibration isolator and maintained
at a stable temperature of 23°C inside a thermostaticchamber.
Figure 2(a) shows the raw data containing interference fringes. The peak of neutron counts was in the
wavelength range from 0.8 nm to 1.1 nm, which canbe reflected by the mirrors. It also shows that the interference fringes disappear when one of the two pathsis blocked by cadmium plate. This proved that the observed intensity oscillation was an interference between
the two paths. Figure 2(b) and (c) show the interference
fringe with and without inserting a 0.3-mm-thick Si

Figure 1. Experimental setup for the multilayer interferometer with pulsed neutrons at BL05 NOP.

55

Research and Development Highlights

MLF Annual Report 2022

various nuclei. Scattering lengths for silicon, aluminum,and titanium were measured and found to be consistent
with literature values. Deviations from literature values
were found for the neutron-vanadium scattering length.
A precise analysis of our sample did not reveal any impurities. This suggests the uncertainty of previous studies.
These results show that our new interferometer is robust
and highly reliable [8].

Figure 2.	(a) TOF spectra of neutron intensity in the O and H
beams. The interference fringes disappear when oneof the two paths was blocked by cadmium plate.
(b) Normalized interference fringes without sample.
I( λ) = (IO / IOCd - IH / IHCd ) / ( IO / IOCd + IH / IHCd ), where IO
and IH are the intensity of O and H beam respectively,
IOCd and IHCd are the intensity of O and H beam withblocking one path respectively. (c) Normalized interference fringes with silicon sample inserted into oneof the two paths.

sample into one of the paths, respectively. A distinct
phase change was observed with and without the sample. The obtained uncertainty in the measured phaseshift was 0.02 rad per 20 min. This sensitivity exceededthat measured by NIST (0.31 rad per min) [6] by a factorof 3 and was comparable to that measured by ILL [7](0.08 rad per min).
The refractive index of the sample can be determined using the phase shift. From the refractive index,
the neutron-nuclear scattering length of the nuclei inthe sample can be calculated. To demonstrate our interferometer’s capabilities, we conducted experiments
to determine the neutron-nucleus scattering lengths of

3. Future plans
The number of neutrons available for measurements can be increased by optimizing the configuration of the multilayer mirrors in the interferometer forthe spectrum of the incident beam by two orders ofmagnitude. Systematic uncertainties originating fromthe sample shape can be suppressed by ultra-high precision machining technology. By expanding the air gaps
in the BSEs, the interferometer can be utilized for various physics experiments, such as the scattering lengthof gas samples requiring containers of sufficient size [9].
The utilization of a high-sensitivity neutron interferometer opens possibilities for a wide range of new physics
search experiments.
References[1] H. Rauch and S. A. Werner, “Neutron Interferometry ”,
2nd ed. (Oxford, New York, 2015)[2] H. Rauch, W. Treimer, and U. Bonse, Phys. Lett. 47A,
369 (1974).
[3] M. Kitaguchi, et al., Phys. Rev. A 67, 033609 (2003).
[4] Y. Seki, et al., J. Phys. Soc. Jpn. 79, 124201 (2010).
[5] K. Mishima, et al., Nucl. Instrum. Methods A 600, 342(2009).
[6] P. Saggu, et al., Rev. Sci. Instrum. 87, 123507 (2016).
[7] Y. Hasegawa, et al., Nature (London) 425, 45 (2003).
[8] T. Fujiie, et al., Phys. Rev. Lett. 132, 023402 (2024).
[9] K. Li, et al., Phys. Rev. D 93, 062001 (2016).

T. Fujiie1,2, M. Hino3, T. Hosobata2, G. Ichikawa4,5, M. Kitaguchi1,4,6, K. Mishima4,5, Y. Seki7, H. M. Shimizu1,4, and Y. Yamagata2
Department of Physics, Nagoya University; 2Center for Advanced Photonics, RIKEN; 3Institute for Integrated Radiation and Nuclear Science,
Kyoto University; 4Institute of Materials Structure Science, KEK; 5Neutron Science Section, Materials and Life Science Division, J-PARC
Center; 6Kobayashi-Maskawa Institute, Nagoya University; 7Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
1

56

MLF Annual Report 2022

Research and Development Highlights

Measurement of the 241Am Neutron Capture Cross
Section with Fe and Si-filtered Neutron Beam Using
the NaI(Tl) Spectrometer of the ANNRI Beamline
1. Introduction
Partitioning and transmutation have been the approaches taken by Japan in order to solve the long-term
accumulation of High-Level nuclear Waste (HLW). At theJapan Atomic Energy Agency (JAEA), the transmutationof minor actinides (MA) is currently targeted by meansof Accelerator Driven-Systems (ADS), a sub-critical facility that employs a proton accelerator to generate keV
neutrons within the core, via spallation reactions. The
reaction core is meant to be constituted of mainly MAs,
with a high concentration of 241Am amongst all MAs.
Hence, accurate data of all neutron induced reaction for
all MAs that will constitute the ADS core is paramountfor the design and safety assessments. In particular, theneutron capture cross section has been found to be oneof the main sources of criticality uncertainty of ADS.
The reason for this is that, while transmutation of MAs
is meant to be carried out by fission reactions, the neutron capture reaction is the main reaction channel open
for most MAs in the core in the keV region. Hence, anaccurate characterization of not only the fission channel
but the competing neutron capture channel is of utmost
importance for the design of ADS facilities [1] .
Regarding 241Am, the uncertainty in evaluated nuclear data libraries such as JENDL-5 [2] stems from thefact that experimental data in the keV for the neutron
capture cross section presents high uncertainty. The
reason for this is that 241Am is highly radioactive, a factthat limits the amount of mass that can be measured.
This combined with the low overall value of the neutron

capture cross in the keV range, means that continuous
experimental efforts are required using highly intense
pulsed-neutron beams. The past experimental data withhigh uncertainty for 241Am in the keV-neutron region,
which can reach up to 45%, are shown in Fig 1.
2. Experimental setup
The experiments were performed at the Accurate
Nucleon-Nucleus measurement Reaction Instrument(ANNRI) using the newly developed neutron filtering
technique. This technique hinges on molding the incident neutron flux, which is in double-bunch mode, intoquasi-monoenergetic neutron beams by using materials
that present the characteristic of sharp minima in theneutron total cross section, since only neutrons withthe energy of the sharp minima can stream through thefilters and reach the sample position while the rest are
stopped. A schematic of the neutron filtering technique
can be seen in Fig. 2
With the neutron filtering technique, the effects ofthe double-bunch can be severely diminished. At thesame time, since most of the high-energy neutrons are
not allowed to reach the sample position, the background events caused by such neutrons after interacting with the sample, which carry a delay in time and,hence, are seen throughout long time-of-flight regions,
are mostly removed, allowing for accurate experiments
to be performed. This is of particular importance formeasurements with radioisotopes, such as 241Am, as
they have to be sealed, with the casing becoming one

Figure 1.	Present status of the experimental and evaluated data for theneutron total cross-section of 241Am

57

Research and Development Highlights

MLF Annual Report 2022of the main sources of background. Nonetheless, withthe use of the neutron filtering technique the influenceof the casing is massively reduced due to minimal highenergy neutrons reaching the sample. Further information about the neutron filtering technique is provided
here [3].
In the present experiment, natFe and natSi were employed as filters in order to tailor the incident doublebunch neutron flux into quasi-monoenergetic neutron
beams with averaged neutron energies of 23.5 keV (Fe);and 51.5 and 127.7 keV (Si). A 241Am sample with a massof 7.47 ± 10 mg and an activity of 957 MBq, was measured in the present experiment together with dummycase and a carbon sample to derive the sample-dependent background. The pulse-height weighting technique[4] was employed to derive the 241Am neutron capture
yield and the neutron cross section of 241Am was determined relative to the 197Au neutron capture yieldmeasured with a Au sample and using the reference
cross section value of JENDL-5. This process can be

expressed as:
(

)=

(

)

(

(

)

)

(

)

(

ℎ

)

where σAm(E­n) is the neutron capture cross section of
241
Am. Yx(E­n), Cx(E­n), Sx(E­n), Px(E­n), are the neutron capture
yield, the correction for self-shielding and multiple scattering effects, the sample area density and the numberof proton shots for 241Am and 197Au, respectively. Cfis(En)is the fission correction for 241Am, while Ctresh is thecorrection for undetected events below the detection
threshold of 600 keV. Finally, σAm(E­n) is the neutron capture cross section of 197Au from JENDL-5.
3. Cross section results
The present results for the neutron capture crosssection of 241Am obtained with the neutron filtering
technique at the neutron averaged energies of 23.5,
51.5 and 127.7 keV are shown in Fig. 3. As can be clearly
seen, the present results signify a massive improvement

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

241
Figure 3.	Am neutron capture cross section results using the Si (51.5
and 127.7 keV) and Fe (23.5 keV) neutron filters with experimental and evaluated data.

58

MLF Annual Report 2022

in cross section accuracy, since they display with much
lower uncertainty (8–12%) than that of the past experimental data (15– 45%). This is important in orderto reduce the nuclear data uncertainty influence in thedesign of ADS facilities.
4. Conclusions
The neutron capture cross section of 241Am wasdetermined in the ANNRI beamline at the averaged
neutron energies of 23.5, 51.5 and 127.7 keV by meansof the newly developed neutron filtering technique,that allows for the neutron induced cross section to bemeasured with high accuracy. The present cross section results for 241Am were determined relative to theneutron capture yield of 197Au and display uncertainties of 8–12%, much lower than those present in past

Research and Development Highlights

experimental data of 15–45%, signifying a major crosssection uncertainty improvement for the design of ADS
facilities. Further information about the present experiment can be found here [5].
References[1] Iwamoto H, Nishihara K, Sugawara T, et al. J Nucl Sci
Technol. 2013;50:856–862.
[2] Iwamoto O, Iwamoto N, Kunieda S, et al.. J Nucl Sci
Technol. 2023;60:1–60.
[3] Rovira G, Kimura A, Nakamura S, et al. Nucl Inst
Methods Phys Res A. 2021 ;1003:165318.
[4] MacKlin RL, Gibbons JH. Phys Rev. 1967;159:
1007–1012.
[5] Rovira G, Kimura A, Nakamura S, et al. J Nucl Sci
Technol . 2023;60:489–499.

G. Rovira1, A. Kimura1,2, S. Nakamura1,2, S. Endo1,2, O. Iwamoto1, N. Iwamoto1, T. Katabuchi3, Y. Kodama3, and H. Nakano3
Nuclear Science and Engineering Center, JAEA; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center; 3Laboratory
for Zero-Carbon Energy, Tokyo Institute of Technology

159Research and Development Highlights

MLF Annual Report 2022

Development of Pulsed Magnet System for Sample
Environment equipment

2. Development of pulsed magnet system
Figure 1 shows the cross-section of the developed
pulsed magnet equipment. It comprises a vacuum
chamber, a closed-cycle refrigerator for sample cooling
down to 4 K, and a nitrogen bath made of a rectangular cross-section stainless-steel (SUS) tube. The coil is
inserted in the nitrogen bath. It is immersed in liquid
nitrogen to reduce the resistance and quickly remove
the Joule heat generated by the pulsed current of thecoil. Automatic liquid nitrogen supply equipment (LNAS,
Value-impact Co., Ltd.) is introduced to achieve a fully
automatic repetitive operation.
60

Figure 2 depicts a photograph of the coil. A hightensile strength Cu–Ag alloy with 1 mmφ (CA100PIWC-7, SWCC Showa Cable System Co., Ltd.) for thewire is used. The sum of the turns is approximately 200.
The coil inductance and resistance at 100 Hz are 670 μH
and 100 mΩ at 77 K, respectively. The current to thecoil is applied by a capacitor bank pulsed power supply
made by pulsed magnet Gr. in the MLF [3].
The sample is attached to a 7 mmφ single-crystalline
sapphire rod that is connected to the GM refrigerator
and cooled down to 4 K through heat conduction. The
sample is placed in the center of the coil. The scattering angle, 2θ, is 42°. Thermometers (Cernox, Lake Shore
Cryotronics Inc.) are attached near the end of the sapphire rod and the second stage of the GM refrigerator.
The sample and the sapphire rod are enclosed by an aluminum radiation shield of 1 mm thickness to preventa temperature rise. Figure 1 shows only the aluminum

Figure 1. Cross-section of the pulsed magnet equipment.

44 mm
21 mm

1. Introduction
With the development of various measurement
techniques, such as magnetization, electric resistance,
specific heat, ESR and NMR, high magnetic field environment has become indispensable in material science.
Neutron scattering experiments under high magnetic
fields have unique features, they allow us to trace theorigin of the induced phase in the high magnetic field.
These technologies have been mainly developed in
the so-called high magnetic field facilities in the world.
On the other hand, neutron scattering experiments using a high magnetic field can directly determine themagnetic structure, so it is possible to obtain information on the origin of the phase induced by a high magnetic field.
To meet the growing demand for high magnetic
field applications for neutron diffractions, several highmagnetic field environments have been developed inneutron facilities globally. Superconducting magnets
have been used with magnetic fields of up to 17 T [1].
A 4 MW hybrid magnet comprised of superconducting
and normal resistive magnets with magnetic fields of up
to 26 T had been operated at the Extreme Magnet Field
Facility (HFM) of the Helmholtz Center Berlin Institute(HZB) in Germany [2].
High-intensity pulsed neutron beam at the MLF
has already become available, and we have received
requests from users to introduce pulsed-type highmagnetic-field equipment to the MLF. Pulsed magnetic
equipment does not only require large power, but canalso be made compact and movable. Therefore, we havedeveloped a pulsed high magnetic field device that cangenerate more than 30 T.

Figure 2. Photograph of the coil.

MLF Annual Report 2022

Research and Development Highlights

frame to which the shield is connected to show the inside. For the temperature control of the sample, a polyimide film insulation heater is wound around the second
stage of the GM refrigerator. The temperature can be adjusted by a temperature controller (Model 336 Cryogenic
Temperature Controller, Lake Shore Cryotronics, Inc.)
which can be controlled approximately from 4 K to room
temperature. We have confirmed that the temperature
gradient between the sample and the refrigerator coldhead is as small as 1.2 K.
3. Experiment and results
The pulsed magnet system was commissioned on
NOBORU (BL10) [4]. A single-crystalline multiferroic
TbMnO3 [5] was used as a test sample. Its size was approximately 4.5 × 4 × 3.5 mm3. It was placed in a position that would facilitate the application of the magnetic
field along the a-axis. It is a multiferroic material thatcoexists in magnetic and ferroelectric orders. For example, it is expected to be a multifunctional and highperformance next-generation electric/magnetic device.
At zero magnetic fields, the magnetic moments of Mn
in TbMnO3 are incommensurate, and the propagation
wave vector (0, kMn, 1) in the Pbnm orthorhombic unit is(0, 0.28, 1) below 28 K. In a magnetic field of 30 T, they
become commensurate and show a propagation wave
vector of (0, 0.25, 1).
As a demonstration of the pulsed magnet system,
the change in the TOF spectrum of the Mn momentswith and without a magnetic field is experimentally
validated. The TOF spectra are shown in Fig. 3. The TOF
spectra of the red and blue points are 0 and 30 T, respectively. Because the neutron counts are integrated
for approximately 10,000 incident beam pulses (approximately 7 min) at 0 T, the count number displayedin Figure 3 is reduced to 1/100 to match the count number of 40 shots at 30 T. Figure 3 is also depicted as an
example of a pulsed magnetic field waveform applied
to a sample.
There are Bragg peak signals in Fig. 3 that correspond to the propagation wave vector (0, 0.28, 1) of theMn moments at 0 T and (0, 0.25, 1) of it at 30 T. The TOFof the Bragg peaks are estimated to be approximately
10.25 ms and 10.4 ms using the Gaussian function, respectively. The magnetic field dependence of the diffraction peaks with and without a magnetic field was

Figure 3. TOF spectra applied to the sample.

clearly observed using the pulsed magnet system.
N. Qureshi et al. also performed a pulsed magnetic
field experiment using TbB4 as a sample [6]. However,this was a single-wavelength experiment using a nuclear reactor at ILL (thermal neutron three-axis spectrometer, IN22), so it is not possible to see a wide range ofwave number space such as at the MLF.
4. Future plans
We have successfully developed 30 T pulsed magnet
equipment, so next we will proceed with the development of higher pulsed magnet equipment. So far, wehave succeeded in increasing the maximum magnetic
field up to 35 T and performing a neutron experiment.
We are developing pulsed magnet equipment up
to 40 T, which is the largest class of sample environment
devices for neutron facilities.
References[1] Meissner, M.; Smeibidl, P., Neutron News 2001, 12,
12–18.
[2] Steiner, M.; Tennant, D.A.; Smeibidl, P., J. Phys. Conf.
Ser. 2006, 51, 470–474.
[3] Watanabe, M.; Nojiri, H., J. Neutron Res. 2019, 21,
39–45.
[4] M. Watanabe, T. Kihara, H. Nojiri, Quantum Beam Sci.
2022, 7, 1.
[5] Quezel, S.; Tcheou, F.; Rossat-Mignod, J.; Quezel, G.;
Roudaut, E., Phys. B 1977, 86–88, 916–918.
[6] N. Qureshi.; F. Bourdarot, E. Ressouche, W. Knafo,
F. Iga, S. Michimura, L.-P. Regnault, and F. Duc,
PHYSICAL REVIEW B 106, 094427, 2022.

M. Watanabe1, T. Kihara2, and H. Nojiri3
Technology Development Section, Materials and Life Science Division, J-PARC Center; 2Research Institute for Interdisciplinary Sci-ence,
Okayama University; 3Institute for Materials Research, Tohoku University

161Research and Development Highlights

MLF Annual Report 2022

New Material Exploration to Enhance Neutron Intensity
Below Cold Neutrons
1. Introduction
Slow neutrons, such as cold neutrons, are important nondestructive probes not only for basic physics
but also for the structural genomics advancements inthe life sciences and the battery technology advancements needed for the transition to a hydrogen society.
Neutron-based science, also known as high-intensitydependent science, demands that we increase thesource’s intensity as high as possible.
A new unique method focusing on nanosized particle aggregation has been proposed to increase neutron intensity below the cold neutron energy region[1–3]. The aggregation of nanosized particles matches
the wavelength of below cold neutrons, resulting ina similar effect to coherent scattering, or so-called
Bragg scattering, leading to higher neutron intensities.
Nanodiamonds [4–6] (Fig. 1) and magnesium hydride(MgH2) [7] have recently been determined numericallyand experimentally to have the potential to increase
neutron intensity by several orders of magnitude. The
major challenge with nanodiamonds in practical applications is the molding method.
In order to find a solution to this problem, we focused on another carbon structure, graphene. Graphene[8] is expected to be the lightest and strongest material
in the world due to its geometric structure. It is being
scaled up for practical applications, such as aerospaceand space, etc [9].
Conversely, large amounts of nanosized end materials are also being produced in this development
progress.
We conceived that nanosized graphene could cause
coherent neutron scattering under particle size conditions similar to nanodiamonds. Moreover, it might be

1 cmFigure 1. Photograph of nanodiamond powder [4].

62possible to use it in high neutron radiation conditions
due to graphene’s strong sp2 bonds. We performed
neutron scattering measurement experiments, suchas total neutron cross-section and small-angle neutron
scattering on nanosized graphene using the RIKEN
Accelerator-driven compact Neutron Source (RANS) [10]and iMATERIA at J-PARC [11].
The potential of nanosized graphene aggregationis reported as a reflector material below cold neutrons,
together with experimental results.
2. Nanosized graphene flower aggregation
A distinctive graphene called a “graphene flower”
with a “sunflower” shape [12, 13] is produced by combination of phenolic formaldehyde resin carbonization and the hot isostatic pressing (HIP) process. Notethat this graphene flower is far from how we imagine
graphene as a two-dimensional structure material.
The produced graphene flower, as shown in Fig. 2, wascomposed of multiple petal-like graphene layers ofless than 20 nm thick growing from the carbonizedsphere surface. Seed-like graphene was composed ofmany 1–100 nm sized graphenes inside the sphere,
forming a concave–convex structure. Finally, graphene
flowers were combined to form a nanosized grapheneaggregate.
For this study, two graphene sample types, namely,graphene 1 and 2, were prepared under different HIP
conditions. As shown in Fig. 3(a), graphene 1 produced
petal-like graphene on the surface and granular seedlike graphene inside the sphere. Graphene 2 formed petal-like graphene but almost no seed-like graphene, as
shown in Fig. 3(b). The samples were shaped to 20 mm
in diameter × 2 mm in thickness.
3. Experiment
In order to evaluate the total neutron cross-section,
the neutron transmission experiment was carried out
using the RANS neutron source [10], which was generated by the p-Be reaction of a 7 MeV proton bombardment. In a slab-type mesitylene moderator arrangement
neutron beamline, a slit-type collimator was installed toincrease the available neutron intensity at the sample
position.
Small-Angle Neutron Scattering (SANS) Experiments
were performed at the J-PARC iMATERIA [11].

Research and Development Highlights

MLF Annual Report 2022

Seed-like graphene
Petal-like graphene

1µmFigure 2.	The SEM image of a graphene flower produced by the HIPtreatment [13]. As indicated by the arrows in the figure, thegraphene flower is composed of multiple petal-like graphene and seed-like graphene. Petal-like graphene forms
multiple layers of petals less than 20 nm thick growing fromthe carbonized sphere surface. The seed-like graphene iscomposed of many 1–100 nm sized graphenes inside thesphere, forming a concave–convex structure [13].

(a) Graphene 1

100nm

1cm

1µm

(b) Graphene 2

Petal-likegraphene

Seed-likegraphene

100 nm1cm

1µm

Figure 3.	Photographs of graphene materials prepared under various HIP
conditions [13]. (a) Graphene 1, which formed petal-like graphene
and nm-sized granular seeds, called “seed-like graphene”, wasfabricated under HIP conditions with a maximum temperatureof 1390°C at a rate of 900°C/h, 1 h holding time, then cooled
naturally; (b) Graphene 2, which formed petal-like graphene,
but no seed-like graphene, was fabricated under HIP conditions
with a maximum temperature of 1300°C at a rate of 200°C/h
and then cooled immediately without any retention time.

4. Results and discussion
Total neutron cross-sections were calculated using the transmission data, as shown in Fig. 4, where
coherent scattering predominated for the 0.5–2 meVregion, concerning the nanodiamond literature [4].

Compared to graphite, nanodiamond had several hundred higher total neutron cross-sections below the meV
region. Graphene 1 was approximately one-third of thetotal neutron cross-section data of nanodiamonds.
Conversely, it was several tens of times higher than63

Research and Development Highlights

MLF Annual Report 2022

Figure 4. Total neutron scattering cross-section [13].

Table 1. Calculated invariant Q [13, 14].
SampleGraphene1

Graphene2

Graphite

NanodiamondInvariant Q

0.02130.01140.00810.0164graphite. Graphene 1 had somewhat higher total crosssection than graphene 2, showing seed like graphenerather than petal like graphene are more effective forcoherent scattering.
Table 1 shows the velues of invariant, 𝑄 [13, 14] formeasured SANS data, representing the scattering crosssection due to small-angle scattering. In particular, nanodiamond and graphene 1 showed a larger 𝑄. Thesefindings agree with the scattering cross-section values
determined by transmission experiments.
Note that the nanosized graphene, which is still inthe early development stages, has the potential to rivalor even surpass nanodiamonds with further fabrication
process optimization, including nanosized grapheneaggregation.
5. Conclusions
We concentrated on nanosized graphene aggregation to intensify below cold neutrons, which aresimilar to those of nanodiamonds. For the first time,the measured data revealed that nanosized grapheneaggregation increased total neutron cross-sections
and small-angle scattering in the cold neutron energy

region, most likely due to coherent scattering, implying
the possibility of below cold neutron applications.
References[1] V.V. Nesvizhevsky et al., Physics of Atomic Nuclei, 65
400 (2002).
[2] V.V. Nesvizhevsky et al., NIM A, 595 632 (2008).
[3] E.V. Lychagin et al.,NIM A, 611 302 (2009).
[4] M. Teshigawara et al., NIM A, 929 113 (2019).
[5] T. Ersez et al., Physica B Condens. Matter, 551 278(2018).
[6] M. Jamalipour et al., NIM A, 1033 166719 (2022).
[7] J. R. Granada et al., EPJ Web of Conferences, 231
04002 (2020).
[8] K. S. Novoselov et al., Science, 306 (5696) 666 (2004).
[9] L. Zou1 et al., J. Data Inf. Sci., 3 82 (2018).
[10] Y. Ikeda et al., J. Neutron Res., 1 1 (2022).
[11] S. Koizumi et al., Quantum Beam Sci., 4 42 (2020).
[12] US8951451B2[13] M. Teshigawara et al., Nanomaterials, 13 (1) 76(2023).
[14] G. Porod, Kolloid-Z, 124 83 (1951).

M. Teshigawara1, Y. Ikeda2, M. Yan2, K. Muramatsu3, K. Sutani3, M. Fukuzumi4, Y. Noda5, S. Koizumi5, K. Saruta1, and Y. Otake2
Neutron Source Section, Materials and Life Science Division, J-PARC Center; 2Center for Advanced Photonics, RIKEN; 3INCUBATIONALLIANCE INC; 4Department of Materials and Analysis, Hyogo Prefectural Institute of Technology; 5Institute of Quantum Beam Science,
Ibaraki University

164

Neutron SourceNeutron Source

MLF Annual Report 2022

Neutron Source Section
1. Organizational change
The 3NBT group, which belonged to the neutron
source section, was reassigned as the 4th accelerator
section from fiscal year 2022 to promote rational organizational management. The tasks and responsibilitiesof the 3NBT group, which were the operation, maintenance, and R&D for the beam transportation line fromthe 3 GeV synchrotron to the neutron source, and related devices, including the cooling water system, weretransferred to the 4th accelerator section.
2. Operational overview
In the beginning of fiscal year 2022, on April 7, thebeam power at the MLF was raised from 730 kW to830 kW, which was the highest level of beam power onrecord for the long-term user program. Since the proton
beam pulses at the 3 GeV rapid cycle synchrotron (RCS)
outlet are shared between the MLF and the 30 GeV main
ring (MR), the beam power at the MLF becomes lower
than that at the RCS outlet and is changed in accordance with the operation mode of the MR. The share of
the MR is 3.1% in slow extraction mode and 11.8% in fast
extraction mode. 830 kW at the MLF was attained when
the power at the RCS outlet was raised from 760 kW to860 kW with a slow extraction mode of the MR, but due
to the mode change to fast extraction, the power at the
MLF was reduced to 770 kW from June 4, even though
the power at the RCS outlet was raised to the highest
value on record of 870 kW. The stable operation continued, and the beam operation of the MLF ended onJune 26 after a two-day operation for beam study andthe maintenance works during the long outage started.
After almost 5 months of maintenance works,
the beam operation of the user program started on
November 21 with a beam power of 780 kW at the MLF,
which was a little bit less than that before the long outage due to the trouble with the accelerator component.
The beam power at the MLF was changed several times
between 730 kW and 810 kW due to the change of thebeam operation mode of the MR for beam study. The
beam operation of the MLF had continued very wellwith the excellent availability of more than 95% andended on March 15 as scheduled.
3. Remote-handling operations of the proton beam
window and the moderator and reflector assembly
Here, some important remote-handling operationsin the hot cell are highlighted. One was the replacement66of the used proton beam window and volume reduction. The proton beam window is mounted on theshielding plug and integrated into one unit, as shownin Fig. 1 left photo. When the operation of the proton
beam window reaches the material lifetime, whichis ca.10000 MWh, the unit is replaced with a new one
with a new proton beam window mounted on it, andthe used unit is temporally moved to the storage space.
Then, usually in later years, the used proton beam window is dismounted from the unit and replaced in the
hot cell by remote handling to reuse the shielding plug.
In 2022, the used proton beam window, which ended
its operation in 2020, was replaced and the utility pipes
were cut into pieces by the cutting machine shown in
Fig. 1 right photo for volume reduction by remote handling operation. The operations were successful, and the
new unit was ready to be used as a spare proton beam
window.
Another notable operation was the remote handling test of the moderator and reflector assembly carried out using a spare assembly, as shown in Fig. 2. An
assembly consists of a shielding plug, a reflector, andthree different types of moderators with utility pipes
for liquid hydrogen and water fixed to them, and only
the used moderators with utility pipes and reflector are
replaced while the shielding plug is reused just like theproton beam window. Because the operating lifetimeof a moderator and reflector assembly is comparatively
long, 30000 MWh corresponding to 8 years at 1 MW, thelast remote handling operation was done during the

Figure 1.	Unit of a proton beam window (left) and the cutting machine (right).

MLF Annual Report 2022

Neutron Source

narrow channel

Shieldingplug

U�litypipes
Moderator
exchangerbulk sideP

Mercury

Inner wall
2mm

Outer wall (t:3 mm) Bubbler Bubbler position

Narrow channel side ofouter wall specimenof original type

Cutting out specimens
Target vessel

No damageVideo
cameraHole saw

Reﬂector

Coupledmoderator

50 mm
Figure 3.	Structure of the target vessel (top) and the surfaceof the outer wall specimen (bottom left) and thecutting machine (bottom right).

Supportstand
Figure 2.	Moderator and reflector assembly and a coupledmoderator held by the moderator exchanger.

commissioning period before the beam operation of the
MLF started more than 10 years ago, so the inheritanceof skills and experiences is very important. The remotehandling procedures were checked carefully to handle
the actual radioactive assembly in the near future.
4. Investigation of pitting damage mitigation effectand target vessel replacement
All the handling works of the used target vessel are
conducted fully remotely by the remote-handling devices such as the master-slave manipulator, the power
manipulator, the crane, and video cameras, because thedose rate at the outer surface of the used target vessel ismore than 1000 Sv/h.
On September 26, specimens were cut out from theforefront wall of the used target vessel, as shown in Fig. 3
bottom right photo, which was operated with 836 kW
at maximum. This time, the specimen of the inner wallof the mercury vessel, which was protected against thepitting damage by micro-bubble injection into mercury
flow as shown in Fig. 3 top, could not be obtained, because the specimen fell into the mercury vessel. But thedamage on the specimen of the outer wall of the mercury vessel, the mercury boundary wall, was negligibly

small as shown in Fig. 3 bottom left photo, which wasa promising result for the stable beam operation withgreater beam power.
On October 11, the used mercury target vessel was
replaced with a new one which had the same structure
as the former one. This type of target had an improved
structure of the mercury flow channel. That is, the bubbler was installed at a position 92 mm closer to the beam
window than the original type, as shown in Fig. 3 top, toincrease the bubble number density near the beam window for promoting the pressure wave mitigation effect.
5. International collaborations
Three international collaboration workshops were
held during the reporting period. One took place from
October 10 to 11 with the European Spallation Source(ESS) on-site at Lund in Sweden with online capability.
The main topics were commissioning works in every aspect of the project. The others were organized on-site at
J-PARC. One was held from February 27 to March 1 with
ISIS of Rutherford Appleton Laboratory. Information exchange in the field of the accelerator system and neutron/muon target system was its primal scope. Anotherworkshop was held from March 22 to 24 with theSpallation Neutron Source (SNS) of Oak Ridge National
Laboratory to discuss the neutron source system issues.
Many fruitful discussions were held at all workshops.

K. Haga, M. Ohi, M. Teshigawara, T. Naoe, T. Wakui, H. Kinoshita, H. Kogawa, Y. Yamaguchi, and M. Harada
Neutron Source Section, Materials and Life Science Division, J-PARC Center67

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MLF Annual Report 2022

Transportation of Used Mercury Target Vessel #3

Table 1. Beam operating condition during the use of mercury target vessel #3 and state after use.
Period of beam operation
Beam operating time

2011.12–2014.6
7537 hAveraged beam power

272 kW

Accumulated beam power

2050 MWh

Total irradiation damage

2.3 dpa

Maximum surface dose rate after beam
operation (86 days cooling)

382 Sv/h

Maximum surface dose rate of storage
container before transportation

796 mSv/h

4.	Components and trailer required for storage andtransportation
4.1 Shielding cask
Since the surface dose rate of the storage container,
including the mercury target vessel used in the design
beam operation conditions is very high, it was put into ashielding cask with a maximum thickness of 235 mm in
the MLF with the purpose to secure a surface dose rateof less than 2 mSv/h at contact and stored in the RAM
building for a prolonged period of time, still in its shielding cask. The size and weight of the shielding cask are ca.
2.2 m × 2.4 m ×3.3 m and 47 ton, respectively.
4.2 Shipping cask
Specialized type II shipping cask that can withstanda fall from a height of 1.6 m was used repeatedly totransport the shielding cask, including the used mercury
target vessel. The size and weight of the shipping cask
are ca. 3.2 m × 3.4 m × 4.0 m and 29 ton, respectively.

Storageroom
in MLF（B1F）
Storageroom
in MLF（B1F）

Rack stand
Rack stand

PBW
PBW
Handling Moderator
Moderator
HandlingReflector
area
Reflector
area Transfer
pipesTransfer pipes
Muon target
Muon target
Pressure sensors
Pressure sensors
ValvesValvesExhaust filter
Exhaust filter

Area for target vessels
Area for target vessels
8m

2. Mercury target vessel #3
The used mercury target #3 with a size of ca.
1.2 m × 1.2 m × 2.4 m was put in a storage container
with a size of ca. 1.8 m × 1.8 m × 2.9 m. The total weightwas ca. 5 ton. The beam operating condition during theuse of the mercury target vessel #3 and its state after use
are shown in Table 1.

3. Storage space of used radioactive components
MLF has a storage room connected to the hot cellwith a space of ca. 18 m × 8 m as shown in Fig. 1. 5 usedmercury target vessels and 3 used proton beam windows covered with storage container have been stored
there. The RAM building has three large storage pits
with a space of ca. 10 m × 7 m and two small storagepits with a space of ca. 5 m × 7 m as shown in Fig. 2.

18 m
18 m

Figure 1. Storage room in MLF.
RAM
RAM
Building
Building

Storage pits
Storage pits

Figure 2. Storage pits in RAM building.

688m

1. Introduction
Mercury target vessels for the pulsed spallation neutron source suffer cavitation and irradiation damages,
which depend on the beam power and operating time.
To assess the current situation of the cavitation damage, as a preventive maintenance, the usage period of
the mercury target vessel has been set at one year andafter that, it is replaced. The used mercury target vessel covered with an airtight storage container without
shielding functions and other used radio-active components are temporarily stored in the storage room in the
MLF (B1F). Due to the limited storage capacity of thestorage room, the transportation of the used mercury
target vessel to the RAM (Radio Active Material) building in the J-PARC site began in 2019 and has been conducted during the summer shutdown period every year.
The transportation of the used mercury target vessel #3
was conducted from the end of June 2022, and this was
the fifth transport work.

MLF Annual Report 2022

4.3 Trailer
A trailer was used to transport the vessel from the
MLF to the RAM building. There are very few trailers that
can accommodate the width (ca. 3.4 m) of the shippingcask, the total weight (ca. 81 ton) and the height of thebuilding entrance (ca. 4.7 m) in MLF, so the lowboy trailer with a maximum capacity of 100 ton was selected.
5. Transportation from the MLF to the RAM building
The procedure for transporting the used mercury
target vessel from the MLF to the RAM building is shownin Fig. 3. The used mercury target vessel covered withthe storage container was moved from the storage room
to the hot cell (1F) and placed in the shielding cask witha maximum thickness of 235 mm by remote handling.
The shielding cask, including the used mercury target
vessel, was moved to the large components handlingroom (3F), and then the airtightness, surface dose rateand surface contamination were inspected. The maximum surface dose rate of the shielding cask, including

Mercury target vessel #3

Neutron Source

the used mercury target vessel #3, was 87 μSv/h. The
shielding cask was moved to the components gateway (1F) and placed in the shipping cask on the trailer.
The airtightness, surface dose rate and surface contamination of the shipping cask were inspected. The
measurement results are shown in Table 2. Under traffic restrictions, the shipping cask, including the usedmercury target vessel #3, was transported by the trailer
within ca. 10 minutes to the RAM building which is ca.
300 m away from the MLF. The shielding cask, including the used mercury target vessel #3, was taken out
from the shipping cask and then stored in the large storage pit in the RAM building. The transportation work,
including the preparation, took 10 working days. After
this transportation work, 5 used mercury target vessels
were stored in the large storage pit and other radioactive components were stored in small storage pits. The
shielding casks were removed from the large storage
pit and visual and airtight inspections were conducted
every year.

Storage container

Shielding cask

Storage pit in RAM building

Shipping cask

Transportation

Figure 3. Transportation of used mercury target vessel from MLF to RAM building.
Table 2. Measurement results of dose rate and surface contamination density.
Regulation
Surface dose rate

< 2 mSv/h

Dose rate at 1 m< 100 μSv/h

Dose rate at driver’s seat< 20 μSv/hResults
7.5 μSv/h (Shipping cask)
0.5 μSv/h (Trailer)
2.5 μSv/h (Shipping cask)
0.3 μSv/h (Trailer)
0.2 μSv/h (B.G.)
2

Surface contamination density

β(γ) < 0.4 Bq/cm
2
H-3 < 4 Bq/cm

2β(γ) < 0.4 Bq/cm
2
H-3 < 4 Bq/cm

T. Wakui, A. Futakawa, T. Naoe, H. Kogawa, H. Kinoshita, M. Harada, T. Ito, M. Sekijima, and K. Haga
Neutron Source Section, Materials and Life Science Division, J-PARC Center69

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MLF Annual Report 2022

Preparation of the Proton Beam Window in 2022
1. Introduction
The proton beam window (PBW) is a boundary of
the proton beam line and the neutron target in the
Materials and Life Science Experimental Facility (MLF)(Fig. 1). The proton beam line is evacuated to a pressureof around 10–5 Pa. The neutron target is inserted into thehelium vessel, which is filled with helium gas with ambient pressure. The PBW is irradiated with a 3 GeV protonbeam, with current of 333 μA at maximum. Because of
the radiation damage of the PBW material, the lifetimeof the PBW is estimated to be 10 GWh and we replace
the PBW every 3 years [1]. In 2020, PBW No.3 was replaced with PBW No.4, and the used PBW No.3 wasstored in the drying room in the MLF to cool down theradioactive materials. Because the PBW was irradiatedby a 3 GeV proton beam, it is highly radioactive. Even
after 2 years cooling time, the PBW itself has high radioactivity. During this summer maintenance period, we
replaced the used PBW mounted on the shielding plugwith the new one using remote handling work.

Figure 1. Bird’s-eye view of the proton beam window.

2. Proton beam window (PBW)
Figure 2 shows the structure of the PBW. The PBW
is made with two layers of aluminum plate (thickness
2.5 mm) and is cooled by water. The water channel is
3.0 mm thick, and the water velocity is 1.2 m/s at thebeam window. The proton beam passes this aluminumwall. A pillow seal is used for the proton beam duct andremotely set and released for maintenance. The PBW’s
height is 4 m, including a shielding plug, and its weightis 10 tons. The PBW itself is replaced with a new one but
the shielding plug is reused for the next PBW. Because
the used PBW is highly radioactive, we have to do remote handling work to replace the PBW with a new one
in the hot cell.
3. Handling of the PBW in the hot cell
The PBW handling work was done from July 25 toAugust 5, 2022. At first, the water pipes of the PBW weredried up in the drying room. Pipes above the shielding
plug were cut by handy saw to improve the workability of
the remote handling (Fig. 3). Then, the PBW was moved
to the hot cell by shielding cask. The shielding cask has a
30 cm thick iron shield and remote handling gripper for the
PBW shielding plug and reflector plug (Fig. 4).
The PBW was held by the remote handling device andits bolts were removed by a power manipulator. Then, thePBW was detached from the plug and passed to the cutting device for size reduction for storage.
The photo on the left side of Fig. 5 shows the PBW on
the cutting device and the one on the right shows the process of cutting the pipes. The window itself was placedin a storage box and the pipes were cut by the cutting
device (left of Fig. 5). Then, the PBW was stored in a storage room under the hot cell. The pipes, cut into threepieces, were put into another container (right of Fig. 5).
After the cutting process was completed, the new

Figure 2. Structure of the proton beam window.

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MLF Annual Report 2022

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Figure 3.	Pipe cutting above the shielding plug (Left: before cutting.
Right: after cutting.)

Figure 4. Shielding cask (left) and gripper of the cask (right).

Figure 5. PBW on the cutting device (left). Cutting of the pipe (right).

71

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MLF Annual Report 2022

Figure 6.	Results of the dose rate and surface contamination
measurement of the PBW. The left figure shows theneutron target side and the right figure shows the accelerator side.

PBW was installed to the shielding plug by remote handling; then, it was stored in the drying room until the next
replacement work.
4. Dose rate measurement of the PBW
Before removing the PBW from the shielding plug,
the dose rate and surface contamination were measured. Figure 6 shows the dose distribution and surface
contamination of the PBW and the shielding plug. The
dose rate at the center of the window was the highest,
it measured 1.26 Sv/h at 10 cm from the surface. The
surface contamination of the PBW of the neutron target
side was the highest and it was larger than 770 Bq/cm2.
PBW No.3 was used from October 2017 to June
2020 and its accumulated beam power was 5.63 GWh.
The dose measurement was conducted in August 2020.

5. Summary
The used PBW #3 was removed from the shielding
plug and the new PBW #5 was installed, completing the
preparations for the next PBW replacement in 2023.
6. Future plans
The lifetime of the PBW was estimated referring to
the result of the post irradiation experiment (PIE) test of
the PBW in PSI [2, 3]. Now we are preparing for the PIE
test in the MLF.
References[1] S. Meigo et al., J. Nucl. Mat. 450 141–146 (2014).
[2] Y. Dai, Y. Foucher, M.R. James, B.M. Oliver, J. Nucl.
Mater. 318 (2003) 167.
[3] Y. Dai, D. Hamaguchi, J. Nucl. Mater. 343 (2005) 184.

M. Ooi
Neutron Source Section, Materials and Life Science Division, J-PARC Center72

Neutron ScienceNeutron Science

MLF Annual Report 2022

Neutron Science Section
1. Introduction
Even though we still suffer the consequences of the
COVID-19 pandemic in Japan, the MLF has already been
opened to foreign users in addition to Japanese users.
The strict safety measures against the spread of newstrains of the CORONA virus have already been lifted,
although some restrictions for immigration still remain.
The user operation in the Materials and Life Science
Experimental Facility (MLF) was also back to normal. The
operation of the accelerator was quite stable, achieving
830 kW of operational power and over 95% operating
rate, which have been the best performances ever inthe MLF. Also, the numbers of MLF users are obviously
recovering after COVID-19 as shown in Fig. 1.
2. User program
303 and 291 in general proposals (involving oneyear proposals and new-user proposals) were submitted

for the operation periods of 2022A and 2022B, respectively. The number of applied proposals has remained
almost stable in recent years, and 266 of them werecarried out in 2022. In addition, out of five long-term
proposals, four have been approved. The trend of thetotal number of proposals is shown in Fig. 2. The number
seems to be again similar to the number before COVID,
in the range between 300 to 400 in each proposal round.
The proposal competition rate is also quite constant.
3. Instruments up to date
Initially, 23 beamlines (BL) for neutron experiments were designed for future instruments in the MLF
and 21 of them are under operation at the moment.
Experiments performed in the MLF require variety ofso-called sample environments (SE), which can tune
physical conditions on sample, such as temperature,magnetic field, pressure, ambient gas, electrical field,

Figure 1.	The number of unique users* in J-PARC MLF (*Number of issued personal dosimeters).

Figure 2.	The breakdown for PI’s affiliation of approved short term
proposals in JFY2022.

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MLF Annual Report 2022

and so on. The SE devices are the key to the success not
only of the experiments themselves but also activating
the facility. The versatile SE devices can attract many users from all over the world. All BL in the MLF keep making effort to install and develop new or characteristic SE
devices for advanced experiments.
The newly designed Paris-Edinburgh high-pressure
apparatus has been developed for investigating properties of quantum harmonic oscillators under pressureof hydrogen material. Hydrogen vibration excitationsof fluorite-type ZrH1.8 and TiH1.84 were investigated atpressures up to 21 GPa by incoherent inelastic neutron
scattering experiments. From the pressure dependenceof lattice parameters determined by diffraction experiments, the relations between metal-hydrogen distanceand the first excitation energy E1 of ZrH1.8 and TiH1.84 at
high-pressures were found [1]. The developed highpressure system for this experiment is depicted in Fig. 3.
Most of the neutron experiments are facing thebackground (BG) issues, in particular the BG from thesample container/cavity, which sometimes causes

Neutron Science

seriously distorted interpretation of the obtained data.
A team of BL02 (DNA) developed a low-backgroundsample container (sample-cell) specifically for aqueous protein solution samples, to be used with a neutron back-scattering spectrometer (Fig. 4). It was foundthat the scattering intensity of an aluminum samplecell coated with boehmite using D2O was lower thanthat of a sample cell coated with regular water (H2O).
Meticulous attention to cells with small individual
weight differences and the positional reproducibilityof the sample cell relative to the spectrometer neutron
beam position enabled the accurate subtraction of thescattering profiles of the D2O buffer and the sample container. Consequently, high-quality information on protein dynamics could be extracted from diluted protein
solutions [2].
4. Other activities
The 11th International Workshop on Sample
Environment at Scattering Facilities (ISSE-WS) was
held in Nasu, Japan from August 28 to September 1.
This workshop series takes place every 2 years under
the patronage of the International Society for Sample
Environment (ISSE). Engineers, technicians and scientists
working on sample environment at the neutron/synchrotron facilities in the world and industrial partners
participate in this workshop to present various topics
related to sample environment and to discuss new techniques, collaboration among facilities and so on. There
were 87 participants, including five online participants,
gathered in Japan from 11 countries [3]. Also, some ofthe other activities were as follows: The Commissioning
Workshop of ESS & J-PARC collaboration (October 10,2022); The 6th Neutron Muon School (December 12 to

Annular shapeliquid sample

Figure 3. The Paris-Edinburgh cell for inelastic scattering experiments at high pressure installed at (top) BL01
and (bottom) BL21 [1].

Figure 4. C ross section of a cylindrical aluminum container
commonly used for neutron quasi-elastic scattering [2].

75Neutron Science

MLF Annual Report 2022

16, 2022); Quantum Beam Science Festa 2022 in Tsukuba(March 13 to 15, 2023).
5. Scientific achievements
Important scientific outcomes are frequently produced from the MLF neutron activities. In 2022, thenumber of published papers was 208, also, 11 press releases were done. One of the achievements was introduced in the article “Development of Metal Exhibiting
Gigantic Elastic Strain Exceeding 4.3% ~ Expectations
for Application to High Performance Spring Materials
by Realization of Large Elastic Deformation ~” [4].
The compatibility of low Young’s modulus and highstrength has been a challenge for artificial bones, dental materials, springs, other mechanical element parts,
etc. Bulk single crystals in a copper-aluminum-manganese alloy system with large crystal elastic anisotropy
were successfully synthesized. Structural analysis by insitu neutron diffraction during tensile tests at the MLF
TAKUMI revealed that the crystal lattice expands andcontracts while maintaining its structure. The alloy has

unparalleled properties in terms of elastic strain andYoung’s modulus compared to conventional materials, and is expected to be applied to high-performancesprings, connectors, sealing materials, precision machinery, medical equipment, etc.
6. Award
MLF won two awards this year. The JSNS (JapaneseSociety for Neutron Science) Encouragement Award:
Dr. Wu Gong for “Studies on Microstructure Evolution andMechanical Properties in Structural Metallic Materials byin-situ Neutron Diffraction”, and the JSNS Poster Award:
Dr. Wenqi Mao for “Effect of Grain Refinement on
Deformation-induced Martensitic Transformation”.
References[1] T. Hattori et al., Phys. Rev. B, 106 134309 (2022).
[2] T. Tominaga et al., Life, 12 675 (2022).
[3] S. Ohira-Kawamura, Neutron News, 34 2 (2023).
[4] S. Xu et al., Nature Communications, 13 5307 (2022).

M. Nakamura1, T. Yokoo1,2, and A. Sano-Furukawa1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK

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MLF Annual Report 2022

Neutron Science

BL01: 4D-Space Access Neutron Spectrometer 4SEASONS
1. Introduction and use trends
4SEASONS is a direct-geometry time-of-flight neutron spectrometer for thermal neutrons, and one of the
Public Beamlines in the MLF [1]. In 2022, 16 General Use(short-term) proposals, 1 Long-Term proposal, 1 FastTrack proposal, and 1 Instrument Group Use proposal
were approved for 4SEASONS. 10 reserved proposals
were given beamtime to compensate for the vacancy.
Conversely, one General Use proposal was postponed
to 2023 because of an instrument trouble. 72% of theGeneral Use proposals were submitted by international
users. 61% of the submitted proposals were in the fieldof magnetism, while the rest of them targeted phonons
and other atomic vibrations. 14 peer-reviewed papers
were published.
2. Instrument upgrade
Detectors: 4SEASONS utilizes 2.5-m-long position
sensitive 3He detectors (PSDs) to cover a wide solid angle. However, this kind of detector tends to cause pileup when it detects strong neutron counts [2], which
results in spurious signals in the processed data. To mitigate the problem, we are introducing the pulse-widthand-height (PWH) limitation function of a new detector
electronic module (new NEUNET [3]). Following thepreliminary work in 2021, we performed a test measurement in 2022 to evaluate the effectiveness of thefunction for eliminating the spurious signals. We applied
one new NEUNET board to 8 PSD tubes, and observed
two strong Bragg peaks of a single crystal of SrTiO 3
and spurious streak signal caused by them [Fig. 1(a)].
Figure 1(b) shows position dependence of the intensity along the tube in which the strong spurious signal
was observed. There is a broad spurious signal over
the tube in addition to the strong Bragg peaks at bothends. By applying the PWH limitation, the spurious signal was reduced by a factor of five. Although this reduction is outstanding, finite spurious signal still remained[Fig. 1(b)-B]. Then, we further applied rejection of highcount-rate signals. By rejecting the signals over 80 kcps,
the spurious signal was reduced to the background level[Fig. 1(b)-C]. This work was published in Ref. [4]. We areconsidering applying the new NEUNET boards and thefunction to all the PSDs.
Disk chopper: 4SEASONS had been utilizing two disk
choppers rotating at 25 Hz at maximum to define thewavelength band of the incident beam. In 2022, the disk
chopper placed on the downstream side was replacedwith a new one [Fig. 2(a)]. The new disk chopper was developed by the Technology Development Section of the
MLF and has a maximum rotation speed of 50 Hz. The
high rotation speed is expected to cut the unnecessary
neutron wavelength band more sharply without interfering with the usable band. We measured the transmission of the new disk chopper with a vanadium standard
and white beam with several phase delays. Figure 2(b)compares the observed and calculated transmission
curves for one of the phase delays. Both curves show
good agreement proving the chopper was manufactured as designed.
Sample environment: 4SEASONS had recently prepared several new sample environment devices. One is a
new sample stick for the top-loading GM refrigerator; it
can heat a sample up to 500 K. Another one is a bottomloading GM refrigerator, which can cool a sample down
to 4 K, and is expected to provide lower backgroundenvironment compared with the top-loading refrigerator. In 2022 we performed test operations of thesedevices, and confirmed the designed performances. We
also introduced a remote-control system for the bottom

Figure 1.	(a) Bragg peaks (white arrows) and spurious streak (orange arrow) detected on the PSDs. The incident energy (Ei) was
26.3 meV. (b) Position dependence of the intensity of the Bragg peaks and the spurious signal [4].

77Neutron Science

MLF Annual Report 2022

loader, which can monitor and control the compressor of the refrigerator remotely through the software
IROHA2 [5]. In addition, we purchased a new cryofurnace, which is designed to heat the sample up to 750
K. The cryofurnace will be open to users next year aftercommissioning work is completed.
Vacuum system: The vacuum system to evacuate orvent the scattering chamber of 4SEASONS consists ofa roughing pump, a turbo-molecular pump, and a cryopump. It was significantly upgraded in 2022. First, theroughing pump was replaced with a pair of new roughing pumps, which provide higher pumping power near
the atmospheric pressure compared with the previous
pump [Fig. 3(a)]. Second, a set of air dryers was incorporated into the system [Fig. 3(b)]. This set of air dryer
introduces dry air into the chamber during venting tominimize moisture absorption by the chamber walls.
Lastly, the controller of the vacuum system was renewed
to operate the pumps and relevant valves automatically.
These upgrades enable a faster and safer operation of
the system.

Acknowledgements
We thank R. Komine, H. Hasemi, H. Tanaka, K. Inoue,and W. Kambara for their support and advice. The onbeam test of NEUNET was performed with the help of
S. Sato. The instrumentation works described here 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] D. Raspino et al., 2015 IEEE Nuclear Science
Symposium and Medical Imaging Conference, doi:
10.1109/NSSMIC.2015.7581915.
[3] S. Sato et al., EPJ Web of Conferences 231, 05004(2020).
[4] S. Sato et al., J. Neutron Res. 24, 427 (2022).
[5] T. Nakatani et al., JPS Conf. Proc. 8, 036013 (2015).

Figure 2.	(a) Renewed disk chopper. (b) Transmission curve of the disk chopper operated at 50 Hz as a functionof time. The phase delay is −18000 μs. Symbols and lines denote the observed and calculated curves,
respectively.

Figure 3. (a) New roughing pumps (Kashiyama NeoDry300E). (b) The set of air-dryers (Orion Q700B-EDCT and RAX55F).
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 2022

Neutron Science

Current Status of BL02 DNA in 2022
1. Introduction
DNA is a TOF type Si crystal analyzer backscattering
spectrometer installed at the neutron spallation sourceof the Japan Proton Accelerator Research Complex(J-PARC) [1, 2]. DNA uses a pulse-shaping chopper toextract pulsed neutrons with sharp time-structure fromstrong but broad ones of the coupled moderator, which
achieves μeV-order energy resolution in wide energy
transfers of the meV-order. Furthermore, the signalto-noise ratio at DNA achieves ~105, which makes it
possible to cover a variety of research fields with small
scattering amplitudes or with small quantities of samples (of the order of milligrams).
The number of peer-reviewed papers from DNA in
2022 was 14, including 1 proceedings paper, and it hascontinued to increase since 2017. Five press releases ofhigh-impact results were issued in 2022. In addition,
Mr. Yuki Hirota, who is third-year doctoral student at
Setsunan University, stayed as a “JAEA Fellow of advanced science” for three months to conduct researchon the dynamics of water within chitin and chitosan
for the application of polysaccharides to fuel cell membranes. The outcomes were compiled in two original
papers [3, 4], and he successfully completed his degreein September 2023.

mirrors in 2021. It was confirmed that the neutron flux
measured by gold foil irradiation doubled compared tothe amount before the replacement. The I (λ) at the sample position also doubled in all energy regions up to 20
meV. Additionally, the beam became more focused after
the replacement, as shown in the lower pictures of Fig. 1.
Together with the replacement of the focusing mirror,
the steel guide jackets of the focusing mirror were also
replaced with new nonmagnetic ones. This replacement enabled us to use safely the magnet developed
for BL02 without the interference from the magnetic
steel materials.
Although DNA has already achieved a very high signal-to-noise ratio of ~105, the split elastic line from thesample environmental instruments interferes with the
QENS signal. In 2021, we introduced an oscillating radialcollimator that successfully reduced the backgroundfrom the sample environment equipment. In particular,
the background for the Si311 analyzer, which contains
the Bragg reflection of Al, was greatly reduced, as shownin Fig. 2 for the Vanadium standard sample before andafter introducing the oscillating radial collimator. Now,
the Si311 analyzer data have become clean and readyfor practical use.
In recent years, we have continued to work on theautomation of our equipment. We used to operate

2. User Program in the periods 2021B and 2022A
In 2022, 26 (2021B) and 17 (2022A) General
Proposals (GP) were submitted to BL02. 7 GPs, including
2 New User Promotion (NUP), and 11 GPs including 2
NUP’s were approved for 2021B and 2022A, respectively.
The ratio of the approved beamtimes to total proposed
beamtimes was 18% for 2021B and 63% for 2022A.
The competition rate was high: 3.7 and 1.5 for 2021B
and 2022A, respectively. Additionally, 3 and 1 reserved
proposals were also conducted in 2021B and 2022A,
respectively.
After the recovery from the pandemic situation,
almost all experiments were conducted with the users present. In addition, 2 General Proposals (LongTerm Program) (hereafter LTP) ran at BL02 in 2021B and
2022A.
3. Beamline activities
In DNA, a focusing mirror is placed just before thesample to increase the neutron flux. The focusing mirror installed at the time of construction had low neutron reflectivity, so we replaced it with highly reflective

Figure 1.	(Upper) I(λ) measured at sample position before(April 2022) and after (January 2023) the replacement of the focusing mirror. (Lower) Beam intensity
distribution before and after the replacement.

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MLF Annual Report 2022

Figure 2.	Intensity map of Vanadium standard in Q(horizontal)E(vertical) map obtained with Si311 analyzer before and after introducing the oscillating radialcollimator.

manually the high voltage power supply for the 3He inelastic detectors and had to wait until the prescribedvacuum level has been reached after replacing the sample environment equipment. To resolve this situation,
we replaced the high voltage power supply with a new
system, which can be remotely controlled. The commissioning for the automatic operation has been proceeding this year.
As for the software development, we are developing a kernel density estimation (KDE) method. In 2021,
we estimated the error bars for the fitting parameter using actual QENS data and found that the KDE method
improved the fitting error, especially for data with low
statistics.
In parallel with the development of new equipment
and software, we are also working on the problems ofaging. Followed by the replacement of two banks withdamaged Si111 analyzer mirrors in 2021, two more of
the Si111 analyzer mirrors at scattering angles (2θ) of
7.5° < 2θ < 16.5° and 43.5° < 2θ < 52.5° were successfully
replaced in 2022, which improved the homogeneity of
the QENS signal.
Unfortunately, breakage of the timing cable ofthe inelastic detector located in the vacuum chamber
was discovered at the end of the long maintenanceperiod, which excluded DNA from the user program in
December. After the replacement of the cable with a
new one during the year-end shutdown, the DNA dataacquisition system safely restarted. User beamtimes cancelled due to the trouble at the timing cable were all
reallocated in the supplemental MLF operation for overone month that the government decided for compensation against the rapid raise of electricity rate. During
the replacement of the cable, we found that some ofthe other cables have hardened and may break in near
future. We plan to replace all these cables in the vacuum
chamber in the summer long shutdown of 2023. Since
the hardening of the cable sheath materials occurred
10 years after the construction was completed, we decided to renew all the cables in the vacuum chamber
every 10 years.
4. Other activities
The ‘Basis for supporting innovative drug discovery
and life science research (BINDS)’ is a national project
aimed at accelerating Japanese life science by providing a range of technologies to life and pharmacy scientists. Neutron probe is regarded as one of the promisingtechnologies since 2022 (Phase 2 of BINDS) and BL02
at the MLF supports utilization by the BINDS programfor innovative studies on protein dynamics within our
instrument group beamtime. We aim at contributing
to outstanding life science research through successful
measurements of dilute protein solution samples.
5. Future plans
We will proceed further with the replacement of thedamaged Si111 analyzer mirrors. At the same time, weplan to make a new N2 monitor and 3He detectors, which
will be safe from the aging caused by the strong pulsed
neutrons of the MLF.
References[1] Kaoru SHIBATA et. al., JPS Conference Proceedings,
8 (2015), 036022.
[2] Y. Kawakita et al., EPJ Web of Conferences 272 (2022)
02002.
[3] Y. Hirota et al., Bioengineering 9 (2022) 599.
[4] Y. Hirota et al., Bioengineering 10 (2023) 62.

M. Matsuura1, Y. Kawakita2, T. Yamada1, T. Tominaga1, H. Tamatsukuri2, H. Nakagawa2,3, and K. Tatsumi4
Neutron Science and Technology Center,CROSS, 2Neutron Science Section, Materials and Life Science Division, J-PARC Center 3Materials
Sciences Research Center, JAEA, 4Technology Development Section, Materials and Life Science Division, J-PARC Center

1

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Neutron Science

IBARAKI Biological Crystal Diffractometer iBIX
1. Introduction
The complementary use of both neutron diffraction
data and X-ray diffraction data is one of the powerful
methods to obtain the structure information of all atoms in the protein samples because neutron diffraction
data include more information about hydrogen (deuterium) atoms, and X-ray diffraction data include more
information about non-hydrogen atoms. Understanding
the enzyme chemistry of proteins at the atomic level requires the visualization of hydrogen atoms at active sites
and remote residues, co-factors, substrates, and water molecules. IBARAKI biological crystal diffractometer, iBIX is a
TOF neutron single crystal diffractometer to elucidate thehydrogen, protonation, and hydration structure of mainly
biological macro-molecules [1, 2]. In 2019, the iBIX diffractometer, equipped with 34 detectors, was available for user
experiments on mainly biological macromolecules, organic
compounds, and polymer samples. The specifications of
iBIX are shown in Table 1.

the iBIX at the accelerator power of 700 kW. The maximum
unit cell size was 135 × 135 × 135 Å3. The typical crystal
volume of the sample measured by the iBIX was around
1.0 mm3. In 2022, neutron protein structure analysis with
iBIX is supported by BINDS (Basis for supporting innovation drug discovery and life science research). Using theiBIX, the following tests were performed: 1 test measurement for industrial use proposal (applied from BINDS),
2 test measurements for a J-PARC proposal, 6 test measurements for a proposal of an innovative research project of
the Ibaraki Neutron Beamline and 6 test measurements
for a proposal of a leading research project of the Ibaraki
Neutron Beamline. Subsequently, 9 proposals weremoved on to the full data collection for neutron structure analysis.
3. Maintenance and development
It has been over 10 years since the iBIX instrument
was installed on the beamline, so some of the beamline
instruments have been already replaced in the last few
years due to age deterioration. One of the remaining
instruments due for replacement is the disk-chopper.
The cumulative time of servomotor rotation has exceeded the service life. We replaced the servomotor
and the servo amplifier of the disk chopper (Fig. 1).

2. Current status
In 2022, J-PARC was operated regularly at an accelerator power of 800 kW. We were able to collect a full data setof biological macromolecules for neutron structure analysis
with around 2.0 Å resolution in less than one week by using

Table1. Specifications of iBIX.
Moderator
Range of wavelength ofincident neutron (Å)
Neutron intensity
2(n/s/cm ) (@1 MW)
L1 (m)
L2 (mm)Solid angle of detectors(% for 4π str)
Detector covered region(deg.)
Detector size2
(mm )Detectors pixel size
2(mm )No. of detectors
Sample environment

Coupledst
0.7 ~ 4.0 (1 frame)nd
4.0 ~ 8.0 (2 frame)8

0.7 × 10
40
491
22.0

15.5 ~168.5
133 × 133
0.52 × 0.52
34
Gas flow type cooling system
by N2 gas (~100 K)
Heating system for polymer
sample (~600 K)
Tensile loading system forpolymer sample (~200 N,~90 mm, 1~1000 mm/sec)81

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MLF Annual Report 2022

Figure 1. Neutron disk-chopper for iBIX.

The disk-chopper system is already available for user
experiments.
The measurement software of iBIX is renewed basedon the standard instrument control software frameworkof the MLF (IROHA2). We can carry out the operation andmonitor the devices (detector, goniometer, and chopper) under the remote access environment. We are able
to use all its functions under a multi-platform environment (Windows, Mac, Linux etc.) via a web browser (e.g.
at AQBRC with J-LAN network).
4. Future plans
In the near future, the accelerator power of J-PARC
will increase to about 1 MW. iBIX should be available
regularly for full data-set measurement of samples
with a volume of less than 1 mm3. However, the sample size is still large, and the measurement time is still
long, especially for the users. We would like to reducethe difficulties of preparation of a large crystal as muchas possible. In other words, it is necessary to further improve the measurement efficiency of iBIX by developing
the beamline instrument. Currently, we are considering

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

82

the possibilities for improvement of the measurement
efficiency. Furthermore, to automatize the measurement process, firstly we will develop a new goniometerwith an automatic sample centering system and control
software. As the next step, we will develop a simple automatic sample changer. And then, we will realize thetest measurement under the remote access environment (without entering and leaving the experimental
hatch).
To promote the industrial use of iBIX, we will enhance the support system and exploration of materials
field research. That will include, for example, development of a new sample environment and a new measurement method and so on.
References[1] I. Tanaka, K. Kusaka, T. Hosoya, N. Niimura, T. Ohhara,
K. Kurihara, T. Yamada, Y. Ohni-shi, 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).

MLF Annual Report 2022

Neutron Science

Resonance Parameter Analysis in Double-bunch mode
at MLF (BL04 ANNRI)
1. Introduction
Neutron cross sections, particularly in the epithermal neutron energy range, can be reproduced byresonance formalisms with parameters. The resonanceparameters can be determined by the cross-section
measurements and the resonance shape fitting. The
evaluated resonance parameters are listed in nuclear
data libraries: JENDL [1], ENDF/B [2], and JEFF [3], which
are used for studies of nuclear technology, radiation,and physics. The Accurate Neutron-Nucleus Reaction
measurement Instrument (ANNRI) in the Material andLife science experimental Facility (MLF) was constructed to measure the neutron cross sections [4, 5]. In the
MLF, proton beam incident is injected into the spallation target of the MLF in a double-bunch mode to increase neutron beam intensity. In this mode, one pulsed
proton beam consists of two groups of protons 600 ns
apart from each other. This double-bunch mode turns
one resonance into two peaks at a high neutron energy
region, especially more than several tens eV. This is why
it is necessary to take into account the double-bunch
structure in the shape fitting to derive the correct resonance parameters. In this study, we incorporated the effect of double-bunch structure into a resonance analysis
code, REFIT [6], and adapted it to determine the resonance parameters.
2. Implementation of the double-bunch effectFigure 1 shows the time distribution of the proton
current measured by the current transfer monitor in

Intensity (arb. units)

0.012

Proton distribution
Approximation by Gaussian

0.01
0.008
0.006

Graph

0.004
0.002
0
0

200

400

600

Time (ns)

800

1000

Figure 1.	Time distribution of proton current measured by
the current transfer monitor in the MLF and two
gaussian distributions.

the MLF [7]. The width of the proton beam is approximately 100 ns, and the shape (red) is slightly distorted
compared to the Gaussian distribution. The black line
represents two Gaussian distributions with FWHM of
100 ns for reference.
In addition to the time distribution of the protonbeam, there is a resolution function, ( , ), whichcomes from the time distribution of neutrons caused by
the deceleration of the neutron velocity in a moderator. The resolution function in ANNRI was reported byKino et al. [8]. The double-bunch effect was taken into
account by convolving the time distribution of protons,ℎ( ), with this resolution function as follows:
′(

, )=

(

, )ℎ(

)

where ( , ) is the modified resolution function which
denotes the time distribution of neutrons on the moderator surface.
3. Resonance analysis and results
The neutron capture and total cross sections of 181Ta
were measured in ANNRI. The details of the experimentand analysis are described in Ref [9]. Here, we just report on the effects of proton distributions on resonanceanalysis using these data.
The resonance parameters were obtained by fitting the experimental data with resonance formula using REFIT. For comparison, the fittings were performed
using the proton distributions of single- and doublebunches in Figs. 2 and 3. The proton distribution of
the single-bunch was assumed to be a single Gaussian
distribution with FWHM of 100 ns. Table 1 lists the obtained resonance parameters, together with the valuesof JENDL-4.0 [10].
In the low energy region (Fig. 2), the effect of the
double-bunch is small, and it appears that the fitting
results for two proton distributions do not show significant differences. However, the gamma widths in the
single-bunch tend to be a little larger than those of the
double-bunch because the resonance broadening due
to the double-bunch affects the resonance parameters.
On the other hand, in the high energy region (Fig. 3),
the figure indicates that the fitting is no longer possible
with the distribution of single-bunch. The experimental
data, especially the capture cross section, clearly showsthat the double-bunch makes one resonance two peaks.
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MLF Annual Report 2022

Capture Cross Section (b)

250
200
150
100
50
0

400
350
300
250
200
150
100
50
0

1

1

0.8

0.8

Transmission

Transmission

Capture Cross Section (b)

300

0.6
Experimental result

0.4

Double bunch

0.2
0

18

0.6
0.4

Single bunch

0

19

20

21

Neutron Energy (eV)Experimental result
Double bunch

0.2

22

23

Figure 2.	Fitting results and experimental results in the low
neutron energy region.

100

Single bunch

105

110

115

120

Neutron Energy (eV)

125

130

Figure 3.	Fitting results and experimental results in the highneutron energy region.

Table 1. Obtained resonance parameters.
Resonance Energy (eV)Gamma width (meV)

Neutron width (meV)

Double-bunch
Single-bunch
JENDL-4.0 [10]20.293 ± 0.001
20.298 ± 0.001
20.29

55.5 ± 0.6
61.2 ± 0.7
52.0

1.042 ± 0.003
1.003 ± 0.003
1.097

Double-bunch
Single-bunch
JENDL-4.0 [10]115.03 ± 0.01
115.09 ± 0.01
115.0844.9 ± 1.4
64.6 ± 2.0
57.0

39.9 ± 0.5
29.7 ± 0.4
39.6

Therefore, taking into account the double-bunch structure is essential for deriving resonance parameters.
4. Conclusion
In order to derive the resonance parameters fromthe capture and total cross sections of 181Ta measured
in ANNRI of MLF, the fitting was employed with REFIT in
which the double-bunch structure of the MLF is considered. The comparison is made with the result for whicha single-bunch proton distribution was adopted. From
this research, it was found that the application of a double-bunch structure to the fitting has an essential role toperform resonance analysis of experimental data.

References[1] O. Iwamoto et al., Jour. Nucl. Sci. Technol., 60, 1 (2023).
[2] D. Brown et al., Nucl. Data Sheets, 148, 1 (2018).
[3] A. J. M. Plompen et al., Eur. Phys. Jour. A, 56, 181 (2020).
[4] M. Igashira et al., Nucl. Inst. Meth. A, 600, 332-334(2009).
[5] A. Kimura et al., Jour. Nucl. Sci. Technol., 49, 708-724(2012).
[6] M. C. Moxon et al., NEA-0914/08, Organization for
Economic Co-operation and Development, Nuclear
Energy Agency (2011).
[7] S. Endo et al., Jour. Nucl. Sci. Technol., 59, 318 (2021).
[8] K. Kino et al., Nucl. Instr. Meth. A, 736, 66 (2014).
[9] S. Endo et al., Nucl. Sci. Eng., (2023) published online.
[10] K. Shibata et al., Jour. Nucl. Sci. Technol., 48, 1 (2011).

S. Endo1,2, A. Kimura1,2, S. Nakamura1,2, G. Rovira1, O. Iwamoto1, and N. Iwamoto1
Nuclear Data Center, Nuclear Science and Engineering Center, JAEA; 2Neutron Science Section, Materials and Life Science Division, J-PARC
Center1

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Status of Fundamental Physics Beamline BL05 (NOP) in 2022
1. Introduction
Neutron Optics and Physics (NOP/ BL05) at the
MLF in J-PARC is a beamline for studies in the field offundamental physics. The beamline is divided at the
upstream into three branches, the so-called Polarized,
Unpolarized, and Low-Divergence branches, used in different experiments in a parallel way [1-2].
A neutron lifetime measurement is conducted at
the Polarized beam branch with a spin flip chopper.
Pulsed ultra-cold neutrons (UCNs) by a Doppler shifter
are available at the Unpolarized beam branch. At the
Low-Divergence beam branch, the search for an unknown intermediate force is performed by measuring
neutron scattering with nano particles. The beamline isused also for R&D of optical elements and detectors.
2. Measurement of the neutron lifetime
The decay of neutrons is closely related to themechanism of the synthesis of elements in the universe
and to particle physics. The neutron lifetime has beenmeasured in two ways: 1) by counting the incident neutrons and the protons from neutron beta decay (beammethod) and 2) by storing UCNs in a container and determining the neutron lifetime according to the disappearing time (storage method). Currently, the lifetime
determined via the former method is 888.0 ± 2.0 s, andthat for the latter is 878.4 ± 0.5 s, with a difference of 9.5 s(4.6 σ) [3]. This discrepancy is called “neutron lifetime
puzzle” and has remained unsolved for nearly 20 years.
The smaller decays compared with the disappearance
suggest that neutrons are lost owing to decay into dark
matter or collisions with dark matter. In general, different methods are needed to validate the experimental

results, as utilizing the same experimental methods
may lead to the same mistakes. Using the polarization
beam branch at NOP/BL05, an experiment was conducted via a different method, in which instead of protons, electrons were measured from the neutron beta
decays. The first lifetime result was published in 2020 as+15898 ± 10(stat.) −18 (syst.)s, which is consistent with boththe beam and bottle methods [4]. A spin-flip chopper(SFC), which shapes the neutron beam into bunches,
was replaced with a larger one in 2020, and the intensity was increased by 3 times [5]. Commissioning began
in 2021, and physics run for the neutron lifetime began
after the SFC was tuned. So far, a statistical uncertainty
achieved at 1.5 s, and another 100 days of beamtime
brings it to 1 s. The largest source of systematic uncertainty is undefined background. Research is underway
to resolve this background event.
3. Measurement of diffuse scattering of ultracold
neutrons
UCNs are transported through guide tubes like a dilute gas, with losses due to absorption and inelastic scattering by the nuclei in the tube walls. Diffuse reflections
at the guide surfaces increase the losses because they
make the UCN residence times longer. Therefore, for acorrect estimation of the UCN transport, it is necessary
to accurately estimate the effect of diffuse reflection. For
this purpose, a setup for diffuse scattering of UCN wasconstructed with the Doppler shifter-type pulsed UCN
source of BL05 (Fig. 1) [6].
When diffuse scattering occurs in the guide tube,
the spectrum of time-of-flight (TOF) distribution changes due to the large orbit dispersion. In this experiment,

Figure 1. Schematic diagram of the experimental setup.

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MLF Annual Report 2022

Figure 2.	Comparison between the velocity distribution of pulsed UCNs injected and transported at an angle of 30° and atransport simulation calculated with different reflection models (Left) Lambert only (Right) Lambert and mf-BRDF.

a pulsed UCN source was injected into a cylindricalguide tube (1000-mm-long, 95.50-mm-diameter, madeof aluminum with electroless nickel-phosphorus plated
surface) inclined at 0°, 10°, 15°, and 30° to the injection
direction, and the transport efficiency and deformationof the TOF peak were observed. The simultaneous use ofLambert’s cosine law and the mf-BRDF model could explain the post-transport velocity distribution better thanLambert’s cosine law alone (Fig. 2) [6]. This setup can beapplied to the measurement of various guide tubes, andwe plan to use these measurements to fabricate better
UCN guide tubes in the future.
4. Multilayer-type neutron interferometerA neutron interferometer is a device that splits the
wavefunction of a single neutron into two paths, superimposes them, and detects the potential difference
between the two paths as a phase difference. It was put
into practical use in the 1970s and it has contributed
significantly to the development of quantum mechanics, e.g., the verification of spinors and the phase shift ofmatter waves due to gravity. Thus far, neutron interferometers have been cut out of silicon ingots, which could
only use mono-energetic neutrons and were limited insize.
A multilayer-type neutron interferometer is expected to be a new device to overcome these limitations and improve the sensitivity by using neutrons
with longer wavelength and/or making the flight pathlonger. Especially with TOF method, the time-dependent systematic uncertainty can be suppressed, since theinterference fringes are observed on the TOF spectrum.

The Jamin-type neutron interferometer using
beam splitting etalons [5, 6], which is a high-precisionassembly of multilayer neutron mirrors on a quartz substrate, was demonstrated at the low-divergence beam
branch at BL05. The beam width is 100 μm while thebeam paths are 300 μm apart, so they are completely
separated. When a certain material is inserted into a
path, the phase changes depending on the refractive
index of the material. This can be applied to measureneutron scattering length of nuclei. Fujiie et al. have successfully demonstrated the measurements of the scattering lengths of some nuclei [11]. We will advance thesophistication of this interferometer and its application
research in the future.
References[1] K. Mishima et al., Nucl. Instruments Methods Phys.
Res. Sect. A, vol. 600, no. 1 (2009)342–345.
[2] K. Mishima, Hamon Neutron Netw. news,vol. 25,
no. 2 (2015) 156–160.
[3] R.L. Workman et al., (Particle Data Group 2022), Prog.
Theor. Exp. Phys. 2022, 083C01 (2022).
[4] K. Hirota et al., Prog. Theor. Exp. Phys. (2020) 123C02.
[5] G. Ichikawa et al., Proceedings of science, PoS(PANIC2021) 457.
[6] S. Imajo et al., Phys. Rev. C 108, 034605 (2023).
[6] N. Naganawa et al., Eur. Phys. J. C 78, 11 (2018) 959.
[7] N. Muto et al., J. Instrum, 17 (2022) P07014.
[8] K. Hirota et al., J. Imaging 7 (2021) 4.
[9] M. Kitaguchi, et al., Phys, Rev. A 67, 033609 (2003).
[10] Y. Seki, et al., J. Phys. Soc. Jpn. 79, 124201 (2010).
[11] T. Fujiie et al., Phys. Rev. Lett. 132, 023402 (2024).

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, KEK

86

MLF Annual Report 2022

Neutron Science

BL06: Commissioning Status of Village of Neutron
Resonance Spin Echo Spectrometers (VIN ROSE)
1. Introduction
Neutron spin echo (NSE) is a variety of inelastic andquasi-elastic neutron scattering techniques realizing
the finest energy resolution in the field of neutron scattering [1]. Because the energy resolution of the energy
transfer measurement is not limited by the energy spectrum of the incoming neutrons in the NSE technique, amoderately (10–15% FWHM) monochromatic neutron
beam can be acceptable. In addition, the intermediate
scattering function can be directly derived by NSE, sothat the method is suitable for investigating slow relaxation dynamics in condensed matter, and high-intensity
and high-energy-resolution NSE spectrometers havebeen developed [2].
Kyoto University and The High Energy Accelerator
Research Organization (KEK) have been working jointly
on the beam line BL06 construction since 2011. BL06
consists of two types of resonance NSE spectrometers,
which are a modulated intensity by zero effort (MIEZE)
instrument and a neutron resonance spin echo (NRSE)
instrument by branching the beam with two curved
supermirror guide tubes [3]. The spectrometers areequipped with neutron resonance spin flippers (RSFs),
which enable us to downsize the instruments, so thatthe two spectrometers have been able to be locatedvery closely [4].
In this report, the status of the MIEZE and NRSE
spectrometers at BL06 in FY2022 is summarized.
2. Commissioning status at BL06 in FY2022
At BL06, the user program has started partiallywith the MIEZE spectrometer since the 2017B proposalround, while the NRSE spectrometer for fine-energy
resolution is still under commissioning.
In FY2022, the achieved scientific highlight of BL06
is the spin dynamics in MnSi1-xGex with the MIEZE spectrometer [5], which is described in section 3 in detail.
To upgrade the detectors at BL06, a flat-panel PMT(FRP) system [6] with a 6Li-glass scintillator was tested. It
is described in section 4.
3. Spin dynamics in MnSi1-xGex
In this study, the spin dynamics in MnSi1-xGex wasinvestigated. Polycrystalline samples were used, and thetemperature was controlled by a 4 K GM cryostat, whichis available as sample environment at BL06. BL12 HRC,

which gives S(Q, ω), was also complementary used, andthe observed quasi-elastic scattering data were compared with the obtained intermediate scattering function S(Q, t) at BL06. Since the Q resolution of the MIEZE
spectrometer is better than that of BL12 and S(Q, t) canbe directly observed from the MIEZE experiments, therelaxation time of the spin dynamics can be clearly deduced, which shows good agreements with the values
derived from the obtained intrinsic energy width fromthe HRC experiments. The results have been summarized and published (see ref. [5]).
4. FRP system
A Flat-panel and Resistor type PMT (FRP) systemdeveloped for a two-dimensional position-sensitive
neutron detector was tested at the MIEZE spectrometer. Since the FRP system consists of a multi-anode PMT(MA-PMT), a resistor network board and an FRP amplifier, and provides similar signals to those of the RPMT
detector [7], it can easily substitute the RPMT system.
In this study, the FRP system with a 6Li glass scintillator was tested at the MIEZE spectrometer. A flat-panel-type MA-PMT assembly H12700A-10 (Hamamatsu
Photonics K.K.) and an enriched lithium 6 glass scintillator GS20 (Scintacor) with 0.8 mm thickness were used
as an FRP system, which was compared with a current
RPMT system with a 0.2-mm-thick 6Li glass scintillator.
In Fig. 1, the measured direct-beam intensities with
the FRP system and the RPMT system are compared. At
long wavelengths (> 12Å), the ratio is almost in agreement, and increases gradually to around 1.6 as the wavelength gets shorter. Because the quantum efficiencies
given by the catalogues are similar (~0.3) for the FRP and
the RPMT, this result suggests that the long-wavelength
neutrons are fully captured with the 0.2-mm-thick scintillator, while the short-wavelength neutrons transmit
partially the 0.2-mm-thick scintillator. The 0.8-mm-thickscintillator captures more short-wavelength neutrons,
then the FRP system could count more neutrons thanthat of the current RPMT system. In Fig. 2, the specularreflectivities measured by the FRP system and the RPMT
system from the same sample are compared. The results
show very good agreements. Because the RPMT system
has been discontinued, this result confirms that the FRP
system can substitute the RPMT system.
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Figure 1.	Comparison of the measured direct-beam intensities normalized by the kicker pulse between the
FRP system (blue line) and the RPMT system (light
blue line), in which the thicknesses of scintillators
are different (0.2 mm for the RPMT system and
0.8 mm for the FRP system). The corresponding intensity ratio is shown by red circles.

5. Summary
In this report, the activities of BL06 VIN ROSE in
FY2022 were summarized. The main achievements wereintroduced, i.e., the spin dynamics in MnSi1-xGex investigated by MIEZE and the attempt to substitute the current RPMT detector system with the FRP system. In thecase of the spin dynamics of MnSi1-xGex, very fast diffusion in rather low-Q region is observed, which is very
suitable for the MIEZE spectrometer. To upgrade thedetector system of the MIEZXE spectrometer, the FRP
system can substitute the current RPMT system.

Figure 2.	Comparison of the reflectivity measurements between the FRP system (red line) and the RPMT system (blue line).

References[1] F. Mezei ed., Neutron Spin Echo, Lecture Notes inPhysics, (Springer, Berlin) 128, (1982).
[2] B. Farago et al., Neutron News 26, (2015) 15.
[3] M. Hino et al., J. Nucl. Sci. Tech, 54, (2017) 1223.
[4] M. Hino et al., Physics Procedia 136-141, (2013) 136.
[5] S. Aji et al., Phys. Rev. B. 108, (2023) 054445.
[6] S. Sato, Hamon 27, (2017) 8.
[7] K. Hirota et al., Physica B 385-386 (2006) 1297.

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

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MLF Annual Report 2022

Neutron Science

BL08: Maintaining the Aluminum Window of theSuperHRPD Sample Vacuum Chamber
1. Introduction
The BL08 Super High Resolution Powder Diffractometer [1, 2] scattering chamber currently in use wasinstalled at the MLF in the summer of 2009. The sample
vacuum chamber has five large vacuum windows, eachmade of a 1.5 mm thick aluminum plate. The largest
window is 790 mm high and 740 mm wide. The sample
vacuum chamber, which has been in operation for morethan ten years, requires a vacuum break when the sample or the sample environment is changed, and has been
repeatedly vacuumed and broken more than 1300 times
as of the beginning of FY2022. The aluminum vacuum
windows have reached the originally scheduled maintenance period, then the windows were replaced during
the summer maintenance.
2. The sample chamber of SuperHRPD
The SuperHRPD diffractometer consists of a vacuum
sample chamber and each detector bank surrounding
it, as shown in Fig. 1. The sample chamber and detectorbanks are divided into separate sections and are locatedat several positions 10 mm from the vacuum window.
The main body of the SuperHRPD diffractometer ishoused in a 300 mm thick concrete instrument shield.
Replacing the vacuum window requires extensive work
to dismantle the shield and each detector bank andremove only the vacuum chamber, but this could not
be done during the summer maintenance period due
to cost, schedule, and temporary storage space issues.

Therefore, a method to remove only the vacuum chamber was considered to minimize the number of parts tobe removed.
3. For safe and secure construction
A method of lifting only the sample chamber by
crane was proposed, but since the sample chamber was
not a simple cylindrical shape and the center of gravity
position was inaccurate, it was lifted by crane using a
combination of a lifting jack and a guided frame (Fig. 2).
The jack used was a model JWM025URL10D manufactured by Tsubakimoto Chain Co. The sample chamber,weighing nearly 400 kg, was raised at a slow rate of 100 cm
in 30 minutes by a jack installed at the bottom and carefully lifted so as not to damage the vacuum window. The
vacuum window and O-ring for the removed vacuum
sample chamber were replaced, and after an off-line
vacuum test with the new vacuum windows, it was returned to its original position in a reverse process. Afterthe installation, alignment work was carried out and avacuum test was performed with the existing vacuum
system, and this work was successfully completed.
Verification by actual measurements confirmed that
there were no differences in the data before and after
the vacuum sample chamber maintenance.
Prior to the replacement, a 1.5 mm thick aluminum
window was used, but considering future maintenancecycles, it was decided to use a 3.0 mm thick aluminum
window for this replacement. There was concern that

Guided frame

Vacuum sample chamber

Inci

beam
dent

Backward bank
608 PSDs (φ8mm)

Low angle bank
192 PSDs (φ1/2inch)
90degree bank
512 PSDs (φ1/2inch)

Figure 1.	3D image of the SuperHRPD diffractometer. The
vacuum sample chamber and each detector bankhave independent structures.

Lifting jackFigure 2.	Structural diagram of the guide frame and lifting
jack that are assembled to safely lift the vacuum
sample chamber.

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the increased window thickness would affect the scattering intensity and background, but as shown in Fig. 3,
verification experiments confirmed that the effect of thewindow thickness was negligible.

References[1] S. Torii, M. Yonemura, T. Y. S. Panca Putra, et al., J.
Phys. Soc. Jpn., SB020 SB020-1-4 (2011).
[2] S. Torii, M. Yonemura, Y. Ishikawa, et al., J. Phys.: Conf.
Ser., 502 012052 (2014).

4. Summary
The vacuum window of the SuperHRPD sample
chamber has been replaced. The thickness of the aluminum window was changed to 3.0 mm, which is expected to have a service life longer than the previous
replacement cycle.

arb. unit

0.6

4
2

8
6

0.4

10

1

4

0.2
0.0

2

1

2

3

4
5
wave length / Å

1.0

0.1

7

8
6

0.4

4

0.2
0.0

0.8
0.6

8
6
4
2

8
6

0.4

4

0.2
0.0

10

1

2

1

2

3

4
5
wave length / Å

6

7

0.1

10

2

0.6

90degree bank data
3.0mm
1.5mm
ratio

1

ratio (1.5mm/3.0mm)

Low angle bank data 8
6
3.0mm
4
1.5mm
ratio

0.8
arb. unit

6

1.0

ratio (1.5mm/3.0mm)

0.8

8
6

ratio (1.5mm/3.0mm)

Backward bank data
3.0mm
1.5mm
ratio

arb. unit

1.0

2

1

2

3

4
5
wave length / Å

6

7

0.1

Figure 3. Verification of the change in diffraction peaks due to different thicknesses of the vacuum window. No effect of thickness
was observed for each detector bank. The reason why the backward bank detector has a large ratio swing is because thebinning width is very fine.

S. Torii1,2, S. Yamauchi1,2, and K. Mori1,2
1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK

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Neutron Science

Current Situation of BL09 in FY2022
1. Introduction
The special environment powder diffractometer(SPICA) located at BL09 of J-PARC MLF was founded by
the New Energy and Industrial Technology Development
Organization (NEDO), together with the High Energy
Accelerator Research Organization (KEK) and Kyoto
University. In the NEDO projects (i.e., RISIN (FY2009– 2015), RISING2 (FY2016 – 2020) [1], and RISING3 (inprogress; FY2021 – 2025) [2]), SPICA is dedicated tostructural investigations for the next-generation rechargeable batteries, as well as commercial lithium-ion
batteries. SPICA was designed and developed to achievea high resolution (Δd/d) of 0.08% with high intensity [3].
To realize the high Δd/d, SPICA has been situated at
approximately 50 m from the neutron source system.
SPICA focuses on neutron diffraction experiments under
special environments, especially in charge-discharge
operations (i.e., operando measurements). In addition,an annex building for SPICA (next to the 1st experimental hall of J-PARC MLF) was built to prepare samples forneutron diffraction experiments, assemble rechargeable
batteries and conduct their charge-discharge evaluations before and/or after operando measurements.
Currently, SPICA is widely used in various experiments,
particularly in the field of battery science [4–10].
2. Specifications of SPICA
SPICA was installed at BL09, which has the thin sideof a decoupled poisoned moderator with the shortest
time resolution (or the shortest pulse at full width in half
maximum (FWHM) region) of all MLF moderators. The
neutron intensity on the thin side is weaker than thaton the thick side (i.e., BL18, 19, and 20 on the 2nd experimental hall); however, the thin side has the advantage ofa symmetrical peak profile, which can be used to extract

strain information from the samples. The primary flightpath from the moderator to the sample position (L1) is
52 m, and the secondary flight path from the sample
position to the detectors (L2) is approximately 2 m, as
shown in Fig. 1. An elliptical supermirror guide graduallychanges the mirror coating from m = 3 to 6 toward thesample position, making it efficient to increase the number of neutrons at the sample position. SPICA utilizes
1568 3He gas-filled one-dimensional position-sensitive
detectors (PSDs) with a diameter of 1/2 inch and an active length 0.60 m from a total of 0.67 m. The detectorbanks are formally grouped according to the scattering
angle (2θ ): backscattering bank (150 ≤ 2θ ≤ 175°), highangle multi-purpose bank (120 ≤ 2θ ≤ 150°), 90-degree
multi-purpose bank (60 ≤ 2θ ≤ 120°), low-angle multipurpose bank (10 ≤ 2θ ≤ 60°), and small-angle bank
(5 ≤ 2θ ≤ 15°). In particular, the detectors in the multipurpose bank (10 ≤ 2θ ≤ 150°) have been placed continually on a cylindrical locus approximately 2 m fromthe sample position. The Δd/d value was evaluated foreach bank: Δd/d = 0.12% for the backscattering bank,Δd/d = 0.47% for the 90-degree multi-purpose bank,and Δd/d = 1.27% for the low-angle multipurpose bank.
The chopper rotated at a frequency of 25 Hz, which was
the same as the repetition rate of the proton beam injection. The natural bandwidth of the SPICA is 2.9 Å. Threesingle-disc choppers were used for bandwidth selection
to prevent frame overlapping and operated with 25/4 to
25/1 Hz repetition to select bandwidths.
3.	Organized “charging station” for experimental
rechargeable batteries in the BL09 annex building
The BL09 group has been organizing the “charging
station” for experimental rechargeable batteries in a radiation-controlled area of the BL09 annex building. As

Figure 1. Layout of BL09 SPICA.

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Figure 2. BL09 SPICA and the “charging station” in the BL09 annex building.

shown in Fig. 2, there are some apparatuses, like potentiostats, thermostatic chambers, glove boxes, etc., at the
charging station by SPICA. After the operando neutron
diffraction experiments on SPICA, the rechargeable batteries can directly move to the charging station in orderto charge/discharge again for a long time. As a matterof course, the rechargeable batteries can be assembled
at the charging station as well as at the chemical laboratory (Chem. Lab.). The charging station is critical tomonitor the battery reaction from structural point ofview, using neutron diffraction.

References[1] https://www.rising.saci.kyoto-u.ac.jp/rising2/[2] https://www.rising.saci.kyoto-u.ac.jp/en/[3] M. Yonemura et al., J. Phys. Conf. Ser., 502 012053(2014).
[4] Y. Kato et al., Nat. Energy, 1 16030 (2016).
[5] S. Taminato et al., Sci. Rep., 6 28843 (2016).
[6] K. Mori et al., ACS Appl. Energy Mater., 3 2873 (2020).
[7] K. Mori et al., J. Phys. Chem. C, 125 12568 (2021).
[8] F. Takeiri et al., Nat. Mater., 21 325 (2022).
[9] K. Kino et al., Appl. Phys. Express, 15 027005 (2022).
[10] Y. Izumi et al., Adv. Energy Mater., 13 2301993 (2023).

K. Mori1,2, T. Saito1,2, S. Song1,2, and S. Torii1,2
Institute of Materials Structure Science, KEK; 2Neutron Science Section, Materials and Life Science Division, J-PARC Center

1

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MLF Annual Report 2022

Neutron Science

BL10: NOBORU
1. Introduction
In FY 2022, fifteen general-use proposals, one longterm proposal and two project-use proposals werecarried out at NOBORU. One long-term proposal was
postponed due to the entry restriction for foreigners
because of the COVID-19 pandemic. This year, in addition to the fixed-point observations that have been conducted every year, we tested a fast-response gamma-ray
detector using a plastic scintillator (BC-404) and a photomultiplier tube (Hamamatsu R329-02). Recently,
requests to use high-energy neutrons above eV have
gradually begun to increase. In order to respond to such
requests, a test to measure the pulse shape functions athigh energy neutrons was performed at NOBORU.
2. Experimental setup
The pulse shape of the neutrons in the time-offlight (TOF) region of milliseconds or less was measured
by detecting prompt gamma-rays generated by neutron
resonances. In this measurement, it was necessary to
sufficiently suppress contamination by flash gammarays coming from upstream. Therefore, the gamma-ray
detector was enclosed in a shield of lead blocks (forgamma-ray suppression) and lithium fluoride plates(for neutron-absorption). Various samples of gold, silver, copper, tantalum, hafnium, and zinc with 0.1, 0.2, 2,
0.030, 0.025, and 5 mm thicknesses, respectively, were irradiated by neutrons. The distance between the surfaceof the plastic scintillator and the samples was 20 cm. A
5 cm thick lead collimator with a φ 37 mm aperture was

located in front of the scintillator. An aluminum platewith the samples was mounted on an XY stage with a
movable range of 15 cm × 10 cm. The stage movementand data acquisition were controlled by IROHA2 and automatic measurements were performed while changing
samples. Figure 1 shows the experimental setup.
3. Results
A TOF spectrum measured with the tantalum sample is shown in Fig. 2. Resonance peaks with a goodsignal-to-noise ratio were obtained at TOF greater than
50 μs for tantalum and 10 μs for copper. The sample wasplaced at about 14 m from the moderator, indicatingthat resonances up to several hundred eV were measured. In the early TOF region, the double-bunch structure of the proton beam is reflected in the resonancespectrum. Figures 3a and 3b show resonance spectra
measured with a gold target. It is seen that each resonance forms as a pair of peak structures 600 ns apart.
The peak shapes tailing to low energy side also reflect
the time structure of the incident neutrons.
A previous study using PHITS simulation data concluded that a time structure based on the Cole-Windsor(CW) function is the most suitable pulse shape function
for NOBORU viewing the decoupled moderator [1, 2].
Figure 3a also shows that the spectrum acquired without sample (only with an aluminum plate) well reproduce the background distribution in the spectrum takenwith the gold target. Such clean data allow for real data
analysis in the higher energy region. The measured data

Figure 1. Experimental setup for the low background gamma-ray measurement at NOBORU.

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Figure 2. TOF spectra measured with tantalum (upper) and copper (lower) target.

Figure 3.	(a) TOF spectra measured with (black) and without (green) Au target. (b) TOF spectrum derived
with background subtraction (black points) and fitted using CW function (red curve).

obtained in this study will re-evaluate the validity of theprevious study (Fig. 3b) and is expected to provide amore realistic pulse shape function for future measurements with high-energy neutrons.

References[1] H. Hasemi et al., Nucl. Instr. and Meth. A, 773, 137149 (2015).
[2] https://www.j-parc.jp/researcher/MatLife/ja/
instrumentation/

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

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MLF Annual Report 2022

Neutron Science

Developments at BL11 PLANET
1. Introduction
This year, we have tackled the following challenges:i) Extension of the available pressure range with ParisEdinburgh (PE) press equipped with 1-mm-cup diameter non-toroidal anvilsii) Performance evaluation of radial collimators (RCs)with a gauge size (GS) of 0.75 mmiii) Background reduction by Cd screens in front of thedetector shielding panelsiv) Diffraction experiments using a DAC with vertical geometry to improve data reliability
The details are shown below.
2. Extension of the available pressure range with
Paris-Edinburgh (PE) press equipped with
1-mm-cup diameter non-toroidal anvils
In 2018, we tried to extend the available pressure
range by reducing the cup diameter of the double toroidal anvils for a PE press. The world record reaching 40
GPa has been achieved by using 1.5-mm cup diameter
anvils [1]. However, the further extension using 1.0-mm
cup diameter anvils failed, although a higher-pressure
generation was expected. This would be due to consumption of the applied load by a toroidal part, leading
to less efficient compression of the sample. To further
extend the maximum available pressure range, nontoroidal anvils with 1.0-mm cup diameter are tested.
Figure 1 shows the new anvil design and the comparison of the pressure generation curve with those

Figure 1.	(Top) Enlarged view of the new design. (Bottom)
Comparison of the pressure generation curve withthose for previous designs.

for previous designs. No saturation of pressure generation has been observed and a pressure of 45 GPa wasachieved. However, the signal to anvil peak ratio is verysmall; thus, further improvement of the beam optics will
be necessary.
3. Performance evaluation of RCs with a GS of
0.75 mm [2]As the beam power increases, the use of a smaller
sample that enables experiments at higher pressures
has become possible. Last year, radial collimators witha nominal GS of 0.75 mm were developed for experiments above 30 GPa using PE presses or diamond anvil
cells (DAC). This year, the performance is quantitatively
evaluated in terms of GS, transmission, and efficacy inthe experiments using the above high-pressure devices.
Figure 2 (upper) shows the scan profile of the 0.996mm diameter iron ball mounted on a vanadium needle,
along with the fit by convolution of radial collimatorfunction, T (z) and the cross-section profile of the ironball. Figure 2 (lower) compares the T (z) obtained by fitting with those simulated based on the design parameters. The true GSs of three RCs with nominal GS of 3.0,
1.5, and 0.75 mm are 2.78(2), 1.07(2), and 0.50(3) mm,
respectively. The detailed results of other tests will beshown in Ref. [2]. These results indicate that the 0.5 mm
GS radial collimators have been fabricated as intended
and display the smallest GS among those ever manufactured for neutron scattering experiments in the world.

Figure 2.	( Top) Scan profile of 1-mm diameter iron ball with
3.0 mm, 1.5 mm, and 0.75 mm GS radial collimatorsand the fit by convolution of the radial collimatorfunction and the cross-section profile of the ironball. (Bottom) Radial collimator functions obtainedby the fit (left) and those simulated using design
parameters (right).

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MLF Annual Report 2022

Intensity normalized byproton numbers

4. Background reduction by Cd screens in front of
the detector shielding panels
The detector banks of PLANET are equipped withshielding panels to block neutrons coming aroundfrom the side of RCs. The panels are designed to folddown to make room for replacing the huge 6-axis presswith smaller presses. However, the folding mechanism
left gaps in the panels, resulting in incomplete shielding [see Fig. 3 (upper right)]. As the signal intensity decreased with a decreasing sample volume, backgroundcoming from the gaps became non-negligible. Last
year, the 1-mm-thick Cd screens were installed in frontof the shields to eliminate it. This year, the efficacy wasevaluated.
Figure 3 compares detector maps before and after
installation of Cd screens. Many horizontal lines in theupper right figure are mostly eliminated and the integrated intensity is reduced into approximately one-third in
the energy range below Cd cut-off (0.5 eV) (Fig. 3 lower).

0.05

the incident beam was injected into the sample throughone of the diamond anvils (horizontal geometry). This
setup has caused problems, such as contamination ofdiffraction patterns by diamond Bragg spots and loss ofneutron beam in certain wavelength range due to Bragg
scattering by the single-crystal diamond (the so called“Diamond Dips”). Last year, we introduced software that
helped to eliminate these effects but failed to eliminate
them completely.
This year, we have tried vertical geometry in which
the compression axis of DAC is aligned vertically. It isbecause with this geometry, incident beam introduced
into the sample does not hit the diamond anvils in its
path, which would fix the aforementioned problems.
To achieve this setup, we developed beamline optics,
including the motorized X-Z stage to precisely align the
beam collimator with an exit size of 0.5 mm wide and
0.1 mm high (Fig. 4), and software to control it. Next
year, the performance will be evaluated in on-beamexperiments.

With screen

0.04

Without screen

0.03
0.02
0.01
0.00

0

10,00020,00030,00040,000

TOF(us)Figure 3.	Detector maps before (upper right) and after installation of Cd screens (upper left) and integrated intensity over the whole detector area (lower).

5. Diffraction experiments using a DAC withvertical geometry to improve data reliability
In recent years, we have developed an experimental
technique using a DAC. In the previous data measurements, with the compression axis of the DAC horizontal,

Figure 4.	(Upper) Newly devised collimator and motorizedstage (Lower) Stage with them installed.

References[1] T. Hattori, et al., High Press. Res. 39 417 (2019).
[2] T. Hattori, et al., Nucl. Instrum. Methods. Phys. Res. A
1059 168956 (2024).

T. Hattori1, A. Sano-Furukawa1, S. Machida2, J. Abe2, K. Funakoshi2, and N. Okazaki2
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS

1

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Neutron Science

High Resolution Chopper Spectrometer HRC
1. Introduction
The High Resolution Chopper Spectrometer (HRC)
is being operated at BL12 in the MLF under the S-type
project of IMSS, KEK, and the IRT project of ISSP, theUniversity of Tokyo, in order to study dynamics in condensed matter, especially in a wide range of correlated
electron systems. The activities of the HRC in FY2022 aresummarized in this report.
2. Instrumentations
A cryofurnace (T = 4 – 700 K) was manufactured
and delivered in the last fiscal year, and the experimentcontrol program YUI was modified to accommodate it.
We performed the commissioning and confirmed thatthe highest temperature was 760 K at the heater control position and 700 K at the sample can bottom with astandard sample can.
For low temperature experiments down to 0.3 K, a
3
He gas sorption type refrigerator, Heliox, was used forcollaborative experiments on the S-type project. Heliox
maintains the lowest temperature, 0.3 K, for 40 hours.
The performance of 3He gas sorption type refrigerators,
which are commercially available, was surveyed and reviewed by cryogenic engineers and instrument staffs of
HRC and POLANO, and specifications were developed
for a refrigerator with a higher performance than Heliox.
We manufactured a 3He gas sorption type refrigerator,
where the lowest temperature, 0.3 K, is maintained for
100 hours, and it was delivered in March 2023, as shownin Fig. 1.
The phase control algorithm of the Fermi choppers
was improved by introducing the algorithm developed
for the correlation chopper on POLANO, and its performance will be investigated. The wave shape of the 25 Hz
timing signal input to the Fermi chopper was disturbed
by noise from the T0 chopper control system, causing
disruption of the Fermi chopper’s control. The 25 Hz timing signals were wired from the signal distributor to the
choppers individually, and as a result, the problem wassettled. The touch panel of the T0 chopper was repaired.
Backups of the stabilizer of the T0 chopper were purchased, because production will be discontinued soon.
A scheduled maintenance was performed for theroughing pumps and the air dryer in the vacuum systemof the scattering chamber, and for the vacuum pumps of
the T0 chopper and the guide tube. During the regeneration process of the cryopump, the ultimate pressure
was increased. A small broken piece, probably from theB4C liner of the vacuum chamber or from the vane of the
cryopump, was stuck in the pressure relief valve of the
cryopump, where the vacuum was leaked. The ultimate
pressure was recovered by removing the piece. Since
the autumn of 2022, there has been a small leak in thevacuum scattering chamber and a loss of neutron intensities. It was discovered that the holding mechanismof the incident collimators was broken and the neutron
intensities decreased due to changing the position of
the collimators. By repairing the holding mechanism of
the incident collimators, the neutron intensities wererecovered. However, the vacuum leak was not resolved.
We have not yet found the cause of the vacuum leak.
In the computational environment, scheduled export process of spe files from HANA, detector diagnostic
program, and import of a beam monitor detector were
implemented. The FLnet server that monitors the vacuum system has been malfunctioning due to aging, andwe attempted to update it, and we purchased as many
parts as we could in FY2022. The remaining parts will bepurchased in FY2023 to complete the renewal.
On the HRC, high angle detectors and low angle
detectors are mounted at L2 = 4 m and φ = 3 − 62° and

Figure 1.	3He gas sorption type refrigerator delivered to the
HRC in March 2023.

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3. Scientific results
The magnetic anisotropy in the van der Waals compounds CeTe3 and CeTe2Se was investigated. In CeTe2Se,
the magnetic moments in the ordered state point along
the magnetic hard axis, whereas they point along themagnetic easy axis in CeTe3. Using the HRC, the crystalline electric field (CEF) excitations were observed, andthe magnetic anisotropy was discussed [2]. Figure 2
shows CEF excitations at E = 22.9 meV and 26.3 meV in
CeTe2Se. In a previous study, it was suggested that themagnetic moments in CeTe2Se point along the magnetic
hard axis due to the quantum order-by-disorder. In an
order-by-disorder, an unexpected order emerges due tosome large fluctuations (disorder). The antisymmetricspin-orbit interaction (ASOI) due to a lack of inversion
symmetry has been reported to give anisotropy to magnetic fluctuations. An enhancement of the magnetic
quantum fluctuations is possibly controlled by the competition between the magnetic anisotropy determinedby CEF and the influence of the ASOI in these systems.
Magnetic excitations were investigated on the metallic magnet FeSn with a Kagome spin-lattice using

35
30

CeTe2Se
T = 5.0 K

25

3.0 x10
2.5

20

2.0
1.5

15

1.0
0.5

10

0.0

5
0
0

-2

Intensity [arb. unit]–13 − –31° and at L2 = 5.2 m and φ = –0.6 − –5.1°, respectively, where L2 is the distance between the sample and the detector, φ is the scattering angle. Due todifference in the resolution and the background, it was
hard to connect the data on high angle detectors andthe data on low angle detectors. We tried again to connect both data and found out that these data might becompared by removing noise reasonably and correcting
the detector efficiency with calculated values. We also
found noise signals related to the detector electronics
and noise signals when the beam shutter was closed.
Some improvements are required. The low angle detectors are aligned in a double-layered configuration toincrease the counting rate: the detectors in the front
layer face the sample and the detectors in the rear layer
are placed just at the lower stream of the front layer [1].
However, the rate of increasing intensities depends on
the neutron energy. This configuration should be also
reconsidered.

E [meV]

Neutron Science

1

2
|Q| [

3
-1

4

5

]

Figure 2. Background-subtracted inelastic neutron scattering
intensity in the momentum(Q)-energy(E) space measured at T = 5 K for CeTe2Se (Reproduction from Ref.
[2]).

the HRC, 4SEASONS (BL01) at the MLF, and SEQUOIA at
the Spallation Neutron Source (SNS) [3]. Well-defined
spin waves were observed at low energies and the
Hamiltonian parameters were determined. Broad Diracmagnons were observed at high energies, reflecting interactions with the Stoner continuum.
HoB2, which shows giant magnetocaloric effect, is
expected to be a target material for magnetic refrigeration in the liquid hydrogen temperature range. Using
the HRC, CEF excitations were observed and five CEF levels were found to be densely located in the low energy
region: pseudo-degeneration [4]. This indicates that thepseudo-degeneracy of the CEF ground state in a zeromagnetic field plays a major role in producing the giant
magnetocaloric effect. The relationship between magnetocaloric effect and CEF parameters derived in thisstudy can provide a guideline in the search for magnetocaloric materials. Details are described in Research andDevelopment Highlights in this report.
References[1] S. Itoh et al., MLF Annual Report 2016,101 (2017).
[2] D. Ueta et al., J. Phys. Soc. Jpn., 91 094706 (2022).
[3] S.-H. Do et al., Phys. Rev. B, 105 L180403 (2022).
[4] N. Terada et al., Commun. Mater., 4 13 (2023).

S. Itoh1,2, T. Masuda3,2, D. Ueta1,2, T. Nakajima3, T. Yokoo1,2, S. Asai3, H. Saito3, D. Kawana3, R. Sugiura3, T. Asami3, S. Yamauchi1,2,
S. Torii1,2, T. Seya1,2, H. Ohshita1,2, N. Kaneko1,2, Y. Ihata4, and H. Tanino1,2
1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3The Institutefor Solid State Physics, The University of Tokyo; 4Technology Development Section, Materials and Life Science Division, J-PARC Center98

MLF Annual Report 2022

Neutron Science

BL14 AMATERAS
1. Introduction
AMATERAS is a cold-neutron disk-chopper spectrometer designed for studying dynamical properties
in atomic, molecular, and magnetic systems from cold
to sub-thermal energy range with high efficiency andflexible resolution [1, 2]. It has been 14 years since
AMATERAS was opened for the user program. During
this time, we have continuously upgraded various components of the instrument while facilitating the users’
experiments. In FY2022, Dr. Masami Nirei, a postdoctoral
researcher, joined the instrument group. Furthermore,this fiscal year, we obtained funding granted by the
JAEA President for upgrades to the neutron detectors
and the vacuum control system, aiming to enhance theuser program.
2. User program, outcomes, and outreach activities
35 and 34 general proposals (short-term) were submitted to AMATERAS in the 2022A and 2022B rounds,
respectively. Consequently, 16 experiments for the
short-term general proposals, including some “reserved”
proposals, one experiment for the long-term proposal
and one experiment for the project proposal were carried out this year. 13 of the performed general proposals
were submitted by foreign users. Most users were still
unable to visit the facility for their experiments due totravel restrictions, so the instrument group carried themout in their absence. The first user group that visited

after the Covid-19 pandemic restrictions were lifted wasfrom Europe. As usual, the majority of the proposals submitted to AMATERAS were in the research field of magnetism and strongly correlated electron systems. On
the other hand, the humidity control system, a sharedsample environment in the facility, was used for the firsttime for an experiment for industrial application.
In FY2022, 14 refereed papers related to scientificresearch by using AMATERAS and one proceedings paper were published, and two students received theirdegrees. As of our outreach activities, we hosted forthree months a doctoral student, Ms. Kotomi Nakamura,from Ochanomizu University, as a Fellow of Advanced
Science. In addition, AMATERAS accepted four students during the 6th Neutron and Muon School heldin December 2022. They learned the techniques of theinelastic neutron scattering measurement on a low-dimensional magnetic system in a hands-on experimentat AMATERAS (Fig. 1).
3. Instrument-related upgrades
We have proceeded off-line and on-beam commissioning on the top-loading cryofurnace that wepurchased last year. This is a cryogen-free system incorporating a pulse-tube cryocooler and a one-shot3
He cooling system (Fig. 2). This cryofurnace enables
measurements at temperatures ranging from 0.3 to~700 K, utilizing low-T, mid-T, and high-T probes. After

Figure 1.	Students and staff members of AMATERAS mounting the sample
onto the sample rod of the cryostat.

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Figure 2.	Photos of the cryogen-free top-loading cryofurnace. (a) Inside the cryofurnace andsample probes and (b) the cryofurnace being set onto the dedicated radial collimator.

conducting offline cooling tests, we carried out onbeam commissioning to investigate the background,sample position and cooling performance in the vacuum scattering chamber. Based on the results of thiscommissioning, we are improving the design of the cryostat to ensure safer and easier sample installation andto reduce the cooling time in the initial cooling process.
Additionally, we have integrated a new chiller to circulate the cooling water on the helium compressor forthe pulse-tube cryocooler included in this cryofurnace,
allowing its operation independently of the facility’s
cooling water. In the coming year, we will be introducing
more improvements to the system for the user program.
We have also developed an automatic vacuum control system for the vacuum scattering chamber over thelast few years. Our vacuum control system comprises
two sets of a screw pump, a mechanical booster pump,a gate valve, and a butterfly valve for rough evacuation
and a cryopump with a main gate valve to achieve highvacuum. In FY2022, we completed the full automationof the evacuation process. Our next step is to upgrade
the control system to fully automate the venting process
to improve safety and work efficiency and to reduce ourworkload.
There are 286 one-dimensional position sensitive
neutron detectors inside the vacuum chamber with alength of 3 m and diameter of 1 inch each. When we
start evacuation/vent of the vacuum chamber, highvoltage applied to the detectors should be turned off
to prevent their damage due to vibrations caused by air
currents. In near future, we are planning to prepare aninterlock system for the high voltage that automaticallyturns off the high voltage of the detectors monitoring
status of the vacuum control system.
References[1] K. Nakajima et al., J. Phys. Soc. Jpn. 80, SB028 (2011).
[2] K. Nakajima, RADIOISOTOPES 66, 101 (2017).

S. Ohira-Kawamura1, M. Kofu1, N. Murai1, Y. Inamura1, M. Nirei1, D. Wakai1,2, and K. Nakajima3,1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2NAT Corporation; 3Materials Sciences Research Center, JAEA

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Upgrading TAIKAN
1. Introduction
The small- and wide-angle neutron scattering instrument TAIKAN (BL15) has been developed and upgraded to analyze the microstructure and hierarchicalstructure of materials in various scientific fields withhigh precision and efficiency using a 1 MW spallation
neutron source at J-PARC [1]. In FY2022, the software forthe instrument control and the sample exchanger for 1
Tesla (T) magnet filed measurement were developed topromote efficient and remote measurements.
2.	Development of the software for instrument control
for BL15
Since the beginning of the TAIKAN operation in
2011, as shown in Fig. 1, the application-type GUI software called “Utusemi-1” [2] using Python scripts has
been used to control the sample environment (SE) devices and the measurement with He3 detectors. It was asimple GUI with a user-friendly operation. However, it
did not allow an easy set up of complicated measurement conditions and prevented the integration of new
software for the control of devices.
As shown in Fig. 2, many SE devices, such as temperatureand humidity control systems [3], viscosity measurement, tensile tester, UV/VIS [4], and magnetics, havebeen developed at BL15 for user experiments in various research fields (polymers, proteins, steel materials,
magnetic materials, etc.)
To overcome the limitations of Utusemi-1 whichcaused difficulties in the operation of complex measurements, the scalability of SE devices, and the displayof measurement information, “Utusemi-2”, a browserbased GUI software (see its screenshot in Fig. 2) has
been developed by the MLF computational environment team.
In FY2022, the Utusemi-2 was installed and customized for the BL15 measurement system, including thedevelopment of control software for SE devices.
3. Development of the sample changer for 1 T magnet
In SANS measurements at BL15 under magnetic
fields below 1 T up until last year, it was necessary to exchange the samples after each measurement. Therefore,
to perform automatic sample exchange in the magnetic
fields, a new sample changer with 7 sample positions
was developed as shown in Fig. 3.

Figure 1.	Screenshots of the GUI of Utusemi-1 (previous) and Utusemi-2 (new) for themeasurement control system in BL15.

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Figure 2. Sample environment devices devel-oped at BL15 TAIKAN.

sequencing measurements and the addition of userdeveloped SE devices. In addition, the development of
the sample changer for 1 T magnet filed measurement
is expected to further promote the usage of the analysis
of magnetic structure for magnetic and steel materials.

Figure 3. Drawing of 1 T magnet with sample changer.

4. Future plans
In the BL15 user experiments, the installation of
Utusemi-2 software for instrumental control in BL15
will lead to simplifying the execution of complex

References[1] S. Takata, et al., JPS Conf. Proc., 8 036020 (2015).
[2] Y. Inamura, T. Nakatani, J. Suzuki, and J. Otomo, J.
Phys. Soc. Jpn., 82 (2013) SA031.
[3] H. Arima-Osonoi, et al., J. Appl. Cryst. 56 1802-1812(2023).
[4] Hiroki Iwase, Masaaki Akamatsu, Yasuhiro Inamura,
Yoshifumi Sakaguchi, Kazuki Kobayashi, and Hideki
Sakai, Langmuir 39 12357-12364 (2023).

S. Takata1, K. Hiroi1, K. Ohishi2, H. Iwase2, Y. Kawamura2, T. Morikawa2, and M. Ueda2
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS

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Developments of Multi Incident-angle Neutron
Reflectometry
1. Introduction
Neutron reflectometry (NR) is very useful for investigations of structures of surfaces and buried interfaces.
SOFIA is a horizontal-type neutron reflectometer constructed at BL16 of the MLF, J-PARC [1, 2]. Due to thehigh-flux beam of J-PARC, less than one hour is needed
for taking full Q-range data and only a few seconds forlimited Q-range data in the case of a sample with 3 inches (76 mm) in diameter. However, several hours are stillneeded for a small sample, such as 10 mm × 10 mm,
which is a typical size of a sample for X-ray reflectometry.
So far, the SOFIA employed double frame modewith chopper rotation speed of 12.5 Hz (half of theneutron pulses generated at the source) to extend the
Q-range by using wider wavelength band. This enables
us to perform time-slicing measurements within a wider Q-region without any incident-angle scan. However,the Q-region is still limited, even with the double framemode, due to the limitation of the wavelength band,and the neutron flux is reduced by a half because every
other neutron pulse is cut by the chopper. With taking
the merit and demerit of the double frame mode mentioned above, a multi-incident neutron reflectometry(MI-NR) [6] at the SOFIA reflectometer is going to berealized by the combination of the higher flux beam at

25 Hz for higher incident-angle and wider wavelengthband beam at 12.5 Hz for lower incident-angle. It should
be noted here that the longer exposure time is required
for the measurement at higher incident-angle becauseof the reduced reflectivity. Therefore, the reduction of
the flux due to the double frame mode at the lower
incident-angle has no effect on the total measurement
time because it is limited by the statistic at the higher
incident-angle.
To realize the combination of the two beams above,
two disk choppers were installed at the exit of the guidetube last year. The choppers were made of circular aluminum plates with thickness of 4 mm, and Gd2O3 waspainted on them to stop neutrons by the choppers. As
two beams with different tilt angles, 2.22° and 5.71°, areacceptable at the SOFIA, the choppers have two windows: one is at the edge to realize the MI-NR at the 2.22°
beam, and the other at the middle of the disk to cut thebeam with the tilt angle of 5.71° to illuminate free-liquidsurface with high incident-angle.
In order to transport the two beams at the chopper
position to the virtual sources 4500 mm from the choppers, a focusing guide was installed at the middle of the
choppers and virtual sources. The guide is 1300 mm inlength and equipped with 3 Qc supermirrors inside, in

Figure 1. Design of optics for realizing MI-NR at the SOFIA.

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which the shapes of the top and bottom sizes are ellipses with foci at the upper and lower half of the beamat the chopper position and lower and upper exit at thevirtual sources, respectively. Note here that a separator
was placed to avoid the cross talk of the two beams after
the chopper, in which an iron plate was placed at thecenter to cut fast neutrons and two 2.5 Qc supermirrors
on glasses were placed on the top and bottom sides of
the iron plate to guide neutrons.
This year, a slit system with two apertures to makevirtual sources with the optimized gaps depending on
the incident angle and sample size was installed. In addition, a set of precise focusing mirrors to transport neutrons from the virtual sources to a sample position withdifferent incident angles was also installed. A set of FRP
detectors was used to count the neutrons reflected on
the sample separately. Because the peeling of the Gd2O3

painting on the chopper blades due to the centrifugal
force occurred, the test measurements of the MI-NR
could not be performed.
2. Beam transport optics
A blueprint of the beam transport optics and photos of the instruments installed are shown in Fig. 2. The
incident beams from the chopper exits are separated toupper and lower beams with the separator and irradiate
the focusing guide tubes as explained above.
Figure 3 shows the beam profiles at the virtual
neutron source. The distance between the upper andlower beams was 34 mm, which was almost equal to thedesigned value. Therefore, we could say that the accuracy of the construction of the guide tubes was precise
enough.

Upstream optics：
Introduce separated beams to the virDisk Chopper/Separator
Focusing Guide Tube

Figure 2. The beam transport optics after the upgrade.

Figure 3. The observed beam profiles of the separated
incident beams at the virtual neutron source.

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Figure 4. The observed beam profiles of the separated
incident beams at the sample position.

3. Precise focusing mirrors
The slits for the virtual neutron source were madeof borosilicated glass with Gd2O3 painting and set parallel at the precision better than 25 μrad. All the partsof the precise focusing mirrors were manufactured withultra-precision cutting machines. Two sets of opposing
mirrors were installed at the beam line at upstream andat downstream. The tilt errors of the mirrors were estimated to be between 30 and 50 μrad in FWHM by usinga laser interferometer.
Figure 4 shows the beam profiles at the sample
position. A misalignment of 60 μm is observed, but thebeam centers could be adjusted by tuning the virtual
neutron source.
4. Detectors
A set of FRP detectors was installed, and the efficiency and the resolution were improved 2 times and1.5 times, respectively.

5. Conclusion and prospects
The necessary items for realizing MR-NR have been
installed and the rough adjustments were performed.
All the instruments worked well but the performance ofsome items was not up to the expectations. The refinements of the instruments will be done in FY2023, andthe first MI-NR measurement will be demonstrated.
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] N. L. Yamada et. al., J. Appl. Crystallogr., 53 (2020)
1462-1470.
[7] S. Satoh, Plasma Fusion Res. 13 (2018) 3-6.
[8] F. Nemoto et. al., Nucl. Instrum. Methods Phys. Res.
Sect. A, 1040 (2022) 166988.

N. L. Yamada1,2, M. Yamada1,2, F. Nemoto3, S. Satoh1,2, and H. Seto1,2
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3National
Defense Academy

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Online Data Processing Application Suite for Polarized
Neutron Reflectometer SHARAKU
1. Introduction
The neutron reflectometer SHARAKU installed at
BL17 in the MLF has been used for the structure analysisof the surface and interfaces in a sample. Because it canperform the spin-polarization analysis of the reflected
neutron using polarizing mirrors and spin flippers, it
can be used for the analysis of the magnetic structure.
Various kinds of sample environments are available:
magnets up to 7T, a 4K-refrigerator, a temperature/humidity-controlled chamber, and so on. Therefore,
SHARAKU has been used for structure analysis in a wide
variety of research fields, such as polymer [1–3] andmagnetic thin films [4, 5]. In recent years, we have beendeveloping a versatile application suite to handle themeasurement data obtained at SHARAKU to maximize
the efficiency of the experiment.
2. Data reduction in neutron reflectometry
The event recording system at the MLF stores thetime-of-flight (TOF), detected time, and position on thedetectors for each neutron. To obtain the NR profile, themomentum transfer, q, for each neutron is calculated
from the TOF and the reflection angle. The histogramof q for the reflected neutron is normalized by that for
the incident neutrons. The data processing to convert
the raw experimental data to the NR profile has been
carried out using the software Refcal or Utsusemi, which
are designed for SHARAKU and the common package
for the instruments in the MLF, respectively [6]. The users
usually transfer the converted NR data to their storage
medium after the experiment before leaving the J-PARC
site because the experimental data cannot be accessedfrom the outside of J-PARC. If they copy not only theconverted NR data but also the raw experimental data
files, they can perform the data analysis on their own
PC by installing the above software packages. However,they sometimes find it difficult to install the software,
including the libraries dependent on the computer environment at the user side. Thus, the data analysis andvisualization at the users’ laboratories are limited outside
J-PARC; therefore, there has been a potential demand
to enable the data processing without an effort to build
the software environment and to handle the massive
raw experimental data after the experiment.

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3. Web application suite for NR
To carry out the data processing of the NR data without installing any software, we developed a web-based
application environment on the intra-network of J-PARC(JLAN). The users can operate the application suite todeal with the reflectivity data via internet browser software. The web application was coded by the application framework Flask with Python. The applications areaccessible in JLAN and can be used for monitoring theexperiment and processing the data during the beamtime. This web application can be used on web browser
software such as Firefox and Chrome.
Figure 1 shows the screenshots of the web applications for SHARAKU. The data information viewer shownin Fig. 1(a) displays a table of the acquisition time, measurement conditions and comment for each run. The user
can refer to each raw data by clicking the run number
at the left column in the table. In order to obtain the NR
data, the observed spectrum of the reflected neutron
intensity is normalized by that of the incident beam.
Such data conversion can be carried out only by clicking the “Reflectivity Converter” button below the table
after selecting the run numbers of the direct and reflection data in the “I0” and “Ref” columns, respectively.
Figure 1(b) shows the application for the data conversion to obtain the NR profile. A conventional NR profile
is constructed by concatenating the reflection data thathave been acquired at several different incident angles
to cover a wide q range. The conversion application automatically estimates the run numbers for the series of
the reflection data for each sample and concatenates
them. Thus, for conventional samples, the NR profiles
are available only by mouse operation. The converted
data can be downloaded with the log file of the sample
environment during the measurement.
4. Internet access
The web application suite described above cannot be used outside of the J-PARC because of the strict
limitation of the network access to the intra-network of
J-PARC. Therefore, the same web application environment is also available on the internet using Amazon
Web Services (AWS) [7]. The experiment data is stored toa cloud storage and the users can view the experiment
data and carry out the data analysis anywhere outside
J-PARC by web browser software without installing any

MLF Annual Report 2022(a)Neutron Science(b)

Figure 1.	Screenshots of the web applications for SHARAKU: (a) list of the experiment data with the sample information and (b) data
conversion application from the raw data to the NR profile.

additional plug-in or network setting on their computer. The access to the experiment data is protected byuser authorization. Each user can handle only the datataken by themselves. The experiment data are automatically uploaded within 30 min after each measurement.
Therefore, the user can discuss the experiment with theoff-site collaborators during the beamtime.
The application suite also includes utility software
to support the experiment and analysis. The sequencebuilder generates the script file for the automatic measurement. The NR profile simulator predicts the experimental data obtained at SHARAKU for a given sample
structure and measurement condition [8]. The users canevaluate the observable q range and the statistical error
in the experiment data. The above utilities are available
on the internet without authorization.
5. Summary
The web application suite was developed for
SHARAKU, and is used to perform the experiment andanalyze the data with an easy-to-use GUI. It can also

be used on the internet. Therefore, the users can handle their data after the experiment in the same manner as they do during the beamtime at the J-PARC site.
Currently, novel functions based on data science, suchas deep learning [9], are being developed. State-of-theart analysis methods will be available in near future.
References[1] K. Yamaguchi et al., Phys. Chem. Chem. Phys., 24,21578 (2022).
[2] K. Shimokita et al., Langmuir, 38, 12457 (2022).
[3] W. Yoshimune et al., ACS Appl. Mater. Interfaces, 14,53744 (2022).
[4] R. Akiyama et al., J. Phys. Chem. Lett, 13 8228 (2022).
[5] S. M. Suturin et al., Mater. Today Commun., 33,
104412 (2022).
[6] https://mlfinfo.jp/groups/comp/en/[7] https://nr.bl17-sharaku.mlf.plus/[8] https://nr.bl17-sharaku.mlf.plus/simulate[9] H. Aoki et al., Sci. Rep., 11, 22711 (2021).

H. Aoki1,2, K. Kasai3, T. Hanashima3, D. Yamazaki4, K. Soyama4, K. Akutsu3, and N. Miyata3
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3Neutron
Science and Technology Center, CROSS; 4Neutron Instrumentation Section, Materials and Life Science Division, J-PARC Center

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Status of SENJU 2022
1. Introduction
SENJU is a TOF single-crystal neutron diffractometer designed for precise crystal and magnetic structure
analyses under multiple extreme environments, suchas low-temperature, high-pressure, and magnetic-field,
as well as for taking diffraction intensities of small single crystals with a volume of less than 1.0 mm3 down
to 0.1 mm3 [1]. Since the operation of SENJU started in2012, our instrument group has carried out continuous
commissioning and upgrades.
In 2022, we installed a newly developed wide area
detector at the bottom of the sample position, and updated the data-processing software, STARGazer-Online.
In addition, we also report on the purposes of the instrument beam-time for SENJU.
2. Installing a wide area detector
The detector is one of the essential components
for a single-crystal neutron diffractometer, and we haveused a wavelength-shift fiber (WLSF) type scintillation
area detector system for SENJU. The original detector size is 256 mm × 256 mm square (64 × 64 pixels).
Recently, Nakamura and collaborators successfully developed a WLSF-type scintillation area detector with alarger detectable area, 512 mm × 512 mm square (128 ×
128 pixels), and we installed the wider detector at thebottom of the sample position of SENJU. Figure 1

shows the latest detector arrangement of SENJU, andNo. 37 is the newly installed area detector. Figure 2
shows a diffraction image of a molecular single crystal
observed by the new detector.
Generally, diffraction data observed at the edge region of an area detector is not used for data processing
because most Bragg peaks observed at the edge region
are partially recorded peaks, and estimations of integrated intensities are difficult. Consequently, the ratio of theavailable region becomes larger when the detectablearea becomes larger. In the case of the WLSF detector for
SENJU, the ratio of the available area is 66% for the original detector and 82% for the newly installed detector.
Figure 1 shows the detector arrangement of SENJU,
including the newly installed detector (Detector No. 37),
and Fig. 2 shows diffraction images observed by boththe original detector and the new detector. Structure
analysis of a standard sample crystal with the new detector showed that the new detector works well for theintensity integrations of Bragg peaks and the structurerefinement. The new detector has been available for theuser program since the 2022B period.
3. Upgrading of STARGazer-Online
STARGazer-Online (SGO) is a remote data-processing
and data-visualization application for SENJU that works
on web browsers such as Firefox, Chrome, and Safari. We

Figure 1. Detector arrangement of SENJU including the new area detector (No. 37).

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Figure 2. Diffraction image of a standard sample crystal observed by the original area detector (left)
and the new area detector (right).

have been continuously upgrading SGO to keep up withthe latest scientific research.
In recent years, multi-condition diffraction measurements, in which one sample is measured under multiple
conditions to investigate the sample-environment-dependent structural changes, have been increasing at
SENJU. In addition, structural analysis of materials containing large neutron absorption coefficient elements,
such as europium and samarium, has also been growing. The data processing for those experiments required
some special processing techniques that were not implemented in SGO, and the data had to be processedby instrument group member’s custom-made scripts.
Consequently, instrument group members had to spend
a long time on such kind of an experiment.
Here, we integrated some custom-made scripts into
SGO to enable users to process the multi-condition data
and the highly absorbing materials data by themselves.
One of the significant upgrades was adding a function
to extract peak profiles and peak intensities from multiple diffraction data, which was initially developed by

Kiyanagi et al. In this function, the profile and intensityof a specified region are obtained from diffraction datawith multi-conditions at once. The diffraction data number and the region are set from the SGO GUI.
Another major update is a function for the absorption correction. In this function, the absorption effectof each Bragg peak is estimated from the shape, cellparameters, and formula of the sample crystal and theneutron wavelength-dependent absorption coefficientsof each element. All parameters are also set from the
SGO GUI.
4. Use of the instrument beam time
In 2022, the instrument beam time was used mainly for measurements of standard samples, and a
vanadium-nickel alloy for calibration of the detector
efficiency.
Reference[1] T. Ohhara et al., J. Appl. Cryst., 49 120 (2016).

T.Ohhara1, R. Kiyanagi1, A. Nakao2, K. Munakata2, Y. Ishikawa2, K. Moriyama2, I. Tamura3, and K. Kaneko1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS; 3New
Research Reactor Promotion Office, JAEA

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Recent Research and Advancements in BL19 TAKUMI
1. Introduction
BL19 TAKUMI, the engineering material diffractometer in the MLF of J-PARC, is mainly used for in situ studiesof the microstructure evolution, mechanical properties,
as well as residual stress mapping in engineering materials. TAKUMI can track various types of crystallographic
information, including phase fraction, lattice strain(stress), texture, dislocation density, stacking fault probability, etc., through carefully analyzing neutron diffraction patterns. Additionally, a variety of specific sample
environments at TAKUMI enable the in situ studies undervarious extreme conditions, such as cryogenic deformation (10 K~), thermomechanical controlled processes(~1473 K), fatigue, etc.
2. User program and publications
In FY2022, 31 general-use programs, 1 long-term
program and 1 project-use program were successfully
conducted on TAKUMI. Thanks to the improvement in
the COVID-19 situation, users have essentially conducted their experiments on-site, and beamline staffs havecarried out four proposals on behalf of the users. The

statistics about the experimental types and the materials of the experiments conducted during FY2022 aresummarized in Fig. 1. The in situ studies during loading
test increased from 60% to 80% compared to FY2021,
mainly due to the increase in the low temperature loading test. On the other hand, the beamtime percentage
for residual stress mapping was 11%, which was mainly
occupied by additive manufacturing samples. Highentropy alloy, which has attracted significant attention
in recent years, dominated the metal and alloy part tooccupy 37% of the beamtime, the same percentage asiron and steel. The rest of the beamtime was used forlight metals (Ti- and Mg- based alloys, 22%) and composites (4%).
Thanks to the efforts of the users and the collaborators, 30 papers using the data measured at TAKUMI havebeen published in 2022. The statistics on experimental
types and materials used in the papers are summarized
in Fig. 2. Additionally, two poster awards and a young
researcher prize were received in relation to the experiments at TAKUMI. Some highlights of the papers are introduced as follows:

Figure 1.	The statistics of beamtime of TAKUMI in FY2022. (a) The types of experiments conducted at TAKUMI and (b) thetypes of materials used in those experiments. The percentages represent the beamtime (in days).

Figure 2.	The statistics of papers using TAKUMI published in 2022. (a) The types of experiments conducted at TAKUMIand (b) the types of materials used in those experiments. The percentages represent the number of papers.

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(a) “Metalloid substitution elevates simultaneously
the strength and ductility of face-centered-cubic
high-entropy alloys”, by Daixiu Wei, et al. [1]. The
quantitative evaluation of dislocation density, volume fraction of martensite, and stacking fault probability, through in situ neutron diffraction, revealed
that the unusual synergy of high strength and extraordinary ductility in high-entropy alloys with Si
addition is attributed to the activity of multiple deformation modes.
(b) “Flexible and tough superelastic Co-Cr alloys
for biomedical applications”, by Takumi Odaira,et al. [2]. Neutron diffraction has verified that a novel
Co-Cr-based alloy exhibits a significant elastic strainof 2.82%, followed by a huge superelastic recovery
strain of 15.8%. The latter is attributed to martensitic
transformation.
(c) “Evidence supporting reversible martensitic
transformation under cyclic loading on Fe–Mn–
Si–Al alloys using in situ neutron diffraction”
by Takahiro Sawaguchi, et al. [3]. The behavior ofmartensitic and reversion transformations during
cyclic tension–compression loading at RT in three
Fe–30Mn–(6−x)Si–xAl (x = 0–2, mass%) steels wasstudied by in situ neutron diffraction. The Fe–30Mn–
4Si–2Al alloy is confirmed to provide a higher plastic
fatigue life compared to the others due to its reversible martensitic transformation.
(d) “Effect of hydrogen on evolution of deformation
microstructure in low-carbon steel with ferrite microstructure”, by Kazuho Okada, et al. [4]. Neutron
diffraction revealed that hydrogen-charge changed
the dislocation structure in a ferritic-pearlitic 2Mn0.1C steel. It was found that hydrogen increased therelative velocity of screw dislocations to edge dislocations, leading to a tangled dislocation morphology at the initial stage of deformation, and increased
the density of screw dislocations at the later stageof deformation.
(e) “Rediscovery of Hall-Petch strengthening in bulk
ultrafine grained pure Mg at cryogenic temperature: a combined in-situ neutron diffraction andelectron microscopy study”, by Ruixiao Zheng,
et al. [5]. In situ neutron diffraction clarified thedominated deformation mode of ultrafine grained
pure Mg at 77 K. Grain boundary sliding, which led

Neutron Scienceto the softening of bulk ultrafine grained pure Mg
specimen at room temperature, was suppressed at
77 K, indicating the regain of Hall-Petch strengthening at cryogenic temperatures.
3. Upgrades and maintenances
The following upgrades and maintenance were performed to make TAKUMI more user-friendly and morestable in FY2022:(1) The chamber for cryogenic loading test was modified for DIC strain measurement. Macro strain as
well as the localized strain can be accurately measured combined with in situ neutron diffraction during cryogenic deformation.
(2) A new compressive jig was developed for the
cryogenic system and has been used for users’ experiments. In situ neutron diffraction experiments
during a compression test can be performed down
to 20 K at TAKUMI.
(3) A set of grips for the high-temperature tensile test
using the induction heating system was fabricatedand tested. In situ neutron diffraction experiments
during the tension test using the induction heating
system is now available.
(4) An option for exporting the averaged loading data
(e.g., strain and stress) corresponding to each slice
was added in Emaki GUI, the software for neutron
data reduction at TAKUMI.
References[1] D.X. Wei, L.Q. Wang, Y.J. Zhang, W. Gong, T. Tsuru, I.
Lobzenko, J. Jiang, S. Harjo, T. Kawasaki, J.W. Bae,
W.J. Lu, Z. Lu, Y. Hayasaka, T. Kiguchi, N. L. Okamoto,T. Ichitsubo, H.S. Kim, T. Furuhara, E. Ma, H. Kato, Acta
Materialia 225 117571 (2022).
[2] T. Odaira, S. Xu, K. Hirata, X. Xu, T. Omori, K. Ueki, K.
Ueda, T. Narushima, M. Nagasako, S. Harjo, T. Kawasaki,
L. Bodnárová, P. Sedlák, H. Seiner, R. Kainuma, Advanced
Materials 34 2202305 (2022).
[3] T. Sawaguchi, Y. Tomota, F. Yoshinaka, S. Harjo, Acta
Materialia 242 118494 (2022).
[4] K. Okada, A. Shibata, W. Gong, N. Tsuji, Acta
Materialia 225 117549 (2022).
[5] R. Zheng, W. Gong, J. Du, S. Gao, M. Liu, G. Li, T.
Kawasaki, S. Harjo, C. Ma, S. Ogata, N. Tsuji, Acta
Materialia 238 118243 (2022).

W. Gong1, T. Kawasaki1, W. Mao1, K. Aizawa2, and S. Harjo1
Neutron Science Section, Materials and Life Science Division, J-PARC Center; 2Materials and Life Science Division, J-PARC Center

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The Current Status of the Versatile Neutron Diffractometer,
iMATERIA
1. Introduction
The local government of Japan’s Ibaraki Prefecture,
where the J-PARC sites are located, has decided to build
a versatile neutron diffractometer (IBARAKI Materials
Design Diffractometer, iMATERIA [1]) (fig. 1) to promoteindustrial applications for the neutron beam in J-PARC.
iMATERIA is planned to be a high-throughput diffractometer that could be used by materials engineers andscientists in their materials development work, including in chemical analytical instruments.
The applications of neutron diffraction in materials
science are (1) to analyse the structure 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 face 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 andsmall-angle scattering detector bank. The angular coverage of each detector bank is also shown in Table 1. The
rotation speeds for the disk-choppers are the same, witha 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 andsmall-angle with gradually changing resolution. Whenthe speed of the wavelength selection disk-choppers is
reduced to 12.5 Hz (DF mode), we can access a wider
d-range, 0.18 < d (Å) < 5 with Δd/d = 0.16%, and 5 < d (Å)< 800 with gradually changing resolution with doubled
measurement time compared to the SF mode.
2. Current status
All of the four banks, high-resolution bank (BSbank), special environment bank (90-degree bank),
low-angle bank and small-angle bank, are operational. It
takes about 5 minutes (in DF mode) to obtain ‘Rietveldquality’ data in the BS bank at 700 kW beam power for
about 1 g of standard oxide samples.
Figure 2 shows a typical Rietveld refinement pattern
for a LiCoO2 sample, cathode material for a lithium-ion
battery (LIB), at the BS bank by the multi-bank analysis
function of Z-Rietveld software [2]. It takes 20 min in

Table 1.	Instrumental parameters of iMATERIA. L2 is the scattered flight path. The d-range (q-range) for eachbank is the maximum value for 2-measurement mode.
L1
26.5 mGuide length
Position of Disk choppers

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

112

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

MLF Annual Report 2022

Neutron Science

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

Figure 3.	PDF refinement pattern for Li(Ni0.5Co0.2Mn0.3)O2 at the
BS bank of iMATERIA.

DF mode to collect the available Rietveld data, due tothe high neutron absorption cross section for natural Li(σsNat = 70 barn).

structure (PDF; Pair Distribution Function) is as important as the average structure of crystals. The iMATERIA
data have been prepared for local structure analysis.
With the cooperation of the NOVA group, the iMATERIA
data were loaded into a program managed by the NOVA
group, allowing a reduced pair distribution function,
G(r), to be derived. Figure 3 shows the results of the PDF
refinement of Li(Ni0.5Co0.2Mn0.3)O2, the cathode material of Li batteries, using PDFgui software [6]. We foundthat acquiring the BS bank data for PDF refinement took
about 30 minutes in DF mode at 800 kW beam power,
3-5 times longer than the measurement time requiredfor Rietveld analysis.

3. Sample environments
The automatic sample changer is the most important sample environment for high-throughput experiments. Our automatic sample changer [3] consists of asample storage, elevating system of two lines, two setsof pre-vacuum chambers and a sample sorting system.
We can handle more than 600 samples continuously atroom temperature (RT) without breaking the vacuum of
the sample chamber.
The vanadium-furnace (~900 °C), the gas flow furnace (~1000 °C), and the 4 K and 1 K cryostats are readyfor experiments.
The rapid heating/quenching furnace with automatic sample changer (RT – 1273 K with heating speed
10 K/s and cooling speed > 20 K/s) [4] and the universal
deformation testing machine (max loading 50 kN with
RT – 1273 K) [5] are available for texture measurements.
The in-operando charge and discharge measurement system for LIB with a sample changer is available
in cylindrical, coin and laminated types of batteries.
4. Application for local structure analysis in
iMATERIA data.
In materials science research, information on local

References[1] T. Ishigaki, et. al., Nucl. Instr. Meth. Phys. Res. A 600(2009) 189-191.
[2] R. Oishi, et. al., Nucl. Instr. Meth. Phys. Res. A 600(2009) 94-96.
[3] A. Hoshikawa, et. al., J. Phys.: Conf. Ser. 251 (2010)
012083.
[4] Y. Onuki, et. al., Metall. Mat. Trans. A. 50 (2019)4977-4986.
[5] Y. Onuki, et. al., Quantum Beam Sci., 4 (2020) 31.
[6] C. L. Farrow, et. al., J. Phys.: Condens. Matter 19(2007) 335219.

T. Ishigaki
Neutron Industrial Application Promotion Center, CROSS

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Status of the High Intensity Total Diffractometer(BL21, NOVA)
1. Introduction
Total scattering is a powerful technique to analyze
non-crystalline 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 ~ 0.35 %)in J-PARC MLF. It is easy to adapt NOVA to a wide rangeof fields: liquids, glass, local disordered crystalline, magnetic structure of long lattice constant and so on.
2. Polarized neutron scattering experiment
A neutron polarizer with polarized 3He gas, referred
to as a 3He spin filter, based on the Spin Exchange
Optical Pumping (SEOP) was equipped to perform polarized neutron scattering experiments at NOVA [1]. The
polarizer was installed at the upstream of the beamline,
and the neutron polarization was held by the magnetic
field produced with a guide field coil to the sample. The
scattered neutrons by the sample were analyzed with a
3
He cell located at 20 mm from the sample position in
the vacuum chamber. Figure 1 shows a schematic viewof the polarized neutron system. In 2022, in addition to
the installation of NOVA-specific polarizer, the beam
duct (downstream of the polarizer in the vacuum chamber) was upgraded to a non-magnetic material (SUS304→ aluminum material). Figure 2 shows the transmittance of the polarized neutron beam before and after
the duct renewal. The blue lines show the transmittanceof the polarized beam in which the spins of polarizer

and analyzer are antiparallel (spin-flip (– +)). The oscillation in Fig. 2(a) is due to the magnetic field on the
beam axis. After the upgrade, it was removed, and we
confirmed that there was no problem with the polarized
neutron beam.
We present examples of polarized neutron experiments. Figure 3 shows the polarized neutron scatteringprofiles of NaH and NiO. Since this was a test analysis,
we used the results of 10-minute measurements. We
performed trial separations of the incoherent component from light hydrogen in NaH, and of the magnetic
scattering component in NiO. We can conclude that theresults are at a sufficiently practical level.
3. Future plans
Currently, we are developing a reduction programfor polarized neutron experiments and a remote-control
system for cell positions.
In the future, we plan to approach the analysis ofpolarized PDFs, such as water.
Acknowledgement
The polarized neutron scattering experiment system was developed with Dr. Okudaira, Dr. Takada, Mr.
Takahashi, Mr. Kobayashi, and Dr. Oku. We would like tothank Mr. H. Maya for his technical support in operating NOVA. The operation and developments of NOVA
was performed under the S1-type program (2019S06)
approved by the Neutron Scattering Program Advisory

Figure 1. The schematic view of the polarized neutron system installed in NOVA.

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MLF Annual Report 2022(a)Neutron Science(b)
Figure 2. The transmittance of the polarized neutron beam (a) before and (b) after upgrading the beam duct.

Figure 3.	The polarized neutron scattering profiles of (a) NaH and (b) NiO. The data were obtained from short scans(10-minute measurements).

Committee of IMSS, KEK.
This work was supported by JSPS KAKENHI [grant
numbers JP18H05518 (“Hydrogenomics”)], Research
Grants in the Natural Sciences, the Mitsubishi foundation.

Reference[1] T. Okudaira et al., Nucl. Instrum. Methods Phys. Res.
A, 977 164301 (2020).

T. Honda1, 2, 3, H. Ohshita1, 4, K. Ikeda5, and T. Otomo1, 2, 3
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, SOKENDAI; 4Technology Development Section, Materials andLife Science Division, J-PARC Center; 5Neutron Industrial Application Promotion Center, CROSS

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MLF Annual Report 2022

Current Status of the Energy-Resolved Neutron Imaging
System RADEN
1. Introduction
The energy-resolved neutron imaging system“RADEN”, installed at beamline BL22 in the MLF of
J-PARC, is a dedicated instrument for wavelength/energy-dependent neutron imaging experiments, which
utilizes fully the short-pulsed neutron’s nature [1]. A variety of imaging experiments have been conducted at
RADEN, such as Bragg edge imaging, neutron resonanceabsorption imaging, and polarized pulsed neutron imaging, in addition to the conventional neutron imaging.
In this report, the recent results of the technical development and remarkable application studies conducted at
RADEN are described.
2. Upgrade of the resonance imaging detector
A two-dimensional neutron detector called lithiumtime-analyzer neutron detector (LiTA) has been developed for energy resolved neutron imaging [1,2]. LiTA
consists of a lithium-6 glass scintillator (Scintacor, GS20),
a 16 × 16 multi-anode photomultiplier tube assembly(Hamamatsu, H9500) and DAQ modules. The detector
has its advantages in measurements in the high neutronenergy range and high counting rate by utilizing its fasttime response and optical transparency of the lithium
glass scintillator. This characteristic has been used forneutron resonance absorption imaging and transmission measurement of high energy neutrons.
The hardware and software of the LiTA detector remained in its development stage for a while, and thatcaused inconveniences when it was used in many applications. Hence, the hardware has been redesigned
to make it a compact and portable detector for wide
and general use (see Fig. 1). With regard to the software
upgrade, the LabVIEW-based dedicated data acquisition software was converted to the DAQ-MW, which is
the MLF standard data acquisition system. The greatest advantage of the migration to DAQ-MW is the realization of sequence measurements controlled by the
IROHA2 server. For example, it is possible to exchange
many samples remotely or to perform CT measurement
while rotating samples. Thus, the LiTA detector is now
operated easily similar to the RADEN’s regular detectors,
such as µNID and nGEM. In addition, online analysis software was also introduced to confirm two-dimensional
images, TOF, and pulse height distribution in real timefrom the data acquired by the LiTA. It is also possible
116

Figure 1. Photo of the modularized LiTA.

to display two-dimensional images gated by a selected
TOF range or pulse height and vice versa.
Next, we describe an upgrade affecting the TOF
measurements. The 3NBT-CT signal, which is mostly
used as the start signal of TOF measurements, is delayed
several microseconds from the actual “T0 timing”. Hence,
the accessible upper energy limit of the measurement
is about 100 keV. Due to this limitation, the identification of light elements, such as lithium, which has a resonance peak at several hundred keV, was not possibleby the resonance absorption technique. In addition, awide energy range of up to 1 MeV was demanded byseveral users. In order to break this upper energy limit,
TOF recording and kicker pulse counting have been
conducted independently with different trigger signals.
That means, the RCS-XT signal, which arrives 100 microseconds before the actual T0, was used for the TOF startsignal and the 3NBT-CT signal, which gives the neutron
generation information, was used for the kicker pulse
counting. This option allows the user to measure fromthe 0th second. For further upgrades, gamma-ray sensitivity and background of the LiTA will be studied, andthe precise pulse function will be measured for quantitative imaging of elemental distribution.
3. A
 pplication study: Residual stress relaxation in
induction-hardened gears using neutron Bragg
edge imaging
Fatigue damage is a significant concern in largescale engineering components. Understanding the distribution of nonlinear strain/stress around fatigue cracks
is crucial for comprehending the behavior of fatigue andMLF Annual Report 2022

4. Summary and future plans
RADEN is used in various fields, not only scientific,
but also industrial, and the application spreads widely
now. The RADEN group continues the development(a)0 cycle8 ×105 cycles
3 ×105 cycles

ε110

0.002
0.000
-0.002-0.004-0.0065 mm

Residual lattice strain ε110

(b)

(c)

Residual lattice strain ε110

crack growth in engineering materials. For example, induction-hardened gears produced by Neturen Co., Ltd
had compressive residual stress from a unique double
induction quenching (DIQ) process, which improved
their fatigue life.
In our previous work, the Bragg edge imaging technique has been employed to map strain and microstructure in these gears [3]. This time, we studied therelaxation or redistribution of residual stress caused by
fatigue loading at the tooth root of the gears by using
Bragg edge imaging. After Bragg edge imaging, destructive X-ray diffraction (XRD) was also used to characterize the residual stress on the same sample’s tooth root
surface. However, the measurement volumes of Bragg
edge imaging and XRD are distinct from each other and,hence, their results are complementary. Moreover, ourstudy focused on non-destructively investigating the residual stress relaxation behaviors at Hofer’s critical section of the teeth with the different loading conditions
during fatigue tests [4]. The spatial distributions of thelattice spacing and the Bragg edge broadening in the
DIQ gear product were obtained via single-edge fitting
so as to evaluate residual strain/stress distribution. Then,the results were assessed together with XRD results. Ourfindings indicate that residual stress relaxation with fatigue damage primarily occurs in the compressive sideof the DIQ gear tooth root (see Fig. 2), suggesting a connection between residual stress relaxation and fatigue
damage. These valuable insights have the potential toenhance our understanding of fatigue damage mechanisms under various loading conditions and allow tomake accurate estimates of the product service life,
which will lead to an improvement of the gear production processes.
Currently, the Bragg edge imaging method is actively used at RADEN for application studies, involving
a wide range of engineering materials and products,
including high-Mn steels, welded components, railway
axles, and more.

Neutron Science

Hardenedzone

Transition
zone

0.000
-0.002-0.004-0.006

Axial direction
LM_0 cycle5
LL_3 × 10 cycles
5
LR_8 × 10 cycles

0.000-0.002-0.004-0.006
0.0

Axial direction
RM_0 cycle
5
RL_3 × 10 cycles
5
RR_8 × 10 cycles

0.2
0.4
0.6
0.8
Depth from the surface (mm)1.0

Figure 2. Residual lattice strain obtained via Bragg edge imaging: (a) a 2D map, (b) distributions for different
load cycles on the tensile side of the teeth root,and (c) distributions on the compressive side of theteeth root in the axial direction.

work on devices, data analysis software and on imaging
techniques and demonstration studies, so as to promoteuser programs from a broad field.
References[1] T. Shinohara et al., Rev. Sci. Instrum., 91 043302(2020).
[2] T. Kai et al., Physica B: Cond. Matt., 551 496 (2017).
[3] Y.H. Su et al., Sci. Rep., 11 4155 (2021).
[4] Y.H. Su et al., Int. J. Fatigue, 174 107729 (2023).

Y. Tsuchikawa1, Y. H. Su2, T. Shinohara1, T. Kai1, K. Oikawa1, H. Hayashida3, J. D. Parker3, Y. Matsumoto3, Y. Nagai3, and Y. Kiyanagi4
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; 4Hokkaido University

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Polarized Neutron Spectrometer POLANO
1. Introduction
POLANO is a direct geometry chopper spectrometerwith medium energy and spatial resolution. For the purpose of conducting high-efficient polarization experiments in inelastic scattering technique, the POLANO has
been optimized for high transfer energy (HTE) polarization analysis [1-3]. Since 2019, the POLANO has opened
to a part of the user program that deals only with unpolarized neutron experiments. Some of the unique
techniques and ideas of the time-of-flight (tof ) methodwith a so-called event recording data acquisition processes came up. The omega-rotation measurement is
one of the excellent ways, which enable us to measure
the entire four-dimensional momentum Q (qx, qy, qz)
and energy E spaces. POLANO can also be available
to measure the inelastic signals with the multi-Ei technique, though this is not a new technique but a resulting event recording system of the tof method. Utilizing
the above-mentioned technique, a reasonable qualityof data is being obtained, and scientific results (articles)
will be generated using the POLANO spectrometer.
We also made significant efforts to develop andinstall polarization devices, including magnetic and related devices, in order to realize the HTE polarization.
The HTE polarization can be realized by combining SEOP
(spin exchange optical pumping) 3He gas spin filter witha 5.5 Qc bending mirror analyzer.
2. On-beam activities
As in the past years, proposals for unpolarized
neutron experiments are open for general use of the
POLANO spectrometer. We constantly receive proposals and their total request beam time is around 30 daysa half round. Most of the users require the same levelof advanced experimental environment as other instruments (beam lines), such as high-magnetic field experiments, scattering angle rotation measurements,
special sample environment experiments, and so on.
The POLANO has been making an effort to meet theseexperimental requirements, in particular, with regard toits computational environment.
Along with the general user experiments, we arepromoting polarized neutron commissioning. In order toaccomplish effective on-beam commissioning, we consulted experts from other facilities. Professor L.J. Chang
of NSRRC in Taiwan and Dr. G. Nilsen of RAL in the UK
were invited as a KEK visiting researchers to contributeto the scientific use of polarized neutrons and provide
technical advice.
3. Polarization commissioning
An in-situ polarized 3He neutron spin filter (NSF) is
installed in the POLANO for incoming neutron beampolarization [4]. The commissioning of the 3He NSF wasstarted using the neutron beam, and the 3He polarization was confirmed to have achieved 80% by measuring the neutron transmission for a cell with 3He gas of
21 atm-cm. The corresponding neutron polarization andneutron transmission are plotted in Fig. 1. The 3He NSF
was operated successfully over 10 days with no trouble
or interruption. During the continuous operation, 3He
polarization was periodically monitored by adiabatic
fast passage NMR [5], as shown in Fig. 2.
4. Newly aligned detectors
New position sensitive detectors (PSD), which areessential for the research of magnetism, have been added to the low-scattering PSD bank. For determining the

Figure 1. Neutron polarization and transmission for 3He gas of 21 atm-cm and 80% polarization.

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Figure 2. 3He polarization measured during a continuous operation of the 3He NSF in the POLANO.

precise neutron position in the detectors, the number ofcharges on both side of PSD tube (Q1 and Q2) has to becorrected by using the relation below.

=

( 1+

2

2)

Here L is the length of the detector, Q1 and Q2 are
the pulse wave height values output from both ends ofthe detector and A, B and C are the coefficients to adjust
the position. Then, the x corresponding to the neutron
detected position can be determined.
In the calibration measurements, a polyethylene
sample and 9 slits of cadmium plate were set up andthree peaks due to incoherent scattering from thesample were observed on each detector. The spacing
between these peaks was calculated according to thegeometrical conditions and the ABC parameters were
determined to match their lengths. The measured incoherent scattering peaks were fitted by a Gaussian function. A 2D detector map with slits pattern corrected by
the fitted new ABC parameters is shown in Fig. 3. The
algorithm for deriving the ABC parameters carried out
in this study is useful and the development of software
to automate its derivation has been planned.
5. Future prospects
In this year we have made significant efforts to refurbish and optimize the devices for the upcoming polarization experiments. Now, the POLANO is almost readyto launch a polarization experiment via an on-beam testat the MLF beamline BL23. In addition to beam commissioning, developments and updating devices andFigure 3. Calibrated position sensitive detector pattern.

methods are indispensable to realize spherical polarimetry with a pulse neutron beam. In particular, the R&Dof new devices, such as a spin flipper after the sample,
high polarization 3He filter, and large solid angle SEOP
analyzer for the future HTE polarization will be conducted for better performance of the neutron polarization
experiments.
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., J. Phys.: Conf. Ser. 862 012011 (2017).
[5] T. Ino, JPS Conf. Proc. 22 011016 (2018).

T. R. Yokoo1,2, N. Kaneko1,2, D. Ueta1,2, S. Itoh1,2, T. Ino1,2, S. Yamauchi1,2, K. Hayashi1, 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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MLF Annual Report 2022

Sample Environment at the MLF
1. Introduction
The MLF sample environment (SE) team provides
the sample environment equipment that is sharedfor use among the MLF beamlines, the so-called BLcommon equipment. The equipment is upgraded according to users’ demands. The equipment that can
produce extreme sample conditions is also developed.
Additionally, we hosted the International Workshop
on Sample Environment at Scattering Facilities (ISSE
Workshop 2022) in this Japan fiscal year, and we would
like to provide an overview of it.
2. Cryogenics and magnets
Six pieces of the BL-common cryogenic equipment areavailable for users’ experiments. In JFY2022, (1) the superconducting magnet was operated for 15 experiments, (2)the 4He cryostat for 10 experiments, (3) the 3He cryostat
for 6 experiments, (4) the 3He-4He dilution refrigerator (DR)insert for 11 experiments, (5) the Gifford-McMahon (GM)cryostat for 2 experiments, and (6) the GM cryofurnace for 1
experiment, including instrument proposals. These equipment pieces were used for 200.5 days of experimentation
in total.
The BL-common cryogenic equipment was used on
the two beamlines where it had not been operated previously; the superconducting magnet on POLANO (BL23),

and a combination of the superconducting magnet andthe DR insert on RADEN (BL22) (Fig. 1). In addition, an
IROHA2 device module, which controls the temperatureof the DR insert, was introduced to be available for users’
experiments.
3. High temperatures
For the niobium furnace, there are two types of thesample stick with different thermocouples according to
the temperature range; chromel-alumel thermocouples
for the temperature range up to 1000°C and tungstenrhenium thermocouples for the temperature range up
to 1500°C. According to the regulations of the MLF, it ismandated that at least one user remain near the furnaceand monitor its condition whenever the heater is in operation. In JFY2021, it was approved to operate the furnacewith the chromel-alumel thermocouple stick monitoring remotely by installing the remote monitoring system with IROHA2. In JFY2022, the tungsten-rhenium
stick was allowed to be used for the remote monitoring operation by the MLF equipment safety inspection.
Using the stick, the high temperature user experiment
above 1000°C has been performed on 4SEASONS (BL01)
for the first time, in which the temperature reached 1227°C(1500 K).

Figure 1. The superconducting magnet and the DR insert on RADEN.

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4. Humidity
The H2O/D2O mixing vapor generator [1], introduced in 2021, was utilized for 27 experiments and operated for 82.5 days in JFY2022. For the first time, it was
integrated into the inelastic scattering instrument BL14.
Humidity control using this device is now available at
BL02, 14, 15, and 17 beamlines, with seamless operation
via IROHA2 control system.
5. ISSE Workshop 2022
The 11th International Workshop on Sample
Environment at Scattering Facilities (ISSE Workshop
2022) took place at Resort Hotel Laforet Nasu, Japan,
from August 28 to September 1. This workshop is heldbiennially and is organized by neutron/synchrotron
facilities in the world that belong to the International
Society for Sample Environment (ISSE) [2]. The 11th
edition marked the first occasion when the workshop

Neutron Science

was held in an Asian country. Despite the effects of the
COVID-19 pandemic, 87 engineers, technicians and scientists engaged in sample environment work participated in the event. 33 oral presentations, including online
talks, and 36 poster presentations were given during theworkshop (Fig. 2). Additionally, a round-table discussion
on the international collaboration regarding sample
environment in this pandemic time was also held. We
exchanged information on new techniques related tosample environment and enjoyed interaction and fruitful discussion. The 12th edition will be held in Sweden
in 2024.
References[1] H. Arima-Osonoi et al., Journal of Applied
Crystallography 56 (2023) 1802-1812.
[2] S. Ohira-Kawamura, Neutron News 34 (2023) 2.

Figure 2. Photos of the oral (left) and poster (right) sessions in the ISSE Workshop 2022.

M. Watanabe1, Y. Sakaguchi2, R. Takahashi1, M. Ishikado2, Y. Yamauchi3, S. Ishimaru3, S. Ohira-Kawamura1,4, M. Nakamura3, H. Arima2,
S. Takata1,4, Y. Su1, S. Zhang2, T. Morikawa2, K. Ohuchi2, and T. Oku1
1
Technology Development Section, Materials and Life Science Division, J-PARC Center; 2Neutron Science and Technology Center, CROSS;
3
NAT Corporation; 4Neutron Science Section, Materials and Life Science Division, J-PARC Center

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MLF Annual Report 2022

Evaluation with Geant4 for Neutron Detector Performance122

1. Introduction
Geant4 [1] is a toolkit for simulating the physicalinteractions of particles passing through matter; it is
widely used in particle and nuclear physics, as well as
astrophysics and medical applications. In Geant4, asshown in Fig. 1, the mean free path of a physical interaction is represented by the concept of a step, and the
trajectory of a particle through a material is composedof multiple steps. In each step, the mean free paths of
discrete physical interactions, such as scattering and absorption processes, are calculated sequentially and thephysical interaction with the shortest distance is selected. Physical interactions that occur continuously, such asenergy loss processes due to charged particles, are considered contributions to the step length, while physicalinteractions that occur at rest, such as decay and annihilation processes, are considered at the beginning of
the step. Since the value of the mean free path depends
on the material, the step is updated at the boundaries
between materials. Generally, in Geant4, particles aretracked until their energy is zero in order to accurately
determine where they stop, such as in an absorption
process. On the other hand, to realize the effective
simulation, a range cut is set as a threshold for particle
production for secondary particles produced by physical interactions. Geant4 is written in C/C++, a generalpurpose programming language. Because of advanced
features such as event displays and multi-threaded processing, programs in Geant4 are often huge, and it is difficult for users to create programs from scratch. On theother hand, Geant4 provides many sample programs sothat users can create their own applications based onthem. This paper describes a simple application createdto evaluate the performance of neutron detectors.

2. Geant4-based simulation
Figure 2 shows a N2-Neutron Beam Monitor (N2NBM) as an example implementation of the simple
neutron detector. The N2-NBM detects neutrons via
the 14N(n, p)14C reaction. The N2-NBM is implemented
as a multi-layer structure of the same size as the active
area (65 mm × 65 mm). The detector housing materialis 1-mm thick aluminum alloy. It is filled with a mixtureof Ar and N2 gases at 107.84 kPa with a mixing ratio of
94.02 : 5.98. The thickness of the gas layer is 12 mm. In
the future, N2-NBM with this detector parameter will be
installed in several MLF neutron beamlines. Note that although the N2-NBM is a gaseous radiation detector withsome anode wires, its existence is negligible because of
the minute size of the anode wires.
In Geant4, Neutron High Precision physics model(HP) is registered to reproduce neutron detection reactions such as the 14N(n, p)14C reaction. The evaluatednuclear data library, JEFF3.3 [2], is employed at HP toreproduce the physical processes of elastic scattering,inelastic scattering, absorption, and fission of neutrons
with energies below 20 MeV. The QGSP_BIC_HP package [3] is applied in this study. The QGSP_BIC_HP package is a general-purpose physical process package usedin radiation protection and shielding and medical applications and can also reproduce radioactive decay,
including activation. In the simple application implemented, information on particles that have lost energy
within the active area is collected, as shown in Table 1.
The following information is collected during the simulation: particle name, track ID, parent ID, parent name,kinetic energy, original position, created process nameand volume name of the original position. Track ID is aunique number assigned to each track, and parent ID is

Figure 1. Concept of particle transportation in Geant4.

Figure 2. Implemented neutron detector (N2-NBM).

MLF Annual Report 2022

Table 1. Information stored in the simulation.
Par ticle infor- particle name, track ID, parent ID, parent
name, kinetic energy, original position,mationcreated process name, volume name oforiginal position
Behavior infor- first position, last position, total energy
mation in an ac- deposit, total path length
tive area

the track ID of the parent particle. Volume name is thename given to the components of the simulation setup.
In addition, the positions of incidence into and emission
from active area, the amount of energy deposit within
the active area, and the length of the track are collected
as the behavior in the active area. These are derived byintegrating the information obtained in each step.
3. Simulation results
Figure 3 shows the amount of energy deposit when
25 meV neutrons are vertically incident on the N2-NBM.
The detector size and material of the N 2-NBM follow Fig. 2. The number of simulation trials is 108. The
initial energies of the proton and 14C produced in the14
N(n, p)14C reaction, the neutron-detected reactionof N2-NBM, are 0.58 MeV and 0.04 MeV, respectively,

Figure 3.	Energy deposit of 25 meV neutrons perpendicularly
incident on the N2-NBM.

Neutron Science

indicating that the N2-NBM analog signal is dominated by the proton contribution. On the other hand, 14C
is a radioactive isotope that emits β-rays, causing theenergy deposit to exceed 0.62 MeV, the Q value forthe 14N(n, p)14C reaction. The neutron efficiency of the14
N(n, p)14C reaction to 25 meV neutrons is expected tobe (6.730 ± 0.259)×10–6. Here, binominal distribution
error is assigned as the error of neutron efficiency. The
same treatment applies to the handling of neutron efficiency errors described below. The 27Al(n, γ)28Al reaction
occurring in the detector housing and the 40Ar(n, γ)41Ar
reaction occurring in the chamber gas are considered ascompeting reactions, as shown in Fig. 3. These competing reactions emit prompt γ-rays by absorbing neutronsand β-rays by β-decay of the radioactive isotopes 28Al
and 41Ar. The half-lives of 28Ar and 41Ar are 2.3 minutes
and 1.83 hours, respectively, and can be a backgroundin actual measurements. On the other hand, the abovementioned half-life of 14C β-decay is 5730 years, so its
contribution is negligible. Note that the simulations performed can be regarded as the amount of energy deposit obtained after an infinite amount of time. The neutron
efficiencies of the 27Al(n, γ)28Al and 40Ar(n, γ)41Ar reactions are (9.800 ± 0.031)×10–4 and (1.974 ± 0.044)×10–5,
respectively, which are much higher than those of the14
N(n, p)14C reaction. On the other hand, the distribution of the total absorption peak from the 14N(n, p)14C
reaction and the energy deposit from the competing
reactions can be separated clearly. Therefore, in actual
operation, it can be expected that the threshold will be
set to match the total absorption peak of the 14N(n, p)14C
reaction to operate the N2-NBM.
References[1] S. Agostinelli, et al., Nucl. Instr. and Meth. A 506(2003) 250.
[2] A. J. M. Plompen, et al., Eur. Phys. J. A 56 (2020) 181.
[3] Geant4 Collaboration, “Physics List Guide rev. 7.0”(2022).

H. Ohshita1,2, H. Endo1,3, and T. Seya1,21Institute of Materials Structure Science, KEK; 2Neutron Instrumentation Section, Materials and Life Science Division, J-PARC Center;3
Neutron Science Section, Materials and Life Science Division, J-PARC Center

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KENS Computing
1. Introduction
To create a stable experimental environment, theDAQ environment was virtualized using KVM. The number of physical machines was reduced from 88 to 5. Until
now, the connection was made via the equipment local
LAN, but by converting the physical switches to virtual
switches, the physical switches and wiring in the rack
were also greatly reduced. Fewer physical machines alsomeans a lower incidence of hardware-related failures.
The introduction cost was reduced by 92%, or more than
100 million yen. Power consumption was also reduced
by 96%. The initial cost per unit has been significantly
reduced, making it easier to secure budgets and plan
replacements. Now 1~2 physical machines are systematically replaced every year, so that all the computerswill be replaced in 5 years.
2. Migration to virtual machines
We have been monitoring resource usage with
Zabbix since the physical machines, and based on CPU
and memory utilization, we thought virtualization was
feasible enough. First, after conducting virtualizationfor each application and confirming that it was working
without problems, all functions of DAQ, storage, experiment control, and analysis were implemented in a virtual environment on a single physical machine, startingwith the least-loaded experimental equipment. Today,

the computational environment for all experimental
equipment is deployed on a single physical machine.
3. Virtual machine configuration
Figure 1 is a diagram of the machine. The DAQ partuses DAQ-MW, and the parallel distributed environment that was also configured on physical machines
is reproduced directly on KVM. In addition, control andanalysis servers are also built as virtual environments.
In addition, two network switches were used to construct two different intra-rack local LANs, which werealso configured in the same network configuration as
before virtualization using virtual switches. CPUs, andmemory are allocated for 8 threads and 16 GB memory
for DAQ, with the necessary resources reserved based on
the Zabbix monitoring results. Although this capacity ismore than sufficient, the increased availability of CPUs,
such as AMD’s EPYC series, which are available at a relatively low cost per Core, has made it possible to secure
more resources. The total amount of memory allocatedpar VM and the number of VMs are used to calculate thetotal amount of memory, and a good cut-off capacity
such as 256 GB, 512 GB, etc. is selected. The storage iscurrently available rack-mount servers, with the largest
capacity being 12 3.5-inch HDDs. This is loaded with theestimated capacity needed for the next 5 years based on
the Zabbix monitoring results. We try to select common

Figure 1. Diagram of the computer environment.

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MLF Annual Report 2022

items as much as possible, such as capacity per pieceof memory, power supplies, HDDs and SSDs, and RAID
boards. This is done so that parts can be freely replacedwhen the machine is used as a testing machine after theend of the operation. Measured data from BL09, 21 exceed 500 TB in total. On the other hand, at the time of
replacement, the most cost-effective capacity was 12 TB,
and the capacity after RAID6 configuration was about
120 TB, which means that all the data on BL09, 21 cannot be contained on a single server. In this case, a separate storage server is prepared and stored there. Since
the annual data volume for both BL09 and 21 is around
50 TB, the data is stored on the local server for about 2
years and then erased from the oldest data. Today, someproducts have capacities exceeding 20 TB per HDD. At
the time of the next replacement, a stand-alone server
for DAQ with a capacity of over 200 TB is likely to be
the product of choice. If this happens, the operation toerase data as described above will be unnecessary. Data
stored on a separate storage server is mounted on a machine in the same analysis environment, so it is configured in a way that the user does not have to worry about
the physical location of the data at the user level.

Neutron Science

4. Virtual machine management
The environment has been developed so that Zabbix
can monitor not only the status of the servers, but also of
iDRAC, UPS, and other devices that can be monitored by
SNMP (Simple Network Management Protocol). This allows
various parameters, such as the intake temperature of theserver, the battery temperature of the UPS, and the qualityof the input power supply to the UPS to be monitored all
at once. In the event of a failure, the system is not only notified by Zabbix, but also by the properly configured alert
email function in the hardware, such as APC and iDRAC,
so that it receives double failure notifications. This is toensure that failure notifications are not missed in the unlikely event that one or another element does not function
properly. These measures enabled immediate detection of
malfunctions. Since the maintenance contract is concluded
directly with the manufacturer, not through a supplier, asystem was established to centralize the process from manufacturer support requests to delivery of replacement partsand restoration work, enabling restoration within one totwo days after a breakdown occurs. The system is designed
to have hardware redundancy so that experiments can becontinued even during restoration work, depending on thesituation.

T. Seya1,2 and H. Ohshita1,2Institute of Materials Structure Science, KEK; 2Neutron Instrumentation Section, Materials and Life Science Division, J-PARC Center

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Muon Section
1. Development of the D2 instrument
In recent years, elemental analysis with muonic
X-rays is becoming popular in the D line. A lot of elemental analyses were conducted on archaeologicalobjects, meteorites, and lithium-ion batteries. To obtain
the data in a shorter time, the sample environment andthe detectors were refurbished. The major change wasin the sample chamber, the newly installed hemispherical chamber has 11 ports to mount the detectors (Fig. 1).
2.	Progress of the laser system for ultra-slow muon
generation
The ultra-slow muons are generated by ionizing
the evaporated muonium from the muon-stopping
target by irradiating coherent lights. To realize the efficient ionization of the muonium, vacuum ultraviolet(VUV) light (122.09 nm Lyman-α) and coherent lightwith wavelengths shorter than 360 nm are required. So
far, over 10 µJ Lyman-α light has been successfully generated and applied to ultra-slow muon generation. To

generate high-power VUV light, the power of the fundamental pulses of 1062.78 nm is required to be 100 mJ,
and specially produced Nd:YGAG and Nd:YSAG ceramics rods (ø4 mm, 80 mm long) are used in the diodepumped amplifiers as a gain medium. However, whenusing such a long rod, it was difficult to eliminate the optical wavefront distortion caused by the inhomogeneity
in the medium. Thus, we decided to change the pumping configuration from a conventional side pump to an
end pump geometry to reduce the optical path length
in the gain medium (Fig. 2). The pump light from the laser diodes (LDs), which used to be injected from the sideof the rod, will be injected coaxially. The new pumping
geometry requires spatial profile shaping for the pumplight beam from LDs, but the wavefront distortion can bedramatically reduced by shortening the crystal length.
In the new method, sapphire substrates are bonded to
the light input and output surfaces of Nd:YSAG for efficient cooling and end-face protection. The amplifier
module is composed of 9.3 mm cubic Nd:YSAG ceramic,
sapphire plates (ø25.4, t=2 mm) bonded on the ceramic,
and a water-cooling holder (Fig. 3).

(a)

Pump
li
from la ght
ser diodegain medium

long dis~100 tance
mm

(b)

Pump
li
from la ght
ser diodeFigure 1.	Picture of the Hemispheric chamber in the view
from downstream of the beam. Gold coins are set
at a sample position. The Ge detectors and multipixel detectors are equipped at Port 1 - 7, and Port 8- 9, respectively. Ports 10 -11 can be used for decay
counters and other detectors.

128

short
d
~10 m istancem
Figure 2.	Schematic of pumping geometry. (a) conventional
side pump for long laser rod and (b) end pump for
short laser disk.

MLF Annual Report 2022

(a)

(b)

(c)

Figure 3.	SNd:YSAG ceramic for power amplifier. (a) polishedceramic cube, (b) bonded ceramic cube with sapphire plates and (c) set in a water-cooling holder.

3. The kicker system of the S line
The kicker is essential for the simultaneous singlepulse operation of the S1 and S2 areas. However, as
shown in Fig. 4, the number of failures has increased in
the last few years. This could be due to MOS-FET degradation in the kicker power supply. Therefore, just before
the start of the 2022B period, we replaced some MARX
boards preventively by measuring the MOS-FET leakage
current. However, many boards identified as healthy inthe preventive diagnosis failed in the 2022B period. Asa next countermeasure, we plan to replace the MOSFET devices with modern SiC devices; we have alreadyselected the SiC devices and verified the operation of
the power supplies alone. The replacement work will bedone after clearing the technical issue of mixing the useof the SiC device with the existing MOS-FET.

Figure 4.	Number of MARX board failures that occurred ineach operating period. Gray (yellow) bars represent
the number of failures in the circuit that kicks thebeam toward S1 (S2), respectively.

Muon Science

4. The H2 area construction
The first branch of the H-line named the H1 area wascompleted in January 2022, and then the commissioning was performed. The intensity of the surface muons
was measured and was almost the same as its design
value (108 muons/s), despite the absence of a DC separator (or Wien filter) and the failure of the power supplies of the capture solenoids. Currently, the H1 area isopen for users. In the second branch of the H line, theH2 area, applying the technique developed in the U line,
ultra-slow muons are produced and re-accelerated up
to 4 MeV, and the world’s first muon accelerator will be
realized. The beamline is planned to be extended further to produce a novel low-emittance muon beam byaccelerating up to 212 MeV. The beam will be used in
the measurement of the muon g-2 and electric dipole
moment and the transmission muon microscope (TμM).
A new building on the east side of the MLF is necessary
to extend the beamline. The engineering design of theextension building will be finalized in the next fiscal
year. The H2 area construction was completed in March2023 (Fig. 5) and the self-radiation inspection was donein April. The commissioning will be performed in thesubsequent periods.

Figure 5. Picture of the H-line after the H2 area construction.

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Muon Rotating Target
1. Present status of the rotating target
As part of the summer maintenance of the muon
production target, the rotary feedthrough and rotary
coupling were replaced. An anomalous increase in therotational torque was observed after a replacement wasdone in the previous year, and this was also investigated. As a result of the investigation, it was found that thestandard vacuum sealing gasket replaced last year, was
0.1 mm shorter in diameter than the regular one, whichcaused a misalignment of the rotary shaft and a loadon the bearing of the rotary feedthrough. The vacuum
sealing gasket was replaced with a regular one, and an
Oldham type coupling with a larger allowable misalignment (from 0.25 mm to 0.6 mm) was adopted for the
replacement work. After the work was completed, arotation test was conducted, and the rotational torque
was found to be normal. Beam operation was resumed
and has continued stably without any increase in torque.
Although the above-mentioned work was performed in a high-dose and tritium atmosphere, themaximum individual exposure dose was successfully reduced by about 40% compared to the previous summer
maintenance work by applying exposure dispersion andinternal exposure prevention measures using an airline
system (see Fig. 1).

Figure 1.	Rotary feedthrough exchanging working with airline mask and anorak suit.

2. Modification of the MPS circuit
At J-PARC, interlocks are issued by the MachineProtection System (MPS) in the event of an anomaly. In
the conventional MPS for rotating targets, the MPS is
triggered when the torque of the rotating motor continuously exceeds the MPS alarm set value for a certain
period of time, because a mechanical lock or the like
was assumed. In this circuit, the MPS could not be triggered when the rotating motor torque fluctuated in ashort period of time. Last year, the circuit was modified
to immediately trigger the MPS when the motor torquemomentarily exceeds the threshold value. In this case,however, the MPS threshold had to be set considerablylarger to prevent false detection. Since the maximum
torque output of a rotating motor is limited, a momentarily large rotating motor torque will not immediately
cause the mechanism to fail. On the other hand, if a larger-than-normal torque is continuously generated, thetarget rotation mechanism continues to be subjected
to a large load, and this situation directly leads to equipment failure.
We have changed the MPS circuit related to themuon target rotating motor torque from a circuit inwhich the MPS is triggered by an instantaneous increase
in torque to one in which the MPS is triggered by using the average value of the rotating torque during acertain period as a threshold value. It detects whether
or not the average torque value is above the thresholdvalue every 30 seconds and counts up the number oftimes the value is above the threshold value. When thenumber of detections in the last 20 minutes exceeds 20
times, the MPS is triggered. The MPS alarm is detected
every 30 seconds. The motor torque value during stablerotation is 5%, and the threshold is set at 12%.
3. Preparation of a spare target
The third rotating target was completed by incorporating the bearing box and cooling jacket fabricatedusing HIP in the previous year. Rotating target No. 3 hasbeen tested at the factory for rotation and attachment
to the plug shield, and it has been confirmed that there
are no problems. The target will be commissioned forremote insertion into a new storage vessel and stored
as a spare unit.

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

1

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Muon Science

Beam Commissioning at D1/2 Areas
1. Introduction
The D line of MLF MUSE has a long superconducting solenoid, which can provide positive and negative
decay muons from a few MeV/c to 120 MeV/c in addition
to surface muons. The primary proton beam energy of
the MLF is as high as 3 GeV, resulting in a high negative
muon yield. In particular, thanks to the recent increase
in beam power, the world’s highest intensity negative
muon beams are available. Using this high-intensity
negative muon beam, various experimental applications
have been developed, such as nondestructive elemental
analysis using negative muon characteristic X-rays andnegative muon spin rotation/relaxation. In this report,
we cover the current status of the decay muon beamcommissioning at the D line and other developments.
2. Radiation control for high energy decay muon beam
As seen in the examples of experiments, such as μSR
under pressure and nondestructive elemental analysis,
the demand for the use of high-energy (momentum)
muons is increasing year by year. There are two main
problems in the use of high-energy muons at the D line.
One is the lack of output power of the quadrupole magnets (triplets) for the D1 area downstream of the branch.
The other is the radiation dose when negative muon
beams are used. The former problem was solved by replacing the magnets and the magnet power supply witha high-specification one (see the report by Yuasa et al.).
On the other hand, the latter radiation problem is atrade-off between the allowable radiation dose and themuon energy required for the experiment and should
be handled carefully. Here, we report on the latter.
When a negative muon is bound to a nucleus, it emits
neutrons through the following reaction
+

−

→

+ +

+

.

utilize higher momentum while suppressing the radiation dose. In order to realize this, an interlock system for
the Q magnets in the pion transport section was studied
and commissioned.
In this interlock system, some or all of the Q magnets in the pion transport section (Fig. 1) are not excited
at momenta above 45 MeV/c. Even if the beam profilechanges in the pion transport section due to a change
in the state of the Q magnets, most of the phase space
information is lost due to the decay of the pions in thesolenoid section. Therefore, it can be assumed that thedownstream beam profile is not significantly affected.
Hence, a simple interlock can be configured to utilize ahigh momentum negative muon beam provided thatone (or more) of the Q magnets is (are) not excited according to the momentum.
The following commissioning was performed
in order to clarify the intensity reduction when the Q
magnets in the pion transport section are not excited.
Beam intensity and dose equivalent rate were measured when all Q magnets in the pion transport section
were not excited. Three points (point C, E, and X in Fig. 1)
were selected for dose equivalent rate measurements
because these points have empirically high dose equivalent rates.

(1)

In the MLF experimental hall, the radiation dose equivalent rate is controlled not to exceed 25 μSv/h to avoid
radiation exposure. For this reason, the maximum momentum of the negative muon beam currently available
is limited to 45 MeV/c.
On the other hand, in the nondestructive analysis
of cultural heritage objects, for example, the demandfor elemental analysis at deeper depths (i.e., higher
momentum) has been increasing year by year. This is anatural demand, since elemental analysis using negative
muons has advantages that other methods cannot imitate. Therefore, a simple interlock system is required to

Figure 1.	Schematic diagram of the D line showing the locations of radiation measurement (points C, E, and X).

131Muon Science

MLF Annual Report 2022

Figure 2 shows the momentum dependence ofthe measured negative muon beam intensity and dose
equivalent rate. Below 45 MeV/c, all Q magnets DQ1-2-3
in the pion transport section were excited, and above
the momentum, all DQ1-2-3 were not excited. The momentum dependence of the dose equivalent rate wassuppressed to approximately 5 μSv/h or less if the magnets DQ1-2-3 were not excited, which was not a problem
at all. On the other hand, the intensity dropped by twoorders of magnitude when DQ1-2-3 was not excited.
Nevertheless, the intensity near 100 MeV/c was strong
enough to be used in experiments (~105 muons/sec).
Based on these results, we can expect to find the conditions to obtain sufficient beam intensity to perform experiments in the momentum region between 45 MeV/c
and 100 MeV/c, while suppressing the radiation dose, by
no excitation of only one or two Q magnets. We plan tofurther refine the conditions in the future.
3. Remote access/experiment
When a user conducts an experiment at the MLF,
once the sample setting and other tasks are completed and the system is in a steady state, it is possible toautomate the process to some extent by setting up asequence in the IROHA2 system. However, if the user
wants to change the sequence during the measurement, or if some trouble (sudden temperature change,etc.) occurs and requires immediate action, the user
must go to the MLF from the dormitory, for example. In
some cases, the user must walk about 28 minutes fromthe dormitory to the MLF, which is about 2.4 km away.
In addition, with the recent trend toward remoteness,
users are required to access the J-LAN intra network(the network in J-PARC where DAQ machines and otherequipment are installed) from an external network.
To solve these problems and improve convenience,
we set up a system for remote access and remote control (Figure 3). We set up a server for remote control,
which can access the IROHA2 sequence server and otherequipment for measurements, in KEK’s Tokai 1 building.
This enabled users to respond quickly to any urgent
situation, such as a sudden change in temperature,by simply going to KEK’s Tokai building 1, which is only
120 meters away from the dormitory.
This system is also useful when you want to accessthe measurement server from outside J-LAN. Outsideaccess is usually complicated due to the need to submit
the IP addresses of all the servers you wish to access, aswell as all the port numbers to connect to them. Thissystem, on the other hand, requires only the completion of a J-LAN VPN connection application to access theserver. This has made the work on the experiment moreconvenient.

Figure 2.	Muon beam momentum dependence of (a) negative muon intensity at D2 area
scaled to 1 MW operation and (b) radiation measured at the positions shown in Fig. 1.

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Muon Science

Figure 3.	(Left) Route from dormitory to the MLF (~28 min). (Right) Route from dormitory to KEK Building No.1 (~ 3 min).

Figure 4. Diagram of the data acquisition system and gateway server for the remote access/experiment.

4. Summary
We have performed basic commissioning to assemble a simple interlock that can utilize high-energy negative muons in the D line while controlling the radiation

dose. We have found that the Q magnets in the piontransport section can be not excited in whole or in partwithout any problem. A system for remote access/experiments was also established.

S. Takeshita1,2, P. Strasser1,2, A. Koda1,2, W. Higemoto1,3, I. Umegaki1,2, S. Doiuchi1,2, A. Hashimoto1,2, Y. Ishikake1,2, N. Kawamura1,2,
and K. Shimomura1,2
1
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK; 3Advanced
Science Research Center, Sector of Nuclear Science Research, JAEA

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Development of D2 (Muonic X-ray Element Analysis)
Instrument and Sample Environment
The D2 experimental area provides various momentum of decay muons with a large space of about 4 m ×
4.5 m, allowing users to bring in their own equipment
or chambers needed to realize their experiments. This
has led to the publications and awards of remarkable
results in several fundamental physics experiments [1, 2]
and elemental analysis [3, 4] in FY2022. Two of the KEK
S1 projects led by Prof. Miyake (KEK) and Prof. Takahashi(The Univ. of Tokyo) have conducted experiments at theD2, providing fruitful results and publications. These include an attempt of CT imaging technique of muonic
x-rays for analysis of archaeological samples using CdTe
detectors [3], an experiment with a TES calorimeter [1],and elemental analysis of the returned samples from
Ryugu asteroid by the Hayabusa2[4].
We had 17 theme experiments conducted at theD2 experimental area in FY2022. The largest numberof the themes was elemental analysis of muonic x-rays(Fig. 1), which was followed by soft error (2 themes),
Atomic Physics (2 themes), μCF(1 theme), and Nuclear
capture(1 theme).
In Prof. Miyake’s S1 project, we developed a sample chamber to install germanium (Ge) semiconductor
detectors. Then, the sample chamber, which was called
hemispherical chamber, became available to any userof the D2. The hemispherical chamber was designed by
Dr. M. Tampo with a capacity to install 9 Ge detectors
to measure muonic x-rays. The goal was to obtain finedata within a shorter time in order to perform effectively
larger numbers of interesting research programs in thelimited beam time. Therefore, the development of thedata taking, and analysis is essential for efficient use of
the beamtime. For each experiment, the difficulties ofadding up all data immediately after completion of themeasurement has been a problem. So, it is desired to
add up all data during measurements of muonic x-rays.
One of the major advancements in the D2 experimental area in FY2022 was the development of software to analyze data instantly during measurements.
Since we have 9 ports to set Ge detectors in the sample
chamber for elemental analysis with muonic x-ray, weneed to check data obtained from each detector andto obtain total count of all data from the 9 detectors toknow whether the statistics is high enough in the measurement. Figure 2 shows a screenshot of the software tosum data from each Ge detectors and to calibrate theenergy of the detectors. On the right side, a run number is set (the number of 204003 can be found in Fig. 2)
at first and trigger modes are selected as beam or selfmodes. Then, channels corresponding to detectors toanalyze are selected by checking a box. The application
displays each spectrum with different colors in the center of the window. The summation of all data can also be
obtained immediately by clicking the sum bottom. The
application is effective even for a still-ongoing run, notonly for a run that has already finished. The software wasrealized by Mr. Y. Ishikake and Mr. S. Doiuchi.
The hemispheric chamber was modified so that nine
Ge semiconductor detectors could be mounted, andvarious elemental analysis experiments were conducted

Figure 1. Experimental themes conducted at D2 in FY2022.

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Muon Science

Figure 2.	A screenshot of software to sum data from each Ge detectors and to calibrate the energy.

using these detectors in FY2022. As an example, the following elemental analysis experiments were conductedin FY2022:[2022A0352(P)] Depth profiling of gradient compositionin diode-type CeTe X-ray detector by position sensitive
muonic atom spectroscopy[2022A0066] Confirmation of the effect on the loss ofmetallic Li deposition in a lithium-ion battery using muonic x-rays[2022B0054] First attempt to apply elemental analysis
with muonic x-rays to commercially available LIBs
[2021MS02] Elemental analysis of cultural property
Other than elemental analysis, the hemisphericalchamber was also used for experiments, such as muontransmission imaging and muon fusion. Particularly, forinvestigation of errors caused by muons in an SRAM,
the depth to analyze can be confirmed by measuringmuonic x-rays during irradiation of muons at the sametime. The research attempts to find the momentum dependence of the rate of error occurrences by irradiationof muons in semiconductor devices.
In FY2022, three new low-energy semiconductor
Ge detectors (LEGe), which we were preparing last year,
have been installed on the hemispherical chamber forexperiments and we conducted further fruitful research
programs in elemental analysis using muonic x-rays.
Acknowledgments
The development of the software that we showed

here was conducted as a part of “integration of arts andsciences” research program promoted by the KEK IMSSMSL and a part of Dr. Miyake’s S1 project. It was also supported by the JSPS Grant-in-Aid for Scientific Researchon Innovative Areas “Toward new frontiers: Encounterand synergy of state-of-the-art astronomical detectors
and exotic quantum beams”. The authors appreciate thecooperation of Mr. Shogo Doiuchi, Dr. Akiko Hashimoto,
Mr. Yudai Ishikake, Dr. Adam Pant and other members of
the Negative Muon Group. The design and productionof the hemispherical chamber and the detector adding
were managed with great diligence by Dr. Tampo.
References[1] T. Okumura et al., “Proof-of-Principle Experiment for
Testing Strong-Field Quantum Electrodynamics with
Exotic Atoms: High precision X-Ray Spectroscopyof Muonic Neon” Phys. Reb. Lett. 130 (2023) 173001(1-7).
[2] S. Nishimura et al., “Rabi-oscillation spectroscopyof the hyper fine structure of muonium atoms”
Nishikawa Prize, Research & Development highlights
in 2022.
[3] T. Nakamura et al., “Formation and evolution ofcarbonaceous asteroid Ryugu: Direct evidence fromretuened samples” Science, 379 (2022) 787.
[4] I-H. Chiu et al., “Non-destructive 3D imaging method
using muonic X-rays and a CdTe double-sided strip
detector” Sc, Rep. 12 (2022) 5261 (1-9).

I. Umegaki, M. Tampo, and Y. Miyake
Muon Science Laboratory, Institute of Materials Structure Science, KEK135

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MLF Annual Report 2022

Muon Beamline Magnets and Power Supplies Update− Upgrade of D1-triplet and Power Supply −1. Introduction
The triplet magnet D1-triplet (DQ10-11-12) is installed just before the D1 area of the decay muon beamline (D-line). This D1-triplet can transport muons with
momentum up to 67 MeV/c because of the limitation of
the temperature rise of cooling water and power supply specifications. But recently, users have requested
higher muon momentum, as high as 90 MeV/c. So, we
decided to upgrade the D1-triplet and power supply.
They were replaced, and new current values that resulted in the same GL product and distance between
the magnet centers were determined so that the beam
optics would not change before and after the replacement. Commissioning was performed at 30 MeV/c. The
current values from the optimization calculations werecompared with the current values obtained after the
beam commissioning.
2. Old and New D1-triplets
As shown in Fig. 1, the D1-triplet is installed just before the D1 area. The old D1-triplet can only transport
muons up to 67 MeV/c. Table 1 shows the parametersthat would be needed for transporting muons of 90
MeV/c with the old and new D1-triplets.
To transport 90 MeV/c muons with the old D1triplet, a current of 504 A would be required, but the existing power supply specification of 375 A is insufficient.
Also, even if 504 A could be supplied, the temperaturerise of the cooling water in the magnet would exceed
30°C, thus violating the J-PARC regulation (temperaturerise of cooling water should be within 25°C). So, we decided to upgrade both the D1-triplet and its power supply. Figure 2 shows the old and new D1-triplets.

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

136

Table 1.	Parameters of the old and new D1-triplets for transporting muons of 90 MeV/c.

Old
Momentum [MeV/c]
Field gradient [T/m]
GL [T]
Magnetomotive force[A*Turns]
Number of coil turns[Turns/coil]
Bore diameter [mm]Pole length [mm]Distance between magnet
centers [mm]Excitation current [A]Excitation voltage [V]Water flow [L/min]
Flow speed [m/s]Temperature rise of coolingwater Δt [°C]

New
90
2.7

1.06

1.09
24170

48

72
300
300

500

490

504
51
10.8
1.6

336
51
25.6
1.9

34

10

Figure 2. Old D1-triplet (left) and new D1-triplet (right).

3. Upgrade of the D1-triplet and power supply
A quadrupole magnet triplet originally designed
for high-momentum muon transport (coil turns N = 72)
was rebuilt and used as a new D1-triplet. The pitch of
the magnets and the position of the field clamps, also
called end guards, were adjusted, and a new support
frame was fabricated. In addition, the power supply was
upgraded from 40 V/375 A to 75 V/1000 A. The replacement of the D1-triplet made transporting muons up to
120 MeV/c possible. At 120 MeV/c, the excitation current
is 448 A, the excitation voltage is 68 A, and the coolingwater temperature rise is 17°C, so it meets the J-PARC
regulation.

MLF Annual Report 2022

4. Beam optics calculation
After replacing the D1-triplet, it was necessary to
optimize the current, considering the magnetic field interference effects and effective length due to changes inmagnetomotive force from the increase in the winding
number of coil, magnet pitch, and end-guard position.
Therefore, the beam transport program Transport wasused to optimize the excitation current so that the beam
size passing through the D1-triplet does not change
downstream. Figure 3 shows the beam envelope of the
new D1-triplet at 30 MeV/c when the current values areadjusted so that the GL products are equal. The upper
half of the graph shows the vertical beam spread, andthe lower half shows the horizontal beam spread.
As a result, when surface muons with a momentum
equivalent to 30 MeV/c are transported, the D1-triplet

Muon Science

Table 2.	Comparison of the current values of the D1-triplet
for transporting 30 MeV/c muon beam.

D1-triplet
DQ10
DQ11
DQ12

Old
68.6 A–124.7 A
124.0 ANew
46.3 A-84.7 A
83.6 A

Commissioning
48.2 A-85.5 A
89.5 Acurrents shown in Table 2 are required to achieve thesame beam envelope as with the old triplet. After the
beam commissioning, the optimum current values arealso shown in Table 2, and they agree well with thebeam optics calculation results.
5. Summary
The D1-triplet and power supply were upgradedwithout problems and now operate smoothly. In the future, users can conduct their experiment at the D1 area
using a muon beam with a higher momentum of up to
120 MeV/c.
6. Acknowledgments
We thank Dr. Y. Irie for helpful discussions aboutmagnetic field interference.

Figure 3. Beam envelope of the new D1-triplet at 30 MeV/c.

Reference[1] T. Yuasa et al., “Upgrade of triplet magnets at J-PARC
MUSE” Proceedings of the 19th Annual Meeting ofParticle Accelerator Society of Japan (in Japanese).

T. Yuasa1,2, H. Fujimori1,2, N. Kawamura1,2, M. Meguro3, H. Sunagawa3, and K. Kawabata3
Muon Science Laboratory, Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science
Division, J-PARC Center; 3NAT Corporation

1

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MLF Annual Report 2022

Muon H-Line PPS Interlock System Update
1. Introduction
The muon H-line has been constructed in experimental hall No.1 of the MLF J-PARC. This beamline includes an experimental area named the H1 area, which
was completed in 2021. In FY2022, the second experimental area (H2 area) was constructed. The Personnel
Protection System (PPS) must be implemented to construct a new experimental area. [1]This article describes the modification of the PPS
done in the H-line to add the H2 area.
2.	Experimental areas in the H-Line, the existing H1
area and the newly constructed H2 area
The structure from the muon target installed on theM2 line in the MLF to the existing H1 experimental area
and the newly constructed H2 area is shown in Fig. 1.
The muon beam is delivered from the muon target
to the experimental areas of the H-line through several
bending magnets. The H2 experimental area and thebeamline downstream from the exit of the bending
magnet named HB2 were newly constructed and accordingly, the PPS system was updated in FY2022.

Figure 1. Experimental areas on the H-Line.

2.1.	PPS system before the construction of the H2
area
When only the H1 area was operated in the H-line,
the supply of muon beams to the H1 area was controlled
by a muon blocker HBB1 and a safety magnet HB2.
Figure 2 shows the PPS logic of the H1 area before
the update. When the door of the H1 area is opened sothat workers can enter the H1 area for sample exchange,
138

Figure 2. PPS logic of the H1 area before the update.

and so on, it is necessary to prevent muon beam irradiation to the experimental area. Safety is guaranteed bykeeping HBB1 closed and by keeping the power supplyof the HB2 magnets turned off.
When the work in the experimental area is finishedand the door is properly closed, the forced OFF command to the HB2 magnet power supply is released and
HB2 excitation is permitted. At the same time, HBB1 isallowed to open, and therefore muon beams can be irradiated to the H1 area.
2.2.	Features of the new PPS for the H-line
The updates of the PPS for the H2 area are slightly
more complicated than usual because the H2 area is located in the straight section through HB2. When entering the H2 area, beam irradiation to the H2 area must be
prevented. However, the safety magnet power supply
HB1 for the H2 area cannot be turned off because themuon beam experiments in the H1 area can be conducted. On the other hand, when entering the H1 area andperforming muon beam irradiation to the H2 area, thepower supply of the safety magnet HB2 for the H1 area
can be turned off.
Therefore, it is difficult to construct the PPS for the
H-line after the H2 area construction by simply referringto the status of entry to the experimental area. The new
PPS of H-line was built to reference the status of the two
safety magnets as well as the information of the entry
to the experimental areas. In addition, a key switch was
installed to select which experimental area is used.
2.2.1 Updated PPS logic for the H1 area
Figure 3 shows the PPS logic of the H1 area after
the update. When irradiating the muon beam to the H1
area, the key switch is set to the H1 mode. At the H1mode, the H1 door is closed, all safety keys for the HBB1
operation are accommodated, and HBB2 is closed, then

MLF Annual Report 2022

Muon Science

Figure 3. H1 area’s PPS logic after the update.

Figure 4. H2 area’s PPS logic after the update.

the muon beam can be irradiated in the H1 area. The
muon blocker HBB1 is allowed to open. The power supply of the safety magnet HB2 is allowed to be turned
on. In order to deliver muon beams to the H1 area, HB1
should be turned on, but the output currents of the HB1
and HB2 are monitored, and HB1 can be turned on only
when these currents satisfy certain conditions. Unlessthe output current of HB2 exceeds a threshold corresponding to the momentum of 12 MeV/c (10% of the
rated momentum of the H-line), the HB1 magnet power
supply is not allowed to be turned on. This logic is necessary to prevent muon beams from traveling straight
through the HB2 magnet and irradiating the H2 area
while work is conducted in the experimental area. In
addition, if the output current of the HB1 is above athreshold that is determined by the current of the HB2,
the HB1 power supply is not allowed to be turned on, sothat muon beams with much higher momentum thanthe HB2 setting will not enter the HB2.

The muon blocker HBB1 is not allowed to open, and
HBB2 is allowed to open. For the safety magnet power
supplies, the HB1 power supply is allowed to be turnedon and the HB2 power supply is not allowed to be turned
on. Since the safety magnet for the H1 area is HB2 in H2mode, the safety of the H1 area is guaranteed by simply
prohibiting turning on the power supply of the HB2.

2.2.2 Updated PPS logic for the H2 area
Figure 4 shows the PPS logic of the H2 area after the
update. When irradiating the muon beam to the H2 area,
the key switch is set to H2 mode. At the H2 mode, the H2door is closed, all safety keys for the HBB2 operation areaccommodated, HBB1 is closed, and the safety magnet
HB2 is turned off, then the muon beam can be irradiatedin the H2 area. The operation permissions for the safety
devices in each experimental area are as follows.

4. Acknowledgements
We would like to thank Dr. Y. Bessho for his continuous support.

3. Summary
The PPS for the H-line experimental area was updated with the construction of the H2 area, which is locatedin the straight section through the safety magnet HB2.
Because of this positional relationship, more complex
logic circuits are required than the PPS for other muon
beamlines, such as a key switch to select experimental
areas and monitoring the output currents of the safety
magnet power supplies.
This PPS logic circuit has passed the operation verification test and started operation in April 2023.

Reference[1] T. Yuasa et al., “Muon Beamlines and Control System(Manufacturing of Spare Coils, and Installation of
PPS Equipment for H1 Area)”, KEK Prog. Rep. 2021-6
Dec. 2021, 9-11.

Y. Kobayashi1,2, T. Yamazaki1,2, N. Kawamura1,2, Y. Ikedo1,2, A. Koda1,2, T. Yuasa1,2, H. Fujimori1,2, K. Sakai3, A. Watanabe4, and A. Suzuki4
1
Muon Science Laboratory, Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science Division,
J-PARC Center; 3Japan Atomic Energy Agency, JAEA; 4NAT Co., Ltd.

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MLF Annual Report 2022

Commissioning of the Ultra-slow Muon Beamline in
FY2022
1. Introduction
The muon spin rotation/relaxation/resonance μSR
technique is valuable for investigating the bulk magnetic properties of materials. In many cases, μSR studies
employ a surface muon beam. Surface muons exhibit
nearly perfect spin polarization and excellent monochromaticity. However, measurements of thin films andtiny samples are challenging due to their kinetic energyof 4 MeV. Low-energy and energy-tunable muon beams
expand the applicability of μSR and pave the way forvarious new potential applications.
At J-PARC MUSE, the generation of ultra-slow muons (USM) through the laser ionization of thermal muonium has been studied with regard to its application inmaterials science. USM can be implanted into a sample
at energies below 30 keV. Furthermore, the time resolution of USM-μSR is several tens of times better than thatof conventional μSR using pulsed muons.
2. Present status and tasks
The beamline is under commissioning for the initiation of scientific measurements using USM-μSR. The layout of the facility was described in last year’s report [1].
To carry out experiments within a realistic measurement
time, it is essential to ensure a certain level of USM flux.
The required statistics depends on the experiment, butwith a flux of 100 cps at the sample position it would
enable the data acquisition of 1 million statistics in half aday, which is sufficient for the initial stages of a scientificcampaign.
3. Progress in FY2022
To achieve a sufficient USM flux, enhancing thepulse energy of ionization laser is crucial, and this will
be explained in detail in another report. In addition tothis, increasing the number of muonium atoms emitted
in vacuum also contributes to flux improvement. In the
U1 beamline, a joule-heated tungsten foil has been used
as a muonium emitter. For a muonium emitted, it is also
known that laser-ablated silica aerogel is promising. In
FY2022, measurements were made to quantitatively
compare the performance of these two emitters.
The flux and profile of USM were measured using
a microchannel plate (MCP) with a delay-line detector(DLD). The flux was evaluated based on two measurements: direct counting of muons and counting of decay
140

positrons. The effects of particle pileup in the muon
measurement were corrected by assuming a Poisson
distribution of USM counts.
In the experiments, the momentum of the surface
muon, the wavelength and timing of laser injection,and the voltage of the extraction electrode were varied
to assess the number, time, and spatial spread of USM.
Figure 1 illustrates the layout from the muonium generation chamber to the USM monitoring position. The
measurements were performed at the intermediate focus between the first and second electric bends.
Figure 2 represents a plot of the USM flux with varying laser injection timing. This result contains information about the velocity distribution of muonium and the
distance from the muonium emitted to the laser beam
position. The differences in the optimal laser timing tomaximize the yield and the width of USM time are attributed to differences in the emitter temperatures. The
tungsten foil was heated to 2000 K, while the silica aerogel was used at room temperature. The spread of thetime width as the delay for laser injection increases isdue to the spacial distribution of muonium expanding
over time.
Due to the different velocity of muonium, theFigure 1.	The USM beamline in the U1 area. “Mu” refers to themuonium generation target, “Extractor” represents
the electrostatic lens, “MB” stands for the magnetic
bend, “EB1” denotes the electrostatic bend, and“F3” indicates the beam monitoring position. The
top-right inset shows the time-of-flight spectrum
obtained at F3. The four peaks in the early time region correspond, in order, to prompt positrons anddegraded muons. Due to the double-pulsed time
structure of the primary protons, these peaks appear in pairs as well.

MLF Annual Report 2022

Muon Science

Figure 2.	The laser timing dependence of USM yield and time
width. Red circles representing the results for tungsten and black squares for silica aerogel. The time
width corresponds to the 1$¥sigma$ obtained byfitting the TOF peak with a Gaussian function. Directcomparison of the yield between different emitters
is not feasible, because the difference in laser pulse
energy is not corrected.

Figure 3.	The extraction voltage dependence of USM yieldand time width. The upper plot represents the results for tungsten, while the lower corresponds tosilica aerogel. The black circles indicate the yieldand refer to the left vertical axis, while the redsquares represent the time width and refer to theright vertical axis.

optimal voltage for the extractor also varies depending on the emitter. Figure 3 shows the variation of yieldand time width with respect to the extraction voltage.
Depending on the application, it is possible to optimize
either the yield or timing resolution.
Through the commissioning measurements, themaximum yield obtained was 180 cps using the silica
aerogel target. Adopting an open area ratio of 0.55 as
the upper limit for the MCP detection efficiency, theUSM flux becomes 330/s. Even considering losses due
to decay during transportation from the intermediate
focus F3 to the experimental area, a flux of 100/s or more
can be expected at the μSR spectrometer.

study on the comparison of muonium emitters and the
optimization of USM generation and transport conditions. The USM flux of 330/s and time width of 1 ns wereachieved, which were sufficient beam specifications toinitiate a practical measurement of USM-μSR. Next year,
we plan to optimize the transportation to the spectrometer and begin experiments using the μSR spectrometer.
The authors would like to express their gratitude
to the J-PARC muon g-2/EDM and Mu 1S-2S groups forproviding the silica aerogel target. We are thankful forthe contributions of S. Kamioka from KEK IPNS to theexperiment.

4. Summary and prospects
In the FY2022 commissioning, we conducted aReference[1] S. Kanda et al., KEK Prog. Rep. 2022-7, 19 (2023)

S. Kanda1,2, Y. Ikedo1,2, Y. Oishi1,2, N. Teshima1,2, and K. Shimomura1,2
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Institute of Materials Structure Science, KEK, 3 Nishina Center
for Accelerator-Based Science, RIKEN.

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MLF Annual Report 2022

Commissioning of the U1A Spectrometer in FY2022
1. Introduction
Muons ﬁnd extensive application in materials science as spin-polarized quantum beams. Muon spin rotation/relaxation/resonance (µSR) is an experimental
method to implant muons into materials for probing
local magnetic ﬁelds. The muon beams primarily usedin µSR experiments are obtained from pion decays at
the surface of the production target. These beams are
the so-called surface muons, which exhibit near-perfectpolarization and monochromaticity. Nevertheless, due
to their high energy of 4 MeV, measurements on thinsamples using a surface muon beam are challenging.
In this regard, low-energy muons have advantages formeasurements with thin-ﬁlm samples and studies oninterfaces.
The ultra-slow muon (USM) beamline at MLF MUSE
provides a low-energy muon beam via laser ionizationof thermal muonium in a vacuum. At the U1A experimental area, a muon spin spectrom eter is located ona high-voltage platform to control the muon implantation energy. USMs can be selectively implanted on
surfaces and interfaces in materials, enabling depth-resolving µSR. Further more, the time width of the beam
is much narrower than that of the pulsed proton beam,
so the frequency range of observable dynamics is wide.
Figure 1 shows the high-voltage platform, transport optics, and the U1A spectrometer.
2. Present status and tasks
The muon spin spectrometer in the U1A experimental area is currently under commissioning in preparation
for the commencement of the user programs. Test experiments conducted since 2020 using a multilayered
ﬁlm sample demonstrated the capability to control the
beam energy and selectively implant muons at speciﬁc
depths within materials [1].
The next step required to initiate the user programs
is to successfully conduct test experiments with a morepractical setup. Speciﬁcally, this involves investigating
the dependence of physical properties on temperature,magnetic ﬁeld, and implantation energy using a small
thin-ﬁlm sample.
3. Progress in FY2022
Due to the improvements in beam ﬂux, time width,and spatial proﬁle achieved in the 2022 beam studies,
we embarked on a scientiﬁc measurement using a thinﬁlm sample. While previous test measurements were
142

Figure 1.	The U1A experimental area: (Top) The high-voltage
platform and beamline, (Bottom) The muon spin
spectrometer. The platform can be elevated up to
30 kV, controlling the implantation energy of the
USM. The spectrometer consists of a positron detector segmented into 512 channels and a pair ofcoils generating a longitudinal magnetic ﬁeld of up
to 0.14 T.

conducted using relatively large samples at room temperature only, this time we conducted measurements at
low temperatures using a thin-ﬁlm sample with a size of
5 mm and a thickness of 33 nm.
The sample was mounted on a titanium plate using
silver paste and was enclosed in a thermal shield, thencooled in a helium ﬂow cryostat. A lowest temperatureof 4.2 K was conﬁrmed, demonstrating the applicabilityof this setup for various applications. Figure 2 displays
the sample mounted on the cryostat.
The beam proﬁle at the sample position was measured using a monitor combining a micro channel plate(MCP) and a delay-line detector (DLD). Position calibration was performed by installing an aligned pinhole upstream of the MCP. The MCPDLD and the sample can be
moved using linear actuators. After beam adjustment
with the MCP, the sample was inserted, and data acquisition was conducted using the spectrometer. Figure 3
shows the positron time spectrum obtained during
the commissioning runs using the spectrometer, along

MLF Annual Report 2022

Muon Science

Figure 2.	Sample and muon implantation simulation: (Top)Sample mounted on the cryostat and surroundedby the thermal shield, (Bottom) Muon stopping distribution in the sample, calculated by using TRIM.SP.

with the time resolution of the detector. In the FY2022
campaign, statistics were not suﬃcient to systematically investigate the physical properties of the sample.
However, we aim to complete the measurements bycontinuing the experiments in the next season.
In addition, we enhanced the interlock system of
the spectrometer’s electromagnet to improve safety
and conducted magnetic ﬁeld measurements. Goodagreement was conﬁrmed between the measurements
and calculations based on the ﬁnite element method.
We developed a water-cooling system to improve thestability of the detector by controlling the temperature. Moreover, simulation studies were performed todesign a new detector for a larger solid angle and full
asymmetry.
4. Summary and prospects
In preparation for initiating the user programs, wehave started a demonstration of scientiﬁc measurement
using the U1A spectrometer. Both the spectrometer andthe sample environment operated as expected, indicating the feasibility of scientiﬁc measurements in the U1A
area.

Figure 3.	Results from the commissioning run. (Top) Positron
time spectrum, (Bottom) Time diﬀerence between
coincidence hits of the inner and outer layers of thedetector. The spectrometer’s detector was split into
two vertically, with black representing the upper
and red the lower. The time diﬀerence distribution
was ﬁtted with a double Gaussian, and the time resolution for a single layer of the detector was evaluated to be 1.2 ns (1σ).

The next year, we aim to complete the test experiment and focus on improving beam quality and thesample environment to accommodate various user
experiments.
The authors are grateful for the sample provided
by the T. Adachi’s group at Sophia University and forthe cooperation in the sample installation by H. Okabe
from Tohoku University. We thank T. Yuasa, N. Teshima,
H. Fujimori, and Y. Irie of KEK MSL for their contributions
for improving and testing the spectrometer’s magnet.
Reference[1] S. Kanda et al., J. Phys.: Conf. Ser. 2462 012030 (2023).

S. Kanda1,2, Y. Ikedo1,2, W. Higemoto2,3, and T. U. Ito2,3
Muon Science Laboratory, Institute of Materials Structure Science, KEK; 2Muon Science Section, Materials and Life Science Division,
J-PARC Center; 3Advanced Science Research Center, JAEA

1

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MLF Annual Report 2022

USM Commissioning at the U1B area
At the U1B area, a transmission muon microscope(TμM) is being constructed. The TμM will visualize thickobjects (>10 μm) in nanometer resolution. Its capabilities are powered by the quantum coherence of the ultra-slow muon beam, and the deep-penetration powerof the muon beam accelerated to 5 MeV. In this FY, the5 MeV muon-cyclotron system was completed and installed to the U1B area. The cyclotron is connected tothe ultraslow muon beam line (Fig. 1). The commissioning of the cyclotron officially started on June 23, 2023.
For safety operation of the system, we constructed

an interlock system which has many inputs and targets. For mutually exclusive and collectively exhaustive(MECE) design and implementation of the interlocking
operations, an interlock matrix is employed (Fig. 2). By
the interlock matrix, chain-reactions of the interlocking
operations are organized and described visually. For example, when the main coil water is short, then the main
coil is shut down, magnetic field disappears, then the
RF input and the HV input should be also shut down
associatively. This associated operation is described by
the mark “A” in the matrix.

Figure 1.	The 5 MeV muon-cyclotron system completed at the U1B area. The RF amplifier provides RFof 108 MHz/20 kW to the cyclotron through the RF coaxial tube. The installation of the RF
controller is temporary, the main column of the TμM will be installed into the place of the RF
controller. The Ultraslow muon beam enters the cyclotron from its rear, and the accelerated
muon beam is ejected diagonally upward and is bended down to the TμM. by a magnet.

Figure 2.	Interlock matrix. The mark “1” means that the input stops the target device directly, the mark“A” means that the related target device is associatively stopped.

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MLF Annual Report 2022

The RF controller (Fig. 3) for the cyclotron has been
completed and installed. Driving of the RF-amplifier anddetection of the RF in the cyclotron are fully controlled
by a FPGA, thorough complex RF-mixers controlled by
DACs and detections by ADCs (Fig. 4). Both continuous
wave- and pulsed wave- operations are available by asoftware directive.
At the next beam time, the cyclotron will be started
to accelerate the ultraslow muon beam to 5 MeV.

Muon Science

Reverence[1] Y.Nagatani, K.Shimomura, Journal of the Crystallographic Society of Japan, Vol 65. 33-41 (2023).

Figure 3. RF low level controller.

Figure 4. Block diagram of the RF-control system.

Y. Nagatani1, T. Yamazaki1, J. Ohnishi2, A. Goto1, T. Yuasa1, Y. Nakazawa2, T. Adachi1, and Y. Ikedo1
Muon Science Laboratory, Institute of Materials Structure Science, KEK; 2Nishina Center, RIKEN

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The Progress of Laser System for Ultra-slow Muon Generation
1. Introduction
Ultra-slow Muon Spin Rotation / Relaxation / Resonance(USµSR) for measuring the material properties in thinfilms and surface/interface has recently begun at
J-PARC [1]. The only method to generate ultra-slow muons, with a momentum range limited below ~0.2 eV,is through laser photoionization of thermal muonium(Mu). This method requires coherent Lyman-α light(122.09 nm) to excite an electron from the ground state
to the 2 p state of Mu, and coherent light at 355 nm todissociate the electron from the 2 p state. So far, we haveconstructed an all-solid-state laser system with a highly
stabilized in the wavelength and output pulse energy,
and achieved the generation of Lyman-α light pulses exceeding 10 µJ through subsequent wavelength conversions. We have also been working on further increasing
the output pulse energy. This fiscal year, we introduced
a new concept amplifier into the all-solid-state laser system to enhance the output energy of Lyman-α light.
2. Nd:YSAG end pumped amplifier
The design of the Lyman-α laser system is describedin Ref. 2. More than 10 µJ Lyman-α pulse is stably generated in a krypton/argon mixture filled gas-cell by
methods of two-photon-resonant four-wave-mixing
which method requires intense 212.556 nm and 820 nm
pulses. These two wavelength pulses were generated
by methods of nonlinear wavelength conversions of
one fundamental pulse (1062.78 nm). To generate
about 100 mJ fundamental pulses, specially produced
Nd:YGAG and Nd:YSAG ceramics rod (ø 4 mm, 80 mmlong) are used in diode pumped amplifiers as a gain medium. To achieve amplification up to several hundred
mJ while avoiding damage to optical components, thebeam diameter must be increased during amplification,
which requires a large-aperture (ø > ~10 mm) gain medium. However, it has been difficult to eliminate the optical wavefront distortion caused by the inhomogeneity
in the medium using not only well-established single
crystal grows but also laser ceramic technology. To compensate for these material shortcomings, we applied adeformable mirror system [3], but such adaptive optics
introduced an optical energy loss and some laser beam
instability. Thus, we decided to change dramatically thepumping configuration from conventional side pump to
end pump geometry to reduce the optical pathlength
in the gain medium. Figure 1 shows a comparison between the conventional geometry, in which the pump
146

(a)

Pump
li
from la ght
ser diodegain medium

long dis~100 tance
mm

(b)

Pump
li
from la ght
ser diodeshortd~10 m istancem

Figure 1.	Schematic of the pumping geometry. (a) conventional side pump for long laser rod and (b) end
pump for short laser disk.

light from laser diodes (LDs) are injected from the sideof the rod, and the new geometry, in which the amplified light and the pump light are injected coaxially. The
new pumping geometry requires spatial profile shaping
for the pump light beam from LDs, but the wavefront
distortion can be dramatically reduced by shortening
the crystal length.
3. New amplifier module
In the new method, sapphire substrates are bonded to the light input and output surfaces for efficientcooling of the laser medium and end-face protection.
Nd:YSAG and the sapphire plate have different thermal expansion coefficient, the bonding was carried out
using room temperature surface activated bonding
technology, which has been developed in the Institutefor Molecular Science [4]. 9.3 mm cubic Nd:YSAG ceramic with bonded sapphire plates (ø 25.4, t = 2 mm)
and water-cooling holder are shown in Fig. 2. We constructed an amplification module using the bonded
Nd:YSAG and carried out an optical pulse amplificationfor 1062.78 nm pulse. The setup of the amplifier module
(a)

(b)

(c)

Figure 2.	Nd:YSAG ceramic for the power amplifier. (a) polished ceramic cube, (b) bonded ceramic cube withsapphire plates and (c) set in a water-cooling holder.

MLF Annual Report 2022

is shown in Fig. 3. The Nd:YSAG ceramic was pumped
by 8.5 mm square shaped beam with the 885 nm wavelength light from two laser diode bar stacks. Since thepump light absorption of a single ceramic was about
51%, two ceramics were placed in series. The horizontally polarized pulse delivered from the intermediate
amplifier was injected into the ceramics, and the transmitted pulse was folded back into the same optical path.
By rotating the polarization by 90 degrees when folding
back, the incident and amplified pulses were separated
by the polarizing-beam-splitter. The double pass configuration amplifier module was installed to the laser
system and the gain factor measurements were carried out using reduced incident pulse energy of 10 mJ
to avoid unexpected optical damage. The function of
the gain factor versus the applied current to the LDs
is shown in Fig. 4. The maximum gain factor of 2.2 was
HWP
from Mid. Amp.

PBS

LD1

HR@1064 nm

LD2
QWP

Nd:YSAG ceramic

f=25mmcyl. lensbeam splitter
HR@820nm HT@885nm

f=75mmcyl. lens

HWP

Figure 3.	Setup of Nd:YSAG ceramic for the power amplifier module. The pump lights from two LD modules
were combined with polarizing-beam-splitter. The
pump beam was shaped into about 8.5 mm squareintensity profile for square shape Nd:YSAG ceramics.
2.4
2.2

Muon Scienceobtained when the 250 A current was applied to LDs.
Since the slope of the graph is not saturated, this amplifier would have a higher amplification gain potential forthe current condition. In the next step, we plan to verify
whether increasing the input pulse energy causes optical damage to the optics in the amplification module
or distortions in the output beam profile and wavefront
that affect the efficiency of subsequent nonlinear wavelength conversions.
4. Summary
We have built a new amplification module for further laser power enhancement and integrated it intoa laser system to evaluate the fundamental amplification characteristics. The new amplification module
uses a pumping method that utilizes a laser medium
with a crystal length that is one order of magnitude
shorter than the conventional one in order to solve thewavefront distortion of the output beam caused by
non-uniformity in the laser medium, which has been aproblem up to now. It has been shown that an amplification factor of more than 2.2 times can be achieved
using this amplification module, making it possible toincrease the output power of the entire laser system. In
the future, the aim is to generate a maximum output of
200 mJ or more and, through subsequent wavelength
conversion, to increase the intensity of the Lyman-α
light by several times.
Acknowledgement
This work was done with Prof. M. Yoshida, Dr. S. Kamioka
and member of Muon Science Laboratory in KEK. The author would like to thank Mr. A. Kausas and Prof. T. Taira at
Institute of Molecular Science for bonding ceramics.

2

Gain

1.8
1.6
1.4
1.2
1
0.8

0

50

100

150

200

250

LD current (A)Figure 4.	The obtained amplification gain corresponds to theapplied current to LDs. The slope shows that thethreshold of laser emission of LD is around 45 A.

References[1] S. Kanda et al., J. Phys. Conf. Ser. 2462(1), 012030(2023).
[2] Y. Oishi et al., J. Phys. Conf. Ser. 2462(1), 012026(2023).
[3] KEK-MSL Report2020, 14 (2021). https://lib-extopc.
kek.jp/preprints/PDF/2021/2123/2123006.pdf[4] A. Kausas et al., 2019 6th International Workshop on
Low Temperature Bonding for 3D Integration (LTB-3D),
Kanazawa, Japan, 2019, pp. 6-6.

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

147

Muon Science

MLF Annual Report 2022

Present Status of the S-line
In this report on the S-line in 2022, we have to mention three issues that have affected the beamtime of theusers of the inter-university experiment program: First,
the S1 area experienced a malfunction in the longitudinal field (LF) power supply. The issue was the system
halt due to a transformer temperature interlock while
operating at 1000 A. The malfunction was traced back to
one of the two thyristor banks not functioning correctly.
Consequently, the operational thyristor attempted tocompensate by outputting a higher current than anticipated, striving to maintain the desired current. Oneof the authors (TY) and the manufacturer’s engineersinvestigated the cause of the problem. Still, for about
two weeks, until the issue was solved, users were asked
to conduct their experiments only with another power
supply to apply a relatively low LF (maximum 160 gauss).
The second incident that occurred at the end of
March 2022, was more critical: it involved the gate valve
SGV1 located at the head of the beamline in the S-line,
which was discovered to be incapable of closing properly. Upon examining various scenarios, it was assumed
that the Kapton foil, which serves as a barrier between
the primary and secondary beamlines, had ruptured
and consequently became lodged in the gate valve. To

repair or replace SGV1, it was necessary to open boththe primary and secondary beamlines, and the closest
opportunity to schedule such work was during the holiday season in May 2022. Therefore, all planned beamtime for the S-line from the beginning of April throughthe May holiday season had to be canceled. Five user
experiments, corresponding to 13 days of beamtime,
were carried over to the 2022B period.
Anticipating the potential release of tritium-containing gases due to the opening of the primary beamline
duct, a safety review meeting was convened. This meeting included experts from outside the MLF Division, andits focus was to meticulously evaluate the work procedures and safety precautions necessary for the situation.
The work was conducted in a negative-pressure controlled workspace, a “Green House,” in which two groupsof three workers wearing air-line masks worked in shifts.
The work was performed between consecutive holidays.
The original plan was to replace SGV1 on May 2. Still,
as a result of gas sampling, it was determined that thetritium concentration should be further lowered, so thework schedule was changed to May 6, and the vacuum
pumping was continued until the replacement work
was resumed.

SGV1

Figure 1. Layout of the S line and location of SGV1.

148

Figure 2. Worksite and the Green House.

MLF Annual Report 2022

On May 6, the SGV1 gate valve was successfully removed, revealing the downstream Kapton foil trapped
within it. At the same time, however, it was also discovered that a section of the Kapton foil was caught in the
beam blocker located upstream of SGV1. Since removing the Kapton foil from the beam blocker was an unplanned task, we decided to take measures to prevent
Kapton foil’s dispersion during the beam blocker’s operation and refocused on the beamline restoration work.
The complete retrieval of the Kapton foils is planned
for a future date. The beamline restoration work wentsmoothly, and the S-line experiments were successfully resumed without any impact on the resumptionof the MLF operation on May 11. The inquiry into thecause of the Kapton foil rupture remains unresolved.
Additionally, in November 2022, efforts were undertaken to install an observation window. This window enables downstream inspection of the Kapton foil’s integrity
without the need to open the beam duct, thereby avoiding potential tritium contamination.
Finally, we report the status of the S-line kicker
power supply, an essential device for the simultaneous
single-pulse operation of the S1 and S2 areas. As mentioned in previous facility reports, unfortunately, there
have been times when failures have affected users’ experiment schedules. As shown in Fig. 3, the number of
failures has clearly increased since the beginning of the
2022B period. Since a trend of increase has already been
observed in the 2022A period, MOS-FET degradation
was assumed as a possible cause. Therefore, in October
2022, just before the start of the 2022B period, we attempted to verify the effectiveness of preventive replacement by measuring the MOS-FET leakage current.
The leakage current was measured to be about 20 µA
for most MARX boards, but some showed a leakage

Muon Science

Figure 3.	Number of MARX board failures that occurred ineach operating period. Gray (yellow) bars represent
the number of failures in the circuit that kicks thebeam toward S1 (S2), respectively.

current of 140 µA, and these MARX boards were replaced. However, as shown in Fig. 3, many MARX boards
with a leakage current of 20 µA failed in the 2022B period. As a next countermeasure, we plan to replace the
MOS-FET devices with modern SiC devices; we havealready selected SiC devices and verified the operationof the power supplies alone, but we are still discussing
the replacement plan and schedule with the manufacturer. The critical technical point is that it is difficult tomix SiC device power supplies with existing MOS-FET
power supplies on a unit-by-unit basis. This means thatto replace them without affecting the beam operation,
power supplies with new SiC devices for replacement
must also be prepared.

A. Koda, T. Yuasa, J.G. Nakamura, S. Nishimura, and P. Strasser
Muon Science Laboratory, Institute of Materials Structure Science, KEK

149

Muon Science

MLF Annual Report 2022

Present Status of the H-line
The H-line is a muon beamline in the east experimental hall #1 of the MLF. It is a general-purpose andhigh-intensity muon beamline that can generate both
positive and negative muons [1,2]. The first branchof the H-line, named the H1 area, began operation in
January 2022. The result of the beam commissioningat the H1 area is summarized in the last progress report [3]. The intensity of surface muons was measured
and found to be almost the same as its design value(108 muons/s), despite the absence of a DC separator(or Wien filter) and the failure of the power supplies of
the capture solenoids. Currently, the H-line is open forusers, and a detector run of the DeeMe experiment [4]searching for μ-e conversion is ongoing. The hyperfine
splitting measurement of muonium (MuSEUM experiment [5]) will be conducted at the H1 area in FY2023.
In FY2022, we worked to resolve the problems of the
DC separator and the power supplies and constructed
the second branch of the H-line (H2 area). This report
describes these updates.
A DC separator is a device used to eliminate positrons/electrons backgrounds in a positive/negative
muon beam by applying crossed electric and magnetic
fields to select particle velocity. The DC separator to beinstalled in the H-line was used at another muon beamline. The insulation of its HV power supply had beendamaged, causing frequent electrical discharges. We replaced the damaged insulation ceramic with a new one.
The repaired power supply was tested at the factory, andit worked normally. The installation of the DC separator
in the H-line is scheduled for August 2023.
The power supplies of the capture solenoids adopt
phase control using thyristors. The output currents ofthe power supplies were limited to about half of theirrated currents due to the misfiring problem in the trigger boards designed to trigger the thyristors. The insufficient rating current of diodes used in the trigger
boards was the cause of the misfiring. These diodes
were replaced with other ones with sufficient ratings,
and subsequently, the power supplies were adjusted insitu during the beam shutdown. The adjustment was
not enough to restore the rated performance, but the
maximum currents were recovered to some extent, asshown in Table. 1. Further adjustment is scheduled forthe summer shutdown in FY2023.
Another advancement in FY2022 is the construction of the H2 area. The H2 area is the second branchof the H-line. At the H2 area, ultra-slow muons will be
150

Table 1.	Status of the maximum currents of the power supplies of the capture solenoids (HS1-1, 2, 3).

Beforerepair (A)Current
status (A)Ratedcurrent (A)

HS1-1

1500

2500

3000

HS1-2

1500

2200

3000

HS1-3

900

2100

3000

produced and then re-accelerated up to 4 MeV. The
beamline is planned to be extended further to produce
a novel low-emittance muon beam by accelerating muons up to 212 MeV. The low-emittance beam will be
used in the measurement of the muon g-2 and electric
dipole moment [6] and the transmission muon microscope (TμM). Adding a new building on the east side of
the MLF is necessary to extend the beamline. Figure 1
shows the overall 3D drawing of the beamline. Its engineering design is going to be finalized in FY2023.
The radiation shields for the H2 area, composed ofconcrete and iron, were manufactured and delivered to
the MLF during the summer shutdown of FY2022. Partial
assembly of these shields occurred during this period
as part of the H2 area's construction. The construction
was then resumed and finalized in the March 2023 shutdown. Figure 2 is a picture of the H-line after the construction. In addition, the safety interlock system of theH2 area was implemented.
While the H2 area was completed and underwent
a self-radiation inspection in April, the installed beamline equipment was minimal and inadequate for commissioning. Beam ducts, vacuum apparatuses, and aquadrupole triplet with a small bore are scheduled to beinstalled in FY2023. This upgrade will enable the delivery
of a low-intensity muon beam to the H2 area, making
possible research and development in ultra-slow muon

Figure 1. 3D drawing of the H-line.

MLF Annual Report 2022

Muon Science

production and its re-acceleration testing.
References[1] N. Kawamura, et al., Prog. Theor. Exp. Phys. 2018(2018) 113G01.
[2] T. Yamazaki, et al., EPJ Web of Conferences 282,
01016 (2023).
[3] T. Yamazaki and N. Kawamura, KEK-MSL Report
2021, pp. 26-27.
[4] H. Natori, et al., Nucl. Phys. B (Proc. Suppl.) 248-250(2014) 52-57.
[5] K. Shimomura, AIP conf. proc. 1382 (2011) 245.
[6] T. Mibe, et al., Chin. Phys. C 34 (2010) 745.

Figure 2. Picture of the H-line after the H2 area construction.

T. Yamazaki1,2 and N. Kawamura1,2
Muon Science Section, Materials and Life Science Division, J-PARC Center; 2Muon Science Laboratory, High-Energy Accelerator Research
Organization (KEK-IMSS)

1

151

MLF Safety

MLF Safety

MLF Annual Report 2022

2. Chemical safety
The total number of chemical substances brought inin FY2022 was the same as in the previous year (Fig. 1).
There were no major changes in the types of substances, but the number of battery-related samples and hydrogen storage alloys increased. The use of flammablegases, such as methane and ethane, also increased. As of
the usage status of the experimental preparation room,
the consumption of inert gas increased after May in response to bringing in of samples that are sensitive tomoisture.
3. Crane safety
Also, this year, due to space limitations, only statistics of the crane usage are shown in Fig. 2. As in previous years, its usage was unaffected by the COVID-19
pandemic.

8000
6000
4000
2000

20
09
2 01
0
20
11
201
2
2 01
3
20
14
20 1
5
20
16
20 1
7
20
18
201
9
20 2
0
20
21
20 2
2

0

Year

Figure 1.	Trend of the amount of user-brought chemical materials for chemical safety check from the start of
the MLF operation to the last year.
25

Number of crane usage

1. Radiation safety
Radiological license upgrade
The applications for radiological license upgrades in
FY2021 were approved on August 24, 2022.
The following items were updated at this application approval:(1)	Extension of the High momentum decay muon
instrument (H-line).
(2) Change of the off-gas treatment system.
(3)	Change of the quantity of produced radioactive
nuclides.
(4)	Change of the number of storage tanks at theRAM building.
(5)	Refinement of the system diagram of the drainage system.
(6)	Permission for use of the muon accelerator
instrument.
The permission for use of the muon accelerator
instrument has been granted for the first time as a radiation generation instrument license for a muon acceleration. The facility inspection of the muon accelerator
instrument will take place in FY2025.
A new application is not planned until FY2024 andthe next application to be approved in FY2025 is being
prepared.

Number of chemical materials

Research Safety

in-house staff
constructor

20
15
10
5
0

4

5

6 7

8

9 10 11 12 1
Month

2

3

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

4. COVID-19 pandemic measures
Although there were sporadic cases of COVID-19
among staff and users entering the MLF experimental
hall, no clusters or other outbreaks occurred. In orderto reduce the burden on those who enter the MLF
experimental hall, the daily record of name, temperature, and location in the MLF experimental hall, which
had been conducted since FY2020, was abolished on
2/24/2023. However, temperature checks, hand sterilization, and multiple daily sterilization of common areas
have continued.

M. Harada1, T. Ito1, H. Morikawa1, N. Hashimoto2, Y. Watanabe2, H. Tanaka2, W. Kambara2, H. Inoue2, T. Oku2, K. Suzuya3, N. Kawamura4,
Y. Sakaguchi5, R. Takahashi2, Y. Yamaguchi5, and K. Aizawa2
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, CROSS154

MLF Operations in 2022

MLF Operations in 2022

MLF Annual Report 2022

Beam Operation Status at the MLF
1. Overall
In Japanese Fiscal Year (JFY) 2022, the beam operation at the MLF started on April 1, 2022, and ended on
March 14, 2023. Despite the influence of the pandemic
and steeply raised electrical fees, the beam operation
was conducted almost as planned.
The records of the beam power and availability are
shown in Fig. 1. In JFY2022, the beam operation started
with a power of 730 kW with a double-bunch beam.
After April 7, the beam power was increased from 730 kW
to 830 kW. During a long holiday called Golden Week,
the beam operation was completely stopped in J-PARC
from April 29 to May 8. The Main Ring (MR) resumed thebeam operation after the improvement of their power
supplies for the power upgrade with the increasing MR’s
duty. Before June, the duty of MR of 3.1% was chosenusing slow extraction of MR with a repetition cycle of
5.2 sec. Every 4 shots of the beam are delivered to theMR with the MR cycle out of the beam at 25 Hz. Due tothe increase of the duty of MR by decreasing the MR
repetition cycle from 5.24 to 1.28 sec, the beam power
to the MLF was decreased by 9.5%. After the user operation on June 24, beam operation with 1 MW wasdemonstrated. Due to the insufficient cooling for the RF
cavities in the 3 GeV Rapid Cycling Synchrotron (RCS) in
the hot summer, the duration of 1 MW lasted only for ashort period of several hours. During the demonstration,

RCS RF cavity #10 malfunctioned due to failure of thetransformer supplied to the cavity for unknown reasons.
Because of the long time required to repair the transformer, cavity #10 cannot be used until April 2024.
During the summer outage, the spent neutron production target #14 was replaced with new target #13,
which had been fabricated before target #14. During the
replacement, no significant problem was found on thetarget. Since no severe damage was found on target #13
by the precise inspection, we decided to continue withthe 830 kW beam after the outage. Due to the failureof the RCS RF cavity, the beam power after the outage
was limited to 830 kW for 25 Hz operation without theloss of duty by the MR operation, as shown in the green
line in Fig. 1.
The beam period of 2022A was switched to 2022B
on November 17, 2022. Due to concerns about the
impact of the insufficient RCS cavity, the beam operation started with a slightly lower power of 780 kW. On
December 2, the beam power was increased since no issue on the RCS cavity was found. After December 7, theMR started a continuous beam operation. Although thebeam power for 25 Hz was maintained after December 2,
the actual beam power to the MLF oscillated as shownin the blue line in Fig. 1, following the change of the MR
cycle.
A high-intensity beam with a stable beam for users

Figure 1. Beam power trend (blue line) at the MLF, beam power for the 25 Hz operation(green line,) i.e., beam power per shot and including the loss of duty for MR delivery), and availability per day (red line).

156

MLF Annual Report 2022

MLF Operations in 2022

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

Duration

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

89
90
2022A
2022B
Overall

April 1 – June 23
November 19 – March 14
April 1 – June 23
November 19 – March 14
April 1 – March 14

1,485
1,984
1,485
1,984
3,468

1,411
1,887
1,411
1,887
3,298

95.0
95.1
95.0
95.1
95.1

Table 2. Events that stopped the beam with a duration longer than 3 hours.
Stop date
May 30November 22
November 24
November 26
December 20
January 22
January 24
February 26
March 6

Cause of beam stop
RCS RF11 failure
MLF anomaly gas pressure in cooling water
MLF PPSMLF anomaly gas pressure in cooling water
MR PPS and LINAC quadrupole magnet failure
LINAC RF Klystron 8 failure
Drop in electricity voltage
LINAC RF Klystron 11 failure
RCS RF5 failure

was carried out in JFY2022. Table 1 shows the scheduled
time and availability in JFY2022. As shown in Table 1,a stable beam operation with 95% availability wasachieved up to June 24 for 2022A. Eventually, the overall
availability in JFY2022 was 95.1%. From March 15 to 31,
the beam study of LINAC was conducted.
The beam operation was stopped on several occasions due to minor failures. The typical causes of thebeam stop with a duration longer than 3 hours are summarized in Table 2 and described below.
2. Causes of the beam stop
LINAC:
During JFY2022, there were no shortages of waterflow for the magnet at LINAC, which had been the main
reason for beam stops before JFY2019. In JFY2022, there
were a few failures related to LINAC RF.

Stop durationfor each event [h]
8.7
3.9
6.7
4.7
3.3
3.5
3.9
4.3
7.2

time to restart the operation. For the case of all cavities
available, the resuming time tends to be shorter because tuning is applied before the cavity malfunctions.
MLF and Personnel Protection System (PPS)
After the summer outage, the water loop systems
for cooling the mercury target vessel and the proton
beam window at the MLF failed twice. The failures werecaused by the gas in the water loop, which exceeded
the allowable pressure at the surge tanks. These failuresoccurred after the last year’s outage. We will improve thegas handling to minimize such long interruptions.
The PPS occurred for the MLF and the MR. The PPS
has redundancy to observe the failure independently and should register the multiple events of failure.
However, both PPS events in JFY2022 observed only
one failure event. Failure of detection due to the noiseis thought to make the PPS.

3 GeV Rapid Cycling Synchrotron (RCS):
Due to the failure of RF cavity #10, it took a long

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

157

MLF Operations in 2022

MLF Annual Report 2022

Users at the MLF
The MLF beam operation for FY2022 started on
April 1 with a beam intensity of 730 kW. Then, the beam
intensity was increased to 830 kW on April 7. From April
29 to May 8, J-PARC suspended the beam operations
entirely for a vacation. Following the user operation on
June 24, a demonstration of a beam operating at 1 MW
was conducted. It should be noted that the overall
availability reached 95%, achieving a very stable beam

supply. The total number of users of the neutron andmuon experimental facilities in FY2022 was 644, anincrease compared to the previous year, indicating a
gradual recovery from the impact of the travel restrictions 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.
FY2008FY2009FY2010FY2011FY2012FY2013

FY2014FY2015

Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
107

Neutron

95

317
12

303

0

38

18

Muon

18

476
14

432

2

42

40

FY2016

259
44

238

8

21

50

FY2017

708
21

628

2

46

23

FY2018

449
80

399

10

50

56

FY2019

824
50

711

11

78

61

FY2020

559
113

476

13

59

91

FY2021

83
69

FY2022

Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign Domestic Foreign
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
Users
852

Neutron

744

927
108

742

99

Muon

83

965
185

789

179
16

149

940
176

827

161
30

146

489
113

448

138
15

127

307
41

11

88

4

Neutron (Foreigners)

Muon (Japanese)

Muon (Foreigners)

30

16

13

10
80

200

0

432
18
12
95

303

185

15
146

176

11

5

35

127
113

35
4

50

399

41
744

711

628

88

742

789

827

476

238

203
5
112

110

50
448
257

296

FY2008 FY2009 FY2010 FY2011 FY2012 FY2013 FY2014 FY2015 FY2016 FY2017 FY2018 FY2019 FY2020 FY2021 FY2022

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

158

203

11

83

50

2
21
21

110
238

59

8
42
44

296

10

600

2
38
14

108

113

46

149

83

78

400

112

Neutron (Japanese)

1000

50
117

1200

800

257

92

406

10

MLF Annual Report 2022

MLF Operations in 2022

MLF Proposals Summary – FY2022
Table 1. Number of Proposals by Beamline
Beamline

2022A
2022B
Submitted Approved Submitted Approved
GU
GU
GU
GU

Instrument

BL01 4D-Space Access Neutron Spectrometer - 4SEASONS
BL02 Biomolecular Dynamics Spectrometer - DNA‡
IBARAKI Biological Crystal Diffractometer (100-β)
BL03†- iBIX(β)
Accurate Neutron-Nucleus Reaction Measurement
BL04
Instrument - ANNRI
BL05 Neutron Optics and Physics - NOP
Village of Neutron Resonance Spin Echo Spectrometers
BL06- VIN ROSE
Super High Resolution Powder Diffractometer BL08
SuperHRPD
Special Environment Neutron Powder Diffractometer BL09
SPICA
NeutrOn Beam-line for Observation and Research Use BL10NOBORU
BL11 High-Pressure Neutron Diffractometer - PLANET
BL12 High Resolution Chopper Spectrometer - HRC
BL14 Cold-Neutron Disk-Chopper Spectrometer - AMATERAS
Small and Wide Angle Neutron Scattering Instrument BL15TAIKAN
BL16 Soft Interface Analyzer - SOFIA
BL17 Polarized Neutron Reflectometer - SHARAKU
Extreme Environment Single Crystal Neutron
BL18
Diffractometer - SENJUBL19 Engineering Materials Diffractometer - TAKUMI‡IBARAKI Materials Design Diffractometer (100-β)
BL20‡- iMATERIA(β)
BL21 High Intensity Total Diffractometer - NOVA
BL22 Energy Resolved Neutron Imaging System - RADEN
BL23 Polarization Analysis Neutron Spectrometer - POLANO
Muon Spectrometer for Materials and Life Science
D1
Experiments - D1
D2 Muon Spectrometer for Basic Science Experiments - D2
S1 General purpose µSR spectrometer - ARTEMIS
S2 Muonium Laser Physics Apparatus - S2
U1A Ultra Slow Muon Microscope - U1A
U1B Transmission Muon Microscope - U1B
H1 High-intensity Muon Beam for General Use - H1
Total

Full Year
Submitted
Approved
PU/S
IU
PU/S
IU

22(0)
18(2)
2
0

8(0)
12(2)
1
0

25(0)
21(1)
4
1

9(0)
7(1)
1
1

0
2
0
24 ※

1
1
0
0

0
2
0
24 ※

1
2
0
0

8

4

4

3

2

1

2

1

6

6

7

5

1

0

1

0

3

2

4

2

1

0

1

0

11

8

6

5

1

0

1

0

5

5

1

1

1

0

1

0

17

3

9

10

2

1

2

1

8(0)
10
35

7(0)
6
8

13(0)
7
35

5(0)
5
8

0
1
1

2
0
1

0
1
1

2
0
1

34(2)

13(2)

36(0)

10(0)

2

4

2

4

21
17(2)

12
14(2)

21
15(1)

10
7(1)

1
3

1
2

1
3

1
2

18(0)

8(0)

17(0)

7(0)

1

1

1

1

27
3
18
21
23(0)
5

12
3
18
19
8(0)
4

29
5
13
14
18(1)
6

7
5
13
10
8(1)
4

2
0
23
1
0
1

1
0
0
0
2
0

2
0
23
1
0
1

1
0
0
0
2
0

12(0)

6(0)

16(0)

9(0)

0

1

0

1

10(4)
28(0)
0(0)
0
0
0
382

5(3)
15(0)
0(0)
0
0
0
207

5(0)
37(1)
0(0)
0
0
0
371

1(0)
12(1)
0(0)
0
0
0
158

1
1
0
0
0
0
65

1
1
1
1
0
1
24

1
1
0
0
0
0
65

1
1
1
1
0
1
24

GU : General Use
PU : Project Use or Ibaraki Pref. Project Use
S : S-type Proposals
IU : Instrument Group Use† : Ibaraki Pref. Exclusive Use Beamtime (β = 80% in FY2022)‡ : J-PARC Center General Use Beamtime (100−β = 20% in FY2022)( ) : Proposal Numbers under the New User Promotion (BL01, BL02, BL11, BL15, BL17, BL18, BL22) or P-type proposals (D1,D2, S1) in GU※ : Operations period is 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.	Number of Long-Term Proposals by Fiscal Year
Application FY

Submitted

Approved

2020

13

3

2021

0

0

2022

5

4

Due to the COVID-19 situation, no Long-Term Proposals were called for FY2021.

159

MLF Operations in 2022

MLF Annual Report 2022

Number of Proposals

1200
1000
800
600

142

400

42
20

200
0

34
67

214

2008

2009

278

293

395

231

309

255

2010

2011

460

422

469

2012

2013

2014

360
389

Not Approved

245

126
45

329

199

321

353

2015

2016

507

630

607

Approved

626
311

2017

2018

2019

2020

2021

458

2022

Fiscal Year

Figure 1. Number of MLF Proposals over Time

JAEA
73
9%

KEK CROSS
34
49
4%
6%

Universi�es (Japan)
Universi�es(Japan)321
38%

Foreign
Organiza�ons
250
29%
Research
Companies
Ins�tutes (Japan) (Japan)
39
81
5%
9%

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

Figure 2. Origin of Submitted Proposals by Affiliation - FY2022

P9
9
1%

Q1
48
7%

P1
54
8%

Q2
59
8%

P1:Structural Science (Crystal, Amorphous and Liquid)
P3:So� Ma�er and Biologocal Ma�er
P4:Magne�c Material and Strongly Correlated Electron System (Structure)
P5:Magne�c Material and Strongly Correlated Electron System (Dynamics)

P8
84
12%

P7
29
4%

P2:Energy Science and High-Pressure Science

P2
71
10%
P3
109
16%

P6
64
9%

P5
109
16%

P4
62
9%

P6:Fundamental Physics, Nuclear Physics, Instrumenta�on, Imaging
P7:Industrial Applica�on
P8:Materials Engineering
P9:New User Promo�on
Q1:Electronic Proper�es of Ma�er & Hydrogen in Ma�er
Q2:General Applica�ons

Figure 3. Submitted Proposals by Sub-committee/Expert Panel – FY2022

160

MLF Operations in 2022

MLF Annual Report 2022

MLF Division Staff 2022
Toshiya Otomo (Head)

Eiichi Wakai

Kazuya Aizawa (Deputy Head)

Kyoko Aizawa

Hiroshi Takada (Deputy Head)
Koichiro Shimomura (Deputy Head)

Neutron Source Section

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

Gen Ariyoshi

Rie Nemoto

Kenji Sakai (Sub-Leader)

Toshiaki Uehara

Shin-ichiro Meigo *Makoto Teshigawara

Hideki Muto

Tetsuya Kai *Masahide Harada

Shigeto Tanaka

Kenichi Oikawa *Tomokazu Aso

Yoshinori Kikuchi

Shoichi Hasegawa *Hiroyuki Kogawa

Toshiyuki Yasuhara

Hiroyuki Uehara *Hidetaka Kinoshita

Akihiko Watanabe

Motoki Ooi *Takashi Wakui

Masakazu Nakamura

Yuji Yamaguchi *Takashi Naoe

Noriyuki Morikawa

Shoya Suda *Koichi Saruta

Akiyoshi Futakawa

Midori Yamamoto *Masakazu Seki

Taku Ito

Shiho Masuda

Shizuka Yoshinari

Neutron Science Section

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

Kosuke Hiroi

Keiko Nemoto

Mitsutaka Nakamura (Sub-Leader)

Naoki Murai

Naoko Shimizu

Kentaro Suzuya

Yusuke Tsuchikawa

Itaru Tamura *Ryoichi Kajimoto

Hiromu Tamatsukuri

Koji Kaneko *Takanori Hattori

Kaoru Shibata

Hiroshi Nakagawa *Stefanus Harjo

Wenqi Mao

Atsushi Moriai *Kenichi Oikawa

Masami Nirei

Satoshi Morooka *Takashi Ohhara

Wang Shan

Atsushi Kimura *Takenao Shinohara

Kotomi Nakamura

Shoji Nakamura *Hiroyuki Aoki

Tatsuya Kikuchi

Shunsuke Endo *Asami Sano

Masashi Harada

Yosuke Toh *Tetsuya Kai

Hiroshi Nozaki

Mariko Segawa *Seiko Kawamura

Takeshi Harada

Masahide Harada *Shinichi Takata

Hideaki Isozaki

Masao Watanabe *Ryoji Kiyanagi

Keiichi Inoue

Dai Yamazaki *Yasuhiro Inamura

Sakai Motonobu

Takuro Kawasaki *Maiko Kofu

Motohiro Aizawa

Kazuo Kurihara *Wu Gong

Hiroko Uchiki

Tarou Tamada *161

MLF Operations in 2022

MLF Annual Report 2022

Yu Hirano *Fumiaki Kono *Takeshi Hiromoto *Tatsuhito Matsuo *<KEK>
Testuya Yokoo (Sub-Leader)

Taichi Ueta

Kazutaka Ikeda

Shinichi Ito

Masako Yamada

Takashi Saito

Hideki Seto

Naokatsu Kaneko

Go Ichikawa

Toshiya Otomo *Shuki Torii

Norifumi Yamada

Kazuhiro Mori

Kaoru Taketani

Nur Ika Puji Ayu

Takashi Kamiyama

Sara Yamauchi

Seungyub Song

Hitoshi Endo

Hiroyuki Aoki *Hidetoshi Oshita *Takashi Ino

Asami Sano *Tomohiro Seya *Takashi Honda

Kenji Mishima

Setsuo Sato *Technology Development Section

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

Ryuta Takahashi

Mitsutaka Nakamura *Kazuyoshi Tatsumi

Nirimichi Hashimoto

Shinichi Takata *Masao Watanabe

Hiromichi Tanaka

Tatsuya Nakamura *Yuhua Su

Hiroyuki Asai

Yasuhiro Inamura *Ryota Komine

Chie Shibazaki

Masahide Harada *Hiroyuki Hasemi

Yukiko Nagai

Tomokazu Aso *Takuya Okudaira

Kenji Sakai *Seiko Kawamura *The Dang Vu

Tetsuya Kai *Rumi Shimizu *Wataru Kambara

Hiroyuki Kogawa *Satoru Fujiwara *Yoko Watanabe

Motoki Ooi *Motoyasu Adachi *Hideaki Takahashi

Kentaro Suzuya *Shigeki Arai *Testuya Yokoo *Naokatsu Kaneko *Hiroshi Fujimori *Shuki Torii *Kaoru Taketani *Shunsuke Makimura *Takashi Ino *Naritoshi Kawamura *<KEK>

Neutron Instrumentation Section

*: additional duties<JAEA>
Tatsuya Nakamura (Leader)

Kaoru Sakasai

Hiroki Kajihara

Dai Yamazaki

Masahiro Tobe

Aoi Yanagi

Kentaro Toh

Yukio Hishinuma

Masumi Ebine *Ryuji Maruyama

Takaaki Hosoya<KEK>
Hidetoshi Oshita

162

Tomohiro Seya

Setsuo Sato

MLF Operations in 2022

MLF Annual Report 2022

Muon Science Section

*: additional duties<KEK>
Naritoshi Kawamura (Leader)

Jumpei Nakamura

Amba Datt Pant

Akihiro Koda (Sub-Leader)

Shiro Matoba

Yasuhiro Miyake

Koichiro Shimomura *Takahiro Yuasa

Hiroshi Fujimori

Patrick Strasser

Ryosuke Kadono

Yasunori Bessho

Takayuki Yamazaki

Yu OishiRyoto Iwai

Sohtaro Kanda

Yukinori Nagatani

Hua LiSoshi Takeshita

Shoichiro Nishimura

Shogo Doiuchi

Izumi Umegaki

Hiroaki Natori

Akiko Hashimoto

Yutaka Ikedo

Sourav Kumar Dey

Yoshinori Ito

Yasuo Kobayashi

Motonobu Tampo

Yuta Ishikake<JAEA>
Wataru Higemoto *Takashi Ito *163

MLF Operations in 2022

MLF Annual Report 2022

CROSS Staff 2022
Director

Mitsuhiro Shibayama

Science Coordinators
Shamoto Shinichi

Matahiro Komuro

Jun Sugiyama

Kazuhisa Kakurai

Midori Kamimura

Research & Development Division*: additional duties

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

Kenichi Funakoshi (Deputy Head)

Kazuki Ohishi (Leader)

Yoshifumi Sakaguchi (Leader)

Masato Matsuura (Deputy Head)

Hiroki Iwase

Nobuo Okazaki (Leader)

Yukihiko Kawamura

Toshiaki Morikawa (Sub-Leader)

Jun-ichi Suzuki *Hiroshi Arima<BL01 Group>

Motoyuki Ishikado

Kazuya Kamazawa (Leader)
Kazuki Iida

<BL17 Group>

Misaki Ueda

Kazuhiko Ikeuchi

Noboru Miyata * (Leader)

Keiichi Ohuchi

Kazuhiro Akutsu

Hiroshi Kira

Takayasu Hanashima

Masae Sahara<BL02 Group>

Shuoyuan Zhang

Masato Matsuura (Leader)
Taiki Tominaga<BL18 Group>

Yuukou Nojiri

Takeshi Yamada

Akiko Nakao (Leader)

Koji Kiriyama *Koji Munakata

Satoshi Kasai

Yoshihisa Ishikawa

Yuuki Nagai<BL11 Group>

Kentaro Moriyama

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

Shinichi Machida

Hirotoshi Hayashida (Leader)

Takayoshi Ito *Joseph Don Parker
Yoshihiro Matsumoto

Safety Division

164*: additional duties

Mitsuhiro Shibayama * (Head)

Tazuko Mizusawa *Koji Kiriyama (Leader)

Masae Sahara *Yasuhiro YamaguchiMLF Operations in 2022

MLF Annual Report 2022

Utilization Promotion Division*: additional duties

Takashi Noma (Head)

Taeko Ishikawa

Hideyuki Niitsuma

Kazuki Mita (Deputy Head)

Tomoko Ishikawa

Tazuko Mizusawa

Takayoshi Ito (Leader)

Maya Endo

Nobuo Okazaki *Toshiki Asai (Leader)

Kaoru Ohuchi

Miho Igarashi

Emi Goto

Administration Division*: additional duties

Michihiko Murasawa (Head)

Mami Uchida

Shinobu Matsumoto

Takashi Hikita (Deputy Head)

Rie Kurosawa

Seiya Konishi *Junichi Sato (Leader)

Tomoko Sakuma

Rei Ito (Leader)

Mutsumi Shiraishi

Industrial Collaboration Promotion Division*: additional duties

Mitsuhiro Shibayama (Head)

Jun Abe *Kazuki Mita *Seiya Konishi (Deputy Head)

Hiroki Iwase *Takeshi Yamada *Noboru Miyata (Leader)

Yoshihiro Matsumoto *165

MLF Operations in 2022

MLF Annual Report 2022

Ibaraki Neutron Beamline Staff in 2022

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

Hideya Anzai

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)

Mitsuyuki Fujii

Taro Yamada

Akinori Hoshikawa

Shinju Shibata

Naomine Yano

Satoshi Koizumi

Tomoyuki Nakazawa

Ichiro Tanaka

Takeshi Matsukawa

Junichi Hiroki

Takaaki Hosoya

Kazuaki Iwasa
Tomoki Maeda
Shigeo Sato
Yohei Noda

166

MLF Annual Report 2022

MLF Operations in 2022

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
JAEA

Director General
KEK

The results of the MLF Advisory
Board’s review of proposals for KEK
Beamlines are ﬁnalized a�er theapproval by the Advisory
Commi�ee for Ins�tute ofMaterials Structure Science.

J-PARC
CenterCollabora�onCommi�ee

Director
J-PARC(JAEA/KEK)

President
CROSS

All except Public Beamlines

Director
CROSS-Tokai

RegisteredIns�tu�on(CROSS)

Public Beamlines Only

Selec�on
Commi�ee

MLF Advisory
Board

Task Forces

Joint Mee�ng

All except Contract
Beamlines

Contract Beamlines
Only

Muon Instrument
Proposal Rev. Comm.

Muon Science
Proposal Rev. Comm.

Neutron Instrument Contract Beamline
Proposal Rev. Comm. Evalua�on Comm.

Muon
Instrument
Proposals

Muon
Scien�ﬁc
Proposals

Neutron Instrument
Proposals

All except Public
Beamlines
Neutron Science
Proposal Rev. Comm.

Joint Mee�ngPublicBeamlines Only
Proposal
Evalua�on Comm.

Joint Mee�ng
Report the results to J-PARC
and CROSS-Tokai Directors
All except Public
PublicBeamlines
Beamlines
JAEA Research
Only
CROSS Development
Proposal Advisory Proposal Evalua�on
Comm.
Panel
Joint Mee�ng

Neutron Scien�ﬁc Proposals

UniﬁedAccess Point

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

167

MLF Operations in 2022 MLF Annual Report 2022

Materials and Life Science Facility Advisory Board

Yoshie Otake

RIKEN

Tadashi Adachi

Sophia University

Toshiya Otomo

Kazuya Aizawa

Japan Atomic Energy Agency

High Energy Accelerator Research
Organization

Hiroshi Amitsuka

Hokkaido University

Yoshiharu Sakurai

Japan Synchrotron Radiation
Research InstituteTaka-hisa Arima(chair)The University of Tokyo

Taku Sato

Tohoku University

Masahiro Hino

Kyoto University

Koichiro Shimomura High Energy Accelerator Research
Organization

Shinich Itoh

High Energy Accelerator Research
Organization

Yoko Sugawara

Toyota Physical and Chemical
Research InstituteYasuhiro Iye

Chubu University

Jun-ichi Suzuki

Takashi Kamiyama

Hokkaido University

Comprehensive Research
Organization for Science and Society

Yukinobu Kawakita

Japan Atomic Energy Agency

Hiroshi Takada

Japan Atomic Energy Agency

Atsushi Takahara

Kyushu University

Masayasu Takeda

Japan Atomic Energy Agency

Osamu Yamamuro

The University of Tokyo

Naritoshi Kawamura High Energy Accelerator Research
Organization
Hiroyuki Kishimoto

Sumitomo Rubber Industries, LTD.

Kenji Nakajima

Japan Atomic Energy Agency

Neutron Science Proposal Review Committee

Kenji Nakajima

Japan Atomic Energy Agency

Hiroshi Abe

National Defense Academy of Japan

Toshiya Otomo

Mitsuhiro Hirai

Gunma University

High Energy Accelerator Research
Organization

Shinich Itoh

High Energy Accelerator Research
Organization

Taku Sato

Tohoku University

Yukinobu Kawakita

Japan Atomic Energy Agency

Toshiyuki Takamuku Saga University
Noriyuki Tsuchida

University of Hyogo

Naritoshi Kawamura High Energy Accelerator Research
Organization

Satoshi Tsutsui

Japan Synchrotron Radiation
Research Institute

Masaaki Kitaguchi

Nagoya University

The University of Tokyo

Takatsugu Masuda

The University of Tokyo

Osamu Yamamuro(chair)Koichi Mayumi

The University of Tokyo

Muon Science Proposal Review Committee

168

Term: through March 31, 2023

Tadashi Adachi

Sophia University

Kenta Amemiya

High Energy Accelerator Research
Organization

Hidehito Asaoka

Japan Atomic Energy Agency

Katsuyuki Fukutani

The University of Tokyo

Wataru Higemoto

Japan Atomic Energy Agency

Adrian Hillier

Rutherford Appleton Laboratory

Hiromi Iinuma

Ibaraki University

Katsuya Inoue

Hiroshima University

Shinichi Itoh

High Energy Accelerator Research
Organization

Term: through September 30, 2023

Ryosuke KadonoHigh Energy Accelerator Research
Organization

Yukinobu Kawakita

Japan Atomic Energy Agency

Naritoshi Kawamura High Energy Accelerator Research
Organization
Yasushi Kino

Tohoku University

Akihiro Koda
Kenya Kubo (chair)High Energy Accelerator Research
Organization
International Christian University

Roderick Macrae

Marian University

Kenji Mishima

High Energy Accelerator Research
Organization

Takehito Nakano

Ibaraki University

MLF Annual Report 2022

Seiko OhiraKawamura

Japan Atomic Energy Agency

Chihiro OhmoriHigh Energy Accelerator Research
Organization

Toshiya Otomo

High Energy Accelerator Research
Organization

Hideki Seto

High Energy Accelerator Research
Organization

Tatsushi ShimaMLF Operations in 2022

Osaka University

Koichiro Shimomura High Energy Accelerator Research
Organization
Takashi Suemasu

University of Tsukuba

Yoko Sugawara

Kitasato University

Toshiyuki Takayanagi Saitama University
Term: through March 31, 2023

Selection Committee

Yoshie Otake

RIKEN

Tadashi Adachi

Sophia University

Yoshiharu Sakurai

Hiroshi Amitsuka

Hokkaido University

Japan Synchrotron Radiation
Research InstituteTaka-hisa Arima(chair)The University of Tokyo

Taku Sato

Tohoku University

Yoko Sugawara

Masahiro Hino

Kyoto University

Toyota Physical and Chemical
Research InstituteYasuhiro Iye

Chubu University

Atsushi Takahara

Kyushu University

Takashi Kamiyama

Hokkaido University

Osamu Yamamuro

The University of Tokyo

Hiroyuki Kishimoto

Sumitomo Rubber Industries, LTD.

Term: through March 31, 2023

Proposal Evaluation Committee

Taku Sato

Hiroshi Abe

National Defense Academy of Japan

Toshiyuki Takamuku Saga University

Mitsuhiro Hirai

Gunma University

Noriyuki Tsuchida

University of Hyogo

Masaaki Kitaguchi

Nagoya University

Satoshi Tsutsui

Takatsugu Masuda

The University of TokyoJapan Synchrotron Radiation
Research InstituteKoichi Mayumi

The University of Tokyo

Osamu Yamamuro(chair)The University of Tokyo

Toshiya Otomo

High Energy Accelerator Research
Organization

Term: through September 30, 2023

Neutron Advisory Committee (NAC)
NAC convened on 9 and 10 February 2023.

Tohoku University

Toyohiko Kinoshita

Japan Synchrotron Radiation
Research Institute

Guenter Muhrer

European Spallation Source

Ken Anderson

Oak Ridge National Laboratory

Yoshie Otake

RIKEN

Taka-hisa Arima

The University of Tokyo

Sungil Park

Christiane AlbaSimionesco

Laboratoire Léon Brillouin

Korea Atomic Energy ResearchInstituteJamie Schulz (chair)

Bertrand Blau

Paul Scherrer Institut

Australian Nuclear Science andTechnology Organization

Michael Dayton

Oak Ridge National Laboratory

Jon Taylor

European Spallation Source

Phillip King

Rutherford Appleton Laboratory

169

MLF Operations in 2022 MLF Annual Report 2022

170

Muon Advisory Committee (MAC)

Kenya Kubo

International Christian University

MAC convened on 20 and 21 February 2023.

Andrew Macfarlane

The University of British Columbia

Martin Månsson

KTH Royal Institute of Technology

Nori Aoi

Osaka University

Tadayuki Takahashi

The University of Tokyo

Thomas Prokscha(chair)Paul Scherrer Institut

Hiroshi Amitsuka

Hokkaido University

Klaus Kirch

ETH Zurich and Paul Scherrer Institut

MLF Annual Report 2022

MLF Operations in 2022

Workshops, Conferences, Seminars and Schools in 2022

Conferences held jointly by J-PARC MLF and CROSS
2022 Meeting on J-PARC MLF Industrial Use
14-15 Jul. 2022, Akihabara Convention Hall, Tokyo, Online

Photo of 2022 Meeting on J-PARC MLF Industrial Use(photo courtesy of J-PARC)

ISSE workshop 2022th

11 International Workshop on Sample Environment at
Scattering Facilities
28 Aug. - 1 Sep. 2022, Resort Hotel Laforet Nasu, Nasu

Photo of Progress for Fundamental Physics with Neutrons(photo courtesy of J-PARC)

2022 年度中性子実験技術基礎講習会（レベル 1 講習会）
7 Oct. 2022, Online
J-PARC Workshop 2022, Deuterium Science Entering a
Photo of ISSE workshop 2022
(photo courtesy of CROSS)

New Phase
19-20 Dec. 2022, IBARAKI Quantum Beam Research Center,Tokai2022 Workshop on Neutron Imaging
14-15 Sep. 2022, Essam Kanda Hall, Tokyo, Online
J-PARC Workshop, Progress for Fundamental Physics
with Neutrons
28-29 Sep. 2022, KEK Tokai Campus and J-PARC Center, Tokai

Photo of J-PARC Workshop 2022
(photo courtesy of CROSS)

171

MLF Operations in 2022

MLF Annual Report 2022th

2022 Quantum Beam Science Festa (The 14 MLF
thStudy on Cross-correlated Physics by Polarized Neutron

Symposium and the 40 PF Symposium)

Spectrometer, POLANO (BL23)

13-15 Mar. 2023, Tsukuba International Congress Center,

30 Nov. 2022, Online

Tsukuba
Studies on Dynamics in Condensed Matters by using
the High Resolution Chopper Spectrometer (BL12)
2 Dec. 2022, Online
Study on slow dynamics by the neutron resonance spinecho spectrometers VIN ROSE (BL06)
6 Dec. 2022, Online
Fundamental Physics with Pulsed Cold Neutrons (BL05)
15-16 Dec. 2022, Nagoya University, Nagoya
Workshop on Neutron Powder Diffraction using
SuperHRPD (BL08)th

Screenshot of 14 MLF Symposium(photo courtesy of CROSS)

17 Dec. 2022, Online
Workshop on Neutron Powder Diffraction using SPICA(BL09)

中性子小角散乱研究会
16 Mar. 2023, KEK, Tsukuba
2022 Z-Code Intermediate level Training Course
6 Dec. 2022-28 Feb. 2023, On-demandWorkshops and Seminars held by CROSS andother organizations
Workshop on Battery Materials

Conferences held by KEK

10 May 2022, Online

第 7 回文理融合シンポジウム “ 量子ビームで歴史を探る－加速器が紡ぐ文理融合の地平－ ”

第 77 回 Spring-8 先端利用技術ワークショップ / 第 2 回

2-3 Nov. 2022, KEK Tsukuba Campus, Ibaraki, Online

Workshops held by KEK
2022 年度物構研コロキウム“ 放射光および中性子を用いた次世代二次電池の開発 ”
6 June 2022, Online
2022 年度物構研コロキウム

放射光・中性子連携利用研究会 / 第 1 回量子ビームを用いた構造材料研究会
20 May 2022, Online
CBI 研究機構 量子構造生命科学研究所 中性子産業利用推進協議会 生物・生体材料研究会 合同シンポジウム“ 生体分子の動的挙動解析への挑戦

試料調製から解析

まで Ⅲ ”
27 Jul. 2022, Onlineth“ 中性子ビーム利用の有効性を定量的に記述する方法の

8 Symposium on the Collaborative Use of Large

模索 ”
3 Oct. 2022, Online

Research Institutions and the Super Computer

Analysis of ordered/disordered structure in functional

The 26 CROSSroads Workshop

materials with high intensity neutron total scattering“ データ解析ソフトウェアの紹介パート 2 ”
14 Oct. 2022, Online

technique (BL21)
28 Nov. 2022, Online

172

16 Dec. 2022, Online

30 Sep. 2022, Akihabara UDX, TokyothMLF Annual Report 2022

MLF Operations in 2022

Workshops and Seminars held by Ibaraki
Neutron Beamline and other organizations
st2022 1 Workshop on iMATERIA
21-22 Apr. 2022, Hokkaido University, Sapporo, Online
第 4 回中性子産業利用の研究会（茨城県中性子利用研究会 令和 4 年度第 2 回 iMATERIA 研究会
12 Sep. 2022, Essam Kanda Hall, Tokyo, OnlinethScreenshot of 26 CROSSroads Workshop(photo courtesy of CROSS)

合同開催）

rd

2022 3 Workshop on iMATERIA
29 Nov. 2022, Online
stWorkshop on Organic materials and Polymers

2022 1 Workshop on iBIX

“ 有機・高分子材料への反射率法の展開（第 4 回）”
17 Oct. 2022, Online

20 Sep. 2022, Onlinend2022 2 Workshop on iBIX
CBI 研究機構 量子構造生命科学研究所 中性子産業利用

22 Dec. 2022, Online

推進協議会 生物・生体材料研究会 合同シンポジウム

th2022 4 Workshop on iMATERIA“ MicroED の現状と未来 ”
6 Dec. 2022, Online

18 Jan. 2023, Online

2022 Workshop on Magnetic Materials

2022 年度 iBIX-JAXA-KEK 物構研 -QST 合同タンパク質研

11 Jan. 2023, Online究会“「酵素反応の中間体」の観測は可能か ”th

6 Joint Workshop for Complementary Use of

27 Feb. 2023, Online

Synchrotron Radiation and Neutrons“ 小角散乱測定研修会 ”
2 Feb. 2023, IBARAKI Quantum Beam Research Center, Tokaithth2022 5 Workshop on iMATERIA
8 Mar. 2023, University of Tokyo, Tokyoth

7 Joint Workshop for Complementary Use of2022 6 Workshop on iMATERIA

Synchrotron Radiation and Neutrons

24 Mar. 2023, Essam Kanda Hall, Tokyo, Online“ 粉末回折測定研修会 ”
17 Nov. 2022, JRR-3, IBARAKI Quantum Beam Research

Schools in 2022

Center, Tokai
Hello Science from J-PARC
ものづくり基盤研究会“ Form and Motion of Giant Molecules ”“ －接合・加工における課題解決に向けた評価技術－ ”
6 Mar. 2023, Online

29 Jul. 2022, IBARAKI Quantum Beam Research Center,
Tokai, Online

2022 Workshop on Liquids and Amorphous Materials

Hello Science from J-PARC

16 Mar. 2023, KEK, Tsukuba“ What can we do with the Ibaraki Prefectural device
iBIX? ”
30 Sep. 2022, IBARAKI Quantum Beam Research Center,
Tokai, Online

173

MLF Operations in 2022

MLF Annual Report 2022

Hello Science from J-PARC“Artisans’ Techniques in Making Elementary Particles From Site of Muon Production Targets -”23 Dec. 2022, IBARAKI Quantum Beam Research Center,
Tokai, OnlinethThe 6 Neutron and Muon School
12-16 Dec. 2021, J-PARC Center, Tokai

Photo of Neutron and Muon School(photo courtesy of CROSS)

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MLF Annual Report 2022

MLF Operations in 2022

Award List
2022 JMMS Outstanding Achievement Prize
Construction of the high intensity pulsed muon facility anddevelopment of interdisciplinary muon science
Y. Miyake (2023-03-29)
2022 JMMS Young Researcher Prize
層状カルコゲナイドに関するµSR研究

J. Nakamura (2023-03-29)

The JSNS President’s Choice
Application of Muon Beam for Li-ion Battery Research
I. Umegaki (2022-10-26)
The JSNS President’s Choice
Development of Spin-Contrast-Variation Neutron
Reflectometry for Structural Analyses of Multilayer Films
T. Kumada, D. Miura, K. Akutsu, J. Suzuki, N. Torikai(2022-10-26)

2022 JMMS Technology Prize
J-PARC 物質・生命科学実験施設におけるミュオン回転標的の開発と安全な運用･保守

S. Makimura, S. Matoba (2023-03-29)
Young Scientist Award of the Physical Society of Japan
Establishment of techniques using muon beam to detect
Li diffusion and metallic Li deposition in a Li-ion battery
I. Umegaki (2023-03)
SAT Technology Showcase 2023 ベスト産業実用化賞
最先端加速器技術で産業を革新する－超耐熱高靭性・高電気抵

The JSNS Young Researcher Prize
Research on Microstructure Control and Mechanical
Properties of Advanced Structural Materials using Pulsed
Neutron Diffraction
W. Gong (2022-10-26)
Student Presentation Award of the Physical Societyof Japan
Neutron lifetime measurement at J-PARC/BL05: Status of
the neutron lifetime analysis until 2022
T. Mogi (2022-10-15)

抗率タングステン合金

S. Makimura (2023-01-26)
J-PARC Center, Workshop 2022, Deuterium Science
Entering a New Phase, Poster Award
Development of a new analytical method for deuteriumlabeled compounds using NMR techniques
M. Ueda, K. Akutsu, M. Shibayama, T. A. Darwish, T. Yamada,T. Ikawa, H. Sajiki (2023-01-20)
The JSNS Poster Prize
Feasibility Study of Magnetic Scattering Holography using
Polarized Neutrons
T. Kanno (2022-10-27)
The JSNS Poster Prize
Study of local atomic fluctuation in RB6 with cage typestructure by neutron holography
Y. Kobayashi (2022-10-27)
The JSNS Poster Prize
Effect of grain refinement on deformation-induced
martensitic transformation
W. Mao (2022-10-27)

The Japan Institute of Metals and Materials The
Metals Best Poster Award
Deformation microstructure and recrystallization behaviorof Co20Cr40Ni40 medium entropy alloy
K. Yamamoto (2022-09-29)
The JSNS President’s Choice
Neutron Imaging for Observation of Grease Fluidity in Ball
Bearings
N. Kimura, K. Sakai, Y. Ayame, Y. Iwanami Y. Matsumoto(2022-09-28)
The Japan Institute of Metals and Materials MurakamiYoung Researcher Award
金属材料を対象としたAdditive Manufacturingに関する研究
K. Yamanaka (2022-09-21)
JAMS Research Paper Award
Neutron diffraction study of hydrogen site occupancy inFe0.95Si0.05 at 14.7 GPa and 800 K
Y. Mori H. Kagi S. Kakizawa K. Komatsu A. Sano-Furukawa(2022-09-17)

175

MLF Operations in 2022

MLF Annual Report 2022

The JLCS Best Paper Award B
Structural and Dynamical Studies on Liquid Crystalline
Ionic Liquids by Thermal Analysis and Neutron Scattering
F. Nemoto (2022-09-15)
SPSJ Showa Denko Materials Award 2022
Effects of Interfacial Structure and Physical Properties on
Functions in Polymer Thin Films
D. Kawaguchi (2022-09-06)
Acta/Scripta Materialia’s Outstanding Reviewers in
2021
S. Harjo (2022-08)

Progress Award of Japan Oil Chemists’ Society
自己組織体内部の特異な環境を利用した超分子機能の発現と応用

M. Akamatsu (2022-04-20)
Ibaraki UNIV. President Award
太陽電池材料 SnドープSi, Ge 薄膜の活性サイト位置のSn 量の定量評価

S. Hoshi (2022-03-30)
The JSNS Poster Prize
太陽電池材料 SnドープSi, Ge 薄膜の活性サイト位置のSn 量の定量評価

S. Hoshi (2021-12-03)
Nishikawa Prize, the Foundation for High Energy
Accelerator Science for 2021
Rabi-oscillation Spectroscopy in Accurate Measurement ofHyperfine Structure of Muonium Atoms
S. Nishimura, S. Kanda, K. Shimomura, H. Torii, K. Tanaka(2022-05-30)
The 21th Intelligent Cosmos Encouragement Prize
耐摩耗性と耐食性に優れた鉄鋼材料の開発

K. Yamanaka (2022-05-09)

176

JAMS: Japan Association of Mineralogical Sciences
JLCS: The Japanese Liquid Crystal Society
JMMS: Society of Muon and Meson Science of Japan
JSNS: The Japanese Society for Neutron Science
SAT: Science Academy of Tsukuba
SPSJ: The Society of Polymer Science, Japan

MLF Annual Report 2022

MLF Operations in 2022

MLF Publication 2022
1

K. Ohishi, D. Igarashi, R. Tatara, I. Umegaki, A. Koda, S. Komaba, J.
Sugiyama
Operando Muon Spin Rotation and Relaxation Measurement on
LiCoO2 Half-CellACS Appl. Energy Mater., 5 12538–12544 (2022).

2

H. Kawaura, M. Harada, Y. Kondo, M. Mizutani, N. Takahashi, N. L.
YamadaEffects of Lithium Bis(oxalate)Borate Electrolyte Additive on theFormation of a Solid Electrolyte Interphase on Amorphous Carbon
Electrodes by Operando Time-Slicing Neutron Reflectometry
ACS Appl. Mater. Interfaces, 14 24526–24535 (2022).

3

T. T. Chuong, T. Ogura, N. Hiyoshi, K. Takahashi, S. Lee, K. Hiraga,
H. Iwase, A. Yamaguchi, K. Kamagata, E. Mano, S. Hamakawa, H.
Nishihara, T. Kyotani, G. D. Stucky, T. Itoh
Giant Carbon Nano-Test Tubes as Versatile Imaging Vessels for HighResolution and in situ Observation of Proteins
ACS Appl. Mater. Interfaces, 14 26507–26516 (2022).

4

5

6

7

8

9

W. Yoshimune, N. Kikkawa, H. Yoneyama, N. Takahashi, S. Minami,
Y. Akimoto, T. Mitsuoka, H. Kawaura, M. Harada, N. L. Yamada, H.
Aoki
Interfacial Distribution of Nafion Ionomer Thin Films on NitrogenModified Carbon Surfaces
ACS Appl. Mater. Interfaces, 14 53744–53754 (2022).
M. Inutsuka, H. Watanabe, M. Aoyagi, N. L. Yamada, C. Tanaka, T.
Ikehara, D. Kawaguchi, S. Yamamoto, K. Tanaka
Effect of Oligomer Segregation on the Aggregation State andStrength at the Polystyrene/Substrate Interface
ACS Macro Lett., 11 504–509 (2022).
E. Saiki, Y. Nohara, H. Iwase, T. Shikata
Evidence of Long Two-Dimensional Folding Chain Structure
Formation of Poly(vinylidene fluoride) in N -Methylpyrrolidone
Solution: Total Form Factor Determination by Combining
Multiscattering DataACS Omega, 7 22825–22829 (2022).
E. Saiki, M. Yoshida, K. Kurahashi, H. Iwase, T. Shikata
Elongated Rodlike Particle Formation of Methyl Cellulose in Aqueous
SolutionACS Omega, 7 28849–28859 (2022).
K. Ohishi, D. Igarashi, R. Tatara, S. Nishimura, A. Koda, S. Komaba, J.
Sugiyama
Na Diffusion in Hard Carbon Studied with Positive Muon Spin
Rotation and Relaxation
ACS Phys. Chem. Au, 2 98–107 (2022).
T. Kawasaki, M. Takahashi, R. Kiyanagi, T. Ohhara
Rearrangement of Hydrogen Bonds in Dehydrated Raffinose
Tetrahydrate: A Time-of-Flight Neutron Diffraction Study
Acta Crystallogr. Sect. C Struct. Chem., 78 743–748 (2022).

10

T. Chatake, I. Tanaka, K. Kusaka, S. Fujiwara
Protonation States of Hen Egg-White Lysozyme Observed Using D/HContrast Neutron Crystallography
Acta Crystallogr. Sect. Struct. Biol., 78 770–778 (2022).

11

Y. Terasawa, T. Ohhara, S. Sato, S. Yoshida, T. Asahi
Single-Crystal Structure Analysis of Non-Deuterated Triglycine
Sulfate by Neutron Diffraction at 20 and 298 K: A New Disorder
Model for the 298 K Structure
Acta Crystallogr. Sect. E Crystallogr. Commun., 78 306–312 (2022).

12

K. Okada, A. Shibata, W. Gong, N. Tsuji
Effect of Hydrogen on Evolution of Deformation Microstructure in
Low-Carbon Steel with Ferrite Microstructure
Acta Mater., 225 117549 (2022).

13

D. Wei, L. Wang, Y. Zhang, W. Gong, T. Tsuru, I. Lobzenko, J. Jiang, S.
Harjo, T. Kawasaki, J. W. Bae, W. Lu, Z. Lu, Y. Hayasaka, T. Kiguchi, N.
L. Okamoto, T. Ichitsubo, H. S. Kim, T. Furuhara, E. Ma, H. Kato
Metalloid Substitution Elevates Simultaneously the Strength andDuctility of Face-Centered-Cubic High-Entropy Alloys
Acta Mater., 225 117571 (2022).

14

M. Liu, W. Gong, R. Zheng, J. Li, Z. Zhang, S. Gao, C. Ma, N. Tsuji
Achieving Excellent Mechanical Properties in Type 316 StainlessSteel by Tailoring Grain Size in Homogeneously Recovered or
Recrystallized Nanostructures
Acta Mater., 226 117629 (2022).

15

K. Sakaki, H. Kim, E. H. Majzoub, A. Machida, T. Watanuki, K. Ikeda,
T. Otomo, M. Mizuno, D. Matsumura, Y. Nakamura
Displacement of Hydrogen Position in Di-Hydride of V-Ti-Cr Solid
Solution Alloys
Acta Mater., 234 118055 (2022).

16

R. Zheng, W. Gong, J. Du, S. Gao, M. Liu, G. Li, T. Kawasaki, S. Harjo,
C. Ma, S. Ogata, N. Tsuji
Rediscovery of Hall-Petch Strengthening in Bulk Ultrafine Grained
Pure Mg at Cryogenic Temperature: A Combined in-situ Neutron
Diffraction and Electron Microscopy Study
Acta Mater., 238 118243 (2022).

17

R. S. Ramadhan, D. Glaser, H. Soyama, W. Kockelmann, T.
Shinohara, T. Pirling, M. E. Fitzpatrick, A. S. Tremsin
Mechanical Surface Treatment Studies by Bragg Edge Neutron
Imaging
Acta Mater., 239 118259 (2022).

18

Q. Li, Y. Onuki, A. Ahadi, Q. Sun
Large Tunable Thermal Expansion in Ferroelastic Alloys by Stress
Acta Mater., 240 118350 (2022).

19

B. Guo, W. Mao, Y. Chong, A. Shibata, S. Harjo, W. Gong, H. Chen, J.
J. Jonas, N. Tsuji
Unexpected Dynamic Transformation from α Phase to β Phase inZirconium Alloy Revealed by in-situ Neutron Diffraction during High
Temperature Deformation
Acta Mater., 242 118427 (2022).

20

T. Sawaguchi, Y. Tomota, F. Yoshinaka, S. Harjo
Evidence Supporting Reversible Martensitic Transformation
under Cyclic Loading on Fe–Mn–Si–Al Alloys Using in situ Neutron
Diffraction
Acta Mater., 242 118494 (2022).

21

M. Ohira, T. Katashima, M. Naito, D. Aoki, Y. Yoshikawa, H. Iwase, S.
Takata, K. Miyata, U. Chung, T. Sakai, M. Shibayama, X. Li
Star‐Polymer–DNA Gels Showing Highly Predictable and Tunable
Mechanical Responses
Adv. Mater., 34 2108818 (2022).

22

T. Odaira, S. Xu, K. Hirata, X. Xu, T. Omori, K. Ueki, K. Ueda, T.
Narushima, M. Nagasako, S. Harjo, T. Kawasaki, L. Bodnárová, P.
Sedlák, H. Seiner, R. Kainuma
Flexible and Tough Superelastic Co–Cr Alloys for Biomedical
Applications
Adv. Mater., 34 2202305 (2022).

177

MLF Operations in 2022

23

24

25

26

27

28

29

30

31

X. Xu, T. Odaira, S. Xu, K. Hirata, T. Omori, K. Ueki, K. Ueda, T.
Narushima, M. Nagasako, R. Kainuma, S. Harjo, T. Kawasaki, L.
Bodnarova, P. Sedlak, H. Seiner
Tough Yet Flexible Superelastic Alloys Meet Biomedical Needs
Adv. Mater. Process., 180 35–37 (2022).

Hydrate Using Neutron Diffraction
Chem. Phys. Lett., 812 140274 (2022).
36

L. Zheng, Z. Liu, Q. Zhang, S. Li, J. Huang, L. Zhang, B. Zan, M.
Tyagi, H. Cheng, T. Zuo, V. G. Sakai, T. Yamada, C. Yang, P. Tan, F.
Jiang, H. Chen, W. Zhuang, L. Hong
Universal Dynamical Onset in Water at Distinct Material Interfaces
Chem. Sci., 13 4341–4351 (2022).

37

C. Tsutsumi-Arai, K. Akutsu-Suyama, Y. Iwamiya, C. Terada-Ito, Z.
Hiroi, M. Shibayama, K. Satomura
Antimicrobial Surface Processing of Polymethyl Methacrylate
Denture Base Resin Using a Novel Silica-Based Coating Technology
Clin. Oral Investig., 27 1043–1053 (2022).

38

M. Akamatsu, T. Morita, K. Kobayashi, H. Iwase, K. Sakai, H. Sakai
Controlled Recombination Rate of Lophyl Radicals in CationicSurfactant Micelles
Colloids Surf. Physicochem. Eng. Asp., 638 128319 (2022).

39

N. V. Mdlovu, K.-S. Lin, M.-T. Weng, Y.-S. Lin
Design of Doxorubicin Encapsulated pH-/Thermo-Responsive andCationic Shell-Crosslinked Magnetic Drug Delivery System
Colloids Surf. B Biointerfaces, 209 112168 (2022).

40

Y. Furuike, D. Ouyang, T. Tominaga, T. Matsuo, A. Mukaiyama, Y.
Kawakita, S. Fujiwara, S. Akiyama
Cross-Scale Analysis of Temperature Compensation in the
Cyanobacterial Circadian Clock System
Commun. Phys., 5 75 (2022).

41

K. Komatsu
Neutrons Meet Ice Polymorphs
Crystallogr. Rev., 28 224–297 (2022).

42

S. Kanda
A Search for Atomic Parity Violation in Muonic Atoms Using a HighIntensity Pulsed Muon Beam at J-PARC
EPJ Web Conf., 262 01010 (2022).

43

K. Akutsu-Suyama, N. L. Yamada, Y. Ueda, R. Motokawa, H. Narita
New Design of a Sample Cell for Neutron Reflectometry in Liquid–
Liquid Systems and Its Application for Studying Structures at Air–
Liquid and Liquid–Liquid Interfaces
Appl. Sci., 12 1215 (2022).

S. Fukumura, P. Strasser, T. Ino, T. Oku, T. Okudaira, S. Kanda, M.
Kitaguchi, K. Shimomura, H. M. Shimizu, H. A. Torii, S. Nishimura
Proposal for New Measurements of Muonic Helium Hyperfine
Structure at J-PARC
EPJ Web Conf., 262 01012 (2022).

44

Y. Hirota, T. Tominaga, T. Kawabata, Y. Kawakita, Y. Matsuo
Hydrogen Dynamics in Hydrated Chitosan by Quasi-Elastic Neutron
Scattering
Bioengineering, 9 599 (2022).

T. Higuchi, on behalf of the TUCAN collaboration
Prospects for a Neutron EDM Measurement with an Advanced
Ultracold Neutron Source at TRIUMF
EPJ Web Conf., 262 01015 (2022).

45

Y. Kawakita, M. Matsuura, T. Tominaga, T. Yamada, H. Tamatsukuri,
H. Nakagawa, K. Ohuchi
Recent Progress on DNA ToF Backscattering Spectrometer in MLF,
J-PARC
EPJ Web Conf., 272 02002 (2022).

46

R. Kajimoto, M. Nakamura, K. Kamazawa, Y. Inamura, K. Iida, K.
Ikeuchi, M. Ishikado
Possible Future Upgrades of the Direct-Geometry Chopper
Spectrometer 4SEASONSEPJ Web Conf., 272 02007 (2022).

47

K. Nakajima, T. Kikuchi, S. Ohira-Kawamura, W. Kambara
Possible Options for Efficient Wide -Band Polychromatic
Measurements Using Chopper Spectrometers at Pulsed Sources
EPJ Web Conf., 272 02012 (2022).

48

M. Shibata, T. Terashima, T. Koga
Micellar Aggregation and Thermogelation of Amphiphilic Random
Copolymers in Water Hierarchically Dependent on Chain Length
Eur. Polym. J., 168 111091 (2022).

K. Okamoto, F. Takeiri, Y. Imai, M. Yonemura, T. Saito, K. Ikeda, T.
Otomo, T. Kamiyama, G. Kobayashi
Impact of Na Concentration on the Phase Transition Behavior and−
H Conductivities in the Ba–Li–Na–H–O Oxyhydride System
Adv. Sci., 10 2203541 (2022).
E. Nomura, M. Chiba, S. Matsuo, C. Noda, S. Kobayashi, J.
Manjanna, Y. Kawamura, K. Ohishi, K. Hiroi, J. Suzuki
Magnetization Process of Cubic Fe3O4 Submicron Particles Studied
by Polarized Small-Angle Neutron Scattering
AIP Adv., 12 035034 (2022).
T. Ohashi, T. Sakamaki, K. Funakoshi, T. Hattori, N. Hisano, J. Abe, A.
Suzuki
Structure of Basaltic Glass at Pressures up to 18 GPa
Am. Mineral., 107 325–335 (2022).
M. Segawa, Y. Toh, T. Kai, A. Kimura, S. Nakamura
Investigation of Radioactive Samples for Neutron Capture Reaction
Measurements Using Energy-Resolved Neutron Imaging
Ann. Nucl. Energy, 167 108828 (2022).
K. Kino, T. Itoh, T. Fujiwara, R. Kuroda, N. Oshima, M. Tanaka, A.
Watazu, T. Kamiyama, M. Yonemura, Y. Ishikawa
Nondestructive Quantitative Imaging for Spatially Nonuniform
Degradation in a Commercial Lithium-Ion Battery Using a Pulsed
Neutron BeamAppl. Phys. Express, 15 027005 (2022).
K. Hayashi, M. Lederer, Y. Fukumoto, M. Goto, Y. Yamamoto,
N. Happo, M. Harada, Y. Inamura, K. Oikawa, K. Ohoyama, P.
Wellmann
Determination of Site Occupancy of Boron in 6H–SiC by MultipleWavelength Neutron Holography
Appl. Phys. Lett., 120 132101 (2022).

32

T. Sogabe, H. Nakagawa, T. Yamada, S. Koseki, K. Kawai
Effect of Water Activity on the Mechanical Glass Transition and
Dynamical Transition of Bacteria
Biophys. J., 121 3874–3882 (2022).

33

Y. Kameda, N. Arai, Y. Amo, T. Usuki, J. Han, H. Watanabe, Y.
Umebayashi, S. Tsuzuki, K. Ikeda, T. Otomo
34
nat
Neutron Diffraction with S/ S Isotopic Substitution Method on
the Solvation Structure of S8 Molecule in Concentrated CS2 Solutions
Bull. Chem. Soc. Jpn., 95 1481–1485 (2022).

34

S. H. Song, S. Hong, M. Cho, J.-G. Yoo, H. Min Jin, S.-H. Lee, M.
Avdeev, K. Ikeda, J. Kim, S. C. Nam, S.-H. Yu, I. Park, H. Kim
Rational Design of Li Off-Stoichiometric Ni-Rich Layered CathodeMaterials for Li-Ion Batteries
Chem. Eng. J., 448 137685 (2022).

35

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A. Hoshikawa, A. Hachikubo
Observation of Hydrogen Bonding Network in Hydrogen Sulfide

MLF Annual Report 2022

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50

51

52

53

54

55

56

N. Kitamura, K. Kimura, N. Ishida, C. Ishibashi, Y. Idemoto
Effects of Ca Substitution on the Local Structure and Oxide–Ion
Behavior of Layered Perovskite Lanthanum Nickelate
Front. Mater., 9 954729 (2022).
D. Gong, M. Yi, M. Wang, T. Xie, W. Zhang, S. Danilkin, G. Deng, X.
Liu, J. T. Park, K. Ikeuchi, K. Kamazawa, S.-K. Mo, M. Hashimoto, D.
Lu, R. Zhang, P. Dai, R. J. Birgeneau, S. Li, H. Luo
Nematic Fluctuations in the Non-Superconducting Iron Pnictide
BaFe1.9−xNi0.1CrxAs2
Front. Phys., 10 886459 (2022).
K. Yamashita, K. Komatsu, T. Ohhara, K. Munakata, T. Irifune, T.
Shinmei, K. Sugiyama, T. Kawamata, H. Kagi
Improvement of Nano-Polycrystalline Diamond Anvil Cells with ZrBased Bulk Metallic Glass Cylinder for Higher Pressures: Application
to Laue-TOF Diffractometer
High Press. Res., 42 121–135 (2022).
T. Hattori, S. Ohira-Kawamura, T. Kawasaki
Development of a Hybrid Piston Cylinder Cell for Quasielastic
Neutron Scattering Experiments up to 1 GPa
High Press. Res., 42 226–235 (2022).
S. Machida, S. Nakano
Investigation of Null-Matrix Alloy Gaskets for a Diamond-Anvil-Cellon High Pressure Neutron Diffraction Experiments
High Press. Res., 42 303–317 (2022).
K. Sasaki, M. Sugita, M. Abe, H. Iinuma, C. Ogane, T. Mibe, K.
Shimomura, T. Ogitsu
Development of Precise Shimming Technique With Materials Having
Low Saturation Magnetization
IEEE Trans. Appl. Supercond., 32 9002107 (2022).
H. Tada, F. Yoshizu, S. Oyama, T. Tanaka, K. Sasaki, K. Shimomura
Development of Magnetic Field Mapping System for the MuSEUM
Experiment With High Precision Using CW-NMR Probes
IEEE Trans. Appl. Supercond., 32 9002205 (2022).
Y. Iwamiya, D. Nishio-Hamane, K. Akutsu-Suyama, H. ArimaOsonoi, M. Shibayama, Z. Hiroi
Photocatalytic Silica–Resin Coating for Environmental Protection ofPaper as a Plastic SubstituteInd. Eng. Chem. Res., 61 6967–6972 (2022).

MLF Operations in 2022

Int. J. Plast., 158 103417 (2022).
62

D. Wei, W. Gong, T. Tsuru, I. Lobzenko, X. Li, S. Harjo, T. Kawasaki,
H.-S. Do, J. W. Bae, C. Wagner, G. Laplanche, Y. Koizumi, H. Adachi,
K. Aoyagi, A. Chiba, B.-J. Lee, H. S. Kim, H. Kato
Si-Addition Contributes to Overcoming the Strength-Ductility Tradeoff in High-Entropy Alloys
Int. J. Plast., 159 103443 (2022).

63

S. Yoshida, R. Fu, W. Gong, T. Ikeuchi, Y. Bai, Z. Feng, G. Wu, A.
Shibata, N. Hansen, X. Huang, N. Tsuji
Grain Orientation Dependence of Deformation Microstructure
Evolution and Mechanical Properties in Face-Centered Cubic High/
Medium Entropy Alloys
IOP Conf. Ser. Mater. Sci. Eng., 1249 012027 (2022).

64

Y. Oba, S. Morooka, K. Ohishi, J. Suzuki, T. Tsuchiyama
Characterization of Deformation by Cold Rolling in Ferritic SteelContaining Cu Particles Using Neutron Transmission Analysis
ISIJ Int., 62 173–178 (2022).

65

H. Uchima, M. Kumagai, J. Shimbe, A. Tanabe, Y. Mizuno, Y. Onuki
Impact of Dislocation Density and Mobility on Yielding Behavior
in Quenched Medium-Carbon Martensitic Steel Tempered at Low
Temperature
ISIJ Int., 62 998–1003 (2022).

66

S. Harjo, W. Gong, T. Kawasaki, S. Morooka, T. Yamashita
Revisit Deformation Behavior of Lath Martensite
ISIJ Int., 62 1990–1999 (2022).

67

M. Koyama, T. Yamashita, S. Morooka, T. Sawaguchi, Z. Yang, T.
Hojo, T. Kawasaki, S. Harjo
Microstructure and Plasticity Evolution During Lüders Deformationin an Fe-5Mn-0.1C Medium-Mn SteelISIJ Int., 62 2036–2042 (2022).

68

M. Koyama, T. Yamashita, S. Morooka, Z. Yang, R. S. Varanasi, T.
Hojo, T. Kawasaki, S. Harjo
Hierarchical Deformation Heterogeneity during Lüders Band
Propagation in an Fe-5Mn-0.1C Medium Mn Steel Clarified throughin situ Scanning Electron Microscopy
ISIJ Int., 62 2043–2053 (2022).

69

H. Sato, A. Kusumi, Y. Shiota, H. Hayashida, Y. Su, J. Don Parker, K.
Watanabe, T. Kamiyama, Y. Kiyanagi
Visualising Martensite Phase Fraction in Bulk Ferrite Steel bySuperimposed Bragg-Edge Profile Analysis of Wavelength-Resolved
Neutron Transmission Imaging
ISIJ Int., 62 2319–2330 (2022).

57

K. Takaya, M. Hagiwara, S. Matoba, M. Takaya, N. Shibata
A Real-Time Gas Monitoring System Based on Ion Mobility
Spectrometry for Workplace Environmental Measurements
Ind. Health, 60 40–46 (2021).

58

T. Yajima, K. Takahashi, H. Nakajima, T. Honda, K. Ikeda, T. Otomo, Z.
Hiroi
High-Pressure Synthesis of Transition-Metal Oxyhydrides with
Double-Perovskite Structures
Inorg. Chem., 61 2010–2016 (2022).

70

T. Murakawa, K. Kurihara, M. Adachi, K. Kusaka, K. Tanizawa, T.
Okajima
Re-Evaluation of Protein Neutron Crystallography with and without
X-Ray/Neutron Joint Refinement
IUCrJ, 9 342–348 (2022).

59

M. K. Sugumar, T. Yamamoto, K. Ikeda, M. Motoyama, Y. Iriyama
Preparation of Li-Excess and Li-Deficient Antiperovskite Structured
Li2+xOH1–xBr and Their Effects on Total Ionic Conductivity
Inorg. Chem., 61 4655–4659 (2022).

71

S. Sasada, Y. Takahashi, K. Takeuchi, K. Hiroi, Y. Su, T. Shinohara, K.
Watanabe, A. Uritani
Strain Distribution Visualization of Punched Electrical Steel Sheets
Using Neutron Bragg-Edge Transmission Imaging
Jpn. J. Appl. Phys., 61 046004 (2022).

60

Y. Yasuda, F. Nabeshima, K. Horiuchi, H. Nagai
Visualization of the Working Fluid in a Flat-Plate Pulsating Heat Pipeby Neutron Radiography
Int. J. Heat Mass Transf., 185 122336 (2022).

72

Z. Deng, Q. Li, Y. Onuki, Q. Sun
Multifunctional Nanostructured NiTi Alloy with Invar, Elinvar andRinvar Properties
J. Alloys Compd., 909 164682 (2022).

73

D. Yun, H. Chae, T. Lee, D.-H. Lee, H. J. Ryu, R. Banerjee, S. Harjo, T.
Kawasaki, S. Y. Lee
Stress Contribution of B2 Phase in Al 0.7CoCrFeNi Eutectic High
Entropy Alloy61

D. Wei, W. Gong, T. Tsuru, T. Kawasaki, S. Harjo, B. Cai, P. K. Liaw, H.
Kato
Mechanical Behaviors of Equiatomic and Near-Equiatomic FaceCentered-Cubic Phase High-Entropy Alloys Probed Using in situ
Neutron Diffraction

179

MLF Operations in 2022

MLF Annual Report 2022

J. Alloys Compd., 918 165673 (2022).
74

75

76

77

78

K. Tatsumi, Y. Inamura, M. Kofu, R. Kiyanagi, H. Shimazaki
Optimization and Inference of Bin Widths for Histogramming
Inelastic Neutron Scattering Spectra
J. Appl. Crystallogr., 55 533–543 (2022).
T. Kumada, D. Miura, K. Akutsu-Suyama, K. Ohishi, T. Morikawa, Y.
Kawamura, J. Suzuki, T. Oku, N. Torikai, T. Niizeki
Structure Analysis of a Buried Interface between Organic and Porous
Inorganic Layers Using Spin-Contrast-Variation Neutron Reflectivity
J. Appl. Crystallogr., 55 1147–1153 (2022).
K. Ikeda, H. Ohshita, T. Otomo, K. Sakaki, H. Kim, Y. Nakamura, A.
Machida, R. B. Von Dreele
Pressure Cells for in situ Neutron Total Scattering: Time and RealSpace Resolution during Deuterium Absorption
J. Appl. Crystallogr., 55 1631–1639 (2022).
T. Kawasaki, T. Fukuda, S. Yamanaka, T. Sakamoto, I. Murayama, T.
Katou, M. Baba, H. Hashimoto, S. Harjo, K. Aizawa, H. Tanaka, M.
Takeda, T. Sekino, T. Nakayama, Y. Kim
Operando Structure Observation of Pyroelectric Ceramics during
Power Generation Cycle
J. Appl. Phys., 131 134103 (2022).

79

M. Hiraishi, H. Okabe, A. Koda, R. Kadono, H. Hosono
Ambipolarity of Diluted Hydrogen in Wide-Gap Oxides Revealed by
Muon Study
J. Appl. Phys., 132 105701 (2022).

80

Y. Sakuda, J. R. Hester, M. Yashima
Improved Oxide-Ion and Lower Proton Conduction of Hexagonal
6+
Perovskite-Related Oxides Based on Ba7Nb4MoO20 by Cr Doping
J. Ceram. Soc. Jpn., 130 442-447 (2022).

81

82

83

84

85

180

F. Malamud, J. R. Santisteban, Y. Gao, T. Shinohara, K. Oikawa, A.
Tremsin
Non-Destructive Characterization of the Spatial Variation ofγ / γ’ Lattice Misfit in a Single-Crystal Ni-Based Superalloy by EnergyResolved Neutron Imaging
J. Appl. Crystallogr., 55 228–239 (2022).

Y. Mitsuya, K. Shimazoe, T. Fujiwara, H. Takahashi
Energy-Resolved Neutron Imaging with Glass Gas Electron Multiplierand Dynamic Time-over-Threshold Method
J. Instrum., 17 C01006 (2022).
N. Muto, H. Abele, T. Ariga, J. Bosina, M. Hino, K. Hirota, G.
Ichikawa, T. Jenke, H. Kawahara, S. Kawasaki, M. Kitaguchi, J.
Micko, K. Mishima, N. Naganawa, M. Nakamura, S. Roccia, O. Sato,R. I. P. Sedmik, Y. Seki, H. M. Shimizu, S. Tada, A. Umemoto
A Novel Nuclear Emulsion Detector for Measurement of Quantum
States of Ultracold Neutrons in the Earth’s Gravitational Field
J. Instrum., 17 P07014 (2022).
W. Gong, R. Zheng, S. Harjo, T. Kawasaki, K. Aizawa, N. Tsuji
In-situ Observation of Twinning and Detwinning in AZ31 Alloy
J. Magnes. Alloys, 10 3418–3432 (2022).
K. Okamoto, F. Takeiri, Y. Imai, M. Yonemura, T. Saito, K. Ikeda, T.
Otomo, T. Kamiyama, G. Kobayashi−
Stabilization of a High H -Conducting Phase via K Doping of Ba–Li
Oxyhydride
J. Mater. Chem. A, 10 23023–23027 (2022).

86

D. Wei, W. Gong, L. Wang, B. Tang, T. Kawasaki, S. Harjo, H. KatoStrengthening of High-Entropy Alloys via Modulation of Cryo-PreStraining-Induced Defects
J. Mater. Sci. Technol., 129 251–260 (2022).

87

H. Abe, F. Nemoto, K. Hiroi, K. Ohishi, S. Takata
Spontaneous Formations of Nanoconfined Water in Ionic Liquids by
Small-Angle Neutron Scattering
J. Mol. Liq., 346 117035 (2022).

88

W. Q. Zhang, T. Yamaguchi, C. H. Fang, K. Yoshida, Y. Q. Zhou, F. Y.
Zhu, S. Machida, T. Hattori, W. Li
Structure of an Aqueous RbCl Solution in the Gigapascal Pressure
Range by Neutron Diffraction Combined with Empirical Potential
Structure Refinement Modeling
J. Mol. Liq., 348 118080 (2022).

89

T. Yamaguchi, K. Yoshida, S. Machida, T. Hattori
Neutron Scattering on an Aqueous Sodium Chloride Solution in the
Gigapascal Pressure Range
J. Mol. Liq., 365 120181 (2022).

90

K. Yoshida, Y. Sanada, T. Yamaguchi, M. Matsuura, H. Tamatsukuri,
H. Uchiyama
The Translational, Rotational, and Phonon Dynamics of Water in
ZrO2 /Water Nanofluid
J. Mol. Liq., 366 120218 (2022).

91

S. Sato, R. Kajimoto, Y. Inamura
3
Development of a Pulse-Width-Discriminating He Position-Sensitive
Detector System
J. Neutron Res., 24 427–434 (2022).

92

R. Motokawa, K. Kaneko, Y. Oba, T. Nagai, Y. Okamoto, T.
Kobayashi, T. Kumada, W. T. Heller
Nanoscopic Structure of Borosilicate Glass with Additives for Nuclear
Waste Vitrification
J. Non-Cryst. Solids, 578 121352 (2022).

93

D. Ito, H. Sato, N. Odaira, Y. Saito, J. D. Parker, T. Shinohara, T. Kai, K.
OikawaSpatial Distribution and Preferred Orientation of Crystalline
Microstructure of Lead-Bismuth Eutectic
J. Nucl. Mater., 569 153921 (2022).

94

G. Rovira, T. Katabuchi, K. Tosaka, S. Matsuura, Y. Kodama, H.
Nakano, O. Iwamoto, A. Kimura, S. Nakamura, N. Iwamoto
237
KeV-Region Analysis of the Neutron Capture Cross-Section of Np
J. Nucl. Sci. Technol., 59 110–122 (2022).

95

S. Endo, A. Kimura, S. Nakamura, O. Iwamoto, N. Iwamoto, G.
Rovira, K. Terada, S. Meigo, Y. Toh, M. Segawa, M. Maeda, M.
Tsuneyama
Neutron Capture and Total Cross-Section Measurements andResonance Parameter Analysis of Niobium-93 below 400 EV
J. Nucl. Sci. Technol., 59 318–333 (2022).

96

G. Rovira, A. Kimura, S. Nakamura, S. Endo, O. Iwamoto, N.
Iwamoto, T. Katabuchi, Y. Kodama, H. Nakano, Y. Sato, J. Hori, Y.
Shibahara, K. Terada197
KeV-neutron capture cross-section measurement of Au with a Crfiltered neutron beam at the ANNRI beamline of MLF/J-PARC
J. Nucl. Sci. Technol., 59 647-655 (2022).

97

H. Nakano, T. Katabuchi, G. Rovira, Y. Kodama, K. Terada, A.
Kimura, S. Nakamura, S. Endo
Development of a neutron beam monitor with a thin plastic
scintillator for nuclear data measurement using spallation neutron
sourceJ. Nucl. Sci. Technol., 59 1499-1506 (2022).

98

G. Rovira, A. Kimura, S. Nakamura, S. Endo, O. Iwamoto, N.

J. Yang, W. Ren, X. Zhao, T. Kikuchi, P. Miao, K. Nakajima, B. Li, Z.
Zhang
Mictomagnetism and Suppressed Thermal Conduction of thePrototype High-Entropy Alloy CrMnFeCoNi
J. Mater. Sci. Technol., 99 55–60 (2022).

MLF Annual Report 2022

Iwamoto, T. Katabuchi, Y. Kodama, H. Nakano
241
Am Neutron Capture Cross Section in the KeV Region Using Si and
Fe-Filtered Neutron Beams
J. Nucl. Sci. Technol., 60 489–499 (2022).
99

A. Kimura, S. Nakamura, S. Endo, G. Rovira, O. Iwamoto, N.
Iwamoto, H. Harada, T. Katabuchi, K. Terada, J. Hori, Y. Shibahara, T.
Fujii
155
Neutron Total and Capture Cross-Section Measurements of Gd
157
and Gd in the Thermal Energy Region with the Li-Glass Detectors
and NaI(Tl) Spectrometer Installed in J-PARC·MLF·ANNRI
J. Nucl. Sci. Technol., 60 678–696 (2022).

100 M. Uyama, A. Takahara, Y. Higaki, N. L. Yamada, H. Iwase
Neutron Reflectometry & Simultaneous Measurements of Rheology
and Small Angle Neutron Scattering Studies for Polyether Modified
Silicone Vesicle Systems
J. Oleo Sci., 71 1625–1637 (2022).
101 S. Shimono, H. Ishibashi, Y. Nagayoshi, H. Ikeno, S. Kawaguchi, M.
Hagihala, S. Torii, T. Kamiyama, K. Ichihashi, S. Nishihara, K. Inoue,
Y. Ishii, Y. Kubota
Structural Phase Transition in Cobalt Oxyfluoride Co 3Sb 4O 6F 6
Observed by High-Resolution Synchrotron and Neutron Diffraction
J. Phys. Chem. Solids, 163 110568 (2022).
102 T. Yamanaka, S. Rahman, Y. Nakamoto, T. Hattori, B. G. Jang, D. Y.
Kim, H. Mao
Enhancement of Electrical Conductivity to Metallization of
Mn3-xFexO4 Spinel and Postspinel with Elevating Pressure
J. Phys. Chem. Solids, 167 110721 (2022).
103 C. Kim, J. Jeong, G. Lin, P. Park, T. Masuda, S. Asai, S. Itoh, H.-S.
Kim, H. Zhou, J. Ma, J.-G. Park
Antiferromagnetic Kitaev Interaction inJeff = 1/2 Cobalt Honeycomb
Materials Na3Co2SbO6 and Na2Co2TeO6
J. Phys. Condens. Matter, 34 045802 (2022).

MLF Operations in 2022

110 H. Akatsuka, T. Higuchi, S. Hansen-Romu, K. Hatanaka, T.
Hayamizu, M. Hino, G. Ichikawa, S. Imajo, B. Jamieson, S.
Kawasaki, M. Kitaguchi, R. Matsumiya, K. Mishima
Study of Thin Iron Films for Polarization Analysis of Ultracold
Neutrons
JPS Conf. Proc., 37 020801 (2022).
111 T. Ino, S. Fukumura, P. Strasser, M. Fujita, Y. Ikeda, S. Kanda, M.
Kitaguchi, S. Nishimura, T. Oku, T. Okudaira, H. M. Shimizu, K.
Shimomura
Optically Polarized Alkali Metal Cell for Muonic Helium
Measurements
JPS Conf. Proc., 37 021208 (2022).
112 K. Saito, K. Fujii, M. Yashima
Oxide-Ion and Proton Conductivity of the Ordered Perovskite
BaY1/3Ga2/3O2.5
J. Solid State Chem., 306 122733 (2022).
113 K. Fukui, S. Iimura, A. Iskandarov, T. Tada, H. Hosono
Room-Temperature Fast H – Conduction in Oxygen-Substituted
Lanthanum Hydride
J. Am. Chem. Soc., 144 1523–1527 (2022).
114 K. Kakimoto, S. Takada, H. Ohta, Y. Haraguchi, M. Hagihala, S. Torii,
T. Kamiyama, H. Mitamura, M. Tokunaga, A. Hatakeyama, H. A.
Katori
Magnetism of AlxFe2−xGeO5 with Andalusite Structure
J. Phys. Soc. Jpn., 91 054704 (2022).
115 K. Kakimoto, H. Ohta, Y. Haraguchi, M. Hagihala, S. Torii, T.
Kamiyama, H. A. Katori
Sinusoidal Magnetic Structure of Andalusite-Type Alx Fe2−xGeO5 withx = 0.09 and 0.1
J. Phys. Soc. Jpn., 91 054707 (2022).

104 K. Kataoka, D. Hirai, A. Koda, R. Kadono, T. Honda, Z. Hiroi
Pyrochlore Oxide Hg2Os2O7 on Verge of Metal–Insulator Boundary
J. Phys. Condens. Matter, 34 135602 (2022).

116 N. Metoki, K. Shibata, M. Matsuura, H. Kitazawa, H. S. Suzuki, H.
Yamauchi, M. Hagihala, M. D. Frontzek, M. Matsuda
Hyperfine Splitting and Nuclear Spin Polarization in NdPd5Al2 andNd3Pd20Ge6
J. Phys. Soc. Jpn., 91 054710 (2022).

105 T. Xie, C. Liu, R. Kajimoto, K. Ikeuchi, S. Li, H. Luo
Spin Fluctuations in the 112-Type Iron-Based Superconductor
Ca0.82La0.18Fe0.96Ni0.04As2
J. Phys. Condens. Matter, 34 474001 (2022).

117 T. Matsumura, M. Tsukagoshi, Y. Ueda, N. Higa, A. Nakao, K.
Kaneko, M. Kakihana, M. Hedo, T. Nakama, Y. Ōnuki
Cycloidal Magnetic Ordering in Noncentrosymmetric EuIrGe3
J. Phys. Soc. Jpn., 91 073703 (2022).

106 T. D. Vu, H. Shishido, K. Aizawa, T. Oku, K. Oikawa, M. Harada, K. M.
Kojima, S. Miyajima, K. Soyama, T. Koyama, M. Hidaka, S. Y. Suzuki,
M. M. Tanaka, A. Malins, M. Machida, T. Ishida
Narrow-Area Bragg-Edge Transmission of Iron Samples Using
Superconducting Neutron Sensor
J. Phys. Conf. Ser., 2323 012028 (2022).

118 D. Ueta, R. Kobayashi, H. Sawada, Y. Iwata, S. Yano, S. Kuniyoshi, Y.
Fujisawa, T. Masuda, Y. Okada, S. Itoh
Anomalous Magnetic Moment Direction under Magnetic Anisotropy
Originated from Crystalline Electric Field in van Der Waals
Compounds CeTe3 and CeTe2Se
J. Phys. Soc. Jpn., 91 094706 (2022).

107 H. Shishido, T. D. Vu, K. Aizawa, K. M. Kojima, T. Koyama, K.
Oikawa, M. Harada, T. Oku, K. Soyama, S. Miyajima, M. Hidaka, S. Y.
Suzuki, M. M. Tanaka, S. Kawamata, T. Ishida
Neutron Imaging toward Epithermal Regime Using a Delay Line
Current-Biased Kinetic-Inductance Detector
J. Phys. Conf. Ser., 2323 012029 (2022).

119 M. Soda, M. Kofu, S. Ohira-Kawamura, S. Asai, T. Masuda, H.
Yoshizawa, H. Kawano-Furukawa
Magnetic Diffuse and Quasi-Elastic Scatterings in Frustrated Magnet
YBaCo4O7
J. Phys. Soc. Jpn., 91 094707 (2022).

108 M. Nasu, H. Yanai, N. Hirayama, H. Adachi, Y. Kakizawa, Y. Shirase, H.
Nishiyama, T. Kawamoto, J. Inukai, T. Shinohara, H. Hayashida, M.
Watanabe
Neutron Imaging of Generated Water inside Polymer Electrolyte
Fuel Cell Using Newly-Developed Gas Diffusion Layer with Gas Flow
Channels during Power Generation
J. Power Sources, 530 231251 (2022).
109 M. Kitaguchi
T-violation in neutron scattering
JPS Conf. Proc., 37 011010 (2022).

120 K. Yamaoka, N. L. Yamada, K. Hori, Y. Fujii, N. TorikaiInterfacial Selective Study on the Gelation Behavior of Aqueous
Methylcellulose Solution via a Quartz Crystal Microbalance
Langmuir, 38 4494–4502 (2022).
121 D. Ihara, Y. Higaki, N. L. Yamada, F. Nemoto, Y. Matsuda, K. Kojio, A.
Takahara
Cononsolvency of Poly[2-(methacryloyloxy)ethyl
phosphorylcholine] in Ethanol–Water Mixtures: A Neutron
Reflectivity Study
Langmuir, 38 5081–5088 (2022).

181

MLF Operations in 2022

MLF Annual Report 2022

122 Y. Xie, J. Iwata, T. Matsumoto, N. L. Yamada, F. Nemoto, H. Seto, T.
NishinoHydrophobicity of the Pentafluorosulfanyl Group in Side Chainsof Polymethacrylates by Evaluation with Surface Free Energy and
Neutron Reflectivity
Langmuir, 38 6472–6480 (2022).
123 Y. Higaki, R. Furusawa, T. Otsu, N. L. Yamada
Zwitterionic Poly(carboxybetaine) Brush/Albumin Conjugate Films:
Structure and Lubricity
Langmuir, 38 9278–9284 (2022).
124 K. Shimokita, K. Yamamoto, N. Miyata, H. Arima-Osonoi, Y.
Nakanishi, M. Takenaka, M. Shibata, N. L. Yamada, H. Seto, H. Aoki,
T. Miyazaki
Neutron Reflectivity Study on the Suppression of Interfacial Water
Accumulation between a Polypropylene Thin Film and Si Substrate
Using a Silane-Coupling Agent
Langmuir, 38 12457–12465 (2022).
125 T. Tominaga, H. Nakagawa, M. Sahara, T. Oda, R. Inoue, M.
Sugiyama
Data Collection for Dilute Protein Solutions via a Neutron
Backscattering Spectrometer
Life, 12 675 (2022).
126 S. Imai, M. Arakawa, Y. Nakanishi, M. Takenaka, H. Aoki, M. Ouchi, T.
Terashima
Water-Assisted Microphase Separation of Cationic Random
Copolymers into Sub-5 Nm Lamellar Materials and Thin Films
Macromolecules, 55 9113–9125 (2022).
127 N. R. Jaladurgam, A. Lozinko, S. Guo, S. Harjo, M. H. Colliander
Load Redistribution in Eutectic High Entropy Alloy AlCoCrFeNi 2.1
during High Temperature Deformation
Materialia, 22 101392 (2022).
128 Y. Wang, Y. Tomota, T. Ohmura, W. Gong, S. Harjo
Evolution of Austenite Lattice Parameter during Isothermal
Transformation in a 0.4 C Low Alloyed SteelMaterialia, 27 101685 (2022).

135 R. Miyazaki, K. Ikeda, N. Kitamura, Y. Takabayashi, K. Kimura, K.
Hayashi, T. Hihara
Reverse Monte Carlo Analysis of NaI-LiI Solid Electrolyte Based on
the Neutron Total Scattering Data
Mater. Today Commun., 32 104014 (2022).
136 S. M. Suturin, P. A. Dvortsova, L. A. Snigirev, V. A. Ukleev, T.
Hanashima, M. Rosado, B. Ballesteros
Structural Peculiarities of ε-Fe2O3/GaN Epitaxial Layers Unveiled by
High-Resolution Transmission Electron Microscopy and Neutron
Reflectometry
Mater. Today Commun., 33 104412 (2022).
137 E. Rathore, R. Juneja, D. Sarkar, S. Roychowdhury, M. Kofu, K.
Nakajima, A. K. Singh, K. Biswas
Enhanced Covalency and Nanostructured-Phonon Scattering Leadto High Thermoelectric Performance in n-Type PbS
Mater. Today Energy, 24 100953 (2022).
138 H. Sasaki, S. Akiya, Y. Oba, M. Onuma, A. D. Giddings, T. Ohkubo
Characterization of Precipitated Phase in Cu–Ni–Si Alloy by SmallAngle X-Ray Scattering, Small Angle Neutron Scattering and Atom
Probe Tomography
Mater. Trans., 63 1384–1389 (2022).
139 T. Yamada
Quasi Elastic Neutron Scattering Study on Water Dynamics in
Nafion Membrane
MEMBRANE, 47 207–212 (2022).
140 M.-M. Schiavone, Y. Zhao, H. Iwase, H. Arima-Osonoi, S. Takata, A.
Radulescu
On the Proton Conduction Pathways in Polyelectrolyte Membranes
Based on Syndiotactic-Polystyrene
Membranes, 12 143 (2022).

129 M. Kumagai, M. Kuroda, T. Matsuno, S. Harjo, K. Akita
In situ Neutron Diffraction Analysis of Microstructural EvolutionDependent Stress Response in Austenitic Stainless Steel under Cyclic
Plastic Deformation
Mater. Des., 221 110965 (2022).

141 Y. Onuki, K. Umemura, K. Fujiwara, Y. Tanaka, T. Tomida, K.
Kawano, S. Sato
Microstructure Formation and Carbon Partitioning with Austenite
Decomposition during Isothermal Heating Process in Fe-Si-Mn-C
Steel Monitored by in situ Time-of-Flight Neutron Diffraction
Metals, 12 957 (2022).

130 K. S. N. Sesha, K. Yamanaka, M. Mori, Y. Onuki, S. Sato, D. Fabrègue,A. Chiba
Demonstrating a Duplex TRIP/T WIP Titanium Alloy via theIntroduction of Metastable Retained β-Phase
Mater. Res. Lett., 10 754–761 (2022).

142 K. Yamanaka, M. Mori, Y. Onuki, S. Sato, A. Chiba
Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V
Alloys Determined via Time-Of-Flight Neutron Diffraction LineProfile Analysis
Metals, 13 86 (2022).

131 H. Dannoshita, H. Hasegawa, S. Higuchi, H. Matsuda, W. Gong, T.
Kawasaki, S. Harjo, O. Umezawa
Evolution of Dislocation Structure Determined by Neutron
Diffraction Line Profile Analysis during Tensile Deformation in
Quenched and Tempered Martensitic Steels
Mater. Sci. Eng. A, 854 143795 (2022).

143 Q. Li, J. Sun, Y. Zhang, T. Li, H. Liu, Y. Cao, Q. Zhang, L. Gu, T. Honda,
K. Ikeda, T. Otomo, K. Lin, J. Deng, X. Xing
Ferroelectric Ordering in Nanosized PbTiO3
Nano Lett., 22 9405–9410 (2022).

132 P. Thirathipviwat, S. Nozawa, M. Furusawa, Y. Onuki, M. Hasegawa,
K. Matsumoto, S. SatoIn-situ Neutron Diffraction Study on a Dislocation Density in a
Correlation with Strain Hardening in Al–Mg Alloys
Mater. Sci. Eng. A, 855 143956 (2022).
133 T.-N. Lam, A. Lee, Y.-R. Chiu, H.-F. Kuo, T. Kawasaki, S. Harjo, J. Jain, S.
Y. Lee, E.-W. Huang
Estimating Fine Melt Pool, Coarse Melt Pool, and Heat Affected Zone
Effects on the Strengths of Additive Manufactured AlSi10Mg Alloys
Mater. Sci. Eng. A, 856 143961 (2022).

182

134 D. Egusa, R. Manabe, T. Kawasaki, S. Harjo, S. Sato, E. Abe
Quantitative X-Ray Diffraction Analysis of Solute-Enriched Stacking
Faults in Hcp-Mg Alloys Based on Peak Asymmetry Analysis
Mater. Today Commun., 31 103344 (2022).

144 R. Takagi, N. Matsuyama, V. Ukleev, L. Yu, J. S. White, S. Francoual, J.
R. L. Mardegan, S. Hayami, H. Saito, K. Kaneko, K. Ohishi, Y. Ōnuki, T.
Arima, Y. Tokura, T. Nakajima, S. Seki
Square and Rhombic Lattices of Magnetic Skyrmions in aCentrosymmetric Binary CompoundNat. Commun., 13 1472 (2022).
145 P. Luo, Y. Zhai, P. Falus, V. García Sakai, M. Hartl, M. Kofu, K.
Nakajima, A. Faraone, Y. Z
Q-Dependent Collective Relaxation Dynamics of Glass-Forming
Liquid Ca0.4K0.6(NO3)1.4 Investigated by Wide-Angle Neutron SpinEcho
Nat. Commun., 13 2092 (2022).

MLF Annual Report 2022

146 Y. Yu, C. Yang, M. Baggioli, A. E. Phillips, A. Zaccone, L. Zhang, R.
Kajimoto, M. Nakamura, D. Yu, L. Hong3
The ω Scaling of the Vibrational Density of States in Quasi-2D
Nanoconfined SolidsNat. Commun., 13 3649 (2022).
147 L. Chen, C. Mao, J.-H. Chung, M. B. Stone, A. I. Kolesnikov, X. Wang,
N. Murai, B. Gao, O. Delaire, P. Dai
Anisotropic Magnon Damping by Zero-Temperature Quantum
Fluctuations in Ferromagnetic CrGeTe3
Nat. Commun., 13 4037 (2022).
148 S. Xu, T. Odaira, S. Sato, X. Xu, T. Omori, S. Harjo, T. Kawasaki, H.
Seiner, K. Zoubková, Y. Murakami, R. Kainuma
Non-Hookean Large Elastic Deformation in Bulk Crystalline Metals
Nat. Commun., 13 5307 (2022).

MLF Operations in 2022

Spin Excitations Coupled with Lattice and Charge Dynamics inLa2−xSrxCuO4
Phys. Rev. B, 105 014508 (2022).
158 Y. Kojima, N. Kurita, H. Tanaka, K. Nakajima
Magnons and Spinons in Ba2CoTeO6: A Composite System of Isolated
Spin-1/2 Triangular Heisenberg-like and Frustrated Honeycomb
Ising-like Antiferromagnets
Phys. Rev. B, 105 L020408 (2022).
159 Y. Imai, K. Nawa, Y. Shimizu, W. Yamada, H. Fujihara, T. Aoyama,
R. Takahashi, D. Okuyama, T. Ohashi, M. Hagihala, S. Torii, D.
Morikawa, M. Terauchi, T. Kawamata, M. Kato, H. Gotou, M. Itoh, T.
J. Sato, K. Ohgushi
Zigzag Magnetic Order in the Kitaev Spin-Liquid Candidate Material
RuBr3 with a Honeycomb Lattice
Phys. Rev. B, 105 L041112 (2022).

149 F. Takeiri, A. Watanabe, K. Okamoto, D. Bresser, S. Lyonnard, B.
Frick, A. Ali, Y. Imai, M. Nishikawa, M. Yonemura, T. Saito, K. Ikeda, T.
Otomo, T. Kamiyama, R. Kanno, G. Kobayashi
Hydride-Ion-Conducting K 2 NiF 4 -Type Ba–Li Oxyhydride Solid
Electrolyte
Nat. Mater., 21 325–330 (2022).

160 M. Watanabe, N. Kurita, H. Tanaka, W. Ueno, K. Matsui, T. Goto, M.
HagihalaContrasting Magnetic Structures in SrLaCuSbO6 and SrLaCuNbO6:
Spin- 1/2 Quasi-Square-Lattice J1−J2 Heisenberg Antiferromagnets
Phys. Rev. B, 105 054414 (2022).

150 A. D. Hillier, S. J. Blundell, I. McKenzie, I. Umegaki, L. Shu, J. A.
Wright, T. Prokscha, F. Bert, K. Shimomura, A. Berlie, H. Alberto, I.
WatanabeMuon Spin Spectroscopy
Nat. Rev. Methods Primer, 2 4 (2022).

161 M. Saito, R. Takagishi, N. Kurita, M. Watanabe, H. Tanaka, R.
Nomura, Y. Fukumoto, K. Ikeuchi, R. Kajimoto
Structures of Magnetic Excitations in the Spin- 1/2 Kagome-Lattice
Antiferromagnets Cs2Cu3SnF12 and Rb2Cu3SnF12
Phys. Rev. B, 105 064424 (2022).

151 K. Horie, K. Kamada, A. Kobayashi, M. Mihara, S. Shimizu, A.
Yamaji, A. Yoshikawa+
Measurement of Residual μ Polarization in Various Scintillating+
Materials to Search for T-Violating μ+ Polarization in K → π0μ+ν
Decay
Nucl. Instrum. Methods Phys. Res. Sect. Accel. Spectrometers
Detect. Assoc. Equip., 1037 166932 (2022).

162 K. Matan, T. Ono, S. Ohira-Kawamura, K. Nakajima, Y. Nambu, T. J.
SatoBreakdown of Linear Spin-wave Theory and Existence of Spinon
Bound States in the Frustrated Kagome-Lattice Antiferromagnet
Phys. Rev. B, 105 134403 (2022).

152 F. Nemoto, N. L. Yamada, S. SatohPerformance of Position-Sensitive Flat-Panel and Resister Type
Photomultiplier Tube Detector on Neutron Reflectometer SOFIA at
J-PARC
Nucl. Instrum. Methods Phys. Res. Sect. Accel. Spectrometers
Detect. Assoc. Equip., 1040 166988 (2022).
153 K. Isegawa, D. Setoyama, Y. Higuchi, Y. Matsumoto, Y. Nagai, T.
Shinohara
Fast Phase Differentiation between Liquid–Water and Ice by Pulsed
Neutron Imaging with Gated Image Intensifier
Nucl. Instrum. Methods Phys. Res. Sect. Accel. Spectrometers
Detect. Assoc. Equip., 1040 167260 (2022).
154 M. Kawano, A. Tashiro, Y. Imamura, M. Yamada, K. Sadakane, H.
Iwase, M. Matsugami, B. A. Marekha, A. Idrissi, T. Takamuku
Effects of Self-Hydrogen Bonding among Formamide Molecules on
the UCST-Type Liquid–Liquid Phase Separation of Binary Solutions
with Imidazolium-Based Ionic Liquid, [C nMim][TFSI], Studied by
NMR, IR, MD Simulations, and SANS
Phys. Chem. Chem. Phys., 24 13698–13712 (2022).
155 K. Yamaguchi, D. Kawaguchi, N. Miyata, T. Miyazaki, H. Aoki, S.
Yamamoto, K. Tanaka
Kinetics of the Interfacial Curing Reaction for an Epoxy–Amine
MixturePhys. Chem. Chem. Phys., 24 21578–21582 (2022).

163 M. Fujihala, Y. Sakuma, S. Mitsuda, A. Nakao, K. Munakata, R.
A. Mole, S. Yano, D. H. Yu, K. Takehana, Y. Imanaka, M. Akaki, S.
Okubo, H. Ohta
Relief of Spin Frustration through Magnetic Anisotropy in the QuasiOne-Dimensional S = 1/2 Antiferromagnet Na2CuSO4Cl2
Phys. Rev. B, 105 144410 (2022).
164 S.-H. Do, K. Kaneko, R. Kajimoto, K. Kamazawa, M. B. Stone, J. Y. Y.
Lin, S. Itoh, T. Masuda, G. D. Samolyuk, E. Dagotto, W. R. Meier, B. C.
Sales, H. Miao, A. D. Christianson
Damped Dirac Magnon in the Metallic Kagome Antiferromagnet
FeSn
Phys. Rev. B, 105 L180403 (2022).
165 M. Micoulaut, I. Pethes, P. Jóvári, L. Pusztai, M. Krbal, T. Wágner, V.
Prokop, Š. Michalik, K. Ikeda, I. Kaban
S t r u c t u ra l Pro p e r t i e s o f C h a l co g e n i d e G l a s s e s a n d t h e
Isocoordination Rule: Disentangling Effects from Chemistry and
Network Topology
Phys. Rev. B, 106 014206 (2022).
166 K. Tomiyasu, Y. P. Mizuta, M. Matsuura, K. Aoyama, H. Kawamura
Observation of Topological Z2 Vortex Fluctuations in the Frustrated
Heisenberg Magnet NaCrO2
Phys. Rev. B, 106 054407 (2022).

156 H. Kadowaki, M. Wakita, B. Fåk, J. Ollivier, S. Ohira-Kawamura
Spin and Quadrupole Correlations by Three-Spin Interaction in the
Frustrated Pyrochlore Magnet Tb2+x Ti2−xO7+yPhys. Rev. B, 105 014439 (2022).

167 R. Tripathi, D. T. Adroja, C. Ritter, S. Sharma, C. Yang, A. D. Hillier, M.
M. Koza, F. Demmel, A. Sundaresan, S. Langridge, W. Higemoto, T.
U. Ito, A. M. Strydom, G. B. G. Stenning, A. Bhattacharyya, D. Keen,
H. C. Walker, R. S. Perry, F. Pratt, Q. Si, T. Takabatake
Quantum Critical Spin-Liquid-like Behavior in the S = 1/2
Quasikagome-Lattice Compound CeRh1−xPdxSn Investigated Using
Muon Spin Relaxation and Neutron Scattering
Phys. Rev. B, 106 064436 (2022).

157 K. Ikeuchi, S. Wakimoto, M. Fujita, T. Fukuda, R. Kajimoto, M. Arai

168 B. Gao, T. Chen, H. Yan, C. Duan, C.-L. Huang, X. P. Yao, F. Ye, C. Balz,

183

MLF Operations in 2022

MLF Annual Report 2022

J. R. Stewart, K. Nakajima, S. Ohira-Kawamura, G. Xu, X. Xu, S.-W.
Cheong, E. Morosan, A. H. Nevidomskyy, G. Chen, P. Dai
Magnetic Field Effects in an Octupolar Quantum Spin Liquid
CandidatePhys. Rev. B, 106 094425 (2022).

180 M. Matsuura, T. Sasaki, M. Naka, J. Müller, O. Stockert, A. Piovano,N. Yoneyama, M. Lang
Phonon Renormalization Effects Accompanying the 6 K Anomaly in
the Quantum Spin Liquid Candidate Κ−( BEDT-TTF )2Cu2(CN)3
Phys. Rev. Res., 4 L042047 (2022).

169 Y. Ishii, A. Yamamoto, N. Sato, Y. Nambu, S. Ohira-Kawamura, N.
Murai, K. Ohara, S. Kawaguchi, T. Mori, S. Mori
Partial Breakdown of Translation Symmetry at a Structural
Quantum Critical Point Associated with a Ferroelectric Soft Mode
Phys. Rev. B, 106 134111 (2022).

181 S. Bao, W. Wang, Y. Shangguan, Z. Cai, Z.-Y. Dong, Z. Huang, W. Si, Z.
Ma, R. Kajimoto, K. Ikeuchi, S. Yano, S.-L. Yu, X. Wan, J.-X. Li, J. Wen
Neutron Spectroscopy Evidence on the Dual Nature of Magnetic
Excitations in a van Der Waals Metallic Ferromagnet Fe2.72GeTe2
Phys. Rev. X, 12 011022 (2022).

170 T. Hattori, M. Nakamura, K. Iida, A. Machida, A. Sano-Furukawa, S.
Machida, H. Arima, H. Ohshita, T. Honda, K. Ikeda, T. Otomo
Hydrogen Vibration Excitations of ZrH1.8 and TiH1.84 up to 21 GPa by
Incoherent Inelastic Neutron Scattering
Phys. Rev. B, 106 134309 (2022).

182 X. Li, Y. Gu, Y. Chen, V. O. Garlea, K. Iida, K. Kamazawa, Y. Li,
G. Deng, Q. Xiao, X. Zheng, Z. Ye, Y. Peng, I. A. Zaliznyak, J. M.
Tranquada, Y. Li
Giant Magnetic In-Plane Anisotropy and Competing Instabilities in
Na3Co2SbO6
Phys. Rev. X, 12 041024 (2022).

171 Z. Jin, B. Hu, Y. Liu, Y. Li, T. Zhang, K. Iida, K. Kamazawa, A. I.
Kolesnikov, M. B. Stone, X. Zhang, H. Chen, Y. Wang, I. A. Zaliznyak,
J. M. Tranquada, C. Fang, Y. Li
Chern Numbers of Topological Phonon Band Crossing Determinedwith Inelastic Neutron Scattering
Phys. Rev. B, 106 224304 (2022).
172 M. Hiraishi, H. Okabe, A. Koda, R. Kadono, T. Ohsawa, N. Ohashi, K.
Ide, T. Kamiya, H. Hosono
Local Electronic Structure of Dilute Hydrogen in β−Ga2O3 Probed by
Muons
Phys. Rev. B, 107 L041201 (2022).
173 J. Koga, S. Takada, S. Endo, H. Fujioka, K. Hirota, K. Ishizaki, A.
Kimura, M. Kitaguchi, Y. Niinomi, T. Okudaira, K. Sakai, T. Shima, H.
M. Shimizu, Y. Tani, T. Yamamoto, H. Yoshikawa, T. Yoshioka
118
Angular Distribution of γ Rays from the p-Wave Resonance of Sn
Phys. Rev. C, 105 054615 (2022).
174 S. Endo, T. Okudaira, R. Abe, H. Fujioka, K. Hirota, A. Kimura, M.
Kitaguchi, T. Oku, K. Sakai, T. Shima, H. M. Shimizu, S. Takada, S.
Takahashi, T. Yamamoto, H. Yoshikawa, T. Yoshioka
Measurement of the Transverse Asymmetry of γ Rays in the117
Sn( n , γ ) 118Sn Reaction
Phys. Rev. C, 106 064601 (2022).
175 S.-M. Chang, C. Y. Yu, Y.-F. Chen
Mechanism of Endosomal Escape by pH -Responsive Nucleic-Acid
Vectors
Phys. Rev. E, 106 034408 (2022).
176 W. Yao, K. Iida, K. Kamazawa, Y. Li
Excitations in the Ordered and Paramagnetic States of Honeycomb
Magnet Na2Co2TeO6
Phys. Rev. Lett., 129 147202 (2022).
177 M. Fujihala, H. O. Jeschke, K. Morita, T. Kuwai, A. Koda, H. Okabe, A.
Matsuo, K. Kindo, S. Mitsuda
Birchite Cd2Cu2(PO4)2SO4 · 5H2O as a Model Antiferromagnetic Spin1/2 Heisenberg J1−J2 Chain
Phys. Rev. Mater., 6 114408 (2022).
178 S. Shamoto, M. Akatsu, M. Matsuura, S. Ohira-Kawamura, K. Harii,
M. Ono, L.-J. Chang, T. U. Ito, Y. Nemoto, J. Ieda
Magnetic Bragg Peak Enhancement under Ultrasound Injection
Phys. Rev. Res., 4 013245 (2022).
179 Y. Ohmasa, S. Takagi, K. Toshima, K. Yokoyama, W. Endo, S. Orimo,
H. Saitoh, T. Yamada, Y. Kawakita, K. Ikeda, T. Otomo, H. Akiba, O.
Yamamuro
Rotation of Complex Ions with Ninefold Hydrogen Coordination
Studied by Quasielastic Neutron Scattering and First-Principles
Molecular Dynamics Calculations
Phys. Rev. Res., 4 033215 (2022).

184

183 T. Yamanaka, N. Hirao, Y. Nakamoto, T. Mikouchi, T. Hattori, K.
Komatsu, H. Mao
Magnetic and Structure Transition of Mn3-xFexO4 Solid Solutions
under High-Pressure and High-Temperature Conditions
Phys. Chem. Miner., 49 41 (2022).
184 M. Yoshida, H. Iwase, T. Shikata
Conformation and Structure of Hydroxyethyl Cellulose Ether with a
Wide Range of Average Molar Masses in Aqueous Solutions
Polymers, 14 4532 (2022).
185 M. Kamibayashi, K. Kobayashi, M. Hashimoto
Single Bit Upsets Versus Burst Errors of Stacked-Capacitor DRAMs
Induced by High-Energy Neutron -SECDED Is No Longer EffectiveProc. Eur. Conf. Radiat. Its Eff. Compon. Syst. RADECS (2022).
186 F. Suekane, Y. Hino, W. Noguchi, T. Tokuraku, T. Konno, T. Kawasaki,
Y. Hoshino, M. Watanabe
A Plan for Decay at Rest νe + Pb Cross Section Measurement: DaRveX
PoSNuFACT2021, 402 194 (2022).
187 S. Kanda
Toward a High-Precision Measurement of the Muon Lifetime withan Intense Pulsed Muon Beam at J-PARC
PoSNuFACT2021, 402 215 (2022).
188 A. Koda, H. Okabe, M. Hiraishi, R. Kadono, K. A. Dagnall, J. J. Choi,
S.-H. Lee
Organic Molecular Dynamics and Charge-carrier Lifetime in Lead
Iodide Perovskite MAPbI3
Proc. Natl. Acad. Sci., 119 e2115812119 (2022).
189 K. Yamashita, K. Komatsu, S. Klotz, O. Fabelo, M. T. FernándezDíaz, J. Abe, S. Machida, T. Hattori, T. Irifune, T. Shinmei, K.
Sugiyama, T. Kawamata, H. Kagi
Atomic Distribution and Local Structure in Ice VII from in situ
Neutron Diffraction
Proc. Natl. Acad. Sci., 119 e2208717119 (2022).
190 W. Higemoto, M. Yokoyama, T. U. Ito, T. Suzuki, S. Raymond, Y.
YanaseDirect Measurement of the Evolution of Magnetism andSuperconductivity toward the Quantum Critical Point
Proc. Natl. Acad. Sci., 119 e2209549119 (2022).
191 J. Sheng, L. Wang, A. Candini, W. Jiang, L. Huang, B. Xi, J. Zhao, H.
Ge, N. Zhao, Y. Fu, J. Ren, J. Yang, P. Miao, X. Tong, D. Yu, S. Wang,
Q. Liu, M. Kofu, R. Mole, G. Biasiol, D. Yu, I. A. Zaliznyak, J.-W. Mei, L.
Wu
Two-Dimensional Quantum Universality in the Spin-1/2 TriangularLattice Quantum Antiferromagnet Na2BaCo(PO4 )2
Proc. Natl. Acad. Sci., 119 e2211193119 (2022).

MLF Annual Report 2022

192 M. Nishida, S. Harjo, T. Kawasaki, T. Yamashita, W. Gong
Neutron Stress Measurement of W/Ti Composite in Cryogenic
Temperatures Using Time-of-Flight Method
Quantum Beam Sci., 7 8 (2022).
193 T. Fujiwara, H. Miyoshi, Y. Mitsuya, N. L. Yamada, Y. Wakabayashi, Y.
Otake, M. Hino, K. Kino, M. Tanaka, N. Oshima, H. Takahashi
Neutron Flat-Panel Detector Using In–Ga–Zn–O Thin-Film Transistor
Rev. Sci. Instrum., 93 013304 (2022).
194 J. Abe, T. Kawasaki, S. Harjo
Development of Triaxial Compressive Apparatus for Neutron
Experiments with Rocks
Rev. Sci. Instrum., 93 025103 (2022).
195 K. Akutsu-Suyama, H. Sajiki, M. Ueda, M. Asamoto, Y. Tsutsumi
Heavy Water Recycling for Producing Deuterium Compounds
RSC Adv., 12 24821–24829 (2022).
196 N. Okita, E. Iwama, Y. Takami, S. Abo, W. Naoi, P. Rozier, P. Simon, M.
T. H. Reid, K. Naoi
2+/3+
Redox Utilization for FePO4The Origin of Stability and High Co
Coated LiCo 0.90Ti 0.05PO 4/MWCNT Nanocomposites for 5 V Class
Lithium Ion Batteries
RSC Adv., 12 26192–26200 (2022).
197 T. Nakamura, M. Matsumoto, K. Amano, Y. Enokido, M. E.
Zolensky, T. Mikouchi, H. Genda, S. Tanaka, M. Y. Zolotov, K.
Kurosawa, S. Wakita, R. Hyodo, H. Nagano, D. Nakashima, Y.
Takahashi, Y. Fujioka, M. Kikuiri, E. Kagawa, M. Matsuoka, A. J.
Brearley, A. Tsuchiyama, M. Uesugi, J. Matsuno, Y. Kimura, M.
Sato, R. E. Milliken, E. Tatsumi, S. Sugita, T. Hiroi, K. Kitazato, D.
Brownlee, D. J. Joswiak, M. Takahashi, K. Ninomiya, T. Takahashi, T.
Osawa, K. Terada, F. E. Brenker, B. J. Tkalcec, L. Vincze, R. Brunetto,
A. Aléon-Toppani, Q. H. S. Chan, M. Roskosz, J.-C. Viennet, P. Beck,
E. E. Alp, T. Michikami, Y. Nagaashi, T. Tsuji, Y. Ino, J. Martinez, J.
Han, A. Dolocan, R. J. Bodnar, M. Tanaka, H. Yoshida, K. Sugiyama,
A. J. King, K. Fukushi, H. Suga, S. Yamashita, T. Kawai, K. Inoue, A.
Nakato, T. Noguchi, F. Vilas, A. R. Hendrix, C. Jaramillo-Correa, D.
L. Domingue, G. Dominguez, Z. Gainsforth, C. Engrand, J. Duprat,
S. S. Russell, E. Bonato, C. Ma, T. Kawamoto, T. Wada, S. Watanabe,
R. Endo, S. Enju, L. Riu, S. Rubino, P. Tack, S. Takeshita, Y. Takeichi,
A. Takeuchi, A. Takigawa, D. Takir, T. Tanigaki, A. Taniguchi, K.
Tsukamoto, T. Yagi, S. Yamada, K. Yamamoto, Y. Yamashita, M.
Yasutake, K. Uesugi, I. Umegaki, I. Chiu, T. Ishizaki, S. Okumura,
E. Palomba, C. Pilorget, S. M. Potin, A. Alasli, S. Anada, Y. Araki,
N. Sakatani, C. Schultz, O. Sekizawa, S. D. Sitzman, K. Sugiura, M.
Sun, E. Dartois, E. De Pauw, Z. Dionnet, Z. Djouadi, G. Falkenberg,
R. Fujita, T. Fukuma, I. R. Gearba, K. Hagiya, M. Y. Hu, T. Kato, T.
Kawamura, M. Kimura, M. K. Kubo, F. Langenhorst, C. Lantz, B.
Lavina, M. Lindner, J. Zhao, B. Vekemans, D. Baklouti, B. Bazi,
F. Borondics, S. Nagasawa, G. Nishiyama, K. Nitta, J. Mathurin,
T. Matsumoto, I. Mitsukawa, H. Miura, A. Miyake, Y. Miyake,
H. Yurimoto, R. Okazaki, H. Yabuta, H. Naraoka, K. Sakamoto,S. Tachibana, H. C. Connolly, D. S. Lauretta, M. Yoshitake, M.
Yoshikawa, K. Yoshikawa, K. Yoshihara, Y. Yokota, K. Yogata, H.
Yano, Y. Yamamoto, D. Yamamoto, M. Yamada, T. Yamada, T. Yada,
K. Wada, T. Usui, R. Tsukizaki, F. Terui, H. Takeuchi, Y. Takei, A.
Iwamae, H. Soejima, K. Shirai, Y. Shimaki, H. Senshu, H. Sawada, T.
Saiki, M. Ozaki, G. Ono, T. Okada, N. Ogawa, K. Ogawa, R. Noguchi,
H. Noda, M. Nishimura, N. Namiki, S. Nakazawa, T. Morota, A.
Miyazaki, A. Miura, Y. Mimasu, K. Matsumoto, K. Kumagai, T.
Kouyama, S. Kikuchi, K. Kawahara, S. Kameda, T. Iwata, Y. Ishihara,
M. Ishiguro, H. Ikeda, S. Hosoda, R. Honda, C. Honda, Y. Hitomi, N.
Hirata, N. Hirata, T. Hayashi, M. Hayakawa, K. Hatakeda, S. Furuya,
R. Fukai, A. Fujii, Y. Cho, M. Arakawa, M. Abe, S. Watanabe, Y. Tsuda
Formation and Evolution of Carbonaceous Asteroid Ryugu: Direct
Evidence from Returned Samples
Science, 379 eabn8671 (2022).
198 Y. Hanazono, Y. Hirano, K. Takeda, K. Kusaka, T. Tamada, K. Miki
Revisiting the Concept of Peptide Bond Planarity in an Iron-Sulfur

MLF Operations in 2022

Protein by Neutron Structure Analysis
Sci. Adv., 8 eabn2276 (2022).
199 H. Kwon, S. Harjo, T. Kawasaki, W. Gong, S. G. Jeong, E. S. Kim, P.
Sathiyamoorthi, H. Kato, H. S. Kim
Work Hardening B ehavior of Hot-Rolled Metastable
Fe 50 Co 25 Ni 10 Al 5 Ti 5 Mo 5 Medium-Entropy Alloy: in situ Neutron
Diffraction Analysis
Sci. Technol. Adv. Mater., 23 579–586 (2022).
200 Y. Qin, Y. Shen, C. Liu, H. Wo, Y. Gao, Y. Feng, X. Zhang, G. Ding, Y.
Gu, Q. Wang, S. Shen, H. C. Walker, R. Bewley, J. Xu, M. Boehm, P.
Steffens, S. Ohira-Kawamura, N. Murai, A. Schneidewind, X. Tong,
G. Chen, J. Zhao
Field-Tuned Quantum Effects in a Triangular-Lattice Ising Magnet
Sci. Bull., 67 38–44 (2022).
201 H. Hashimoto, Y. Onodera, S. Tahara, S. Kohara, K. Yazawa, H.
Segawa, M. Murakami, K. Ohara
Structure of Alumina Glass
Sci. Rep., 12 516 (2022).
202 I.-H. Chiu, S. Takeda, M. Kajino, A. Shinohara, M. Katsuragawa,S. Nagasawa, R. Tomaru, G. Yabu, T. Takahashi, S. Watanabe, S.
Takeshita, Y. Miyake, K. Ninomiya
Non-Destructive 3D Imaging Method Using Muonic X-Rays and a
CdTe Double-Sided Strip Detector
Sci. Rep., 12 5261 (2022).
203 M. Maeda, M. Segawa, Y. Toh, S. Endo, S. Nakamura, A. Kimura
Effect of Sample Density in Prompt γ-Ray Analysis
Sci. Rep., 12 6287 (2022).
204 K. Iida, K. Kodama, Y. Inamura, M. Nakamura, L.-J. Chang, S.
ShamotoMagnon Mode Transition in Real Space
Sci. Rep., 12 20663 (2022).
205 E. Nocerino, C. Witteveen, S. Kobayashi, O. K. Forslund, N.
Matsubara, A. Zubayer, F. Mazza, S. Kawaguchi, A. Hoshikawa, I.
Umegaki, J. Sugiyama, K. Yoshimura, Y. Sassa, F. O. Von Rohr, M.
Månsson
Nuclear and Magnetic Spin Structure of the Antiferromagnetic+
Triangular Lattice Compound LiCrTe2 Investigated by μ SR, Neutron
and X-Ray Diffraction
Sci. Rep., 12 21657 (2022).
206 M.-Y. Luo, T.-N. Lam, P.-T. Wang, N.-T. Tsou, Y.-J. Chang, R. Feng,
T. Kawasaki, S. Harjo, P. K. Liaw, A.-C. Yeh, S. Y. Lee, J. Jain, E.-W.
Huang
Grain-Size-Dependent Microstructure Effects on Cyclic Deformation
Mechanisms in CoCrFeMnNi High-Entropy-Alloys
Scr. Mater., 210 114459 (2022).
207 D. Wei, W. Gong, T. Kawasaki, S. Harjo, H. KatoRegulation of Strength and Ductility of Single-Phase TwinningInduced Plasticity High-Entropy Alloys
Scr. Mater., 216 114738 (2022).
208 N. Tsuchida, R. Ueji, W. Gong, T. Kawasaki, S. Harjo
Stress Partitioning between Bcc and Cementite Phases Discussed
from Phase Stress and Dislocation Density in Martensite Steels
Scr. Mater., 222 115002 (2022).
209 W. Gong, T. Kawasaki, R. Zheng, T. Mayama, B. Sun, K. Aizawa, S.
Harjo, N. Tsuji
Compressive Deformation Behavior of AZ31 Alloy at 21K: An in-situ
Neutron Diffraction Study
Scr. Mater., 225 115161 (2022).
210 E. Zhao, K. Wu, Z. Zhang, Z. Fu, H. Jiang, Y. Ke, W. Yin, K. Ikeda, T.
Otomo, F. Wang, J. Zhao

185

MLF Operations in 2022

MLF Annual Report 2022

Quantifying the Anomalous Local and Nanostructure Evolutions
Induced by Lattice Oxygen Redox in Lithium‐Rich Cathodes
Small Methods, 6 2200740 (2022).
211 F. Nemoto, N. L. Yamada, M. Hino, H. Aoki, H. Seto
Neutron Reflectometry-Based in situ Structural Analysis of an
Aligning Agent Additive for the Alignment of Nematic Liquid
Crystals on Solid Substrates
Soft Matter, 18 545–553 (2022).
212 F. Song, H. Chen, H. Hayashida, T. Kai, T. Shinohara, T. Yabutsuka, T.
Yao, S. Takai
Tracer Diffusion Coefficients Measurements on LaPO 4-Dispersed
LATP by Means of Neutron Radiography
Solid State Ion., 377 115873 (2022).
213 T. Tominaga, M. Hishida, D. Murakami, Y. Fujii, M. Tanaka, H. Seto
Experimental Evidence of Slow Mode Water in the Vicinity ofPoly(ethylene oxide) at Physiological Temperature
J. Phys. Chem. B, 126 1758–1767 (2022).
214 S. Hori, R. Kanno, O. Kwon, Y. Kato, T. Yamada, M. Matsuura, M.
Yonemura, T. Kamiyama, K. Shibata, Y. Kawakita
Revealing the Ion Dynamics in Li10GeP2S12 by Quasi-Elastic Neutron
Scattering Measurements
J. Phys. Chem. C, 126 9518–9527 (2022).
215 I. Umegaki, K. Ohishi, T. Nakano, S. Nishimura, S. Takeshita, A.
Koda, K. Ninomiya, M. K. Kubo, J. Sugiyama
Negative Muon Spin Rotation and Relaxation Study on Battery
Anode Material, Spinel Li4Ti5O12
J. Phys. Chem. C, 126 10506–10514 (2022).

217 M. Nakano, H. Nakao, S. Yoshida, M. Fukuda, M. Imai, K. Ikeda
Energetic and Structural Insights into Phospholipid Transfer from
Membranes with Different Curvatures by Time-Resolved Neutron
Scattering
J. Phys. Chem. Lett., 13 6024–6030 (2022).
218 R. Akiyama, R. Ishikawa, K. Akutsu-Suyama, R. Nakanishi, Y.
Tomohiro, K. Watanabe, K. Iida, M. Mitome, S. Hasegawa, S.
KurodaDirect Probe of the Ferromagnetic Proximity Effect at the Interfaceof SnTe/Fe Heterostructure by Polarized Neutron Reflectometry
J. Phys. Chem. Lett., 13 8228–8235 (2022).
219 M. Aizawa, H. Iwase, T. Kamijo, A. Yamaguchi
Protein Condensation at Nanopore Entrances as Studied byDifferential Scanning Calorimetry and Small-Angle Neutron
Scattering
J. Phys. Chem. Lett., 13 8684–8691 (2022).
220 W. Shen, T. Hirayama, N. Yamashita, M. Adachi, T. Oshio, H.
Tsuneoka, K. Tagawa, K. Yagishita, N. L. Yamada
Relationship between Interfacial Adsorption of Additive Molecules
and Reduction of Friction Coefficient in the Organic Friction
Modifiers-ZDDP Combinations
Tribol. Int., 167 107365 (2022).
221 N. Yamashita, T. Hirayama, N. L. Yamada, Y. Shimizu, K. Oda, H.
Kawamoto
Interfacial Structure and Tribological Property of Adsorbed Layer
Formed by Dibasic Acid Ester Derivative
Tribol. Online, 17 246–256 (2022).
222 崔烘福 , 向井智久 , 菖蒲敬久 , 有木克良 , 衣笠秀行

216 T. Sato, K. Ikeda, T. Honda, L. L. Daemen, Y. Cheng, T. Otomo, H.
Sagayama, A. J. Ramirez−Cuesta, S. Takagi, T. Kono, H. Yang, W.
Luo, L. Lombardo, A. Züttel, S. Orimo
Effect of Co-Substitution on Hydrogen Absorption and Desorption
Reactions of YMgNi4-Based Alloys
J. Phys. Chem. C, 126 16943–16951 (2022).

186

中性子イメージング技術を用いた接着系あと施工アンカーにおける接着剤未充填部の特定手法
日本地震工学会・大会 2022, (2022).

MLF Annual Report 2022

Editorial Board

Editorial Board - MLF Annual Report 2022

Chief Editor

Shoichiro Nishimura

Takashi Ino
Neutron Science Section

Muon Science Section

Yoshihiro Matsumoto

Kosuke Hiroi

CROSS

Neutron Science Section

Akiko Nakao

Kaoru Sakasai

CROSS

Neutron Instrumentation Section

Terutoshi Sakakura

Yuhua SuCROSSTechnology Development Section

Takashi Naoe

Misono Fujii

Neutron Source Section

Muon Science Section187

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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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