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J-PARC Project Newsletter
No.54, April 2014
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]
400 MeV LINAC ENERGY UPGRADE WAS SUCCESSFULLY ACHIEVED.
USER OPERATION FOR MLF HAS STARTED.
2. [Accelerator Division]
THE DESIGNED 400 MEV BEAM WAS ACHIEVED IN THE LINAC ON JANUARY 17,
2014.
THE BEAM DELIVERY FROM RCS IS STARTED FOR THE MLF USERS ON FEBRUARY
17, 2014.
BEAM STUDY OF THE MAIN RING SYNCHROTRON (MR) WAS RESUMED AT THE END OF
MARCH 2014.
3. [Particle and Nuclear Physics Division]
INTERNATIONAL REVIEWS FOR IMPROVEMENTS OF HADRON EXPERIMENTAL
FACILITY.
RECENT RESULTS OF SEARCHING FOR NEUTRON RICH HYPERNUCLEI.
T2K STATUS: RELEASE OF THE RESULT WITH ALL DATA ACCUMULATED SO FAR AND
MAINTENANCE WORK FOR NEUTRINO BEAM OPERATION FROM MAY.
CONSTRUCTION OF SUPER-CONDUCTING MAGNET SYSTEM FOR THE MU-E CONVERSION
SEARCH EXPERIMENT HAS STARTED.
PREPARATION OF A PRECISE MEASUREMENT OF MUON MAGNETIC AND ELECTRIC
DIPOLE MOMENTS IS IN PROGRESS.
FIFC: FACILITIES IMPACT AND FUNDING COMMITTEE.
4. [Materials and Life Science Division]
STEADY NEUTRON PRODUCTION WITH 300 KW PROTON BEAM WAS RESUMED WITH
IMPROVING THE PRESSURE WAVE MITIGATION IN MERCURY TARGET SINCE
FEBRUARY 2014.
CONSTRUCTION OF THREE NEW INSTRUMENTS WAS STARTED.
GENERAL NEUTRON PROPOSALS FOR 17 INSTRUMENTS WERE SUBMITTED FOR 2014A
PERIOD.
A NEW MUSR SPECTROMETER WAS INSTALLED AT THE D1 AREA.
5. [Nuclear Transmutation Section]
PROMOTE TRANSMUTATION STUDY AS AN OPTION OF NUCLEAR WASTE MANAGEMENT.
6. [Safety Division]
THE 18TH RADIATION SAFETY COMMITTEE OF J-PARC MET IN JANUARY.
THE SAFETY INSPECTION OF NEW MUON BEAMLINE IN THE MATERIALS AND LIFE
SCIENCE EXPERIMENTAL FACILITY (MLF).
7. [Editorial Note]
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1. [Overview] by Yujiro IKEDA
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400 MeV LINAC ENERGY UPGRADE WAS SUCCESSFULLY ACHIEVED
USER OPERATION FOR MLF HAS STARTED
1) The year of 2014 has started with an exciting achievement that
the LINAC energy upgrade to 400 MeV was successfully demonstrated by
the accelerator team on January 17. It should be an important step
forward to the 1MW power goal of J-PARC.
2) Along a schedule for recovery of the Hadron Experimental
Facility, restructuring of the beam-line structure, shielding block
realignment, installation of a new air-conditioning system, extension
of a building for the radiation control, etc., have been conducted and
there is steady progress in all work in the experimental hall.
3) Resuming the user beam operation to MLF with 300 kW power on
February 17 was encouraging news and after a 9-months long effort on
preventive measures to the Hadron accident last year. This
accomplishment by J-PARC team is also worthy of praise.
4) International Advisory Committee (IAC) meeting was held on
10th and 11th March, 2014. Most importantly, facility safety aspect
was highlighted along with J-PARC progress in the restart of user
operation. Accelerator Technical Advisory Committee (ATAC), Neutron
Advisory Committee (NAC) and Muon Advisory Committee (MAC) meetings
were also held independently, but associated with IAC. Committees gave
us invaluable and critical comments in terms of being a real user
facility.
5) 2014 Budget scheme was announced that operation of 8 cycles
for RCS is to be assured, but it revealed severe cut for MR operation.
All efforts are to be put on a possible recovery of operation cycle of
MR.
6) Two proposals of large scale facility associated with J-PARC
were selected in review of the Japanese Science Council as top 27
important project to be pursued.
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2. [Accelerator Division] by Tadashi KOSEKI
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THE DESIGNED 400 MEV BEAM WAS ACHIEVED IN THE LINAC ON JANUARY 17,
2014
THE BEAM DELIVERY FROM RCS IS STARTED FOR THE MLF USERS ON FEBRUARY
17, 2014
The beam commissioning of the linac with a newly installed
accelerating structure system, Annular-ring Coupled Structure linac
(ACS), was started on December 16, 2013. The designed beam energy of
400 MeV was achieved on January 17, 2014.
The beam commissioning of the Rapid Cycling Synchrotron (RCS) was
started on January 30, 2014 and the 400 MeV injection beam was
accelerated to 3 GeV on February 5, 2014. For the beam injection at
400 MeV, power supplies of horizontal shift-bump magnets were replaced
with new ones in the 2013 shutdown period. The new power supply has 16
power supplies in parallel and is designed to reduce the current
ripple, which induced dipole oscillation of the circulating beam and
caused beam losses. At the present time, the new power supplies have a
problem of current droop on the flat top. This effect is temporarily
compensated by the other injection magnets, two pulse steering magnets
in the beam transport line just upstream of the injection straight
section, and four paint bump magnets in the injection straight section
of the RCS. In the accelerator study, the RCS has demonstrated the
high beam intensity of 560 kW, the same level of the maximum
intensity before the energy upgrade of the linac. The beam losses are
drastically improved by the reduced current ripple in the new shift
bump magnet power supplies. The remaining beam losses are only due to
the foil scattering in the charge exchange beam injection. This high
power demonstration with low beam losses is an important milestone for
1 MW beam operation in the near future.
The user operation of the Materials and Life Science Experimental
Facility (MLF) was resumed on February 17, 2014 with the beam
intensity of 300 kW after the nine months beam shutdown since May 24,
2013. The user operation will be continued till the end of June 2014
before the summer shutdown.
For the upgrade of the linac peak current, a new front-end
system, which is composed of a cesium-seeded rf-driven negative-
hydrogen ion source and a new Radio Frequency Quadrupole linac (RFQ)
for the peak current of 50 mA, is now being tested in an RFQ test
stand. On February 6, 2014, the first 50-mA H- beam was successfully
accelerated by the RFQ. After a test of long-term stability through
continuous beam operation, the new front-end system will be installed
in the linac tunnel in the 2014 summer shutdown period.
BEAM STUDY OF THE MAIN RING SYNCHROTRON (MR) WAS RESUMED AT THE END
OF MARCH 2014
Beam study of the MR was restarted on March 24, 2014. The
injection beam from the RCS was accelerated to 30 GeV and extracted by
the fast extraction system to the abort beam dump on March 30 for the
first time after the accident in the hadron hall. To improve the
optics correction in the beam transport line between the RCS and the
MR (3-50 BT), one multi-ribbon profile monitor (MRPM), three beam
position monitors (BPMs) and three steering magnets have been
additionally installed in the collimator section of the 3-50BT in the
2013 shutdown. The dispersion free optics in the collimator section of
the 3-50BT has been successfully obtained. This optics correction is
necessary to control the balance of the beam losses in the two
collimator systems, the 3-50 BT collimators and the MR collimators,
for the high power operation in the near future.
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3. [Particle and Nuclear Physics Division] by K. OZAWA, T. TSUKAMOTO,
S. MIHARA, T. KOMATSUBARA
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INTERNATIONAL REVIEWS FOR IMPROVEMENTS OF HADRON EXPERIMENTAL
FACILITY
RECENT RESULTS OF SEARCHING FOR NEUTRON RICH HYPERNUCLEI
(by K. OZAWA)
Review committees for the J-PARC Hadron Facility were convened to
evaluate renovation and upgrade plans of the facility.
The first one was held on October 8 and 9 to review our renovation
plan of the target and related matters. The plan was intensively
discussed mainly from several viewpoints including the safety. The
committee agreed the plan is suitable for the renovation,and they also
provided a great deal of advice.
More details of the meeting are shown on the web page:
http://j-parc.jp/en/news/2013/J-PARC_News-e1310.html
A follow-up meeting was held on January 29 to report advances to
the committee.
On January 30, another review committee was held for the primary
beam line to be constructed at the Hadron facility. The design and
safety issues were discussed at the meeting. The committee approved
the design basically filled the requirements for considerations on the
safety.
Results of the J-PARC E10 experiment were published, entitled
"Search for 6(Lamda)H hypernucleus by the 6Li(pi-,K+) reactions at
p_pi = 1.2 GeV/c" (Phys. Lett. B729 (2014) 39). The experiment aimed
to search for neutron-rich Hyper6(Lambda)H hypernucleus; the results
set an upper limit of the production cross section.
T2K STATUS: RELEASE OF THE RESULT WITH ALL DATA ACCUMULATED SO FAR
AND MAINTENANCE WORK FOR NEUTRINO BEAM OPERATION FROM MAY
(by T.TSUKAMOTO)
T2K released the results on muon-neutrino disappearance using all
data accumulated so far (until May 2013) corresponding to 6.57 x 10^20
POT and on combined analysis with muon-neutrino disappearance and
electron-neutrino appearance.
The results were presented at Rencontres de Moriond, 2014.
http://moriond.in2p3.fr/
https://indico.in2p3.fr/materialDisplay.py?contribId=176&sessionId=4&materialId=slides&confId=9116.
Maintenance work for the neutrino beam facility is being carried
out. There are many items as reported in the previous newsletter
(#53). We would like to report as one of results of maintenance that
replacement of all three magnetic horns was carried out successfully
by the end of Mar. The neutrino beam facility and the near detector
ND280 will be prepared for neutrino beam operation which is planned
from May.
CONSTRUCTION OF SUPER-CONDUCTING MAGNET SYSTEM FOR THE MU-E
CONVERSION SEARCH EXPERIMENT HAS STARTED
PREPARATION OF A PRECISE MEASUREMENT OF MUON MAGNETIC AND ELECTRIC
DIPOLE MOMENTS IS IN PROGRESS (by S. MIHARA)
The COMET experiment aims at searching for the mu-e conversion,
which is strictly forbidden in the standard model (SM), with a target
sensitivity of 10^{-14} in Phase I and 10^{-16} in Phase II by using
the J-PARC high-power proton beam. In this experiment, a long chain of
super-conducting solenoid magnets will be used to collect pions/muons
and transport muons to the experiment area. In early 2014, production
of solenoid magnet coils has been successfully started. Coil winding
will be continued until 2015 to produce in total 10 coils. They will
be assembled in a cryostat to form a large collection magnet to
produce a strong magnetic field surrounding the pion production target.
R&D of detectors to identify the signal electrons is also in progress;
detector prototypes were tested using an electron beam in March 2014.
Preparation of the muon magnetic and electric dipole moment
measurement is also in progress. Precise measurement of these
properties of muons is considered to be an important clue to
investigate the physics beyond the SM. At the beginning of 2014, a
series of test experiments verifying efficient production of muonium,
used as a muon source in this g-2/EDM measurement, have been conducted
both at TRIUMF and J-PARC MLF. Detector R&D is being intensively
performed in the framework of the international collaboration.
Related Meetings:
COMET and Muon g-2/EDM collaborations had a joint workshop on
the silicon detector at LPNHE in Paris in February 2014. A mini-
collaboration meeting of the g-2/EDM experiment was held at J-PARC in
March 2013.
FIFC: FACILITIES IMPACT AND FUNDING COMMITTEE (by T. KOMATSUBARA)
This committee evaluates the feasibility of the various aspects
including the safety-related issues of the experiments in the Hadron
Experimental Facility and in other facilities of J-PARC.
It was held on March 24 and the evaluation will be reported in the
next PAC meeting in May.
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4. [Materials and Life Science Division] by Masatoshi ARAI
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STEADY NEUTRON PRODUCTION WITH 300 KW PROTON BEAM WAS RESUMED WITH
IMPROVING THE PRESSURE WAVE MITIGATION IN MERCURY TARGET SINCE
FEBRUARY 2014
1) Neutron Source
Operating the pulsed spallation neutron source was resumed on
the 11th of February, 2014. The flow rate of helium gas micro-bubbles
into the mercury target vessel was increased up to 7.2 l/m, which was
much higher by a factor of six than the previous rate. This increase
of the flow rate was achieved after a maintenance of the mercury
circulation loop. It enhanced mitigation for the effect caused by the
pressure wave induced in mercury by a factor of three to four. The
user program for the 2013B period was started on the 17th of February,
2014 with the 120 kW beam. The beam power was increased up to 220 kW
on the 19th of February and then finally recovered to 300 kW on the
26th of February.
At the 3-GeV proton beam transport facility, the proton beam
profile that was a Gaussian shape was successfully flattened with two
octupole magnets which were installed in the last summer, so that the
peak height was reduced by 30 to 40%.
CONSTRUCTION OF THREE NEW INSTRUMENTS WAS STARTED
GENERAL NEUTRON PROPOSALS FOR 17 INSTRUMENTS WERE SUBMITTED FOR 2014A
PERIOD
2) Neutron Instruments and Science
During the period of shutdown after the accident in the Hadron
Experimental Facility, construction of three new instruments was
started: BL06 (Vin Rose, Spin Echo Spectrometers), BL22 (RADEN, Pulsed
Neutron Imaging Instrument) and BL23 (POLANO, Polarized Neutron
Spectrometer). The user operation for 2013B (the second half of
FY2013) was started on the 17th of February, and it was ended on the
7th of April.
The general proposals for 2014A (from the 14th of April to the
3rd of December) was called for 17 instruments, and 283 neutron
proposals were submitted. Those proposals were reviewed by the Neutron
Science Proposal Review Committee, and finally 155 proposals were
approved by the MLF advisory board; in addition, 43 proposals were
reserved. The total competition rate (requested/ available beam time)
is as high as 2.1 times.
A NEW MUSR SPECTROMETER WAS INSTALLED AT THE D1 AREA
3) Muon Science Facility (MUSE)
A new muSR spectrometer was installed at the D1 area. It consists
of 1280 scintillators (640 telescopes) with their scintillation light
detected by multi-pixel avalanche photo diodes (MPPCs) covering a
total solid angle of 23.4%, which is 3.3 times larger than the
conventional D1 spectrometer, D-OMEGA1. The spectrometer is equipped
with a Helmholtz coil up to 4 kG, separated by a gap of 135 mm, which
can be rotated by 90 degree, and allows us to apply either transverse
or longitudinal magnetic field. It is also designed to be connected to
a fly path chamber with a diameter of 410 mm. During the
commissioning, it was demonstrated that 200 million of coincident
positron events per hour were collected for a sample of 15 x 15 mm2
with a 20 mm collimator. The event rate is 2-3 times higher than that
in ISIS-RAL, thanks to the stronger muon beam intensity of J-PARC.
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5. [Nuclear Transmutation Section] by Toshinobu SASA
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PROMOTE TRANSMUTATION STUDY AS AN OPTION OF NUCLEAR WASTE MANAGEMENT
Last autumn, a national review committee, which is hosted by
Ministry of Education, Culture, Sports, Science and Technology in
Japan, recommended to promote partitioning and transmutation (P-T)
technology as an important alternative option of future nuclear waste
management. Even though the construction of J-PARC Transmutation
Experimental Facility(TEF) is not approved yet, the supplemental
budget was allocated to enhance research and development activities
not only for the design of TEF but also for P-T fuel cycle studies.
For the design study of TEF, the supplemental budget was
allocated to the experimental studies of lead-bismuth eutectic (LBE)
handling for the ADS Target Test Facility (TEF-T) and remote operation
of Minor Actinide (MA) bearing fuel to be used in Transmutation
Physics Experimental Facility (TEF-P). For the study of LBE handling,
engineering studies for loop equipment including an electromagnetic
pump will be performed with newly prepared target mockup loop. Mockup
of spallation target for material irradiation will be also prepared
for cold loop tests. As for the remote operation tests for MA-bearing
fuel, confirmation of remote operation, which is designed to minimize
the effect of experimental accuracy and to maximize the
reproducibility of experiments simultaneously, will be performed. The
experimental equipment will be completed within fiscal year 2014.
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6. [Safety Division] by Tetsuro ISHII
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THE 18TH RADIATION SAFETY COMMITTEE OF J-PARC MET IN JANUARY
The 18th Radiation Safety Committee of J-PARC met on Jan. 22 and
discussed the alternative application of J-PARC facilities and the
revised regulations on prevention from radiation hazards of J-PARC.
The main topic of the application was about the renovation of the
Hadron Experimental Facility.
The application for a license of the renovation of the Hadron
Experimental Facility was approved by the Nuclear Regulation Authority
(NRA) on Mar. 19.
THE SAFETY INSPECTI0ON OF NEW MUON BEAMLINE IN THE MATERIALS AND LIFE
SCIENCE EXPERIMENTAL FACILITY (MLF)
The safety inspection of the new muon beamline (U-line) in the
MLF was successfully conducted on Mar. 3 by the Nuclear Safety
Technology Center (NUSTEC).
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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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