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          J-PARC Project Newsletter
                                                     No.55, July 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]

 USER RUNS AT THE NEUTRINO EXPERIMENTAL FACILITY WERE RESTARTED ON MAY
26 FOLLOWING THE COMPLETION OF THE STRICT INSPECTION TO ENSURE THE 
SAFETY.
 ON MAY 23, THE WORKSHOP FOR FOSTERING SAFETY CULTURE AT J-PARC WAS 
HELD IN ORDER TO IMPROVE SAFETY AWARENESS AND NOT TO FORGET THE 
ACCIDENT AT THE HADRON EXPERIMENTAL FACILITY LAST YEAR.

2. [Accelerator Division]

 ONE-MONTH LONG-TERM OPERATION OF THE RF-DRIVEN NEGATIVE ION SOURCE 
AND THE NEW RADIO FREQUNECY QUADRUPOLE (RFQ) FOR PEAK CURRENT OF 50 MA 
WAS SUCCESSFULLY ACHIEVED.
 THE BEAM LOSS WAS REDUCED AND MINIMIZED IN HIGH INTENSITY BEAM STUDY 
AT THE RAPID CYCLING SYNCHROTRON (RCS).
 THE MR RESUMED BEAM DELIVERY TO THE T2K EXPERIMENT.

3. [Particle and Nuclear Physics Division]

 NEUTRINO BEAM LINE OPERATION RESUMED.
 RENOVATIONS FOR IMPROVEMENTS OF THE HADRON EXPERIMENTAL FACILITY ARE 
IN PROGRESS.
 PROTON BEAM ACCELERATION TEST FOR THE MU-E CONVERSION SEARCH 
EXPERIMENT WAS CONDUCTED AT 8GEV SUCCESSFULLY.
 PREPARATION FOR A PRECISE MEASUREMENT OF MUON MAGNETIC AND ELECTRIC 
DIPOLE MOMENTS IS IN PROGRESS.
 PROGRAM ADVISORY COMMITTEE MEETING.

4. [Materials and Life Science Division]

 NEUTRON PRODUCTION WITH 300 KW PROTON BEAMS HAS STEADILY CONTINUED 
FOR THE 2014A USER PROGRAM PERIOD FROM APRIL TO JUNE.
 CONSTRUCTION OF THREE NEW INSTRUMENTS IS IN PROGRESS.
 USER PROGRAM FOR 2014A HAS BEEN STARTED.
 TWO HUNDRED EIGHTY NINE GENERAL NEUTRON PROPOSALS FOR 17 INSTRUMENTS 
WERE SUBMITTED FOR 2014B PERIOD.
 AT THE U-LINE, DAMAGE OF THERMAL INSULATION WINDOW WHICH PREVENTS 
FROM THE HEAT RADIATION COMING FROM THE COMPONENTS AT ROOM TEMPERATURE 
WAS FOUND.

5. [Nuclear Transmutation Section]

 DEMONSTRATION OF LIQUID METAL HANDLING TECHNOLOGIES FOR TRANSMUTATION 
EXPERIMENTAL FACILITY.

6. [Safety Division]

 THE SAFETY INSPECTION OF NEW NEUTRON BEAMLINE IN MLF.

7. [Editorial Note]


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1. [Overview] by Yujiro IKEDA
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 USER RUNS AT THE NEUTRINO EXPERIMENTAL FACILITY WERE RESTARTED ON MAY
26 FOLLOWING THE COMPLETION OF THE STRICT INSPECTION TO ENSURE THE 
SAFETY
 ON MAY 23, THE WORKSHOP FOR FOSTERING SAFETY CULTURE AT J-PARC WAS 
HELD IN ORDER TO IMPROVE SAFETY AWARENESS AND NOT TO FORGET THE 
ACCIDENT AT THE HADRON EXPERIMENTAL FACILITY LAST YEAR

     1) The FY2015 budget proposal was prepared based on the principle 
for user operation and the strategy for facility improvement at 
J-PARC, which are (1) nine cycles of user operation, (2) development 
of MR power supply, (3) instrumentation of neutron and muon beam- 
lines, (4) improvement of sample environment, and (4) R&D for the 
construction of the Accelerator Driven System (ADS). The total amount 
of the proposed budget is more than 200 Oku-Yen. Due to a difficult 
funding-situation of the government, drastic cutbacks on the budget 
are expected.

     2) Following the resumption of user operations at MLF on February 
17, experiments were resumed at the Neutrino Experimental Facility
(NU) on May 26 after passing the strict safety inspection. Now, two 
facilities were back on the track and renovation work on the Hadron 
facility is being continued.

     3) In this quarterly period, we experienced some problems in 
several components, which led to a suspension of user operation.
However, overall we could have delivered appreciable amounts of beams 
for users at 300 kW for MLF and 200 kW for NU. This thanks largely to 
a sincere endeavor of the accelerator team. The experiments before the 
summer shutdown were safely completed as scheduled on June 26.

     4) The J-PARC center management team had face-to-face sessions to 
discuss issues and also have suggestions directly from more than 200 
J-PARC center staff members at the beginning of FY2014. These sessions 
were being very effective to deepen our understanding and get clues to 
improve the center.

     5) Construction of the J-PARC Users Research Building (a 
tentative name) has begun and will be completed by the end of March 
2015.

     6) On May 23, the first anniversary of the accident at the Hadron 
Experimental Facility, we hosted the workshop for fostering Safety 
Culture at J-PARC. We re-acknowledged that the development process of 
counter and preventive measures was a very important learning process.

     7) In order to improve the response to an emergency, we 
periodically carried out emergency drills on the assumption of an 
abnormal incident, which may cause radioactive materials leakage. The 
most recent one was held at the Neutrino Experimental Facility on June 
26. In this drill, the TV conference system was used for the first 
time to be as a communication tool among local, JAEA, and KEK 
headquarters, whereas JAEA and KEK were supposed to jointly establish 
main headquarters in an emergency. We will continue to make an effort 
to develop an efficient communication method to ensure safety for 
users, workers, and neighbors.


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2. [Accelerator Division] by T. KOSEKI, H. OGURI, M. KINSHO
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 ONE-MONTH LONG-TERM OPERATION OF THE RF-DRIVEN NEGATIVE ION SOURCE 
AND THE NEW RADIO FREQUNECY QUADRUPOLE (RFQ) FOR PEAK CURRENT OF 50 
MA WAS SUCCESSFULLY ACHIEVED (by H. OGURI)

     On June 30, 2014, a HVTR (high voltage transformer) of the 
klystron power supply #5 was broken due to the destruction of the 
diode module. The failure was caused by applying overvoltage to the 
capacitor. We are considering improvement of the transformer to 
protect the device against the surge voltage. Recently, frequency of 
the failure of the klystron power supply system tends to increase. We 
will implement some countermeasures against the failure in the 2014 
summer shutdown period.

     For the upgrade of the linac peak current, a new front-end 
system, which is composed of a cesium-seeded rf-driven negative ion 
source and a new RFQ for the peak current of 50 mA, was tested in an 
RFQ test stand. In June, 2014, a long-term continuous operation test 
was performed. At the operation test, approximately 680 hours 
continuous operation was achieved without any serious trouble. The 
test was terminated at the end of June, and the installation of the 
new front-end system in the linac tunnel was started on July 1, 2014.

 THE BEAM LOSS WAS REDUCED AND MINIMIZED IN HIGH INTENSITY BEAM STUDY 
AT THE RAPID CYCLING SYNCHROTRON (RCS) (by M. KINSHO)

     User operation with beam power of 300kW has been performed with 
no serious trouble except for only one trouble, which happened on the 
15th of April. A choke transformer of a dipole magnet could not work 
due to breakdown of an oil circulating pump which was used for 
cooling. User operation could be restarted after replacing the broken 
pump with new one, but this trouble disabled user operation for one 
week.
High intensity beam study was performed for 3 days from the 28th of 
June. Beam power could be increased to the equivalent of 573kW with 
beam loss of 0.07% by tuning of injection beam and betatron tune.
The cause of beam loss is only charge-exchange foil scattering which 
was used for charge exchange injection and it was found that beam loss 
could be minimized in this beam study.

 THE MR RESUMED BEAM DELIVERY TO THE T2K EXPERIMENT (by T. KOSEKI)

     The MR resumed beam delivery to the neutrino beam line on May 16, 
2014. After high power beam tuning of the MR and the neutrino beam 
line, user operation for the T2K experiment started with a beam power 
of 210-230 kW and continued until the morning of June 30, 2014.
In the high power beam operation, a bunch-by-bunch feedback system 
suppresses transverse beam instabilities, which are observed during 
the injection and beginning of acceleration. The system, however, can 
only damp the coherent dipole motion of the bunch, and internal bunch 
oscillations still remain and occasionally causes the beam loss.
Recently, a new bunch feedback system, called intra-bunch feedback 
system was developed. The intra-bunch feedback system is more wideband 
and precise system than the bunch-by-bunch system and can suppress the 
internal bunch oscillations. The intra-bunch feedback system was 
switched in the user run since the end of May. The bunch feedback 
technique is quite effective and plays an important role at present 
and in future high power operation.


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3. [Particle and Nuclear Physics Division] by T. TSUKAMOTO, K. OZAWA, 
S. MIHARA, T. KOMATSUBARA
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 NEUTRINO BEAM LINE OPERATION RESUMED (by T. TSUKAMOTO)

     During a long period of shutdown, all three electromagnetic horns 
with graphite target and an OTR (Optical Transition Radiation) proton 
profile monitor attached to the most upstream horn were successfully 
replaced. The new horns have higher cooling capacity than the old ones 
and can now accept the beam power of 750kW. Because all the replaced 
components had been highly radioactive, the replacement work had to be 
done by remote handling. The remote maintenance scenario and the 
hardware system have been very carefully designed and developed for 
many years, and they led to this success.
     After commissioning to check the functionality of all the beam 
line components, the neutrino beam line operation was resumed on May
26 to supply neutrino beam for the T2K experiment. The beam power was 
smoothly increased up to about 220kW, which is the same level as the 
last operation in 2013. The first anti-neutrino beam operation in T2K 
was carried out in June. Neutrino beam operation which was accumulated 
with 0.57x10^20 POT (protons on target) before summer maintenance 
finished on June 26.

 RENOVATIONS FOR IMPROVEMENTS OF THE HADRON EXPERIMENTAL FACILITY ARE 
IN PROGRESS (by K. OZAWA)

     Renovation work to improve radiation safety of the Hadron 
Experimental Facility is currently underway. It includes the 
installation of the ventilation equipment with filters in the 
experimental hall and the improvement in the air tightness of the 
primary beam line. Machine buildings beside the hall are also being 
upgraded.

 PROTON BEAM ACCELERATION TEST FOR THE MU-E CONVERSION SEARCH 
EXPERIMENT WAS CONDUCTED AT 8GEV SUCCESSFULLY  
 PREPARATION FOR 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, 
strictly forbidden in the standard model (SM), with a target 
sensitivity of 10^{-14} in Phase I and 10^{-16} in Phase II. The 
experiment requires the proton beam extracted at 8GeV for producing 
muons with a significant suppression of antiproton-induced 
backgrounds. Protons of 8GeV are extracted without destroying its 
bunched time structure for producing the pulsed-muon beam. This pulse 
structure has to be extremely precise; namely there should not be 
proton leakage from a pulse to in-between pulses above the level of 
10^{-9} to 10^{-10}. An acceleration test and beam property 
measurement at 8GeV were conducted with help of the accelerator group 
in May. The leakage ratio, called extinction factor, was measured to 
be well below the level of 10^{-11} at 8GeV using a beam monitor 
installed in the abort line. R&D of detectors identifying the signal 
electrons is also in progress along with superconducting magnet coil 
production.
Preparation of the muon magnetic and electric dipole moments 
measurement is also in progress. A series of test experiments has been 
conducted to verify an efficient production of muonium in an aerogel 
plate with many tiny holes that has been used as a muon source, at 
J-PARC MLF in May. A prototype of the silicon strip detector with a 
new read-out electronics to measure the positron tracks from muon 
decays was successfully tested at MLF in June.

     Related Meeting
     The COMET group had a collaboration meeting at the Institute of 
High Energy Physics (IHEP) in China in May and new collaborators from 
Nanjing, Peking, and North China Electric Power Universities were 
approved to join the collaboration.

 PROGRAM ADVISORY COMMITTEE MEETING (by T. KOMATSUBARA)

     This committee evaluates and assesses joint-usage proposals on 
the experiments at the J-PARC Main Ring as well as important issues to 
push forward the research program. The 18th meeting was held from May 
14 through 16, and the comments and evaluations will be summarized as 
the meeting minutes in the near future.


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4. [Materials and Life Science Division] by Masatoshi ARAI
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 NEUTRON PRODUCTION WITH 300 KW PROTON BEAMS HAS STEADILY CONTINUED 
FOR THE 2014A USER PROGRAM PERIOD FROM APRIL TO JUNE

     1) Neutron Source
     The mercury target has steadily run with the 300 kW proton beam 
for the 2014A user period from the 14th of April to the 24th of June 
during which the gas micro-bubble injection successfully continued to 
mitigate the pressure waves generated in mercury. Other components 
such as the cryogenic hydrogen moderators and water cooling systems 
have also worked without any trouble. As a result, a 59-day neutron 
production was completed for the 2014A user period as of the 24th of 
June, and 6.5 days were cancelled in April due to a trouble occurring 
at the 3-GeV RCS.
     Fabrication of an advanced target vessel, which has a double- 
walled structure with a narrow channel width of 2 mm at the proton 
beam injection portion, has been approaching completion since it began 
in the summer of 2013.

 CONSTRUCTION OF THREE NEW INSTRUMENTS IS IN PROGRESS  
 USER PROGRAM FOR 2014A HAS BEEN STARTED  
 TWO HUNDRED EIGHTY NINE GENERAL NEUTRON PROPOSALS FOR 17 INSTRUMENTS 
WERE SUBMITTED FOR 2014B PERIOD

     2) Neutron Instruments and Science
     Construction of three new instruments BL06 (Vin Rose, Spin Echo 
Spectrometers), BL22 (Pulsed Neutron Imaging Instrument) and BL23 
(POLANO, Polarized Neutron Spectrometer)) is in progress. Beam 
inspection on radiation shielding of three instruments was conducted 
by Nuclear Safety Technology Center on the 22nd of April and passed 
without any serious problems.
     User program for 2014A was started on the 21st of April. It will 
be continued till December after four months break in summer.
     We called the general proposals for 2014B (from the end of 2014).
Call for proposal was closed in the middle of June and 289 neutron 
proposals were submitted. We have recorded the highest number of 
proposals again. Those proposals will be sent to the Neutron Science 
Proposal Review Committee for reviewing process.


 AT THE U-LINE, DAMAGE OF THERMAL INSULATION WINDOW WHICH PREVENTS 
FROM THE HEAT RADIATION COMING FROM THE COMPONENTS AT ROOM WAS FOUND

     3) Muon Science Facility (MUSE)
     In the category of the muon user's program 2014A, 26 proposals 
were submitted. At the D-Line, not only muSR experiments, but also 
non-destructive element analysis utilizing negative muons have been 
performed at the D1 area, or D2 area, without any trouble, yielding a 
variety of interesting results.
     At the U-Line, the front-end superconducting magnet in the 
superconducting curved solenoid transports intense surface muons 
efficiently from the proton beam line to the experimental area. It was 
found that the front-end superconducting magnet has difficulty to cool 
down below the superconducting temperature. By inserting a fiber 
telescope into the superconducting curved solenoid, it was finally 
revealed that thermal insulation window which prevents from the heat 
radiation coming from the components at room temperature, was broken.
We have to remove the shields in the vicinity of the superconducting 
curved solenoid, to get access to it. Therefore, we are planning to 
fix it as soon as beam will stop in the beginning of July, 2014.


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5. [Nuclear Transmutation Section] by Toshinobu SASA
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 DEMONSTRATION OF LIQUID METAL HANDLING TECHNOLOGIES FOR TRANSMUTATION 
EXPERIMENTAL FACILITY

     The Materials and Life Science Experimental Facility (MLF) uses a 
liquid metal as a spallation target in J-PARC. We can apply many 
experiences for design and operation of liquid metal spallation 
target. However, in the case of Lead-Bismuth Eutectic alloy (LBE), 
which is a primary candidate of the spallation target and coolant of 
future Accelerator-Driven System (ADS), the melting point is much 
higher than room temperature and LBE requires special treatment to 
keep it in liquid phase. In an ADS Target Test Facility (TEF-T), which 
is a part of Transmutation Experimental Facility (TEF), LBE loop will 
be installed as a liquid metal spallation target to perform the 
engineering tests for future ADS studies.
     Last year, we manufactured a special test equipment to establish 
the handling technologies of LBE by remote operation. In the 
equipment, the flange itself is designed based on the existing MLF 
mercury loop. We added a detachable preheating device that is designed 
based on the experiences from Fast Breeder Reactor "Monju". We 
performed a first test to handle remote preheating system named 
"Packaged Heater" by master-slave manipulator (MSM). Several 
modifications, which requires to handle a "Packaged Heater" safely by 
MSM, were indicated and revision of fully remote handled "Packaged 
Heater" is underway. The equipment is also used to demonstrate process 
instrumentations that are necessary to operate LBE target loop.
Results obtained from the equipment will be reflected to the newly 
prepared LBE target mockup loop.


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6. [Safety Division] by Tetsuro ISHII
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 THE SAFETY INSPECTION OF NEW NEUTRON BEAMLINE IN MLF

     The safety inspection of the new neutron beamline (BL06) in the 
Materials and Life Science Experimental Facility was successfully 
conducted on Apr. 25 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
++++++++++++++++End of Letter++++++++++++++++++++++++++++++++++++++++