[Neutron] J-PARC Project Newsletter No.91, July 2023

[會澤恭子]

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　 J-PARC Project Newsletter
　　                       No.91, July 2023
Japan Proton Accelerator Research Complex under joint operation by the
High Energy Accelerator Research Organization (KEK) and the Japan Atomic
Energy Agency (JAEA)
http://j-parc.jp/index-e.html
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HEADLINES AND CONTENTS

1.[Overview]
TWO FIRE INCIDENTS

2.[Accelerator Division]
ON APRIL 16TH THE J-PARC MAIN RING SUCCESSFULLY ACCELERATED 750-kW
EQUIVALENT BEAMS AT THE ENERGY OF 30 GeV.
ON APRIL 25TH A POWER SUPPLY IN THE MR BUILDING NO.2 OF J-PARC,
USED FOR MAGNETS, WAS BROKEN BY FIRE. OPERATION OF ACCELERATORS
STOPPED DUE TO THIS ISSUE.
MLF USER OPERATION WAS RESUMED ON MAY 13TH AFTER SAFETY CONFIRMATION
OF THE LINAC AND RCS. MR BEAM RESUMED OPERATION ON JUNE 13TH AFTER
MEASURES WERE TAKEN TO PREVENT A REOCCURRENCE OF THE FIRE IN THE POWER 
SUPPLY.

3.[Particle and Nuclear Physics Division]
ON THE FIRE IN THE POWER SUPPLY BUILDING OF THE HADRON EXPERIMENTAL
FACILITY.

NEUTRINO EXPERIMENTAL FACILITY RESUMED BEAM OPERATION.
STATUS OF THE JSNS2 / JSNS2-II (SEARCH FOR STERILE NEUTRINOS AT
J-PARC MLF, E56 / E82).
STATUS OF THE COHERENT MUON TO ELECTRON TRANSITION (COMET).
STATUS OF THE MUON g-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34).

4. [Materials and Life Science Division]
PULSE INTENSITY REACHED 950 KW FOR USER PROGRAM OPERATION.
EXPERIMENT PROPOSALS FOR 2023B ROUND.
FIRST MUON BEAM DELIVERED TO THE H2 AREA.

5. [Nuclear Transmutation Division]
PRIZE OF "55TH ATOMIC ENERGY SOCIETY OF JAPAN ARTICLE AWARD"

6. [Safety Division]
J-PARC SAFETY DAY 2023
9TH SYMPOSIUM ON SAFETY IN ACCELERATOR FACILITIES

7. [Information]


8. [Editorial Note]


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1. [Overview] by Takashi KOBAYASHI
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TWO FIRE INCIDENTS
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  We have to report and deeply apologize for two fire incidents that
happened during the last several months. One happened in one of the
newly constructed Power Supply for Main Ring (MR) beam power upgrade
on April 25th. One of the transformers used in an initial charging
unit had been exposed to high frequency noise from chopper circuits.
It caused corona discharge, developed deterioration of insulation,
and finally caused the fire. After confirmation of the safety of
other facilities, we could restart the operation of MLF on May 13th.
For the MR, we applied preventive measures and got approval from the
local government to restart the operation of MR on June 13th. Another
fire happened on June 22nd. It happened in a power supply for one of
the Hadron D beam transport magnets. The fire happened in the
polarity changer of the power supply. The remaining user beam before
summer maintenance was canceled. The investigation into the cause,
and the planning of preventive measures are ongoing. As a result of
these fires, the user beam time had to be reduced from 60 days to
44.5 days for MLF users and from 58 days to 12 days for MR users.
We deeply apologize to all the users for the serious impact to the
planned experiments. We plan to restart MLF and NU after the planned
summer maintenance period around late November after confirming the
safety of all the power supply units used in the entire J-PARC.
  For the resumption of HD, applying preventive measures may take
longer than the planned summer shutdown. We will provide updated
information at the appropriate time.

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2. [Accelerator Division] by Michikazu KINSHO
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ON APRIL 16TH THE J-PARC MAIN RING SUCCESSFULLY ACCELERATED 750-kW
EQUIVALENT BEAMS AT THE ENERGY OF 30 GeV.
ON APRIL 25TH, A POWER SUPPLY IN MR BUILDING NO.2 OF J-PARC, USED
FOR MAGNETS WAS BROKEN BY FIRE. OPERATION OF ACCELERATORS STOPPED
DUE TO THIS ISSUE.
MLF USER OPERATION WAS RESUMED ON MAY 13TH AFTER SAFETY CONFIRMATION
OF THE LINAC AND RCS. MR BEAM RESUMED OPERATION ON JUNE 13TH AFTER
MEASURES WERE TAKEN TO PREVENT A REOCCURRENCE OF THE FIRE IN THE
POWER SUPPLY.
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OPERATION STATUS OF THE ACCELERATORS
  After the scheduled maintenance at the end of March, beam operation
resumed on April 14th as part of Run#90, which started in November
last year, and the user program resumed for the Materials and Life
Science Experimental Facility (MLF) on April 16th on schedule. This
user operation could be performed with high availability until
midnight of June 21st, although there was a 19-day interruption from
April 25th to May 13th due to a fire at MR power supply building No.2
on J-PARC during the user operation.
  Beam power was approximately 840 kW until June 8th, when the power
was reduced to 750 kW due to insufficient cooling capacity of the RCS
cooling water system.
  Beam tuning of the Main Ring (MR) for the Neutrino users started on
April 16th on schedule.
  On April 16th, a 750-kW equivalent beam at an energy of 30 GeV was
successfully accelerated in the MR. This is one of the milestone
achievements, and we will continue to make beam adjustments and
strive to achieve beam user operation at a beam power of 750 kW as
soon as possible.
  One of the power supplies for quadrupole magnets (QDN) was broken by
fire on the evening of April 25th in the MR Power Supply Building
No.2 of J-PARC during beam tuning, then beam operation was stopped.
The cause of the fire was investigated, preventive measures were
taken, and beam tuning for Hadron users were resumed on June 13th.
This beam operation for Hadron users was continued until midnight
on June 21st.
https://j-parc.jp/c/en/information/2023/04/25001148.html
  Due to another fire that broke out in the J-PARC hadron power supply
building on June 22nd, the J-PARC accelerator operation has been
canceled until the summer maintenance period scheduled in June.
Summer maintenance work will begin in early July, lasting
approximately four months.


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3. [Particle and Nuclear Physics Division]
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ON THE FIRE IN THE POWER SUPPLY BUILDING OF THE HADRON EXPERIMENTAL
FACILITY (by Takeshi KOMATSUBARA)
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  As reported in [Overview] by the J-PARC Director, at around
0:51 a.m. on Thursday, June 22nd, a fire broke out in the Power
Supply Building of Hadron Experimental Facility. Initial fire
extinguishing was conducted. There was no leakage of radioactive
material to the environment, no radiation exposures, no injuries.
The J-PARC accelerator operation and user beam time, including for
MLF and Neutrino facilities, before the summer maintenance period
were canceled. More on the fire are described at
https://j-parc.jp/c/en/information/2023/06/22001172.html.
  We deeply apologize to the users for the serious delay and reduction
of user beam.

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Neutrino Experimental Facility resumed beam operation
(by Yoshiaki FUJII)
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  On April 17th, the long-awaited beam eventually came to the neutrino
experimental facility for the first time in two-years!
  During the two-year long shutdown, many devices in the neutrino
beamline were upgraded or exchanged, including the beamline's most
downstream "targeting" bending magnet, the neutrino production target
and two of the three hadron focusing horns. Following these
significant upgrades of the beamline, extreme care had to be taken
when restarting the neutrino beam for the first time. The first beam
pulse was taken at very low intensity, to ensure that mis-steered
beam could not damage any beamline equipment. The first beam pulse
reached the target off-center, but after some beam tuning, beam was
established perpendicularly centered on the neutrino production
target. After careful beam tuning, the beam power was successfully
increased to 540kW steady operation, which exceeded the 510kW record
achieved two years ago. The horns were also operated at 320kA
successfully. We were starting various validations and calibrations
for the new beam line configuration.
  Upgrade work of ND280 is in progress, aiming at receiving the first
beam next fall. Assembly work of the main part of the SFGD (Super
Fine-Grained Detector) was successfully done, and system tests of
electronics at test bench were started in April. The first half of
the bottom High-Angle TPC were assembled at CERN and first cosmic
events were successfully observed. The six TOF modules were fully
commissioned at CERN and shipped to J-PARC in June. Installation of
the first two TOF modules into the ND280 basket will be done in July,
and installation of the bottom HA-TPC and SFGD will follow. The
chiller for the ND280 magnet cooling water system was replaced with
a new chiller in JFY2022, and the test operation with ND280 magnet
was successfully done in June 2023.

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STATUS OF THE JSNS2 / JSNS2-II (SEARCH FOR STERILE NEUTRINOS AT
J-PARC MLF, E56 / E82) (by Takasumi MARUYAMA)
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  The JSNS2 (E56) / JSNS2-II (E82) collaboration searches for neutrino
oscillation with a short distance by sterile neutrinos at J-PARC MLF.
  For JSNS2, the third long physics run has been successfully
performed from April to June using a single near detector located on
the third floor of MLF. During this run, 4,279×1021 Proton-On-Target
(POT)were accumulated for a total of 3.276×1022 POT during 2020-2023
corresponding to 29% of approved POT. The new electronics have also
been tested with the neutrino beam in addition to the normal data
taking during this run. For JSNS2-II, the new far detector is under
construction. 142 10-inch PMTs out of 228 in total were installed in
the far detector by end of May-2023. The acrylic tank of the far
detector was moved in the neighborhood of the far detector location,
and it is waiting for installation. JSNS2-II aims to start the data
taking within FY2023.

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STATUS OF THE COHERENT MUON TO ELECTRON TRANSITION (COMET)
(by Satoshi MIHARA)
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  The COMET experiment aims to search for the lepton-flavor violating
muon reaction, mu-e conversion, with a sensitivity better than 10-14
in Phase I. The COMET group carried out an engineering run, called
Phase α, to measure the behavior of the proton beam and of the
secondary particles in February and March 2023. The proton beam was
injected into a thin graphite target and its property was measured
with beam line apparatus. Properties of secondary particles such as
pions, muons, and electrons transported to the experiment area by the
transport solenoid were also measured. Detailed data analysis is in
progress after successfully identifying muons in the beam with its
momentum distribution evaluated by the range counter data. In
parallel to this activity, facility construction continues at J-PARC.
Preparation to install the capture solenoid magnet is in progress at
the COMET beam line area. Conditioning of detectors to be used in
COMET Phase I is under way; the long-term stability of the CDC is
tested using cosmic rays. The straw tube tracker is in operation to
optimize its operating condition in high counting rate environment.
Other detector components are being prepared in collaboration
institutes.

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STATUS OF THE MUON g-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34)
(by Tsutomu MIBE)
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  The E34 collaboration aims for precision measurements of the muon
anomalous magnetic moment and its electric dipole moment.
The collaboration continued taking data to demonstrate muon cooling
by means of the resonant laser ionization of muonium atoms at MLF S2
area. The first-ever demonstration of the RF acceleration of
thermal-energy muons with RFQ is in preparation. The engineering
design of the MLF extension building, the H-line experimental bldg.,
is in progress.
  Prototypes of the tracking vanes for the positron tracking detector
were fabricated at the KEK Tsukuba campus and at Kyushu university.
The collaboration had its 26th collaboration meeting on June 14-16 at
AQBRC in a hybrid format.


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4. [Materials and Life Science Division]
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NEUTRON SOURCE; PULSE INTENSITY REACHED 950 KW FOR USER PROGRAM
OPERATION (by Katsuhiro HAGA)
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  After the short outage from March 15th to April 15th, the user
program resumed with a beam power of 840 kW at MLF, which was
comparable with that achieved in May 2022, but this time the pulse
intensity was raised to the highest record of 950 kW for the first
time for long term user operation. The pulse intensity corresponds to
the beam power at the RCS outlet and is the dominant factor for the
pitting damage of the target vessel by pressure waves. This
accomplishment means that the goal of the stable operation of the
neutron source with 1 MW was almost achieved.
  The beam operation of MLF went on with an excellent daily
availability of 93.7 % on average from April 16th to June 22nd when
the beam operation was stopped due to the fire incident at the HD
experimental facility. The maintenance works in the summer outage
started and the beam operation will be resumed in November.

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NEUTRON INSTRUMENTS AND SCIENCE; NEUTRON EXPERIMENT PROPOSALS FOR
2023B ROUND (by Mitsutaka NAKAMURA)
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  Despite rapid global increases in electricity and energy prices,
many operating hours are expected for the upcoming period of the
2023B operation cycle. MLF received 289 applications for general
and one-year proposals for neutron beams usage, which is even a
larger number than that in 2023A. The proposals will be discussed
by Neutron Science Proposal Review Committee (NSPRC) / Proposal
Evaluation Committee (PEC) on August 8th, after review by each
subcommittee.
  In this fiscal year, a new section Neutron Industrial Application
Promotion Center in CROSS has been founded for operating two Ibaraki
Prefecture beam lines (BL03 and BL20). These two beam lines (BL) are
categorized as "Contract BL" used to be operated by Ibaraki
University.
  The Nishida Prize for Promotion of Geo- and Planetary Science (Japan
Geoscience Union) was awarded to Dr. Asami Sano for “Research on
hydrogen in the Earth’s materials at high pressure and temperature
based on synchrotron X-ray and Neutron beams”.
  Recent press releases from MLF:
(1) BL21 NOVA on Apr. 27
"Hidden chemical order in disordered Ba7Nb4MoO20 revealed by resonant
X-ray diffraction and solid-state NMR"
https://10.1038/s41467-023-37802-4
(2) BL15 TAIKAN & BL18 SENJU on Apr. 21
"Spontaneous topological Hall effect induced by non-coplanar
antiferromagnetic order in intercalated van der Waals materials"
https://doi.org/10.1038/s41567-023-02017-3
(3) BL21 NOVA on Apr. 7
"Lithium ion transport environment by molecular vibrations in
ion-conducting glasses"
https://doi.org/10.1002/eem2.12612

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MUON SCIENCE FACILITY(MUSE); FIRST MUON BEAM DELIVERED TO THE H2 AREA
(by Naritoshi KAWAMURA)
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  Restrictions due to COVID-19 have been largely eliminated since the
beginning of May. In the current beam cycle 2023A, the number of
international users is still affected, but we expect the situation
to be back to normal in the next cycle.
  In April, the H2 area, which is the second branch of the H line,
was constructed and a radiation survey was conducted when the first
beam was delivered to the H2 area. After that, the beam was switched
to the H1 area to perform the DeeMe experiment. The commissioning
work of the accelerator to be installed in the H2 area, which will
be used as the front-stage of the full-spec accelerator for the
g-2/EDM experiment and muon transmission micro-scope, will start
in the next beam cycle.
  The Young Scientists’ Award of the Commendation for Science and
Technology by the Minister of Education, Culture, Sports, Science,
and Technology was awarded to Dr. Masashi Otani of the Accelerator
Division for "Development of Muon Linear Accelerator and
Demonstration of Muon Acceleration" which was performed at MUSE D2
area. The Young Scientist Award of the Physical Society of Japan was
awarded to Dr. Izumi Umegaki for "Establishment of Detection
Technique for Diffusion Motion of Lithium and Metal Deposition
inside Lithium Ion Batteries Using Muon Beam". The Society of Muon
and Meson Science of Japan (JMMS) Meritorious Achievement Award 2022
was awarded to Prof. Yasuhiro Miyake for the "Construction of
High-Intensity Pulsed Muon Facility and Development of Muon
Interdisciplinary Science". The JMMS Technology Award 2022 was
awarded to Mr. Shunsuke Makimura and Dr. Shiro Matoba for the
"Development of Muon Rotating Target at J-PARC MLF and its Safe
Operation and Maintenance". The JMMS Student Incentive Award 2022
was awarded to Dr. Jumpei Nakamura for "muSR Study on Layered
Chalcogenides".


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5. [Nuclear Transmutation Division] by Hiroki IWAMOTO
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PRIZE OF “55TH ATOMIC ENERGY SOCIETY OF JAPAN ARTICLE AWARD”
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  As a means to reduce the radiotoxicity of high-level radioactive
waste, Accelerator-Driven Systems (ADS) have attracted attention. ADS
is a nuclear system that consists of a proton accelerator and
subcritical reactor, which employs neutrons generated by the
spallation reaction induced by high-energy proton beams. Accurate
prediction of neutron intensity in the spallation reaction is crucial
for the ADS design. Although it is widely considered that the
accuracy of nuclear reaction models used in the ADS design decreases
as the incident energy decreases, the lack of experimental data below
200 MeV hinders comprehensive validation. In order to validate the
accuracy of nuclear reaction models in this energy range, we
conducted measurements of neutron intensity produced by the
spallation reaction using the FFAG accelerator at Kyoto University.

In this experiment, 100 MeV proton beams were aimed onto targets
which are made of important materials for the ADS design, and the
energy spectrum of emitted neutrons was measured at various angles.
By comparing the measured spectrum with the model predictions, we
successfully validated the accuracy of the current nuclear reaction
model and identified areas for improvement.

The research paper titled "Measurement of 107-MeV proton-induced
double-differential thick target neutron yields for Fe, Pb, and Bi
using a fixed-field alternating gradient accelerator at Kyoto
University" has been awarded the paper prize by the Atomic Energy
Society of Japan.

Web-address:
150 MeV FFAG Synchrotron
https://www.rri.kyoto-u.ac.jp/en/facilities/irl

H. Iwamoto, et al., "Measurement of 107-MeV proton-induced
double-differential thick target neutron yields for Fe, Pb, and Bi
using a fixed-field alternating gradient accelerator at Kyoto
University", Journal of Nuclear Science and Technology, vol.60,
pp.435 – 449, 2023.
https://doi.org/10.1080/00223131.2022.2115423


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6. [Safety Division] by Kotaro BESSHO
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J-PARC SAFETY DAY 2023
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  The J-PARC Center had previously held "the J-PARC Safety Day" around
May 23rd which is the day on which a radioactive material leak
incident occurred in 2013. The Safety Day in FY2023 was held on May
23rd, ten years after the incident, in a main meeting room and
online.
  In the morning, a safety information exchange session was held to
share various efforts on radiation safety at each J-PARC facility.
In the afternoon, a safety workshop session was held to raise and
sustain our safety awareness. The main talk, "Psychological Safety
as a Foundation for Teamwork," was given by Ms. Mika Aoshima,
Director of the Laboratory for Developing Team Competence.
"Psychological safety" is a state in which everyone believes that
his team is safe even when it involves interpersonal behavior.
Importance of respect for oneself and others, fairness, and
transparency were introduced to create a team climate exhibiting
psychological safety. In the session "Ten Years After the Radioactive
Material Leak Incident", a documentary footage was screened, and a
panel discussion was held on emergency reporting and other safety
topics.

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9TH SYMPOSIUM ON SAFETY IN ACCELERATOR FACILITIES
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  The 9th Symposium on Safety in Accelerator Facilities was held on
June 9th at the Tokai-mura Industry and an Information Plaza (iVil)
with 105 participants in a face-to-face format.
  The topics of the workshop were "Response to the obligation to
ensure reliability of radiation measurement" and "Efforts to prevent
electrical fires and ensure electrical safety". Seven accelerator
facilities introduced their circumstances and approaches to address
these issues. It is expected that the various information shared will
be effectively utilized for improving safety at each facility.


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7. [Information]
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8. [Editorial Note]
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Past issues are available from the link below.
http://j-parc.jp/c/en/topics/project-newsletter/index.html


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┃ Editorial Board:
┃ Hidetomo OGURI(Chair): oguri.hidetomo at jaea.go.jp
┃ Katsuhiro SHINTO: shinto.katsuhiro at jaea.go.jp
┃ Kyoichiro OZAWA: ozawa at post.kek.jp
┃ Kyoko AIZAWA: akyouko at post.j-parc.jp
┃ Hayanori TAKEI: takei.hayanori at jaea.go.jp
┃ Jean-Michel POUTISSOU (English Editor): jmp at triumf.ca
┃ Chiaki SHIRAISHI (Secretary): shiraishi.chiaki at jaea.go.jp
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