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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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Information on the project can be also obtained at the web site:
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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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