[Neutron] J-PARC Project Newsletter No.87
shibata.kaoru
shibata.kaoru at jaea.go.jp
Fri Jul 22 03:54:47 CEST 2022
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J-PARC Project Newsletter
No.87, July 2022
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]
IAC REPORT SUBMITTED.
PROGRESS TOWARD REALIZING J-PARC ACCESS ROAD.
OUTREACH ACTIVITIES.
KEK PROJECT IMPLEMENTATION PLAN 2022 ESTABLISHED AND PUBLISHED.
2. [Accelerator Division]
OPERATION STATUS OF THE ACCELERATORS.
3. [Particle and Nuclear Physics Division]
A PAPER ON THE PRODUCTION TARGET FOR SECONDARY PARTICLES AT THE HADRON.
EXPERIMENTAL FACILITY PUBLISHED.
NEUTRINO COLLABORATORS ARE COMING BACK FROM ABROAD.
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]
USERS FROM ABROAD HAVE COME BACK.
BEAM POWER WAS RAISED TO OVER 800 kW.
PROPOSALS FOR 2022B ROUND WERE RECEIVED.
ROTATING MUON PRODUCTION TARGET WAS DEVELOPED.
5. [Nuclear Transmutation Division]
CURRENT STATUS OF THE SPOKE CAVITY PROTOTYPING FOR THE ADS LINAC.
6. [Safety Division]
J-PARC SAFETY DAY 2022.
7. [Information]
A NEW VIDEO ABOUT A BRIEF OVERVIEW OF J-PARC HAS BEEN RELEASED.
8. [Editorial Note]
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1. [Overview] by Takashi KOBAYASHI
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IAC REPORT SUBMITTED
The International advisory committee (IAC) (http://j-parc.jp/c/en/forum-and-committee/iac-e.html) met on March 3rd and 4th fully online, and we received the final report (https://j-parc.jp/c/en/uploads/2022/JPARC-IAC2022-report.pdf).
We got a lot of valuable advices on all aspects of J-PARC operation ranging from human resource planning, operation budget, radioactive waste management, etc.
We continue to work on all these advices to improve the overall J-PARC performance.
PROGRESS TOWARD REALIZING A NEW J-PARC ACCESS ROAD
During JFY2021, we made great progress toward realizing a new J-PARC access road. JAEA, KEK, and Tokai-village government office agreed to proceed to engineering design in JFY2022 to be ready for construction based on the basic plan proposed by J-PARC.
In this FY, we started contracts for the engineering design. (JFY is from April to March.)
OUTREACH ACTIVITIES
We published the 2022 edition of J-PARC quarterly magazine (https://j-parc.jp/c/public-relations/publication.html, we apologize that this website is not available in English).
This issue is on the neutrino project (https://j-parc.jp/c/uploads/2022/J-PARCmagazine2022_17.pdf).
The PR section has been organizing a monthly "Hello science" (https://j-parc.jp/c/events/hello-science/index.html), which is a science cafe type event with direct communication between researchers and the general public.
Before COVID-19, it was intended for face-to-face communication with local people.
Since April 2021 under the COVID-19 pandemic, we expanded our audience with remote connection. Video of the past events can be found through the above mentioned "Hello science" web page (we apologize that this website is not available in English).
KEK PROJECT IMPLEMENTATION PLAN 2022
ESTABLISHED AND PUBLISHED
In May 2021, KEK published the KEK Roadmap 2021, which described in details the status of research fields related to KEK, including J-PARC, and the strategy for the research program to be implemented at KEK in the future, focusing on its fourth medium-range goals/plans period from JFY2022 to JFY2027. The KEK Project Implementation Plan (PIP) 2022 was developed during JFY2021 as a concrete implementation plan for the realizing of the KEK Roadmap 2021, particularly from the viewpoint of funding resources. Its draft was presented and reviewed at the KEK Science Advisory Committee's third meeting on March 7, 8 and 11. Based on the report of the committee, the KEK-PIP 2022 was established on June 24 and has just been published. The documents can be found at https://www.kek.jp/en/roadmap-en/.
KEK-PIP 2022 emphasizes that operating KEK's major accelerators for sufficient time to produce research outputs is a high priority in KEK's mission. In the resource allocation for J-PARC, priority is given to securing the operation of the Main Ring for six months per year or longer in total for fast extraction and slow extraction, followed by maintenance and improvement of the accelerator and of the three research facilities: MLF, Neutrino Experimental Facility and Hadron Experimental Facility.
In JFY2022, the construction of a new facility for the muon g-2/EDM experiment is to begin.
Among the four KEK projects to make new budget requests, Extension of the Hadron Experimental Facility and Transmission Muon Microscope of J-PARC have been given the first and fourth priorities, respectively, and appropriate efforts will be made to receive new budgetary measures for them in that order.
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2. [Accelerator Division] by Michikazu KINSHO
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OPERATION STATUS OF THE ACCELERATORS
The Main Ring (MR) upgrade, which has been carried out since last July 2021, will be completed soon and beam commissioning is scheduled to begin in mid-June 2022.
The beam operation as an operation run of Run#89, which started middle of January in this year, continued until April 28th on schedule. The beam power for the Materials and Life Science experimental facility (MLF) user program increased from 730kW to 830kW on April 7th. The user program resumed for the MLF on May 11th. The MLF user program will continue until June 24th before the summer shutdown. After the MLF user operation is completed, an accelerator beam study is scheduled for up to 13 days before the summer maintenance work. The main items of this study are a two-day continuous high power beam test at 1 MW beam power in the RCS, and a MR beam commissioning.
The MR has entered a long maintenance period for upgrade from July, 2021. This work is generally progressing well, and all equipment has been successfully tested for simultaneous energization so far. Currently, final adjustments are carried out for the beam commissioning, which is scheduled to begin in mid-June. This beam commissioning is scheduled to run until early July.
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3. [Particle and Nuclear Physics Division]
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A PAPER ON THE PRODUCTION TARGET FOR SECONDARY PARTICLES
AT THE HADRON EXPERIMENTAL FACILITY WAS PUBLISHED
(by S. Sawada)
One of the most important elements at the Hadron Experimental Facility is the production target of the secondary particles. In order to create high-quality secondary particle beams, such as kaons and pions, the size of the primary proton beam should be as small as 2.5 mm (horizontal) and 1 mm (vertical). The heat from the intense primary proton beam is deposited in the tiny volume of the gold target, defined by this beam size and the target thickness (66 mm). The target has to be robust against not only this dense heat deposition but also the extremely high radiation environment.
The team at the Hadron Experiment Facility has developed several production targets to match the upgrades of the intensity of the 30-GeV primary proton beam. The previous target which was installed in the facility in 2014, could accept proton beams up to 50 kW. To accept more intense proton beams, a new target was developed. Its acceptance of 65-kW beam was achieved in 2021.
The target is cooled by circulating water indirectly. The team analyzed the thermal stress caused by the beam irradiation carefully and designed the target accordingly. They measured the stress-strain curves of gold at the operating temperatures as well, which were used in the thermal stress analysis. The temperature of the target is monitored carefully by thermocouples, and the beam is stopped if an abnormal situation occurs. The temperature monitoring of the target also helps the estimation of the beam position. The team published the results as an article (M. Saito, et al., Phys. Rev. Accel. Beams 25, 063001).
NEUTRINO COLLABORATORS ARE COMING BACK FROM ABROAD
(by Yoshiaki Fujii)
After more than a two-years absence, collaborators from abroad are coming back to J-PARC gradually.
The pulse magnets, the horns, used until the last run were successfully taken out from the beam line and stored in the storage area, contained in thick caskets. The new 2nd horn was fabricated at University of Colorado, and has arrived at J-PARC for the final assembly work. Collaborators of University of Colorado came to J-PARC in June for this assembly work. Installation of the 2nd horn will be done in July.
Installation of the new OTR, a beam profile monitor just upstream of the target, was also done in June with Canadian collaborators working together at the target station.
Upgrade work of ND280, the near detector, is also in progress. Plastic scintillator cubes of the SuperFGD, a new tracking target detector, have been shipped out towards J-PARC. The HATPC, a new tracking detector surrounding the SuperFGD, showed some problems in the high-voltage structure, and one is working on a solution. After 8 months of struggling with the visiting procedure to Japan, two Italian collaborators eventually came to J-PARC in June to work on the renewal of the TPC gas system.
The P83 experiment SUBMET collaborators from Korea also came to J-PARC. They examined the availability of resources, and did some background measurement successfully.
JSNS2 experimenters at MLF searching for sterile neutrinos, are working on the blind analysis of the 1.45x10^22 POT data taken until June 2021. They resumed data taking from January 29, 2022, until May 31, 2022. A new step, JSNS-II, has started. A Technical Design Report (TDR) was submitted and stage-II was recommended at the PAC meeting. A new detector 48m from the target, outside of the MLF experimental hall, is under construction.
We are still affected by the COVID-19 situation, but thanks to the return of collaborators from abroad, we are gradually recovering and proceeding.
STATUS OF THE COHERENT MUON TO ELECTRON TRANSITION (COMET)
(by Satoshi MIHARA)
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.
Facility and detector construction work continues; after the completion of the construction of the primary proton beam line to deliver protons to the COMET experiment in March 2022, the area work in progress is to setup a target chamber as well as beam duct to be used in the engineering run in JFY2023. Cooling and excitation tests of the transport solenoid installed in the COMET area in 2015 has started in May 2022. The magnet was successfully cooled down to the level of the super-conducting phase.
The main detector of COMET for its physics measurement, the Cylindrical Drift Chamber (CDC), has been tested at the Tsukuba campus. The final test of electronics cooling with water was completed recently. The CDC will be transported to J-PARC in July for further conditioning on site.
The COMET collaboration plans to have its collaboration meeting in July 2022 in a hybrid style for the 1st time since the last face-to-face meeting in 2019. The collaboration anticipates profound discussion regarding the start of the engineering run (COMET Phase-alpha) as well as the timely start of physics data acquisition (COMET Phase-I).
STATUS OF THE MUON G-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34)
(by Tsutomu MIBE)
The E34 collaboration aims for precision measurements of the muon anomalous magnetic moment and electric dipole moment. The collaboration held a meeting from June 8 to 10 in a hybrid format in J-PARC and at remote connections to share the progress.
The initial stage of commissioning of the surface muon beam at the H-line confirmed the beam intensity and profile at the H1 area. An extension of the H-line is in preparation. The collaboration continues the demonstration of thermal muon production by using the 1S-2S excitation of muonium at the S2 area. The vacuum chamber equipped with electrodes for the initial acceleration and transport of muons, the IH-DTL acceleration cavity for the low-energy part of the RF accelerator were fabricated. Development of magnetic field monitors, injection system, positron detector is in progress.
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4. [Materials and Life Science Division] by Toshiya OTOMO
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USERS FROM ABROAD HAVE COME BACK
For the first time in two years, users from abroad have come back to MLF. The guideline of the government to welcome foreigners still requires additional procedures of PCR test just before travelling, registration from receiving institutes and VISA application from all directions. J-PARC users are requested to start such procedure early enough to be in time for the scheduled experiments.
BEAM POWER WAS RAISED TO OVER 800 kW
1) Neutron Source
The beam operation of MLF is going on very well with the daily availability of 93.5 % on average since April 1st, as of June 1st in 2022. The beam power was raised from 730 kW to 830 kW on April 7th, which is the highest power ever attained for long term user operation of MLF. Due to the mode change of MR operation from slow extraction to fast extraction, the power delivered to MLF was reduced to 770kW from June 4th. After the end of the user program on June 24th, a 1MW beam operation is planned to be tested for two days until June 26th.
As a maintenance work of the off-gas process system which removes radioactive materials from the cover gas of the mercury circulation system, its molecular sieve was replaced by a new one on June 2nd with the special attention to radiation safety. The maintenance works during the long outage will begin at the end of June.
PROPOSALS FOR 2022B ROUND WERE RECEIVED
2) Neutron Instruments and Science
The MLF 2022B call for general use proposals (short-term and one-year) was closed on May 11th; we have 291 neutron proposals including 1 one-year proposal and 3 new user promotion proposals. All the proposals are now under the review process, with results notified by early September 2022. The experimental periods are from November 2022 to March 2023 for short-term proposal (tentative) and from November 2022 to July 2023 for one-year proposal (tentative) respectively.
(https://mlfinfo.jp/en/user/proposals/2022B/)
Meanwhile, we received 5 proposals for the 2022L long-term proposals (The validity period is up to 3 years (or 6 proposal rounds)), and the review process for these proposals is now also underway. A yearly period of the 2022L long-term proposals starts in the 2022B term.
(https://mlfinfo.jp/en/user/proposals/2022L/LTP_application_guidelines.html)
The recent five press releases at MLF neutron science were as follows,
1)"Revisiting the concept of peptide bond planarity in an iron-sulfur protein by neutron structure analysis"
https://doi.org/10.1126/sciadv.abn2276
2)"Flexible and Tough Superelastic Co-Cr Alloys for Biomedical Applications"
https://doi.org/10.1002/adma.202202305
3)"Hyperfine Splitting and Nuclear Spin Polarization in NdPd5Al2 and Nd3Pd20Ge6"
https://doi.org/10.7566/JPSJ.91.054710
4)"Cross-scale analysis of temperature compensation in the cyanobacterial circadian clock system"
https://doi.org/10.1038/s42005-022-00852-z
5)"Determination of site occupancy of boron in 6H-SiC by multiple-wavelength neutron holography"
https://doi.org/10.1063/5.0080895
A NEW ROTATING MUON PRODUCTION TARGET WAS DEVELOPED
3) Muon Science Facility (MUSE)
A new management structure for the facility was launched in April. Under the management of N. Kawamura as Section Leader and A. Koda as Section Sub Leader, some of the instrument managers were changed which has been announced on the facility home page.
The user experiments were conducted smoothly except for the S line (detail is described below).
The rotating muon production target was developed in a collaboration with Paul Scherrer Institute (PSI) in Switzerland, which had developed the rotating target since the 1970s. In PSI, after replacing the bearings with new ones developed in J-PARC, one year of stable operation was achieved the last December, which is the best following a long period of several bearing failures. To commemorate it, PSI, KEK, and J-PARC jointly issued a press release titled "Graphite Disk Keeps Rotation to Produce Muons - The Challenge under International Collaboration between Japan and Switzerland". (https://j-parc.jp/c/en/press-release/2022/06/09000967.html )
In the S line, a malfunction of the beamline gate valve located at the most upstream was found on 30/March: it could not close completely. The S-line operation was stopped until the completion of the replacement work and resumed just after the national holidays in the first week of May. So far, the users' experiments allocated in April had to be canceled regretfully although the repair work was done as quickly as possible. The reason for the failure was that the Kapton (a polyimide film invented by the DuPont Corporation) foil located beside the gate valve had been broken and its debris were caught in it. The measure to prevent recurrence will be taken in this summer shutdown.
In the H line, the on-beam commissioning performed since the first beam delivery in January was completed successfully, and the S-type experiment (DeeMe; an approved proposal of doing muon-electron conversion experiment at J-PARC MLF. http://deeme.phys.sci.osaka-u.ac.jp) which is the first user's experiment in the H line will start at the beginning of June.
In this proposal round, MUSE received 57 muon proposals for the 2022B periods, and the review process for these proposals is now underway.
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5. [Nuclear Transmutation Division] by Jun TAMURA and Yasuhiro KONDO
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CURRENT STATUS OF THE SPOKE CAVITY PROTOTYPING FOR
THE ADS LINAC
Japan Atomic Energy Agency has been proposing an accelerator-driven system (ADS) to reduce the high-level radioactive waste generated in nuclear power plants. One of the challenging R&D aspects of ADS is the reliability of the accelerator.
A superconducting cavity is essential to realize the ADS linac, which can operate in continuous wave (CW) mode with a reasonably low trip rate. The low-beta section of the linac, which previously adopted a normal conducting structure, was redesigned to reflect recent progress in the development of low-beta superconducting cavities.
In preparation for the full-scale design of the CW proton linac for the ADS, we are now prototyping a low-beta (around 0.2) spoke cavity. To ensure the feasibility of the ADS linac, prototyping and performance testing of the cavity is imperative. The prototype spoke cavity has two accelerating gaps with a single spoke electrode. The cavity dimensions are approximately 300 mm and 500 mm in length and diameter, respectively, excluding beam and RF ports. In the fiscal year 2021, we started welding press-formed niobium cavity parts together. At present, we have fabricated the cavity's body part.
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6. [Safety Division] by Yoshihiro NAKANE and Kotaro BESSHO
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J-PARC SAFETY DAY 2022
The J-PARC Center has held "the J-PARC Safety Day" annually around May 23 which was the day a radioactive material leak incident occurred in 2013. The Safety Day in FY2022 was held on May 23 online. The special lecture titled "Improvement of ability to implement safety on site through compliance of manuals: Safety Ergonomics Approach" was presented by Prof. Komatsubara, Waseda University. As a new attempt this year, safety initiatives at four facilities (Accelerator Facility, Materials and Life Science Experimental Facility, Hadron Experimental Facility, and Neutrino Experimental Facility) were introduced and discussed.
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7. [Information] by Chiaki SHIRAISHI
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NEW VIDEO ABOUT BRIEF OVERVIEW OF J-PARC HAS BEEN RELEASED.
A new video about an overview of J-PARC in English has been released on YouTube. This video was made for international people unfamiliar with us in order to let them briefly know J-PARC and be interested in us. We are grateful if you take a look and introduce our video to your close people.
https://youtu.be/Ra1l5BwPczg
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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:
Toshifumi TSUKAMOTO (Chair): toshifumi.tsukamoto at kek.jp
Kaoru SHIBATA: shibata.kaoru@ jaea.go.jp
Takatoshi MORISHITA: morishita.takatoshi 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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