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     J-PARC Project Newsletter
                                                  No.66, April 2017
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]

 MORE BEAMS FOR MORE RESULTS; START OF NEW FISCAL YEAR.

2. [Accelerator Division]

 OPERATION STATUS OF THE ACCELERATORS.
 ACCELERATOR TECHNICAL ADVISORY COMMITTEE (A-TAC) MEETING.

3. [Particle and Nuclear Physics Division]

 OUTSTANDING PAPERS FROM THE HADRON EXPERIMENTAL FACILITY.
 2 X 10^21 PROTONS ON TARGET (POT) AND 470KW BEAM POWER.
 STATUS OF THE COMET (COHERENT MUON TO ELECTRON TRANSITION) (E21) .
 STATUS OF THE MUON G-2/EDM (E34).
 PROGRAMS OF ADVISORY COMMITTEE MEETINGS.

4. [Materials and Life Science Division]

 RELIABLE NEUTRON PRODUCTION OPERATION WITH 150 KW PROTON BEAM.
 USERfS PROPOSALS WERE REVIEWED AND 153 GENERAL USERS' PROPOSALS WERE 
APPROVED FOR 2017A. 
 NAC2017 & IAC2017 GAVE POSITIVE RECOMMENDATION TO THE NEUTRON 
INSTRUMENTS SUITE.
 S1-INSTRUMENT ARTEMIS STARTED USER PROGRAM. 

 5. [Nuclear Transmutation Division]

 SECURE THE FLUID TARGET IN STEEL CONTAINER.

6. [Safety Division]

 4TH SYMPOSIUM ON SAFETY IN ACCELERATOR FACILITIES.
 THE APPLICATION FOR A LICENSE OF THE OPERATION WAS GRANTED.
 
7. [Information System Section]

 EDUROAM IS NOW AVAILABLE AT J-PARC.

8. [Editorial Note]


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1. [Overview] by Naohito SAITO
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 MORE BEAMS FOR MORE RESULTS; START OF NEW FISCAL YEAR

     We have entered the new fiscal year! We have received the report 
from the International Advisory Committee (IAC), which met on 
February 27 and 28. It is an annual review of the overall 
performance of the J-PARC center. The review report contains the 
evaluation of the J-PARC over the past year and recommendations on 
our proposals of future directions for the programs. The report is 
available at the following link. 
(https://j-parc.jp/documents/iac/J-PARC_IAC2017.pdf)

     While IAC meets only for 1.5 days, the presentations and 
discussions are based on the more elaborated discussions in the 
Neutron Advisory Committee (NAC), Muon Advisory Committee (MAC) and 
Muon Science Advisory Committee (MuSAC), and A-TAC (Accelerator 
Technical Advisory Committee), T-TAC (Technical Advisory Committee) 
and PAC (Program Advisory Committee for Nuclear and Particle 
Physics). We really appreciate efforts by the all committee members 
for dense and efficient discussions to help our operation of J-PARC.

     The IAC report says that they have observed much progress in the 
J-PARC operations; improved reliability in the accelerator system, 
which led to an improved operation especially in the Materials and 
Life Science Experimental Facility (MLF). In other experimental 
facilities, there is still some room for improvements in beam 
availability for users. The safety slogan, "Mindful of Others" is 
highly recognized while its evolution into "stop work" is also 
recommended. The report also mentioned some possible risks of the 
facility operations, which includes another target failure with 
extreme rapid increase in the beam power, as well as failure of the 
timely construction of new power supplies at the Main Ring (MR). We 
have been and will be working hard to minimize those risks. And we 
will keep in our mind the very impressive words in the report: 
"Failure is not an option!"

     Now we are starting the operation of Hadron Experimental 
Facility (HEF) after some months, where we will be aiming for the 
new power regime up to 50 kW. This beam power will bring us to a 
distinctive opportunity to investigate the role of the 2nd generation 
in the standard model, either in weak or in strong interactions. The 
experimental group is fully ready for the physics production, and 
we are looking forward to exciting results out of J-PARC produced 
data.

     As you may have been already aware, we have established the 
science group at the MLF. The conveners of each group will work as an 
interface between external users and the facility group so that the 
efforts by users and facility can be well aligned to produce more 
results from the MLF.  The details are available at the MLF web-site.
http://mlfuser.cross-tokai.jp/st/
The pages are still mostly in Japanese. While English pages are in 
preparation, we welcome any inputs to the group leaders.

     Last but not least, we are also excited by the achievements by 
the neutrino group and accelerator group. We have achieved 470 kW for 
user operation and 511 kW for a short time and accumulated 2x10^{21} 
POT which certainly brings human beings to even more enlightened 
picture of the role of neutrino and anti-neutrino in the early 
universe.

     We will deliver more beams for more results to share more 
excitement with users and with the world!


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2. [Accelerator Division] by Kazuo HASEGAWA
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 OPERATION STATUS OF THE ACCELERATORS

     After the New Year's holiday, the beam operation started on 
January 6 as a new operation run of Run#72. The linac beam current 
was 40 mA as before and the startup tuning was done in the linac, the 
3 GeV rapid cycling synchrotron (RCS), and the main ring (MR). The 
user program resumed for the neutrino experimental facility (NU) on 
January 8, and for the Materials and Life Science experimental 
facility (MLF) on January 13 at the beam power of 450 kW and 150 kW 
respectively.
     The linac, the RCS, and the MR provided beams to users without 
serious troubles. But in the meantime, a helium compressor at the NU 
had trouble and the user operation was suspended for about two 
weeks. We took a beam study for the MR to take more optimized 
parameters for high power beam delivery during that period. As a 
result, we increased beam power to 470 kW for the NU.
The accelerator delivered beams successfully to the MLF and NU as 
scheduled until the end of March. The availability in the Japanese 
Fiscal Year 2016 (from April 2016 to March 2017) was high (about 93 
Percent) for the MLF, since we had no serious troubles at the linac, 
the RCS and the MLF. The availabilities for the NU and hadron 
facility users were 77 % and 84 %, respectively.

     ACCELERATOR TECHNICAL ADVISORY COMMITTEE (A-TAC) MEETING

     The 16th A-TAC meeting was held at the J-PARC Research Building 
on February 23 to 25. Seven committee members attended and 15 reports 
were presented such as operational status, commissioning results, and 
performance upgrade. The committee deliberated the improvements, 
directivity, etc., and gave recommendations.


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3. [Particle and Nuclear Physics Division] by T. Takahashi, 
T. Nomura, T. TSUKAMOTO, S. MIHARA, T. MIBE, AND T. KOMATSUBARA
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 OUTSTANDING PAPERS FROM THE HADRON EXPERIMENTAL FACILITY 
(by T. TAKAHASHI and T. NOMURA)

     The paper on the discovery of a Xi hyper-nucleus, published in 
2015 as http://dx.doi.org/10.1093/ptep/ptv008, won the 22th 
Outstanding Paper Award of the Physics Society of Japan. 
     The Xi hyper-nucleus is a bound state between a double-
strangeness Xi meson and a nucleus and it is found in an emulsion 
irradiated in the KEK- PS E373 experiment by a new overall scanning 
method, which is developed for the on-going E07 experiment at J-PARC. 
The obtained Xi-binding energy is much larger than that for the 
atomic binding. In consequence Xi-nucleus potential and the 
underlying Xi-Nucleon interaction were determined to be attractive. 
In E07 which restarts full data-taking from April 2017, double 
strangeness hyper-nuclear events will be obtained 10 times more than 
that in E373. Another physics paper appeared from the KOTO 
experiment, which searches for a CP-violating ultra-rare decay of the 
neutral kaon. KOTO took first physics data for 100 hours in May 2013. 
After a long time since a preliminary result had been announced in 
2014, the paper was finally completed with a great effort by a Ph.D. 
student. It describes not only a new search for the KL->pi0 nu nubar 
decay but also the world-first direct search for KL->pi0 X0, where X0 
remains an invisible particle with a mass of 135 MeV/c^2 (the pi0 
mass). 
     The paper was submitted to Progress of Theoretical and 
Experimental Physics (PTEP) in September 2016, accepted in December 
2016, and published at the very end of February 2017 on 
https://doi.org/10.1093/ptep/ptx001. 

 2 X 10^21 PROTONS ON TARGET (POT) AND 470KW BEAM POWER
(by T. TSUKAMOTO)

     Neutrino beam operation was resumed on January 8 after the 
shutdown during the year-end and New Year holidays. The beam power 
was 440 kW at the beginning and is increased to 470 kW (as of March 
13). POT reached 2 x 10^21 on March 3 by the operation from 2009. T2K 
eagerly desires to achieve 7.3~10^20 POT after the summer 2016 until 
April 12, and will sprint to analyze the data toward summer 
conferences. After April 12 the accelerator operation will be changed 
to slow extraction mode for experiments of the hadron facility. 
     Besides the T2K experiment, there are other activities which 
(will) use the neutrino beam at J-PARC. T59 is preparing detectors to 
measure the neutrino cross section in water, T66 is an experiment 
with emulsion (recently submitted two papers, and it is considered a 
new experiment). E61 was given the stage-1 status with a water 
Cherenkov detector which can change the location vertically for 
different neutrino energy. 

 STATUS OF THE COMET (COHERENT MUON TO ELECTRON TRANSITION) (E21) 
(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. The collaboration is intensively preparing 
detectors toward the start of the experiment. The CDC, main detector 
of Phase-I physics measurement, is being tested by using cosmic rays 
at KEK. The team is optimizing the operating condition to get the 
best performance of the detector. Another ingredient detector, 
composed of a straw-tube tracker and Cerium doped Lutetium Yttrium 
Orthosilicate (LYSO) crystal calorimeter used for beam measurement, 
is irradiated with an electron beam at Research Center for ELectron 
PHoton Science (ELPH) of Tohoku University. This is the final test to 
confirm its performance. Preparations of an 8 GeV proton beam 
acceleration and an extraction test are also in progress with the 
J-PARC accelerator and beam line teams. The parameters of the 
extracted 8 GeV proton beam will be measured for the first time. The 
extinction factor of the primary proton beam will be measured with 
the secondary beam in the Hadron Hall. Certainly, this will be an 
important milestone for the COMET experiment. 

 STATUS OF THE MUON G-2/EDM (E34) (by T. MIBE)

     The E34 collaboration prepares for precision measurements of 
muon anomalous magnetic moment and electric dipole moment. The 
collaboration works for refinement of technical design and resolving 
issues that were pointed out by the focused review in Nov. 2016. In 
the course of realizing the experiment, three tests were carried out 
at the Materials and Life Science Experimental Facility (MLF). The 
muonium production yields from silica aerogel with laser-ablated 
holes was studied systematically by manipulating the depth of holes. 
For the preparation for muon acceleration with Radio Frequency 
Quadrupole (RFQ), an electrostatic acceleration of low-energy muon 
and negatively-charged muonium was demonstrated. A measurement of 
beam emittance was scheduled at the end of March. The first test 
module for the positron tracking detector was developed with the new 
silicon-strip sensor and dedicated Application Specific Integrated 
Circuits (ASIC) chips. The test module was evaluated at the muon 
beamline at MLF. 

 PROGRAMS OF ADVISORY COMMITTEE MEETINGS (by T. KOMATSUBARA) 

     The 23rd Program Advisory Committee (PAC) meeting was held at 
Tokai on January 11-13. Status of the experiments was reported, and 
proposals and near-term machine time allocation were discussed. 
https://kds.kek.jp/indico/event/23410/ 
PAC report will be 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 July 24-26, 2017.


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4. [Materials and Life Science Division] by Toshiji KANAYA
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 RELIABLE NEUTRON PRODUCTION OPERATION WITH 150 KW PROTON BEAM

     1) Neutron Source
     On January 14, the neutron production operation for the 
Materials and Life Science Experimental Facility (MLF) user programs 
resumed at 150 kW after the winter shut-down period. As of March 8, 
43 days of scheduled beam time has been completed without any 
serious trouble. Therefore 147 days of user operation have been 
performed with high availability of 93% since April, 2016.
     In the fabrication of the next target vessel with an improved 
version, forepart of the target vessel was completed. The mercury 
vessel and the water shrouds of the forepart were integrated into a 
single monolithic structure that was cut out from a stainless steel 
block with a wire electron discharge machining. The beam windows of 
those vessels were welded to the forepart at the corresponding 
connecting positions.
     The off-gas process system, which collects gaseous radioactive 
materials generated in the target at the target replacement, was 
improved to increase the number of gas holders from 4 to 7 aiming at 
shortening the target vessel replacement time to 28 days from 32 days 
of estimated duration. Installation of new gas holders was completed 
on March 14, 2017.

 USERS' PROPOSALS WERE REVIEWED AND 153 GENERAL USERS' PROPOSALS WERE 
APPROVED FOR 2017A

 NAC2017 & IAC2017 GAVE POSITIVE RECOMMENDATION TO THE NEUTRON 
INSTRUMENTS SUITE

     2) Neutron Instruments and Science
     Proposals submitted for 2017A were reviewed by the Neutron 
Science Proposal Review Committee (NSPRC) meeting held on January 24, 
2017 and 153 general users' proposals for neutron instruments were 
approved. This result was authorized by MLF Advisory Board on 
February 8, 2017. In this period, the competition rate was relatively 
low and was less than 1.0 in some of beamlines. It might be a serious 
situation, and careful analysis and some actions are needed.
     At Neutron Advisory Committee 2017 (NAC2017) and International 
Advisory Committee (IAC2017), we got positive comments on neutron 
instruments, which are appreciated for our diverse and novel 
instrumentation. One concern mentioned at NAC2017 was budget issue to 
maintain beamlines against aging problems. The official 
recommendations documents were in preparation. 


 S1-INSTRUMENT ARTEMIS STARTED USER PROGRAM 

     3) Muon Science Facility (MUSE)
    
     Commissioning work of the general purpose muSR spectrometer, 
ARTEMIS, furnished in the S1 Area under the sponsorship of Element 
Strategy Initiative Project (headed by H.Hosono of  Tokyo Institute 
of Technology, TiTech), has come to an end in early 2017.  The 
spectrometer was tuned up to show a good performance comparable with 
the D1 Instrument.  Following the proposal from the principal 
investigator (PI) of the S1-type Project Research (who is 
responsible for the operation of ARTEMIS), the instrument has started 
to serve for the General Use Proposals in a "trial mode" in February, 
2017. (Here, the "trial mode" means that the experiment is subject to 
intervention upon whatever necessity of S1-type project.) 
Dr. Fujihara from Tokyo University of Science was the first user of three 
users who enjoyed muSR measurements using ARTEMIS, whose proposals 
lined up on the top of the queue in the "reserved" status for the 
D1 instrument.  Meanwhile, it was announced that ARTEMIS was formally 
open for user program in the call for General Use Proposals in 2017A 
round and we accepted several General Use Proposals.  
     According to the recent Muon Science Proposal Review Committee, 
six 2017A proposals are approved, and they are going to be scheduled 
in the period from the coming April to November.  It is now expected 
that the extremely high competition for muon beam at MUSE will be 
considerably relaxed in the forthcoming proposal rounds.


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5. [Nuclear Transmutation Division] by Toshinobu SASA
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 SECURE THE FLUID TARGET IN STEEL CONTAINER

     Accelerator-driven system designed by JAEA applies the lead-
bismuth eutectic alloy (LBE) for spallation target and reactor 
coolant because of its good neutronic performance for fast neutron 
system, low melting point (similar to that of liquid sodium), and 
chemical inertness. The most serious issue to handle LBE is a 
compatibility with familiar nuclear reactor materials. LBE has a 
characteristic to dissolve out Nickel from structural materials and 
it drastically decreases the lifetime of the materials in LBE.
     The technology management of oxygen potential to suppress the 
dissolution of the steels by flowing LBE especially in higher 
temperature (above 400 degree centigrade) is studied worldwide as an 
optimum solution. When oxygen potential kept in appropriate range 
(10^[-5] to 10^[-7]%), very thin oxide film is formed on the interface of 
structural materials and LBE and then this film suppresses the direct 
contact of materials and flowing LBE. Transmutation Experimental 
Facility (TEF) team also tackled this issue over 10 years and focuses 
the study in recent years. To control the oxygen potential, precise 
measurement of oxygen potential is important. Many challenges to 
establish reliable and cost-efficient oxygen potential sensor were 
performed. The latest oxygen sensor represents the theoretical value 
quite well and manufacturing cost reaches about one-tenth compared 
with our first prototype sensor. 
     Using the signal from oxygen sensor, oxygen potential in LBE is 
controlled by mixture of the two carrier gases, oxygen-rich argon gas 
and hydrogen-rich argon gas. By controlling the flow amount of these 
two gases with inert argon carrier gas,@we succeeded to manage the 
oxygen potential of the LBE in stagnant furnace. Further experiments 
to confirm the oxygen control method in flowing LBE with small 
experimental LBE loop are in preparation. Large-scale corrosion test 
loop (OLLOCHI: Oxygen-controlled Lbe Loop for Corrosion tests in HIgh 
temperature) was also produced and is ready to collect the corrosion 
test data in various experimental conditions.


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6. [Safety Division] by Yukihiro MIYAMOTO and Kotaro BESSHO
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 4TH SYMPOSIUM ON SAFETY IN ACCELERATOR FACILITIES

     Since the radioactive material leak incident at the Hadron 
Experimental Facility in 2013, the J-PARC Center has held safety 
symposiums every year to exchange information and discuss efforts for 
ensuring facility safety and related matters. The 4th Symposium on 
Safety in Accelerator Facilities was held on January 26-27 at Ibaraki 
Quantum Beam Research Center (IQBRC), and 131 participants from 
various accelerator facilities, universities and companies, shared 
information on various safety issues. The featured topics this time 
were emergency response and electrical safety in accelerator 
facilities, and various efforts were reported and discussed through 
12 oral presentations and 11 poster presentations. The participants 
deepened mutual understanding on safety issues at accelerator 
facilities.

 THE APPLICATION FOR A LICENSE OF THE OPERATION WAS GRANTED

     The application for a license of the operation was granted by 
the Nuclear Regulation Authority (NRA) on Feb. 2. The topic was an 
expansion of the waste gas storage tanks for exchanging the neutron 
target vessel in the Materials and Life Science Experimental Facility 
(MLF).


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7. [Information System Section] by Atsushi MANABE
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 EDUROAM IS NOW AVAILABLE AT J-PARC

     eduroam (https://www.eduroam.org/) is the secure roaming access 
service developed for the international research and education 
community and mutually used among a huge number of research 
institutes, universities and others around the world. From April, 
this service becomes available at major buildings and facilities of 
J-PARC. The eduroam will be a convenient third option of internet 
connection service for J-PARC visitors in addition to the User LAN 
and Guest Net.


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8. [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++++++++++++++++++++++++++++++++++++++++