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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
++++++++++++++++End of Letter++++++++++++++++++++++++++++++++++++++++