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J-PARC Project Newsletter
No. 50, October. 2012
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]
YUJIRO IKEDA HAS SUCCEEDED PROF. SHOJI NAGAMIYA AS THE DIRECTOR OF
J-PARC CENTER ON JULY 1, 2012.
USER OPERATION SCHEDULE FOR INCREASING USER BEAM TIME HAS BEEN
CHANGED TILL THE END OF JULY, 2013.
2. [Accelerator Division]
MAINTENANCE AND UPGRADE WORK DURING SUMMER SHUTDOWN.
3. [Nuclear and Particle Physics Division]
KOTO: THE FIRST PARTICLE-PHYSICS EXPERIMENT OF THE HADRON HALL.
T2K STATUS: MAINTENANCE IN THE SUMMER SHUTDOWN PERIOD.
4. [Materials and Life Science Division]
HELIUM GAS INJECTION SYSTEM INSTALLED IN MERCURY TARGET.
A LARGE INCREASE IN THE NUMBER OF PROPOSALS FOR 2012B PERIOD.
FRONT-END COMPONENTS FOR S-LINE AND H-LINE CONSTRUCTED.
5. [Nuclear Transmutation Section]
HIGH EXPECTATIONS FOR RADWASTE TRANSMUTATION.
6. [Safety Division]
APPLICATION FOR LICENSES TO OPERATE THE WHOLE FACILITIES WAS GRANTED
BY THE MINISTRY OF EDUCATION, CULTURE, SPORTS, SCIENCE AND TECHNOLOGY
(MEXT).
7. [Information System Section]
J-PARC NETWORK AND COMPUTING SYSTEM UPGRADE.
8. [Announcement of Symposia and Meetings]
9. [Editorial Note]
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1. [Overview] by Yujiro IKEDA
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YUJIRO IKEDA HAS SUCCEEDED PROF. SHOJI NAGAMIYA AS THE DIRECTOR OF
J-PARC CENTER ON JULY 1, 2012
USER OPERATION SCHEDULE FOR INCREASING USER BEAM TIME HAS BEEN
CHANGED TILL THE END OF JULY, 2013
The new director of J-PARC center, Yujiro Ikeda who has
succeeded Prof. Shoji Nagamiya, started operation on July 1, 2012
with two new deputy directors: Takashi Kato for JAEA and Naohito
Saito for KEK.
We have experienced quite a challenging period under the slogan
"full recovery from the damage of the earthquake". Stable and powerful
beam operation of higher than 200 kW at the Materials and Life science
experimental Facility (MLF), nearly 200 kW at the FX target and 14 kW
beam extraction at the SX target for the Hadron experiment were
achieved. Just before the summer shutdown, it was an exciting report
that the beam power of 275 kW at MLF was demonstrated even for three
days.
During the summer shutdown time, all critical work for high power
operation was completed for the helium bubble injection in the
mercury target and installation of the front end beam line components
for S- and H- ports at MLF. Also, the number of users has increased
steadily with the recovery of stable operation. In the meantime, an
encouraging result was reported that the appearance of electron
neutrino candidate events was increased to 11 by the T2K team,
corresponding to 3.2 sigma accuracy. Though it is an exciting
achievement, a strong request to arrive at 5 sigma statistics urged
the change of the operation schedule to increase user beam time. In
view of the critical importance of the neutrino T2K experiment,
beam-time will be increased around the coming year-end and new-year
season and has been extended till the end of next July.
After the government review of J-PARC, which was finalized at
the end of last June, a summary report has been issued in July,
2012. Although there were several critical comments on the J-PARC
tasks to be done urgently, the review committee has endorsed for the
most part of 5 years plans from now, which includes MW power
achievement, the high-momentum beam-line at the Hadron experimental
facility, extension of the Muon beam channels, completion of Neutron
beam lines along with strengthening the sample environmental
equipments, ADS (Accelerator-Driven System) experimental facility
program revitalization, and a new building for users in the site, etc.
Prioritization was required in any case.
On July 29, the fourth open house of J-PARC facility took
place. A total of 2100 people visited J-PARC. Compared to the
previous numbers, it was rather small due to the earthquake effect.
However, the event was successful because we showed the recovery to
the public in early stages.
We are concerned about the electricity price hike by TEPCO due
to the crippled Fukushima power plant that is pushing the fiscal 2012
budget constraint harder, resulting in a slight reduction of money
for the facility maintenance.
The budget proposal for FY2013 is negotiated between the Ministry
of Education, Culture, Sports, Science and Technology (MEXT) and the
Ministry of Finance. The current proposal comprised the user
operation budget for 6 cycles (132 days), installation items needed
for MW accelerator power, experimental beam-lines, a user building,
ADS R&D and so on, according to the plan we have shown to the review
meeting as the 5 year program.
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2. [Accelerator Division] by Kazuo HASEGAWA
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MAINTENANCE AND UPGRADE WORK DURING SUMMER SHUTDOWN
Beam operation was suspended for the summer maintenance from July
to September. In addition to the usual maintenance, installations,
adjustments of some components for performance upgrade, and
preparation work for linac energy upgrade were carried out.
Linac
One of the acceleration cavities, SDTL5#B, did not work properly
within the designed radio frequency amplitude region after the
earthquake restoration. We took several measures to recover
performance such as improvement of effective vacuum speed,
replacement of oil rotary pumps with oil-free ones, and warm water
baking to accelerate degassing process. Development of Bunch Shape
Monitor is carried out in collaboration with Institute of Nuclear
Research in Russia. Three sets of monitors were installed in the
tunnel and will be tested with the beam after resumption of operation in
October. Restoration work from the earthquake disaster of the linac
building was resumed from July. The repair work of the cranes in the
klystron gallery and in the accelerator tunnel was completed.
In addition, repair of walls and pillars, and pouring grout to the
hollow spaces under the floor were intensively carried out before the
resumption of beam operation.
RCS
In the 3 GeV Rapid Cycling Synchrotron (RCS), re-alignment of
magnets is planned according to the linac energy upgrade of the summer
of 2013. As preparation for that, the spatial relationship between the
ceramic chambers and the electromagnets was measured by a laser
tracker. The pulsed dipole magnet system was installed at the
injection of the RCS. Although the same property beam is currently
injected for the Material and Life experimental Facility (MLF) and
for the Main Ring (MR) destinations, this system is to adjust the beam
to reduce beam loss for each beam destination. The leakage magnetic
field from the electromagnet in the extracted beam transport line was
about 10 Gauss and this causes the beam loss at the RCS. To reduce
the magnetic field to the order of 1/10, the existing vacuum ducts
and bellows were replaced with the products made from a magnetic
material (permalloy).
Main Ring (MR)
The fast extracted beam power for long-time operation was
restricted to 160 kW due to the radioactive level in the exhausted
gas at the machine building. As a countermeasure, two air duct dampers
were exchanged for high airtight ones during the summer shutdown.
Modification of the ring collimator was carried out to raise the
maximum allowable beam loss power from the present 450 W to 2 kW.
Installation of three octupole electromagnets and the 9th unit of
high frequency acceleration system, replacement of the end plate of
septum magnet made from stainless steel with titanium, etc. were
carried out for performance improvement. The MR aims at the design
power by shortening the repetition cycle from the present 2.5 to 1 second.
For that purpose, development of a high repetition rate and low ripple
main electromagnet power supply, and high gradient acceleration
system are indispensable. The power supply equipped with the
capacitor bank for the energy storage is under development and the
turning on test is being conducted. The mass-production test of high
gradient magnetic alloy core was performed in September.
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3. [Nuclear and Particle Physics Division]
by T.K.KOMATSUBARA & T. TSUKAMOTO
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KOTO: THE FIRST PARTICLE-PHYSICS EXPERIMENT OF THE HADRON HALL
(by T.K. KOMATSUBARA)
KOTO is the experiment to investigate the new origin of the
broken symmetry between particles and anti-particles (CP violation)
by measuring the extremely-rare decay mode of the neutral K meson
(kaon) with the high-intensity beam of J-PARC.
KOTO aims at the discovery of the decay of a long-lived neutral
kaon (KL) into a neutral pi meson and a pair of neutrinos; this decay
is predicted in the Standard Model of particle physics to occur once
every forty billion. "KOTO" is the abbreviated name for "K0 at TOkai",
and sixty-five experimental physicists from Japan, USA, Taiwan, Korea
and Russia participate in it.
The KOTO collaborators built the new neutral beam line (KL beam
line) at the Hadron Hall and surveyed the beam in 2009. In 2010, they
constructed a new electromagnetic calorimeter with the 50 cm-long
undoped Cesium-Iodide (CsI) crystals that were used in the KTeV
experiment at Fermilab. After the earthquake in March 2011, they
spent time to check the calorimeter; as a result, it was found to be
undamaged. They started the commissioning including the fast data
readout and acquisition system. In this year, they continue
construction of the detector and expect to start the full
commissioning from December 2012. The new counter to identify charged
particles in front of the calorimeter, called Charged Veto (CV), was
made of thin plastic-scintillator strips. The 5 m-long extra photon
counter surrounding the KL decay region, called Main Barrel (MB), was
constructed during the summer. The new collar-shaped photon counter
at the entrance of the decay region, called Neutron Collar Counter
(NCC), is under construction at Kyoto University and will be moved to
Tokai for installation in the autumn.
T2K STATUS: MAINTENANCE IN THE SUMMER SHUTDOWN PERIOD
(by T.TSUKAMOTO)
Physics results based on accumulated data before the summer
shutdown, were presented at the international conferences Neutrino
2012 and ICHEP 2012 as reported in the previous issue.
After neutrino beam operation was stopped on June 9, maintenance
of the neutrino beam line and the T2K near detector ND280 was started
to overcome problems so far and to have improvement for higher beam
power as expected in near future.
Troubles in the neutrino beam line that caused beam stoppage were
a malfunction in horn cooling water system and a false alarm of quench
detection in superconducting magnet system. The horn cooling water
system was improved by having extra buffer tanks and remote control
valves for efficient flushing without disturbing beam operation. The
electronics circuit of the quench detection system was sent back to
the Saclay group who made this system for detailed investigation. It
was repaired and is ready for operation.
P0D (pi-zero detector) in ND280 (near detector 280) has water
layers (25 layers in total) for neutrino target material and a water
leak was found in one layer during the experiment. A leak was
detected by the monitoring system and the water leak was caught by a
drain pan without problems. The repair was done by replacing it with
new water layer.
All components are becoming ready for the beam on the neutrino
beam line scheduled from October 17.
T2K collaboration meeting was held at IQBRC (Ibaraki Quantum
Beam Research Center) in Tokai from September 24 to 29.
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4. [Materials and Life Science Division] by Masatoshi ARAI
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HELIUM GAS INJECTION SYSTEM INSTALLED IN MERCURY TARGET
1) Neutron Source
Concentration of para-hydrogen in the moderators was analyzed
with Raman spectroscopy using samples that were collected from the
cryogenic loop during the beam operation. It was confirmed for the
first time that the para-hydrogen fraction is almost 100% as expected.
Various maintenances had been carried out during the summer
shutdown period; impellers of hydrogen pumps for the cryogenic loop
were exchanged for spares. In the 3-GeV proton beam transport tunnel,
magnets and beam monitors were realigned carefully to eliminate the
displacement of the floor level from the tunnel to the MLF building,
considering that the beam position at the mercury target was slightly
shifted in the vertical direction during the operation period.
A gas injection system which supplies helium gas bubbles to the
mercury target for mitigating the pitting damage on the target wall
was installed. Beam-on study to evaluate its effect is scheduled in
October. A test module of the Cold-Charcoal-Trap (CCT) system showed high
purification efficiency for radioactive gasses such as Xe-137, which
saves time of exchanging the mercury target.
A LARGE INCREASE IN THE NUMBER OF PROPOSALS FOR 2012B PERIOD
2) Neutron Instruments and Science
User operation for the 2012A period (from April to mid November
2012) has been continuing and 100 accepted general proposals called
by J-PARC as well as 11 general proposals called by Ibaraki prefecture
(proposals from industrial users to two Ibaraki prefecture beamlines)
are being carried out. For the 2012B period (from mid November 2012
to March 2013), 218 general proposals including the proposals to the
Ibaraki prefecture beamlines were submitted and reviewed by the
neutron science proposal review committee. Finally they were approved
by the MLF advisory board: 148 approved and 37 reserved. Separately
11 proprietary proposals were accepted. The trial use program for
novice users of public beamlines has started and 10 proposals were
approved. In total, 185-days beamtime will be available: 88 days for
2012A and 97 days for 2012B. The call for the next general proposals
(2013A) will be started on November 17.
FRONT-END COMPONENTS FOR S-LINE AND H-LINE CONSTRUCTED
3) Muon Science Facility (MUSE)
We constructed front-end beamline components for the S-line
and the H-line in the vicinity of the muon target. In the M2 proton
tunnel, the S-line consists of the two sets of triplet Q-magnets SQ
1-3, SQ4-6 and a bending magnet SB1 in order to extract surface muons
for the material sciences. On the other hand, the H-line consists of
large acceptance solenoid magnets, HS1 and HS2 made of mineral
insulation cables (MIC), a bending magnet HB1 in order to extract
muons or positrons (electrons) up to 120 MeV/c, for the fundamental
physics such as the experiments on the precise Mu hyperfine
measurement, muon-electron conversion experiment, or g-2 experiment.
During the summer shutdown period of 2012, we completed all the
installation of the beamline components in the M2 proton tunnel,
where radiation is very high in the order of several mSv/h to Sv/h in
the vicinity of the muon target.
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5. [Nuclear Transmutation Section] by Toshinobu Sasa
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HIGH EXPECTATIONS FOR RADWASTE TRANSMUTATION
In September, the Science Council of Japan made a recommendation
for disposition of high-level radioactive waste to the Atomic Energy
Commission of Japan. It recommended that the study for reducing
radioactive waste such as transmutation technology should be promoted.
We revised the construction plan for Transmutation Experimental
Facility (TEF) for Accelerator-driven System (ADS) R&D to start the
construction from ADS Target Test Facility (TEF-T) first. Then, design
work and licensing procedure to build Transmutation Physics
Experimental Facility (TEF-P) will be performed simultaneously.
Development for TEF-T equipment such as preliminary tests for
off-beam target loop experiments and preparations for validation of
target instruments are underway.
A prolonged operation of JAEA Lead-Bismuth Loop #2 (JLBL-2),
which simulates sealed-annular tube type spallation target, has
started from August. Within this fiscal year, we are trying to operate
JLBL-2 up to 4,500 hours at the temperature of 300 C. The plan to
modify JLBL-2 for performing simultaneous measurement of Pb-Bi flow
rate by current Electro-magnetic method and newly added Ultrasonic
method is discussed with the experts of Fast Breeder Reactor
development. At the current schedule, simultaneous tests will be
performed next year.
For the design study of spallation target for TEF-T, reference
operation condition was specified, and soundness of the Pb-Bi target
was estimated. By the reference operation condition, which is the
requirement for
the future ADS transmutor, the target casing made of T91 steel has
enough strength for 4,500 hours operation of 400 MeV proton injection.
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6. [Safety Division] by Taichi MIURA and Hiroshi NAKASHIMA
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APPLICATION FOR LICENSES OF THE OPERATION OF THE WHOLE FACILITIES
WAS GRANTED BY THE MINISTRY OF EDUCATION, CULTURE, SPORTS, SCIENCE
AND TECHNOLOGY (MEXT)
The application for licenses of the operation of the whole
facilities was granted by MEXT on Sep.18.
The main topics are 1) the power-up for the all of the
facilities (except Hadron Experimental Facility), 2) the new
secondary beam line (muon) in the Materials and Life science
experimental Facility (MLF). The intended power-up level at this time
is 300 kW for user operation at MLF and is aimed up to 450 kW operation
at the Neutrino Experimental Facility.
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7. [Information System Section] by Atsushi MANABE
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J-PARC NETWORK AND COMPUTING SYSTEM UPGRADE
J-PARC does not have its own computing facility for physics
analysis, so the KEK central computer system at Tsukuba site has
mainly used for the purpose since 2009. For J-PARC, the resources of
1600 SPECint06 computing power, 150 TBytes RAID disks and 2 PBytes
tape libraries were assigned. In April 2011, the KEK central computer
system was upgraded and also computer resources of 25,000 SPECint06
computing power, 1.2 PBytes disks and 5 PBytes tapes are newly
assigned for J-PARC.
In July, the J-PARC network system, called JLAN, was also
upgraded. The older system provided a bandwidth of 100Mbps for
terminal ports, 1Gbps for the Internet and 2Gbps for Tokai-Tsukuba
connection. The new upgraded system does speeds of 1Gbps for terminal
ports, 10Gbps for the Internet and 8Gbps for Tokai-Tsukuba connection
respectively. These two new systems will strongly support J-PARC
experiments, which will be restarted after this summer shutdown.
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8. [Announcement of Symposia and Meetings] by Hiroari MIYATAKE
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1) XVI International Conference on Electromagnetic Isotope
Separators and Techniques Related to their Applications (EMIS2012)
will be held at "Kunibiki-Messe" in Matsue, Japan from 2nd to 7th
Dec., which is hosted by RIKEN Nishina Center, Institute of Particle
and Nuclear Studies, KEK, and Institute of Modern Physics, CAS with
chairs of Hiroyoshi Sakurai (RIKEN), Hiroari Miyatake (KEK), and
GuoQing Xiao (IMP).
Conference web site: http://ribf.riken.jp/emis2012/.
2) Workshop on Low-Energy Radioactive Isotope Beam (RIB)
Production by In-Gas Laser Ionization for Decay Spectroscopy will be
held as a post-conference (EMIS2012) workshop at RIKEN-Wako on
December 10 - 11, 2012. It is chaired by Sunchan Jeong, Hiroari
Miyatake (KEK), Michiharu Wada (RIKEN), Piet Van Duppen (KU Leuven)
and Mark Huyse (KU Leuven). RNB group of KEK hosts the workshop.
Workshop web page: http://kekrnb.kek.jp/workshop/postEMIS2012/.
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9. [Editorial Note]
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Editorial Board:
Toshifumi TSUKAMOTO (Chair): toshifumi.tsukamoto@kek.jp
Nobuaki TAKAHASHI: nobuaki.takahashi@j-parc.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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