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J-PARC Project Newsletter
No.63, July 2016
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]
J-PARC Summer Activities 2016.
2. [Accelerator Division]
OPERATION STATUS OF THE ACCELERATORS: FOUGHT WITH FAILURES.
3. [Particle and Nuclear Physics Division]
NEW GENERATION EXPERIMENTS START AT THE HADRON HALL.
T2K PRESENTS FIRST CP VIOLATION SEARCH RESULT.
STATUS OF THE MUON G-2/EDM (E34).
STATUS OF THE COMET (E21).
4. [Materials and Life Science Division]
STEADY USER OPERATION WAS CONTINUED.
TWO HUNDRED THIRTY EIGHT NEUTRON PROPOSALS WERE SUBMITTED FOR THE
2016B PERIOD.
A SCIENTIFIC MEETING OF NEUTRON APPLICATION IN LIFE SCIENCE WAS HELD.
NEW SPECTROMETER "ARTEMIS" GOES ON A MAIDEN VOYAGE.
5. [Nuclear Transmutation Division]
SCOOPING UP THE 10 W BEAM FROM 250 kW PROTON STREAM.
6. [Safety Division]
FY2016 WORKSHOP 5. 23 FOR FOSTERING SAFETY CULTURE AT J-PARC.
APPLICATION FOR LICENSES OF THE OPERATION WAS GRANTED.
THE SAFETY INSPECTION WAS SUCCESSFULLY CONDUCTED BY THE NUCLEAR
SAFETY TECHNOLOGY CENTER (NUSTEC).
7. [Editorial Note]
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1. [Overview] by Naohito SAITO
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J-PARC Summer Activities 2016
We have ended the beam time at the end of June, and we are in
the middle of the summer shutdown, which is yet another very busy
time for J-PARC. As we have reported in the previous newsletter, we
are re-emphasizing the importance of reliable and stable operation of
the facility so that we can improve the beam availability towards 90
percent. We have learnt from the previous incidents that a large
fraction of the users are longing for a stable and reliable beam
delivery. It is more true for MLF users even with a modest intensity.
While we are continuing our efforts to reach highest possible beam
power at each facility, we have reminded ourselves to keep highest
possible beam availability.
Summer maintenance activities are very important to fulfill
potentially conflicting requirements to the facility: highest beam
power and highest beam availability. Most of the activities are
identified based on their readiness, urgency, and "risk analyses". We
would not refer to our analyses as full-fledged ones, but the impact
of the possible failure and probability for occurrence of such a
failure have been largely considered to determine a series of
maintenance works during shutdown. Such an analysis is becoming more
important especially because the facility is getting close to ten
years old.
In addition, we continue to develop a better relationship with
the local communities. We, J-PARC Center and Tokai Village, co-
organized public lectures by Profs. Kajita and Murayama at Tokai
Culture Center on July 16. The lectures were attended by an audience
of more than 700 comprising a wide age range, from primary school
students to senior science fans. The lectures were followed by many
questions from the audience which triggered a very lively discussion.
The day was filled with smiles of audience, lecturers, and
organizers, including the Mayor of the village.
We will continue our best efforts to bring the beam back on time
after these fruitful summer activities.
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2. [Accelerator Division] by Kazuo HASEGAWA
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OPERATION STATUS OF THE ACCELERATORS: FOUGHT WITH FAILURES
We delivered beam to the Materials and Life science experimental
facility (MLF) by the morning of April 4 as scheduled. But, as we
reported at the previous newsletter, a bending magnet of the Main
Ring (MR) failed on March 29 and beam to the neutrino experimental
facility (NU) was stopped. The failed magnet was replaced by a spare
and the failure was recovered on April 8. In the meanwhile, a vacuum
leak at a collimator in the 3 GeV synchrotron (RCS) occurred and the
start dates of planned user operation were postponed to April 13 for
the NU and 15 for the MLF. After the resumption, the beam powers to
the NU and to the MLF were 390 kW and 207 kW respectively, which were
the same level as before the failures.
There were several beam trips for a total of about 20 hours by
mainly linac related failures in May, but we delivered beam to the
MLF at 207 kW mostly as scheduled. On the other hand, there was an
invasion of a small animal to a transformer unit of the MR
electromagnet power supplies on May 3. It took about 6 days to
recover. Beam power to the NU resumed at 390 kW. Furthermore, we
improved it to 410 - 420 kW from the 23rd as a result of beam tuning.
The operation mode and the beam destination were changed to the
hadron experimental facility (HD) on the 27th and user operation was
performed at 42 kW.
A new operation Run#69 was started after replacement of the ion
source on June 1. About 200 kW and 40 kW beams were supplied to the
MLF and to the HD, respectively. The first half of the run was
relatively smooth. However, several breakdowns of klystron bias power
supplies stopped beam operation for several tens of hours, which were
followed by simultaneous breakdowns due to a timing system failure.
As a result, the availability in this Run was down to approximately
85 percent.
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3. [Particle and Nuclear Physics Division] by T. TAKAHASHI,
T. NOMURA, K. OZAWA, T. TSUKAMOTO, AND S. MIHARA
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NEW GENERATION EXPERIMENTS START AT THE HADRON HALL (by
T. Takahashi, T. Nomura, and K. Ozawa )
Several maintenance works including exchanges of vacuum clamps
finished in this spring and slow extraction (SX) beams from the Main
Ring were delivered for a user operation from May 27 to June 30.
In the beam time, several experiments were executed. Measurements of
neutral Kaon rare decays were successfully resumed after a major
detector upgrade: the installation of an additional cylindrical
photon detector, called "inner barrel", inside the existing detector.
With this new detector which provides further background rejection
power, KOTO accumulated in this 1-month run, a quarter of the amount
of data taken in 2015. At the K1.8 beam line, a new experiment to
study nuclei embedding two strange quarks started using nuclear
emulsions combined with a newly installed KURAMA spectrometer. The
experiment aims to collect 10 times larger statistics than the
previous data. In addition, another experiment to study structure of
strange baryon Lambda(1405) obtained significant data. Also a pilot
experiment for high-resolution Kaonic-Atom spectroscopy using
superconducting Transition Edge Sensor (TES) Micro-Calorimeters was
performed. The TES is expected to achieve the resolution 30 times
better than a Solid State Detector, and this is the first time to use
the TES for a nuclear physics experiment.
T2K PRESENTS FIRST CP VIOLATION SEARCH RESULT (by T. TSUKAMOTO)
Neutrino beam operation finished at 9 AM on May 27 and then the
beam operation was switched to the slow extraction mode.
Unfortunately we experienced many accelerator troubles.
T2K collected 3.97x10^20 POT before the summer in 2016. Beam power
reached 420 kW at the end. Stable and higher power operation is
expected from autumn.
In total, T2K has collected 1.51x10^21 POT from the beginning.
Collected data has been analyzed and the result for the appearance
measurement of anti-electron neutrino was presented at the
international conferences, NEUTRINO 2016 (http://neutrino2016.
iopconfs.org/home ) and ICHEP2016 (http://www.ichep2016.org/) in this
summer. At ICHEP2016 T2K presented observation of 32 electron
neutrinos and 4 electron antineutrinos, when they expect around 24
neutrinos and 7 antineutrinos with no CP violation. When analyzed in
a full framework of three neutrino and antineutrino flavors, and
combined with measurements of electron antineutrino disappearance
from reactor experiments, the T2K data favor maximal CP violation.
The CP conserving case (delta_CP=0 or pi(180deg)) is outside the 90
percent Confidence Interval for the first time. Though the statistics
are still low, the result indicates the CP violation in the lepton
sector.
Test experiments, T60 (emulsion) and T64 (neutron/gamma
discrimination), were finished. A prototype water module was
constructed in T59 and the commissioning started to be ready for
neutrino beam from autumn.
Maintenance work of remote operation for its enhancement has
been started and the test of improved proton beam monitor is planned.
The Third International Meeting for Large Neutrino
Infrastructures organized by High Energy Accelerator Research
Organization (KEK), Institute for Cosmic Ray Research (ICRR),
Fermilab, the Astroparticle Physics European Consortium (APPEC), the
International Committee for Future Accelerators (ICFA) Neutrino
Panel, Astroparticle Physics International Committee (ApPIC)/ the
International Union of Pure and Applied Physics (IUPAP)and also
several worldwide funding agencies was held at KEK on the 30th and
31st of May 2016.
https://kds.kek.jp/indico/event/20176/
http://www.kek.jp/ja/NewsRoom/Release/20160606134000/ (only in
Japanese)
This meeting was to follow up the discussions in the previous two
meetings held in Paris and Fermilab to develop a strategy toward
realization of next generation large neutrino infrastructures in a
coherent manner.
https://kds.kek.jp/indico/event/20176/page/2
STATUS OF THE MUON G-2/EDM (E34) (by. S. MIHARA)
The E34 collaboration prepares for precision measurements of
muon anomalous magnetic moment and electric dipole moment.
The experimental design is being refined towards construction. There
are two publications on an interdigital H-mode drift-tube linac
design with alternative phase focusing and a three-dimensional spiral
injection scheme from April.
STATUS OF THE COMET (E21) (by. S. MIHARA)
Technical design of the COMET experiment (E21) was reviewed by
an international review panel on June 30 based on the updated
Technical Design Report (TDR) prepared by the collaboration. The
collaboration succeeded in publishing an article describing the
cryogenic design of the super-conducting magnet system.
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4. [Materials and Life Science Division] by Toshiji KANAYA
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STEADY USER OPERATION WAS CONTINUED
1) Neutron Source
From April to June in 2016, Materials and Life Science
Experimental Facility (MLF) user operation has been steadily
conducted: 3-week operation at 200 kW plus 6-day maintenance period
for purification of the helium refrigerator of the cryogenic hydrogen
circulation system. In the summer shut-down period, we are going to
clean the heat exchanger to remove contamination, replace the
adsorber with a new one, overhaul the compressor, and so on to
recover the performance of the helium refrigerator.
Efforts to improve the robustness of the neutron production
target vessel are also made. Redesign of the next target vessel is
almost finalized. Currently, investigations of fabrication procedure
and devising of better inspection methods for detecting defects at
the welding are eagerly underway. We are afraid that it will take
time to fabricate the next target vessel. Therefore, we are going to
use the current target vessel even after the summer shutdown period.
TWO HUNDRED THIRTY EIGHT NEUTRON PROPOSALS WERE SUBMITTED FOR THE
2016B PERIOD
A SCIENTIFIC MEETING OF NEUTRON APPLICATION IN LIFE SCIENCE WAS HELD
2) Neutron Instruments and Science
The general proposals for 2016B period were called during 17th
May to 7th June. The number of the neutron proposals received was
238, a slight decrease from 275 for 2016A. Those proposals was
reviewed in the Neutron Science Proposal Review Committee. The
approvals will be given by MLF Advisory Board and Selection Committee
at the end of August.
A scientific meeting entitled "Present Status and Future
Prospect of Neutron Application in Life Science" was held in Ibaraki
Quantum Beam Research Center (IQBRC) on 17th May and in J-PARC
Research Building on 18th May, co-hosted by J-PARC Center and
National Institutes for Quantum and Radiological Science and
Technology. A total of 45 researchers including 11 invited speakers
from a wide research area such as structural biology, bio-matter
solution and dynamics participated in this meeting. They discussed
deeply on what sciences are expected by utilizing a new single
crystal diffractometer for large bio-matter molecules under design
and a deuteration laboratory in preparation in J-PARC.
The European Spallation Source (ESS) - J-PARC collaboration
meeting was held at J-PARC Center from 1st to 2nd June. The meeting
was carried out under the agreement on cooperation in the field of
spallation neutron related development between ESS and J-PARC. 16
delegates from ESS visited J-PARC center and we exchanged information
about management of organization, radiation and general safety
issues, accelerator technology, neutron source, and neutron
instruments. The next meeting will be held at the ESS site in the
next year.
NEW SPECTROMETER "ARTEMIS" GOES ON A MAIDEN VOYAGE
3) Muon Science Facility (MUSE)
Following the successful optimization of surface muon beam
transport to the S1 experimental area on the S-line toward the end of
March, 2016, the focus of commissioning work shifted to a new μSR
spectrometer, named "ARTEMIS" (an acronym of Advanced Research
Targeted Experimental Muon Instrument at S-line). The spectrometer
was built with support from the Element Strategy Initiative Project
for Electronic Materials (headed by H. Hosono, Tokyo Institute of
Technology), primarily serving for the development of materials with
their evaluation using on-demand μSR. The commissioning work has been
conducted under S1-type Inter-University Muon Research Program
(Principal Investigator, K. M. Kojima), and it recently passed a
milestone in the performance for exceeding that of the twin
spectrometer running at the D1 area. Now, ARTEMIS has started
accepting specimens from Tokyo Inst. Tech. for the real μSR runs.
It is a maiden voyage in a quest for innovative materials.
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5. [Nuclear Transmutation Division] by Toshinobu SASA and
Hayanori TAKEI
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SCOOPING UP THE 10 W BEAM FROM 250 kW PROTON STREAM
The accelerator-driven system (ADS) is discussed as one of the
efficient devices to transmute long-lived nuclides. The core of the
ADS mainly loads the minor actinide (MA) bearing fuel and is kept in
subcritical condition during whole system lifetime. For the efficient
transmutation of MA, precise prediction of neutronic performance of
ADS is indispensable. The Transmutation Physics Experimental
Facility, TEF-P, is a part of the Transmutation Experimental Facility
(TEF) and aimed at obtaining experimental data for improving the
accuracy of neutronics evaluation of MA-loaded ADS. The critical
assembly installed in TEF-P, which is a small and low power reactor,
operates below 500 watt to prevent excessive radio-activation of the
assembly. However, proton beam injected to the assembly is legally
considered as one of the devices to determine the thermal power of
the assembly, and then high accuracy and stability is required.
For the separation of low power beam from J-PARC intense proton
accelerator, a meticulous low power beam extraction method from high
power proton beam stream is required. The laser charge exchange
method (LCE) is originally developed to measure the proton beam
profile and can be applied to the beam separation device for TEF-P.
The LCE device consists of a bright YAG-laser and laser transport
system with beam position controllers. The negative proton (H-) beam
from the J-PARC linac is exposed to the YAG-laser beam, which can
strip one of the two electrons, so as to change H- to neutral ones
(H0). The other electron of the H0 is finally stripped by a carbon
foil so that the positive protons (H+) are introduced into TEF-P. We
performed the stability tests for laser power and position under no
H- beam collision and considered the LCE can be applicable for TEF-P
beam source. From this fiscal year, we will try further tests with
the H- beam in cooperation with J-PARC accelerator division. The LCE
system is installed at the end of the 3-MeV linac in J-PARC and is
certified by the Nuclear Regulation Authority of Japan. In future
tests, data on the stability of the H+ beam intensity will be
obtained.
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6. [Safety Division] by Yukihiro MIYAMOTO and Kotaro BESSHO
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FY2016 WORKSHOP 5. 23 FOR FOSTERING SAFETY CULTURE AT J-PARC
The Workshop for Fostering Safety Culture at J-PARC is held
every year around May 23 on which the radioactive material leak
incident occurred at the Hadron Experimental Facility in 2013.
FY2016 workshop was held on May 20 at the auditorium of the Nuclear
Science Research Institute in order to raise safety awareness of the
staff members and not to forget the lessons learned from the incident.
The workshop began with an overview of the current status for
safety at J-PARC by the director, N. Saito. The invited talk entitled
"Safety Efforts in Airlines and Railways" was given by Keiji Abe,
principal researcher at the Safety Research Institute of West Japan
Railway Company. Mr. Abe spoke based on his experiences that human
error cannot be avoided, nevertheless we can prevent human error from
leading to an accident by improving prediction, recognition, and
recovery capabilities. At the end, the deputy director T. Ishii spoke
on the importance of not allowing major injuries and social injuries
leading to a loss of trust. An approach "Making safety activities
cheerful and fun" was also introduced.
APPLICATION FOR LICENSES OF THE OPERATION WAS GRANTED
The application for licenses of the operation of the whole
facilities was granted by the Nuclear Regulation Authority (NRA) on
April 18. The main topics were a new secondary beam line BL23 of the
Materials and Life Science Experimental Facility (MLF) and the change
of test bench for the Radio Frequency Quadrupole (RFQ) in the linac.
THE SAFETY INSPECTION WAS SUCCESSFULLY CONDUCTED BY THE NUCLEAR
SAFETY TECHNOLOGY CENTER (NUSTEC)
The safety inspection of MLF and RFQ in the linac was
successfully conducted, and the certificate was issued on June 27 by
NUSTEC. The inspection items were on the operation tests regarding
the safety interlocks and the measurement of radiation dose rates of
a new secondary beam line BL23 of MLF, and the test bench for the RFQ
in the linac.
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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
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