[Neutron] J-PARC Newsletter No. 63

shibata.kaoru shibata.kaoru at jaea.go.jp
Mon Aug 22 05:12:15 CEST 2016


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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 at kek.jp 
Kaoru SHIBATA: shibata.kaoru@ jaea.go.jp 
Takashi ITO: itou.takashi at jaea.go.jp 
Dick MISCHKE (English Editor): mischke at triumf.ca 
Junko BEANBLOSSOM (Secretary): beanblossom.junko at jaea.go.jp
++++++++++++++++End of Letter++++++++++++++++++++++++++++++++++++++++






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