J-PARC Project Newsletter No.98, April 2025 dispatch
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J-PARC Project Newsletter
No.98, April 2025
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]
INTERNATIONAL ADVISORY COMMITTEE MEETING WAS HELD
2. [Accelerator Division]
- ACCELERATOR OPERATION RESUMED AFTER THE NEW-YEAR HOLIDAYS
- PROF. EMER. TOMIZAWA RECEIVED THE NISHIKAWA PRIZE
- THE 24TH A-TAC MEETING WAS HELD IN FEBRUARY
3. [Particle and Nuclear Physics Division]
- PROGRAM ADVISORY COMMITTEE MEETING
- OPERATION OF THE NEUTRINO BEAMLINE AND
HYPER-KAMIOKANDE COLLABORATION MEETING AT J-PARC
- STATUS OF THE JSNS2 / JSNS2-II (SEARCH FOR STERILE NEUTRINOS AT J-PARC MLF, E56 / E82)
- 2025 TOWN MEETING ON THE EXTENSION PROJECT FOR J-PARC'S HADRON EXPERIMENTAL FACILITY
(HEF-EX TOWN-MEETING 2025)
- STATUS OF THE COMET EXPERIMENT
- STATUS OF THE MUON g-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34)
4. [Materials and Life Science Division]
- WORKS ARE UNDERWAY TO RECOVER THE SEALING PERFORMANCE OF THE MERCURY PIPING
- PROPOSALS FOR 2025A ROUND WERE APPROVED
- MAC WAS HELD
5. [Nuclear Transmutation Division]
CONCEPTUAL STUDY OF J-PARC PROTON BEAM IRRADIATION FACILITY
6. [Safety Division]
AN EMERGENCY DRILL WAS HELD ASSUMING A FIRE ACCIDENT
7. [Outreach Activities]
8. [Editorial Note]
Past issues are available from the link below.
http://j-parc.jp/c/en/topics/project-newsletter/index.html
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1. [Overview] by KOBAYASHI Takashi
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INTERNATIONAL ADVISORY COMMITTEE MEETING WAS HELD
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A meeting of the J-PARC International Advisory Committee (IAC) chaired by Dr. Robert McGREEVY of STFC was held on Feb 24th and 25th at J-PARC in person. The committee heard presentations, discussed and gave us valuable advice to improve the performance and operation of the entire J-PARC.
https://j-parc.jp/c/en/uploads/2025/JPARC-IAC2025-report_final.pdf
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2. [Accelerator Division] by YAMAMOTO Kazami
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- ACCELERATOR OPERATION RESUMED AFTER THE NEW-YEAR HOLIDAYS
- PROF. EMER. TOMIZAWA RECEIVED THE NISHIKAWA PRIZE
- THE 24TH A-TAC MEETING WAS HELD IN FEBRUARY
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The beam commissioning of the accelerator system started on January 10th, and the MR user operation started on January 17th. Just after resuming the slow extraction (SX) operation in MR, some of the SX magnets malfunctioned. However, these issues were fixed by January 24th, and the user operation resumed. After that, the accelerator became stable, and an 80-kW beam was delivered to Hadron users until February 26th. MR operation mode was switched to fast extraction (FX) mode for the neutrino experiment on February 27th, providing an 830-kW beam. Unfortunately, the cooling system of the neutrino target failed on the morning of March 4th, so the neutrino user operation was suspended. On March 9th, there was an issue with the power supply of a bending magnet family in MR. The problem with the neutron target at the Materials and Life Science Facility (MLF) has not been resolved, and the MLF user operation in JFY2024 has been canceled. Instead, accelerator beam studies for the linac and RCS were intensively conducted from Match 10th.
We are pleased to announce that Professor Emeritus TOMIZAWA Masahito received the Nishikawa Prize from the Foundation for High Energy Accelerator Science (FAS). This award is for his research on improving the performance of SX operations in MR. He was responsible for the beam dynamics design, R&D of the hardware, the construction and installation of the components and the practical operation. His work led to the world's highest extraction efficiency of 99.6% for J-PARC MR.
(https://www.heas.jp/award/2024zyusyou.html in Japanese)
The 24th A-TAC (Accelerator Technical Advisory Committee) meeting was held from February 5th to 7th. The meeting was held in a hybrid format, with the meeting mainly held on-site (seven of the nine committee members attended the meeting on-site). The main topics of discussion at this meeting were the status of the accelerator and responses to the previous recommendations. The committee was shown the improvements, the prospects and other things and it gave recommendations to the accelerator division.
https://j-parc.jp/c/en/forum-and-committee/a-tac-e.html
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3. [Particle and Nuclear Physics Division]
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PROGRAM ADVISORY COMMITTEE MEETING (by NAKADAIRA Takeshi)
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The 39th Program Advisory Committee (PAC) meeting was held on January 6th - 8th, 2024. Updates were provided on the status of J-PARC accelerator operations following the summer maintenance in 2024, prospects for Main Ring (MR) beam power improvements, and the status of experiments along with plans for operations leading up to summer 2025. A summary of experimental proposals for the coming years was also presented.
This time, five proposals - including those for test experiments - were submitted. Details can be found at the following link:
https://kds.kek.jp/event/53355/
The PAC report will be available on the following webpage:
https://j-parc.jp/researcher/Hadron/en/PAC_for_NuclPart_e.html
The next PAC meeting is scheduled to be held in July 2025.
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OPERATION OF THE NEUTRINO BEAMLINE AND THE HYPER-KAMIOKANDE COLLABORATION MEETING AT J-PARC (by ISHIDA Taku)
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The T2K experiment, which injects neutrinos from J-PARC to Super-Kamiokande, resumed operation in neutrino mode at the end of November, switched to antineutrino mode in mid-December, and has been operating stably at a beam power of over 800 kW, accumulating 2.3 x 10^20 pots (proton on target) by the end of the year (45.7 x 10^20 pots accumulated since 2010). At the beginning of the year, after the completion of the Hadron facility operation, the operation was resumed on February 28 and was adjusted to a maximum of 830 kW. In the early morning of March 4, an anomaly was detected in the helium cooling system of the production target, and the operation was stopped. The equipment in question is currently being investigated, but further investigation inside the helium vessel of the target station was necessary to determine the cause. Since this work will take more than three months, it was decided to suspend the beam operation of the neutrino experimental facility in the first half of 2025.
A meeting of researchers of the Hyper-Kamiokande International Collaboration was held at the AYA'S LABORATORY Quantum Beam Research Center (AQBRC) from February 17 to 22, 2025. Approximately 600 researchers from 22 countries are participating in the collaboration (as of October 2012). Since a huge underground cavity for the detector has just revealed itself and many discussions are needed to address various issues towards the start of the experiment in 2027, about 120 members gathered at the AQBRC and had a very active discussion, including participants with remote connections. Furthermore, toward the verification of matter-antimatter symmetry breaking, a neutrino detector, a miniature version of Hyper-Kamiokande, will be constructed near J-PARC to accurately characterize the properties of the neutrino beam immediately after its production. The device, called "IWCD" (short for Intermediate Water Cherenkov Detector), will be installed in a 50-m-deep shaft filled with water, and the detector can be moved up and down by buoyancy. Since the neutrino beam produced by the accelerator has an angular dependent energy spread, the neutrino beam properties can be observed in detail by changing the position of the detector. During the conference, a tour of the J-PARC beamline was conducted, including the planned construction site for IWCD.
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STATUS OF THE JSNS2 / JSNS2-II (SEARCH FOR STERILE NEUTRINOS AT J-PARC MLF, E56 / E82) (by MARUYAMA Takasumi)
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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 fifth long physics run from Jan-2025 using a single near detector located on the third floor of MLF was postponed due to the trouble of the mercury target system at J-PARC MLF. Meanwhile, we unblinded the signal region in the data taken in 2022 without neutron background reductions, and the results were shown in the 39th J-PARC PAC.
For JSNS2-II, the new far detector located outside of the MLF building is in the commissioning phase. Cosmic rays data are taken to improve the data acquisition system.
The far detector aims to soon start commissioning data taking with beams.
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2025 TOWN MEETING ON THE EXTENSION PROJECT FOR J-PARC'S HADRON EXPERIMENTAL FACILITY (HEF-EX TOWN-MEETING 2025) (by SAKUMA Fuminori)
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On February 20th, 2025, the "Town Meeting on the Extension Project for J-PARC Hadron Experimental Facility (HEF-ex town-meeting 2025)" was held at the KEK Tokai-1 building in a hybrid format, with both in-person and online participation (https://kds.kek.jp/event/53533/). A total of 101 people registered for the meeting, including approximately 40 in-person participants. The extension of the Hadron Experimental Facility is an important project that has been strongly advocated and promoted by the community. In particular, the J-PARC Hadron Hall Users' Association (HUA) Task Force (TF) has played a key role in promoting it. The project has been selected as the highest-priority project for future funding in the KEK PIP2022. However, due to the recent increase in construction costs, it is currently difficult to start the project immediately. The purpose of this town meeting was to present a new staging plan based on the existing extension plan to realize the project at an earlier date and to gather a wide range of opinions on it. As this was the first meeting, it was held in Japanese and in person to ensure open and active discussion at the national level. A second town meeting is planned for 29 - 30 September near Tokyo as a pre-workshop for the HYP2025 conference, aiming to promote broader international discussions.
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STATUS OF THE COMET EXPERIMENT (by MIHARA Satoshi)
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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 facility construction is in progress. After delivery of the capture solenoid magnet used to collect pions and transport them to the beam transport magnet, installation work and preparation for an on-site excitation is in progress. The precise alignment of the capture solenoid magnet was completed and the connection between the capture solenoid and transport magnets was confirmed. The construction of another important component of the magnet system, the radiation shielding inside the capture solenoid to protect its superconducting coils, was started in FY2024. Four stainless steel blocks out of 12 blocks to form a cylindrical shape were delivered. Construction of the remaining will start in FY2025.
The COMET group had a hybrid collaboration meeting in March at J-PARC. More than 50 members including 36 on-site participants joined the meeting to discuss the status of the facility, the detector construction, the analysis tool development as well as simulation study, and the schedule toward the start of physics data acquisition. In addition to these, the COMET group elected a new co-spokesperson, Prof. Ye YUAN of IHEP, who will lead the group together with other Executive Board members.
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STATUS OF THE MUON g-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34) (by MIBE Tsutomu)
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The E34 collaboration aims for precision measurements of the muon anomalous magnetic moment and its electric dipole moment. The surface muon beam line was extended by installing a solenoid and quadrupole triplet magnets in the H-line. The first beam delivery is expected in spring 2025. The laser system for the cold muon source is under development. In January, laser tables were installed in the laser room. A new beam diagnostics system is being developed to evaluate the properties of muon sources. The collaboration meeting was held at KMI, Nagoya University from December 11-13, 2024. In FY2024, one PhD thesis and four master theses were completed by the collaborating students. The collaboration is preparing for a progress review by KEK IPNS in April.
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4. [Materials and Life Science Division]
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NEUTRON SOURCE: WORKS ARE UNDERWAY TO RECOVER THE SEALING PERFORMANCE OF THE MERCURY PIPING (by HAGA Katsuhiro)
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The mercury pump was replaced during the 2024 long-term maintenance period and the MLF beam operation started on December 9. As this was the first replacement work of the mercury pump since the MLF started beam operation in 2008, we carefully increased the beam power during the test operation. As a result, the monitoring value of the radioactivity at the MLF exhaust tower showed a tendency to be higher than normal, and the beam operation was stopped. As it was suspected that the sealing performance of the mercury pipe flange fastened during the replacement of the mercury pump was insufficient, the flange bolts were retightened several times by remote handling in December and January and the beam test was carried out, but the situation did not improve. During these operations, it was determined that the lack of sealing performance was most likely due to an uneven fastening of the metal O-ring, so a further remote operation test was carried out using a mock-up of the flange to determine how to fasten the metal O-ring evenly. As a result, we found a way to achieve its goal by improving the remote handling method and work procedures and are now working to replace the metal O-ring on the mercury pipe flange to recover the seal performance and start beam operation in April.
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NEUTRON INSTRUMENT AND SCIENCE; PROPOSALS FOR 2025A ROUND WERE APPROVED. (by NAKAMURA Mitsutaka)
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The issue of the neutron target is still under investigation, and the rest of the schedule in the 2024B term will be carried over to the 2025A term. The 2025A call for general use proposals was closed on November 7, and 312 applications for neutron experiments were received. Notably, the number of applications from abroad increased by 11, accounting for 54% of the total. Of these, 157 were officially approved by the MLF Advisory Board on March 10. The proposal acceptance rate was 50%.
The Neutron Advisory Committee (NAC-2025) reviewed major activity outcomes by the MLF. The NAC meeting chaired by Philip King (the vice director of the ISIS Neutron and Muon Source) was charged to evaluate the target maintenance and development, the user programs, and the roadmap of the MLF. The NAC also summarized the meeting and made appropriate recommendations for the items in its charge.
https://mlfinfo.jp/_src/resource/P3iPXAjHJS/J-PARC_NAC_2025_FinalReport.pdf
The Quantum Beam Science Festa 2024 (QBSF) was held on March 12-14 at the Tsukuba International Congress Center. As part of the meeting, the 16th MLF Symposium was held to foster a great liaison between facilities and users. The main purpose of this event is to provide an opportunity for researchers using different probes to interact with each other and to discuss the future of quantum beam research.
Recent press releases from Neutron Science at MLF:
cBL17 SHARAKU on Feb. 17th
"Water-Intercalated and Humidity-Responsive Lamellar Materials by the Self-Assembly of Sodium Acrylate Random Copolymers"
https://doi.org/10.1021/jacs.4c16219
BL08 SuperHRPD on Feb. 21st
"High Oxide-Ion Conduction in Rb-Containing Oxides"
https://doi.org/10.1021/acs.chemmater.4c03148
BL18 SENJU and BL19 TAKUMI on Feb. 27th
"A lightweight shape-memory alloy with superior temperature-fluctuation resistance"
https://doi.org/10.1038/s41586-024-08583-7
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MUON SCIENCE FACILITY (MUSE); MAC WAS HELD (by KAWAMURA Naritoshi)
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The user programs have not been conducted as scheduled last December due to a problem with the neutron target. The rescheduled date is the middle of April 2025.
In the Muon Science Proposal Review Committee (MSPRC) meeting, 55 proposals submitted for the 2025A period were reviewed, resulting in 34 approved, 19 reserved, and 2 not approved. In addition to these approved programs, the programs carried over from 2024B will be assigned a higher priority in the 2025A period, which will end in mid-February next year. Thus, the call for the 2025B proposals will differ from the usual one.
The Muon Advisory Committee (MAC) meeting was held from February 20th to 21st under the chair of Prof. Klaus Kirch, Paul Scherrer Institute (PSI). The instrumental scientists reported the progress in each beamline/instrument. The committee was impressed and suggested meaningful recommendations for continuous development. The committee also validated the proposed strategy for dealing with aging devices, which are recognized as potential risks, for stable and continuous operation.
https://www2.kek.jp/imss/msl/meeting/MAC24.html
The KOSHIBA Prize of the Foundation for High Energy Accelerator Science was awarded to Drs. S. Okada, S. Yamada, T. Hashimoto, and T. Okumura for "Advancing Precision X-ray Spectroscopy of Exotic Atoms Using Cryogenic Detectors" studied in the D1 area of the D Line and the Hadron facility.
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5. [Nuclear Transmutation Division] by MEIGO Shin-ichiro
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CONCEPTUAL STUDY OF J-PARC PROTON BEAM IRRADIATION FACILITY
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Based on the design of the accelerator-driven system (ADS) Target Test Facility (TEF-T) at the J-PARC Transmutation Experimental Facility, a conceptual study was conducted on the J-PARC proton beam irradiation facility. This research followed the recommendations of the Nuclear Transmutation Technology Evaluation Task Force of the Ministry of Education, Culture, Sports, Science, and Technology, which suggested emphasizing the attractive benefits of using the existing J-PARC proton accelerator while also solving the engineering issues of the ADS. To clarify the diverse needs of the accelerator, we investigated the usage status of representative accelerator facilities worldwide. In considering the facility concept, we established a user community to reflect user opinions in the design directly. As a result, the facility design was investigated for the following purposes: (1) Material irradiation, (2) Soft error testing of terrestrial semiconductor devices using spallation neutrons, (3) Production of radioisotopes for medical use, and (4) Proton irradiation for the test of space devices. The results of the conceptual study of this facility were summarized and published as a technical report [1]. This report summarizes the results of the conceptual study of the proton irradiation facility, various needs and responses to them, and the roadmap for facility construction.
[1] "Conceptual Study of J-PARC Proton Beam Irradiation Facility", S. Meigo, et al., JAEA-Technology 2024-026 (2025).
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6. [Safety Division] by NAKANE Yoshihiro
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AN EMERGENCY DRILL WAS HELD ASSUMING A FIRE ACCIDENT
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On Dec. 24th, an emergency drill was performed at the Main Ring. It assumed that a fire broke out in the power distribution panel of the waste management facility. The purpose of the drill was to confirm the following; 1. Initial response to a fire outbreak, 2. How public firefighters have access to the radiation-controlled area, 3. Information exchange between the fire location and the command post, and 4. Communication between the command post, JAEA Nuclear Science Research Institute (NSRI) local headquarters, and KEK director at TSUKUBA campus via TV conference system.
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7. [Outreach Activities]
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★ Visiting Class, KIPP Nakameguro Children's Class at Nakameguro Elementary School(December 14th)
★ Visiting Class at Nakamachi Elementary School, Hitachi City (December 18th)
★ Guest lecture at Takamatsu Campus, National Institute of Technology, Kagawa College (January 6th)
★ Muographic Investigation of Ancient Burial Mounds in Tokai (January 19th)
- Building the second detector -
https://www.j-parc.jp/c/en/topics/2025/02/21001473.html
★ Visiting Class at Tanaka Elementary School, Namekawa City, Toyama (January 22nd)
★ Guest lecture at National Institute of Technology, Nagano College (January 27th)
★ Visiting Class at Ichige Elementary School, Hitachinaka City (January 31st)
★ Visiting Class at Katsuta Third Junior High School, Hitachinaka City (February 4th)
★ Visiting Class at Shirakata Elementary School, Tokai Village
★ Muographic Investigation of Ancient Burial Mounds in Tokai (February 16th)
- The "Detector for History and the Future" reports on the status of data analysis and the construction of the second detector -
https://www.j-parc.jp/c/en/topics/2025/03/18001486.html
★ Guest Lecture at Takuma Campus, National Institute of Technology, Kagawa College (February 18th)
★ Visiting Class at Katsukura Elementary School, Hitachinaka City (February 26th)
★ Sakurie Science Festival at the Hitachi Civic Center Science Museum, Hitachi City (March 15th)
https://www.j-parc.jp/c/en/topics/2025/04/11001502.html
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┃ Editorial Board:
┃ OGURI Hidetomo (Chair) : oguri.hidetomo[at]jaea.go.jp
┃ SHINTO Katsuhiro: shinto.katsuhiro[at]jaea.go.jp
┃ OZAWA Kyoichiro: ozawa[at]post.kek.jp
┃ AIZAWA Kyoko: akyouko[at]post.j-parc.jp
┃ TAKEI Hayanori: takei.hayanori[at]jaea.go.jp
┃ Jean-Michel POUTISSOU (English Editor) : jmp[at]triumf.ca
┃ SEKI Eiko (Secretary) : seki.eiko[at]jaea.go.jp
┃ * Please replace "(at)" with "@" when you enter an email address.
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