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J-PARC Project Newsletter
No.72, October 2018
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]
POWER TO THE USERS, PRESENT AND FUTURE.
2. [Accelerator Division]
BEAM OPERATION RESUMPTION AFTER SUMMER SHUTDOWN.
3. [Particle and Nuclear Physics Division]
UPGRADES OF HADRON EXPERIMENTAL FACILITY IN THIS SUMMER.
NEUTRINO BEAMLINE UPGRADE TO MW POWER.
STATUS OF THE MUON G-2/ ELECTRIC DIPOLE MOMENT.
STATUS OF THE COHERENT MUON TO ELECTRON TRANSITION (COMET).
PROGRAM ADVISORY COMMITTEE MEETING.
4. [Materials and Life Science Division]
VARIOUS MAINTENANCE IS IN PROGRESS AS SCHEDULED.
PROPOSALS FOR 2018B PERIOD WERE REVIEWED.
ANNUAL MEETING OF INDUSTRIAL APPLICATION AT J-PARC MLF WAS HELD.
THE THIRD WORKSHOP OF CONCEPT OF NEUTRON SOURCES (CoNS-III) WAS
HELD.
MUON SPIN ROTATION USING NEGATIVE MUONS IS READY TO GO.
5. [Nuclear Transmutation Division]
EXCHANGE THE TARGET WITHOUT MANUAL OPERATION.
6. [Safety Division]
FY2018 MEETING OF THE LIAISON COMMITTEE ON SAFETY AND HEALTH FOR
CONTRACTORS WORKING AT J-PARC.
THE CHANGES OF THE RADIOLOGICAL LICENSE WAS GRANTED AND THE "RAM"
FACILITY STARTED.
THE EMERGENCY DRILL ASSUMING A FIRE IN THE ACCELERATOR TUNNEL WAS
HELD.
7. [Editorial Note]
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1. [Overview] by Naohito SAITO
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POWER TO THE USERS, PRESENT AND FUTURE
(This issue was delayed due to several activities in the last few
months. )
The beam operation has been successfully resumed after the
summer maintenance, and the user program at the Material and Life
science experimental Facility (MLF) has been successfully executed
at over 500 kW stably. The Main Ring (MR) is still in the maintenance
time taking the advantage of continuing upgrading work at both Hadron
Experimental Facility (HEF) and Neutrino Experimental Facility (NEF)
and Super-Kamiokande (SK).
I would like to report three major areas of progress: actions
for more firm collaboration with users, targetry activities,
and near future projects of J-PARC.
On November 13, we had a great honor to have His Excellency Mr.
Magnus Robach, the Ambassador of Sweden visiting J-PARC on the
occasion of the 3rd ESS-J-PARC Workshop held at the J-PARC Main
Research Building. His Excellency visited the MLF and Neutrino
Facility and discussed with the researchers, then encouraged us for
even deeper collaboration between Sweden and Japan.
We have also been strengthening the tie with universities. Nagoya
University has opened its branch at J-PARC on October 26. The Vice
President, Prof. Takahashi visited us to sign the agreement to
launch the branch office, and visited MLF, and the NEF, and the brand
new branch office. It is the 4th university branch at J-PARC, and we
are looking forward to even deeper collaborations with researchers
from universities.
The target vessel for neutron production at MLF has been renewed
to #9. The structure of the target vessel is identical to #8. The
beam exposure onto the target started from 300 kW then moved to 500
kW after careful confirmation of the target performance to be as
expected. We keep accumulating various data to develop a more robust
roadmap for future target vessels. A series of J-PARC-wide meetings
are planned to discuss the future of the targetry gathering various
experts. We should be able to report the outcome of the meetings in
upcoming newsletters.
Looking at the future, we are hearing that Japan Science Council
(JSC) is going to call for the proposal of large-scale research
program to renew its Master Plan (Master Plan 2020). We have several
proposals to enhance the J-PARC capability by upgrading accelerators
as well as experimental facilities: beam power upgrades, extension of
hadron hall, the 2nd target station at MLF, and Accelerator Driven
System for nuclear transmutation, and more. We are going to organize
J-PARC-wide discussion of the proposals to be ready for the
submission to JSC. The progress will be reported in a future
newsletter.
We hope to develop J-PARC science further by steady progress of
the facilities as well as active science discussions with users from
around the globe.
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2. [Accelerator Division] by Kazuo HASEGAWA
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BEAM OPERATION RESUMPTION AFTER SUMMER SHUTDOWN
Beam operation was suspended for maintenance during the summer
shutdown from July to September. Maintenance of the components and
some improvement work were conducted in the accelerator facilities.
The linac has been operated stably in these several months with
improvement work such as stabilizing cooling water flow rates, high
voltage power supply system for klystrons, etc. Although the trip rate
at the radio frequency quadrupole linac (RFQ) is high (about 10-20
per day), the recovery time is short and it doesn’t degrade the
availability totally. To mitigate the number of trips, we installed
three vacuum manifolds on the RFQ to consolidate the vacuum speed.
We had a vacuum leak issue at one of the collimators at the 3
GeV Rapid Cycling Synchrotron (RCS) in April 2016. We had operated
with another collimator that does not have movable function as a
temporary measure. We installed a new collimator with movable
function this summer and prepare for higher power operation.
At the Main Ring synchrotron (MR), upgrade work of the main magnet
power supply was conducted to prepare for a high-power test.
The J-PARC accelerator facilities resumed beam operation from
the linac on October 7 as scheduled. After beam tuning and study of
the accelerators, the user operation in the new period is expected to
start at the middle of October for the Materials and Life science
experimental Facility (MLF). The beam operation of the MR is
suspended from October to December period due to upgrade work at the
Kamioka site and the hadron experimental facility.
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3. [Particle and Nuclear Physics Division] by T. NOMURA, K. OZAWA,
T. ISHIDA, T. KOBAYASHI, T. MIBE, S. MIHARA, and T. KOMATSUBARA
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UPGRADES OF HADRON EXPERIMENTAL FACILITY IN THIS SUMMER
(by T. NOMURA and K. OZAWA)
Upgrades of the KOTO experiment and a lot of construction work
for a new beam line were performed in this summer.
The detector of KOTO experiment is upgraded. The main project is
a calorimeter upgrade. The KOTO calorimeter consists of 2,716 undoped
CsI crystals. Each of these is equipped with a photomultiplier on its
downstream end. The calorimeter must have a good photon-to-neutron
separation in order to reduce backgrounds from neutron interactions
as well as energy and position measurements of photons from KL
decays. A new idea for this purpose is a both end readout of each
crystal; the time difference between upstream and downstream signals
provides depth information of shower development and thus improves
separation.
Multi-Pixel Photon Counter (MPPC) is adopted as an upstream photo-
detection device. The MPPC installation is being done. The whole work
will conclude by January 2019 and the KOTO experiment will be ready
for beam by the end of February.
A new beamline to provide primary 30 GeV protons is under
construction in the transport tunnel (Switch Yard) and the south area
of the Hadron Experimental Facility. In this summer, septum magnets
at a branching point were placed in the Switch Yard. In the Hadron
Experimental Facility, the construction of an experimental area for
the new beam line is in progress. A radiation shield door was set up,
and the construction of the entrance part was completed.
NEUTRINO BEAMLINE UPGRADE TO MW POWER (by T. ISHIDA and
T. KOBAYASHI)
In 2018 Neutrino Conference, T2K made a remarkable report that
the CP symmetry might be broken in the lepton sector, through the
measurement of appearances of electron neutrino and antineutrino.
https://zenodo.org/record/1286752#.W7CQcPaYRPY
T2K collaboration is proposing to extend the data-taking period
aiming at reaching more than three sigma sensitivity for maximum CP
violation with the beam power upgrade to 1.3MW and near detector
upgrade. The beam power upgrade is also essential for future Hyper-
Kamiokande experiment. A critical review of the beamline upgrade has
been organized in the end of June by the committee members invited
from world-wide high intensity proton accelerator and facility
communities. Intensive discussion had taken place on the
presentations relevant to the key components such as target, beam
window, horns, beam monitors, DAQ (data acquisition), and radioactive
waste treatment. The report can be found here:
https://kds.kek.jp/indico/event/27832/.
STATUS OF THE MUON G-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34)
(by T. MIBE)
The E34 collaboration prepares for precision measurements of the
muon anomalous magnetic moment and electric dipole moment. The
technical design of the experiment was reviewed by Program Advisory
Committee (PAC), and readiness for the stage-2 was discussed.
Construction of the surface muon beamline (H-line) is in progress.
The collaboration prepares for measurements of longitudinal
distribution of accelerated beam accelerating muon to 1 MeV with a
IH-DTL test cavity, spin rotator, demonstration of spiral beam
injection to the storage ring, and construction of the positron-
tracking detector. An international school on muon dipole moment and
hadronic effects was organized at the Budker Institute of Nuclear
Physics (BINP) (Russia) in September 17-21, 2018 to encourage young
scientists who start working in this field around the world.
STATUS OF THE COHERENT MUON TO ELECTRON TRANSITION (COMET)
(by S. MIHARA)
The COMET experiment aims to search for the lepton-flavor
violating muon reaction, mu-e conversion, with sensitivity better
than 10^{-14} in Phase I.
Construction of the COMET facility is in progress; proton beamline
elements are installed and coil winding for the pion capture solenoid
is in progress. Assembly of coils and installation to the cryostat
will follow this process to complete the construction.
The collaboration is working intensively on summarizing experiment
details in the Technical Design Report (TDR). Concise version of the
report will be published in this year.
PROGRAM ADVISORY COMMITTEE MEETING (by T. KOMATSUBARA)
The 26th Program Advisory Committee (PAC) meeting was held at
Tokai on July 18-20. The committee membership was renewed from April;
Rik Yoshida (Jefferson Lab) was assigned as the new chairperson.
Status of the experiments was reported, and proposals and near-term
machine time allocation were discussed.
https://kds.kek.jp/indico/event/28286/
PAC report is 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 on January 16-18, 2019.
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4. [Materials and Life Science Division] by Toshiji KANAYA
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VARIOUS MAINTENANCE IS IN PROGRESS AS SCHEDULED
1) Neutron Source
Various maintenance and overhauls planned for the summer shut-
down period are in progress as scheduled. The highlight is the target
vessel replacement from #8 to #9. Prior to the replacement, a part of
the beam window portion with 3-mm thickness was cut out with a
remote-handling cutting device as a specimen to investigate the
damage of that part. It was observed that an inner surface of the
specimen facing with a high-speed mercury flow was eroded but not
severely damaged. Further detailed inspection of damages on the
specimen will be carried out in October. For the target vessel #8,
the accumulated beam power on target was 1,812 MWh at average power
of 434 kW. The measurements of the inspection such as depth of the
damage will be very useful for us to make further plan for power
upgrade. New target vessel #9 has the same structure as the target #8
and will be in operation from October 20.
PROPOSALS FOR 2018B PERIOD WERE REVIEWED
ANNUAL MEETING OF INDUSTRIAL APPLICATION AT J-PARC MLF WAS HELD
THE THIRD WORKSHOP OF CONCEPT OF NEUTRON SOURCES (CoNS-III) WAS HELD
2) Neutron Instruments and Science
The general/ new user promotion proposals for the 2018B period
and long-term proposals were reviewed by the Neutron Science Proposal
Review Committee on August 23. The total number of submitted neutron
proposals was 302 (the general proposals: 285, the new users
proposals: eight, long-term proposals: nine). Finally, 198 general
proposals, eight new user promotion proposals and five long-term
proposals were approved by the MLF Advisory Board on September 3. The
total competition rate (the number of submitted/ approved proposals)
for the general proposals become as high as 1.4 times gradually
improving from the past crowded situation. From the 2018B period, we
started to accept proposals from graduate students. In this round, 22
proposals were submitted, and 17 of them were approved. Annual
meeting of industrial application at J-PARC MLF was held on July 23
and 24 at Akihabara Convention Hall. Total number in attendance has
grown up to 303. The 10th anniversary celebration after the
foundation of Industrial Users Society for Neutron Application and
Report Session of Ibaraki prefecture beamlines were held on the first
day. On the second day, according to the theme -Collaborative
Creation of Innovation-, several examples of collaborative research
between industry and the instrument group were reported as well as
poster session and consultation of neutron beam usage for industrial
purpose.
A J-PARC workshop, the 3rd workshop of Concept of Neutron
Sources (CoNS-III), was held on concepts of new neutron sources not
limiting spallation sources with proton on August 21 at the KEK Tokai
Building No.1. Participants were 25 including three from abroad.
MUON SPIN ROTATION USING NEGATIVE MUONS IS READY TO GO
3) Muon Science Facility (MUSE)
Positive muons have a great advantage over negative muons for
probing magnetic field in matter, as the spin polarization for the
former remains much higher than for the latter. However, it has been
demonstrated recently that negative muons could be useful for
studying hydrogen diffusion in magnesium hydride. The rotational
motion of spins monitored by muon decay into positrons/electrons
tells the magnitude and distribution/fluctuation of internal fields
that carry information on nearby atoms exerting fields to muons. In
magnesium hydride, while the diffusion of hydrogen ions within the
material should cause such fluctuation, the possibility for positive
muons to exhibit diffusional motion via interstitial sites (that also
leads to the fluctuation of internal field) makes it difficult to
discern the cause of fluctuation. With negative muons that are deeply
bound to magnesium nuclei as heavy electrons, researchers succeeded
in observing the field fluctuations that can be uniquely attributed
to hydrogen diffusion. The result also proves that the disadvantage
of low spin polarization for negative muons can be overcome by their
unprecedented high flux recently achieved at the D-line of J-PARC
MUSE.
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5. [Nuclear Transmutation Division] by Toshinobu SASA
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EXCHANGE THE TARGET WITHOUT MANUAL OPERATION
Spallation target for ADS technology developments requires heavy
irradiation to prepare irradiation database. It means that targets
are also heavily irradiated and should be replaced according to the
injected proton beam strength. In present designed irradiation
performance, we plan to replace target annually during long
maintenance period in summer. Even the lead-bismuth eutectic alloy,
LBE, is dumped into a drain tank, remaining target vessel should be
changed by full remote operations like existing mercury target in
J-PARC.
The mercury target head in J-PARC has a special flange to
connect the mercury loop mounted on the trolley. At first, we tried
to use same method for our LBE target system. However, the operation
temperature is extremely higher than that of mercury target. The
special flange cannot be used because of temperature problems such as
thermal expansion and/or thermal stress of a flange body and gaskets,
and seizing of bolts/nuts. Finally, we decided to connect the target
head and a target LBE loop by weld of piping under full remote
operation condition.
The method using automatic welding system, pipe cutters to
minimize machining dusts, and master-slave manipulators, MSM, were
almost established. Besides, we build up the mockup of target
exchange procedure with two units of MSM along this method.
Functional tests of remote target exchange technique, the world’s
first trial, will be performed. The development of remote welding
inspection method will be continued.
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6. [Safety Division] by Yukihiro MIYAMOTO and Kotaro BESSHO
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FY2018 MEETING OF THE LIAISON COMMITTEE ON SAFETY AND HEALTH FOR
CONTRACTORS WORKING AT J-PARC
Aiming to share safety-consciousness and ensure safety with the
contractors, the J-PARC Center has been holding a liaison meeting on
safety and health for contractors annually. This year's committee
meeting was held on June 29 and had 70 participants from 68 companies
and 15 participants from J-PARC. Tetsuro Ishii, Deputy Director
(Safety), introduced recent topics in J-PARC, good safety-activities,
and troubles in J-PARC and JAEA.
THE CHANGES OF THE RADIOLOGICAL LICENSE WAS GRANTED AND THE "RAM"
FACILITY STARTED
The application for minor changes of the radiological license
was granted by the Nuclear Regulation Authority on Aug. 22. The
approved changes in the application were a modification of the
shielding configuration for the proton beam line in the Materials and
Life Science Experimental Facility and a slight increase of the beam
intensity for the Hadron Experimental Facility due to a change of the
repetition time for slow extraction.
The facility of the Radio-Activated Materials, abbreviated as
"RAM", began operation officially as a radiation-controlled area on
Aug. 29.
THE EMERGENCY DRILL ASSUMING A FIRE IN THE ACCELERATOR TUNNEL WAS
HELD
The emergency drill assuming a fire in the accelerator tunnel of
LINAC was held on Sep. 6. Secure evacuation of workers from the
tunnel area and procedure for fire extinguishing by suffocation were
the most important points in this training, and these actions were
executed successfully. In gathering information and communication, a
number of improvement points were found for further strengthening the
ability to respond in emergency situations.
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7. [Editorial Note]
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Editorial Board:
Toshifumi TSUKAMOTO (Chair): toshifumi.tsukamoto@kek.jp
Kaoru SHIBATA: shibata.kaoru@ jaea.go.jp
Takashi ITO: itou.takashi@jaea.go.jp
Dick MISCHKE (English Editor): mischke@triumf.ca
Junko BEANBLOSSOM (Secretary): beanblossom.junko@jaea.go.jp
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