[Neutron] J-PARC Newsletter No. 84
shibata.kaoru
shibata.kaoru at jaea.go.jp
Mon Oct 25 07:15:56 CEST 2021
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J-PARC Project Newsletter
No.84, October 2021 Japan Proton Accelerator Research Complex under operation jointly 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]
“SUWA PRIZE” AWARDED TO THE ACCELERATOR DIVISION FOR THEIR ACHIEVEMENT ON 1 MW BEAM ACCELERATION AT 3 GeV RCS.
SPECIAL EXHIBITION AT THE NATIONAL MUSEUM OF NATURE AND SCIENCE SUCCESSFULLY CLOSED WITH 78272 VISITORS.
FIRST J-PARC USERS COUNCIL MEETING UNDER THE NEW MANAGEMENT HELD ON JULY 13th.
2. [Accelerator Division]
OPERATION STATUS OF THE ACCELERATORS.
3. [Particle and Nuclear Physics Division]
PROGRAM ADVISORY COMMITTEE MEETING.
HADRON HALL EXTENSION PLAN.
ON GOING UPGRADE WORK TOWARDS HIGHER BEAM POWER AND PRECISE NEUTRINO MEASUREMENT.
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]
BEAM OPERATION ENDED SUCCESSFULLY AND MAINTENANCE WORKS ARE GOING ON.
PROPOSALS FOR 2021B ROUND WERE REVIEWED.
CONSTRUCTION AND MAINTENANCE WORKS IN PROGRESS.
5. [Nuclear Transmutation Division]
IMPURITY EVAPORATION BEHAVIOR OF ALKALI ELEMENTS FROM LEAD-BISMUTH EUTECTIC.
6. [Safety Division]
8TH SYMPOSIUM ON SAFETY IN ACCELERATOR FACILITIES.
7. [Editorial Note]
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1. [Overview] by Takashi KOBAYASHI
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“SUWA PRIZE” AWARDED TO THE ACCELERATOR DIVISION FOR THEIR ACHIEVEMENT ON 1 MW BEAM ACCELERATION AT 3 GeV RCS
With pleasure we would like to report that the J-PARC accelerator division was awarded the honorable “Suwa Prize” in memory of Dr. Shigeki Suwa, the first director of KEK, for their achievement on 1 MW beam acceleration at 3 GeV RCS. All the scientific outcomes from J-PARC are relying on the continuous efforts by the accelerator team on improving the performance of the J-PARC accelerator complex. We, together with users, congratulate and thank the accelerator team.
https://j-parc.jp/c/topics/2021/06/04000699.html (only in Japanese) http*//www.heas.jp/award/jusyo.html (only in Japanese)
SPECIAL EXHIBITION AT THE NATIONAL MUSEUM OF NATURE AND SCIENCE SUCCESSFULLY CLOSED WITH 78272 VISITORS
A Special Exhibition on Accelerator, at the National Museum of Nature and Science in Ueno, Tokyo, was held during July 13 to Oct 3rd and 78,272 visitors visited it. J-PARC was deeply involved in the preparation; exhibitions from J-PARC include the mercury target vessel of MLF and the graphite target for Neutrino Facility. On July 24th, a special lecture by Prof. Hitoshi Murayama (UC Berkeley/Kavli IPMU) was given with COVID protection in place.
https://www.kahaku.go.jp/event/2021/07accelerator/ (only in Japanese)
FIRST J-PARC USERS COUNCIL MEETING UNDER THE NEW MANAGEMENT HELD ON JULY 13th
On July 13th, the J-PARC Users Council was held online. Committee members consist of representatives from relevant user communities of J-PARC. Prof. Toshio Yamaguchi (Fukuoka University) was elected mutually as the new chair of the council. This time, the council was asked to summarize the needs/requests from user communities, and will summarize the requests in a document to the J-PARC director.
https://kds.kek.jp/event/38692/ (only in Japanese)
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2. [Accelerator Division] by Michikazu KINSHO
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OPERATION STATUS OF THE ACCELERATORS
The beam operation for the MLF users was completed on July 15 as scheduled with high availability (~ 97%).
The beam operation as an operation run of Run#87, which started in May, has been continued until July 20th on schedule. The beam operation for the MLF users was completed on July 15 as scheduled with high availability (~ 97%). The beam power for the Materials and Life Science experimental facility (MLF) user program was reduced from 740 kW to 630 kW from June 24 due to insufficient cooling capacity of the cooling water system of the RCS in summer. After the user operation, beam studies were carried out for 5 days at the linac and at the RCS to reduce beam loss and further increase intensity. After the beam study, the summer maintenance work started at the linac and the RCS and is still in progress.
The linac had been operated stably in these several months. But one of the Separated-type Drift Tube Linac (SDTL) cavities had a symptom of increasing radio frequency reflection power in the vicinity of the designed operation power. The reason was a dirty surface of the cavity. So it was cleaned with dilute hydrochloric acid dipped cloths.
The 3 GeV Rapid Cycling Synchrotron (RCS) also had been operated stably before summer. However, beam power had to be reduced from 740 kW to 630 kW due to insufficient cooling capacity of the cooling water system for high power operation of the RCS in summer. It was found that this insufficient cooling capacity was due to the reduction of the heat exchange efficiency of the heat exchanger in the cooling water system. Since this reduction in heat exchange efficiency was due to contamination, we have been performed cleanup this heat exchanger.
The Main Ring (MR) has entered a long maintenance period for upgrade from July 1st until next autumn . The work has been progressing smoothly in preparation for the beam study operation in June next year.
The J-PARC accelerator facilities are scheduled to start beam tuning at the linac on November 15. After the tuning, beam studies of the accelerators (linac and RCS) are planned till the end of this year; the user operation of the MLF is expected to start in the middle of January next year.
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3. [Particle and Nuclear Physics Division] by Toshiyuki TAKAHASHI and Kyoichiro OZAWA
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PROGRAM ADVISORY COMMITTEE MEETING (by Takeshi KOMATSUBARA)
The 32nd Program Advisory Committee (PAC) meeting was held as a video conference on July 14-16. In the committee, chaired by Dr. Rik Yoshida (Argonne National Laboratory), status of the experiments were reported and prospects for the operation after the long shutdown of Main Ring were discussed.
This time seven new proposals, including the ones for the extended Hadron Experimental Facility, were submitted.
https://kds.kek.jp/indico/event/38719/
The PAC report will be available through the following web page.
http://j-parc.jp/researcher/Hadron/en/PAC_for_NuclPart_e.html
The next PAC meeting will be held in January 2022.
HADRON HALL EXTENSION PLAN (Toshiyuki TAKAHASHI, Tadashi NOMURA, Kyoichiro OZAWA)
Near future upgrade plans of the Hadron Experimental Facility are under discussion. The current plan contains a new production target and four new beamlines, such as new K1.1 beamline, High-Intensity-High-Resolution (HIHR) beamline, K10 beamline, and new KL beamline. Further studies in strangeness nuclear physics will be performed at the K1.1 and HIHR beamlines. Experimental information of hyper-nucleus and hyperon-nucleon interactions are crucial to understand the QCD equation of state for dense hadronic matter.
Experiments for spectroscopic studies of multi-strange baryons will be performed at the K10 beamline using a high-momentum K- beam. The experiments aim to have new experimental information for light (u, d, s) diquarks and their role in strange baryons.
The KOTO step-2 (KOTO-2) experiment will be carried out at the new KL beamline. The KOTO-2 aims to measure the branching ratio of KL -> pi0 nu nu-bar with ~30 % precision, assuming the Standard Model decay rate. This branching ratio is one of the most important measurements to explore the physics beyond the Standard Model.
Three new proposals, which are related with the upgrade plan, were submitted to the last PAC meeting and a dedicated review was held on August 10, 11, and 17, 2021. The review committee made several positive comments on the plan.
ON GOING UPGRADE WORK TOWARDS HIGHER BEAM POWER AND PRECISE NEUTRINO MEASUREMENT (by Yoshiaki FUJII)
The neutrino experimental facility and T2K experiment group are working very hard on improvement of apparatuses toward beam restart expected around the end of 2022.
The neutrino experimental facility is working on the beam-power upgrade project aiming at achieving 1.3MW by 2027, when HyperK is planned to start data taking, without disturbing T2K beam running. Not only the secondary beamline but also the primary beamline, which is basically beam-loss driven, needs careful optimization for the high-power beam. Especially at the most-downstream part of the primary beamline, it suffers intense radiation from the downstream target and becomes highly radio-active in the Hyper-K era. New maintenance scheme under such high radiation environment is being implemented during this maintenance period.
The ND280 upgrade projects are speeding up the construction toward their on-site work starting from early 2022. The Super-Fine-Grained Detector group started fabrication of the structural container of the two-million scintillator cubes, and is reviewing the final assembly work at J-PARC. The high-angle TPC group plans to start on-site gas system reconfiguration from early 2022. Procedures to travel to Japan under COVID situation is extensively being examined.
Dr. Sara Bolognesi (CEA/DAPNIA Saclay), one of the most active collaborator of T2K, has been awarded "The Summer 2021 Emmy Noether Distinction of the European Physical Society". As is described at https://www.eps.org/blogpost/751263/375831/, the Summer-2021-EPS-Emmy-Noether-Distinction was awarded to Sara Bolognesi for her work at CMS.
However it is also a pleasure for the T2K collaborators to salute a colleague's great honor.
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; along with beam line and experiment area construction the COMET detector construction team is intensively preparing detector components and related electronics. The main physics detector CDC is conditioned on the KEK campus by using cosmic rays. The CDC group is finalizing the cooling system for the readout electronics equipping the detector. A beam measuring detector composed of a straw-tube tracker and a LYSO calorimeter is constructed at J-PARC step by step. The 1st station of the straw-tube tracker is now ready for an initial test and calorimeter assembly work is starting.
There is another intensive activity in the data analysis of the 8 GeV acceleration test and beam extinction measurement carried out in May 2021. A preliminary analysis reports that a beam extinction factor better than 10^{-10} is achieved, which is sufficient to realize the COMET phase-I sensitivity. Further improvement is expected by carefully investigating the details of proton leakage mechanism in the accelerator as well as improving the measurement technique of the beam extinction factor. This result has already been reported in a summer conference and at the JPS meeting.
The COMET collaboration members started planning to visit J-PARC in JFY 2021 in order to make direct contributions to detector integration for the COMET engineering run Phase-alpha and physics data acquisition in Phase-I.
STATUS OF THE MUON G-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34) (by Tsutomu MIBE)
The E34 collaboration prepares for precision measurements of the muon anomalous magnetic moment and electric dipole moment.
The virtual workshop on the precise calculation of muon anomalous magnetic moment in the standard model was organized by KEK from June 28 to July 2nd. There were 283 participants from 27 countries to discuss improvements of the theory precision in the framework of the muon g-2 theory initiative which is a worldwide initiative formed since 2017.
The workshop was organized in memory of Prof. Simon Edelman who played a central role in this initiative and in the E34 collaboration.
KEK worked on the design of the experimental building as well as the relocation of the access road and buried facility infrastructure on the construction site. The collaboration assisted the construction and commissioning of new experimental area with surface muon, the S2 experimental area, where the demonstration of laser ionization of muonium is planned.
Development of ionization lasers are in progress at KEK Tsukuba campus. The design of the extension of the H-line for E34 installation is also in progress.
The area layout and radiation shields have been designed.
The collaboration continues to work on developments of the key experimental components.
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4. [Materials and Life Science Division] by Toshiya OTOMO
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BEAM OPERATION ENDED SUCCESSFULLY AND MAINTENANCE WORKS ARE GOING ON
1) Neutron Source
The beam operation of MLF continued stably with 600 kW, which was brought down from 700 kW on June 24th to secure the cooling capacity of the accelerator devices, and ended on July 17th. The daily availability since April 1st was 97.5 % on average.
On July 29th, the used mercury target vessel, which was in operation from 2014 to 2015, was transported from MLF to the storage building, which is called RAM building where a total of 4 used target vessels are stored now.
The cooling tower of the coolant water loop for the devices of 3GeV proton beam transport line (3NBT) was replaced as a countermeasure against aging deterioration. The cooling capacity was increased that will contribute to stable beam operation during the summer.
PROPOSALS FOR 2021B ROUND WERE REVIEWED
2) Neutron Instruments and Science
The neutron proposals for the period 2021B starting next January, were reviewed. The total number of submitted neutron general proposals was 338. Finally, 137 neutron general proposals were approved by the MLF Advisory Board on September 1st.
The Annual meeting of industrial application at J-PARC MLF was held as an online meeting on July 15th and 16th. This meeting can be a great communication channel between the industrial society and MLF for sharing information and to discuss for practical use of neutron technique in the industry. 352 participants including 150 from companies attended. Several talks on facility report, status on industrial use and its expectation, and advanced scientific case were presented.
Three recent scientific press releases at MLF were issued as follows:
(1)."Behavior of light elements in iron-silicate-water-sulfur system during early Earth’s evolution"
https://doi.org/10.1038/s41598-021-91801-3
(2)."Local Structure of Li+ in Superconcentrated Aqueous LiTFSA Solutions"
https://doi.org/10.1021/acs.jpcb.1c04693
(3)."Hydrogen storage by earth-abundant metals, synthesis and characterization of Al3FeH3.9"
https://doi.org/10.1016/j.matdes.2021.109953
CONSTRUCTION AND MAINTENANCE WORKS IN PROGRESS
3) Muon Science Facility (MUSE)
Although the COVID-19 pandemic continues to have a negative impact on muon experiments under Inter-University Research Program at MUSE, the scheduled proposals for the 2020B-2021A period were carried out relatively smoothly thanks to the efforts of the staff, and were successfully completed on July 15th, 2021.
The highlights of the experiment were the initial analysis of the samples returned by Hayabusa-2 , using a non-destructive elemental analysis method with negative muon capture characteristic X-rays, and the first successful muon beam transport to the S2 Area.
Following the shutdown of accelerator facility, construction works for the remaining part of H line has resumed in the MLF building, which will continue throughout the remaining of the year as the resumption of operation has been postponed till January, 2022. The installation works for infrastructures such as electricity and cooling water supplies to beamline magnets are in steady progress since last summer. The regular maintenance is also in progress for the rotating target and other beamline components in parallel with the construction works.
Meanwhile, MUSE received many proposals for the 2021B round nearly equal to the last call for 2020B-2021A round, making it highly competitive for users to get beamtime. In response to this situation, the Muon Science Proposal Review Committee has taken the temporary measure of limiting the number of proposals approved for one PI to one, so that as many users as possible can be given the opportunity to do experiment. Finally, for the 2021B round, the total number of submitted proposals was 73 for the muon general proposals, of which 32 were approved.
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5. [Nuclear Transmutation Division] by Hayanori TAKEI
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IMPURITY EVAPORATION BEHAVIOR OF ALKALI ELEMENTS FROM LEAD-BISMUTH EUTECTIC
Lead-Bismuth Eutectic (LBE) is a candidate material as a neutron generation target and a coolant in an Accelerator Driven System (ADS) proposed by Japan Atomic Energy Agency (JAEA). In the LBE of ADS, many radioactive materials are produced as spallation products (SPs) via spallation reactions between a proton beam and the LBE, which leads to highly radioactive LBE. It is crucial to evaluate the release and transport behavior of the SPs from the LBE coolant to the cover gas from the viewpoints of the radiological hazard both in the cases of normal operation and accident.
In order to understand the evaporation behavior of Cs and Rb, which are produced in large amounts among alkaline metal elements from the LBE, the chemical species and vapor pressures were measured using a Knudsen effusion mass spectrometer (KEMS). As a result, Cs and Rb were found to be easily evaporated from LBE. This experimental result was announced at the 2021 Fall Meeting of the Atomic Energy Society of Japan on September 8th.
The results of this study were obtained through a contract research to the University of Fukui.
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6. [Safety Division] by Yoshihiro NAKANE and Kotaro BESSHO
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8TH SYMPOSIUM ON SAFETY IN ACCELERATOR FACILITIES
The 8th Symposium on Safety in Accelerator Facilities was held on August 27th by online meeting, and 121 participants exchanged information on safety issues at accelerator facilities.
Six presentations from accelerator facilities were made on recent situation of each facility and safety activities under the novel coronavirus pandemic. Circumstances and difficulties concerning application for a license of the accelerator operation at each facility were also shared.
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7. [Editorial Note]
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Past issues are available from the below link.
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
Keiko NEMOTO (Secretary): nemoto.keiko at jaea.go.jp
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