External Evaluation of Neutron Science Division(KENS) within the Institute of Materials Structure
Science at KEK
Robert A. Robinson and Sung-Min Choi, June 2020•

Executive Summary
The instruments are competitive with those at ISIS and SNS, in terms of technicalspecifications and physics performance. The J-PARC source is now running at sufficient
power, and a reasonable number of days per year. The number of operating days iscomparable with those at ISIS and SNS, and the instruments are of similar quality.
We note that the average ratio of staff per instrument (excluding postdocs and students) isjust above 3:1 at KENS, whereas the world-standard is 6:1, if one wants to run a full-service
user program for ~200 days per year. This is the historic standard at the Institute LaueLangevin (in Grenoble, France) and at ISIS (near Oxford in the UK), and it is achieved at theOPAL Research Reactor (in Sydney, Australia). We do not believe that KENS (or the MLF, forthat matter) can be fully research competitive with ISIS, SNS and the leading research
reactors, unless this major handicap is rectified.
We strongly support the idea of harmonizing the user access regime (and support levels)
across the KEK and JAEA instruments at J-PARC.
In general, the quality of research performed by KENS (and done on KEK’s instruments at JPARC) is high, is published in very good journals, and receives international recognition.
There is a good array of international connections, both in terms of overseas users of theinstruments, and of KENS staff using other facilities when necessary.
However the volume of research is low compared with other facilities, particular in America,and particularly in powder diffraction. We strongly urge the KEK management to try todiagnose the underlying causes for this discrepancy, and to rectify it, if they can.

•Evaluation of present status of KENS
The KENS is equipped with 8 internationally competitive neutron instruments. Considering
the limited budget and fairly low staff members, compared with other facilities such as ISISand SNS, KENS is doing a very good job. However, there is a large room for improvement,
which absolutely requires additional budget and staff members.
As far as we can tell, the operation of KENS is consistent with the Japanese Government’s
definition of an “Inter-University Research Institute Corporation”, which is itself not so
different from how most other leading international neutron-scattering facilities are run,aside from the fact that J-PARC has a very complicated multi-party management system (i.e.
KEK, JAEA, Ibaraki University and CROSS).

•Evaluation of instrument performance
There are two aspects to instrument performance: (a) the actual technical specifications andphysical performance, i.e. how good are the instruments? And (b) the scientific productivityof each instrument, in terms of demand, user satisfaction and the number and quality ofpapers produced.
Technical performance:Flux onsample
Resolution

Dynamic
Range
Solidangle ofdetector% ofdetector
complete
Other

SHRPD
Comparablewith SNS andISIS
Comparablewith SNS andISIS

NOVA>> ISIS
< SNSComparablewith SNS andISIS
Notbenchmarked

Comparablewith SNSand ISIS
Comparablewith SNSand ISIS

90%; 67%;
100%

73%

Comparablewith SNSand ISIS

SPICA
Comparablewith SNS andISIS
Better thaniMATERIA;
comparable
withPOWGEN
Comparablewith SNS and
ISIS
Notbenchmarked
100%

HRC
SOFIA
Not
Not
benchmarked benchmarked
Comparablewith SNS andISIS

Comparable
with, orbetter than,
SNS and ISIS

Comparablewith SNS andISIS
Smaller than4SEASONS,ARCS andMERLIN
57%

Comparablewith SNS andISIS
sufficient

100% ofrelevant solidangle
Rmin of 10-8 isstate-of-theart

Research productivity:
Of the 4 KENS instruments (SOFIA, HRC, SHRPD and NOVA) that have been operating formany years, we have benchmarked the number of refereed research papers resulting frombeam time on them, against similar instruments at ISIS and SNS.

The SOFIA reflectometer is producing at a world-competitive rate. An average of 15 papers
per year is typical for reflectometers at other neutron sources. By some measures, SOFIA is
the most research productive instrument at the MLF.
The NOVA liquids/glass diffractometer is competitive with the two similar instruments atISIS, but all three of these instruments significantly underproduce compared with theNOMAD diffractometer at SNS (Oak Ridge), by a factor of 3 or so.
The HRC chopper spectrometer (and the 4-SEASONS instrument, also at J-PARC) produce
papers at a similar rate to the 2nd-tier instruments at ISIS, but fall well behind the SNSinstruments and the flagship ISIS instrument, by a factor of 4 or so.
The high-resolution powder diffractometer SHRPD has underproduced compared withsimilar instruments at ISIS and SNS. This is a major issue for KEK and J-PARC, in that this typeof instrument is generally the most productive of all instruments at spallation sources, with aworld standard of ~50 papers per year being the norm. There are similar issues withiMATERIA, and the initial indications are that SPICA is doing no better. If KENS (and/or JPARC) could diagnose and resolve these problems, it would make the whole facility look
much more competitive.
We have not performed any citation analysis, but would make the following observation
regarding the quality of the publications in the last three years (2017-2020):
HRC has a healthy mix of publishing user institutions, including 4 Japanese universities, somein-house research and two overseas labs (in China and Switzerland). There has been one
Phys. Rev. Letter, one in each of Scientific Reports and Science Advances, as well as three inPhys. Rev. B. There was also a Nature Communications article in 2016.
NOVA has a very broad user base, with refereed articles from 10 different Japanese
universities (the most important collaborations being with Tokyo Institute of Technology,
Tokyo University of Science, Yamagata University and Kyoto University), 2 Japanese
government labs (AIST and NIMS), one Japanese company (DENSO), and 3 papers fromChina, as well as 4 papers from KENS, JAEA and J-PARC. There have been 3 articles in Journalof the American Chemical Society, 3 in Nature-family journals, and one each in Proceedingsof the National Academy of Science (USA), Scientific Reports and Adv. Mater.
SOFIA has a very broad user base with refereed articles from 9 different Japanese
universities (the most important collaborations being with Kyushu University and Universityof Tokyo), 3 Japanese government labs (AIST, RIKEN and the National Defence Academy),
two Japanese companies (Toyota[3x] and Nitto Denko), and papers from each of the USA,
Taiwan and Australia, as well as 2 papers from KENS and J-PARC. There have been 5 papers
in Langmuir and 4 in Macromolecules.
SHRPD has a reasonable mix of publishing user institutions, including 7 Japanese universities(the most important of which is Tokyo Institute of Technology), and institutions in Korea,
Germany and Thailand. A much larger proportion of the papers (33%) are internally driven
by KENS (and J-PARC), than on the other instruments. While this speaks well for the KENS
staff, it would appear that SHRPD is insufficiently engaged with the broader Japanese
research community, and/or that they are not analysing and publishing their results. There
have been 2 papers in Journal of the American Chemical Society, one each in Nature
Communications, Scientific Reports and Adv. Mater., as well as five in Physical Review.

It is early days on SPICA but, so far, the instrument seems to have been exploited almost
exclusively by Kyoto University and Tokyo Institute of Technology. The user base will have tobroaden out significantly, as the user program grows, to involve more universities, othergovernment labs and commercial companies. There has been one article in the Journal of
the American Chemical Society, and one in Phys. Rev. B.
•Evaluation of research outputs
Aside from science done on the KENS instruments, KEK staff have reported on their researchdone using other neutron, synchrotron, and SR instruments. Seven other non-KEK
instruments feature on KENS publications, as well as the KEK SR facilities at J-PARC. Threesynchrotrons feature on KENS papers: the Photon Factory, SPRing-8 and the Taiwan Light
Source, in that order, and KENS papers feature data taken on 5 different overseas neutronsources. There are also papers from the TRIUMF accelerator in Vancouver and using optical
microscopy and mass spectrometry. This is all very healthy.
The number of postdoctoral fellows (almost 2 per beamline; or one per scientific staffmember) and graduate students (>1 per beamline; almost one per scientific staff member) is
quite healthy by international standards.
We note that KENS staff won the 2017 JSNS Technology Prize, for the implementation ofNeutron Brillouin Scattering on HRC.
Notable recent work includes that on a new class of layered perovskites with high oxygen
conductivity (2020 in Nature Communications; SHRPD), 9-fold hydride formation (2017 in
Scientific Reports; NOVA), Ionic conduction via orientational disorder (2020 in Applied
Physics Letters, NOVA), Observation of the Higgs mode in CsFeCl3 (2018 & 2019, in Phys. Rev.
B and Science Advances; HRC), and new curved mirrors for reflectometry and spin-echo,•Evaluation of Funding situation
We do not believe that KENS (or the MLF, for that matter) can be fully research competitivewith ISIS, SNS and the leading research reactors, unless it is staffed at the international
standard for neutron sources that run 200+ days per year.
The difference between the requested budget and actually funded budget is extremely high.
Therefore it is clear to us that it has been very difficult to do as planned or aimed for, resulting
in the extended instrument improvements and shortage of staff members.

•Is KENS moving in the right direction? Are the future development items adequate?
The future research directions and plans to understand the cross correlations in materials by
precise neutron scattering measurements, which are dealing with important issues in eachfield, are well laid out. These efforts are expected to help to understand the fundamental
interactions in materials and design materials of new emergent functional properties.
The continuing instrument improvement plans are adequate and well laid out, which is very
good thing to do. However, it is concerned that the limited budget may have extended theperiod of instrument improvement, possibly interrupting stable use of instruments by users.
Sufficient budget support for the instrument improvement is highly recommended so thatthe instruments can be operational with full capacity in a short period of time.

•Evaluation of KENS and MLF Leadership – Is MLF a core academic research hub?
The leadership of KENS and MLF in the field of neutron science is very highly regarded. TheMLF receives ca. 650 general beamtime proposals in 2020A from Japanese universities (43%),
foreign institutes (31%), Japanese companies (9%) and others. The high proportion ofproposals from foreign countries clearly demonstrates the very high international reputationand leadership of KENS and MLF.
The instruments at KENS and MLF provide world top level measurement capability. The
experiments performed at KENS and MLF by Japanese and international scientists andengineers cover a broad spectrum of academic disciplines including physics, chemistry, biology,
soft matter, and materials science, resulting in publications in high profile journals such as
Nature Materials, Nature Physics, Physical Review Letters, Advanced Materials, The Journal ofAmerican Chemical Society and so on. There is no doubt that the KENS and MLF have been an
excellent core academic research hub for Japanese and international communities.
We believe that the international leadership of KENS and MLF, and their roles as a coreacademic research hub will be significantly further strengthened if the budget and staff
members are properly allocated at the international standard.