Article 73 at 15/10/29 17:31:45 From: ito.hiroshi45@jaea.go.jp Subject: [news-l:00073] J-PARC Project Newsletter No.60, October 2015

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J-PARC Project Newsletter
No.60, October 2015
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 PRIMED FOR MORE SCIENCE AND USER COMFORT.

2. [Accelerator Division]

MAINTENANCE AND IMPROVEMENT WORK DURING SUMMER SHUTDOWN.

3. [Particle and Nuclear Physics Division]

BEAM TIME AND MAINTENANCE WORKS AT HADRON HALL.
FIRST LOOK AT ANTINEUTRINO APPEARANCE FROM T2K.

4. [Materials and Life Science Division]

MERCURY TARGET VESSEL HAS BEEN REPLACED.
CKORJ-PARC AND J-PARC HOSTED THE 1ST JAPAN-KOREAN JOINT WORKSHOP.
CONSTRUCTION OF A NEW INSTRUMENT AND MAINTENANCE FOR EXISTING
INSTRUMENTS.
BRAND-NEW SOLENOID AND SCRAPER ARE IN PLACE.
CONCLUDED ARRANGEMENT ON COOPERATION WITH THE AUSTRALIAN NUCLEAR
SCIENCE AND TECHNOLOGY ORGANIZATION (ANSTO).

5. [Nuclear Transmutation Division]

NATIONAL REVIEW WORKING PARTY ENDORSED RESEARCH ACTIVITIES FOR
PARTITIONING AND TRANSMUTATION.

6. [Safety Division]

THE FIRST MEETING OF THE LIAISON COMMITTEE ON SAFETY AND HEALTH FOR
CONTRACTORS WORKING AT J-PARC.

7. [Editorial Note]

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1. [Overview] by Naohito SAITO
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J-PARC PRIMED FOR MORE SCIENCE AND USER COMFORT

We are very happy to begin this message with congratulations to
Prof. Takaaki Kajita of University of Tokyo, who will be awarded the
Nobel Prize in physics together with Prof. Arthur B. McDonald of
Queen's University. This moment has been hoped for by many
collaborators and relevant people including us. We are proud of
ourselves for carrying out the T2K experiment at J-PARC, the precision
measurements of neutrino oscillations which are the subject of the
award. We will continue our efforts to provide more beam power and
more protons onto the T2K target to solidify a hint for CP violation
in the neutrino sector.

Our summer was very busy as usual for maintenance and
improvement work in all facilities. A major challenge was the
replacement of the mercury target at MLF, which had a minor water leak
from the protection layer surrounding the mercury vessel. As reported
in the previous newsletter, the problem led to two months of beam time
loss.

We have formed a dedicated review committee for the target vessel
issues comprising experts external to J-PARC. Our investigation of the
causes of the leak and preventive measures were evaluated and endorsed
by the committee. In addition, we have received many useful
suggestions for upcoming replacements. We are very grateful to the
committee members for their dedicated work even with a short notice.

As for the lost beam time for users at the MLF, we decided to
provide the beam to all users based on the 2015A proposal evaluations.
Consequently, we will not call for proposals in the period of 2015B,
while emergency proposals are always accepted as in the past. We will
continue to operate the facility with special care for stable and
reliable operation, balancing the beam power upgrade and careful
inspection of target health. We aim to achieve more than 90%
beam availability, which was achieved in the past with lower beam
power. We are also open to any suggestions from users so that we can
provide more convenient and comfortable research environment to the
users.

There were many other work activities during the summer shutdown
period, including the neutrino facility, hadron facility, and
accelerator facilities. Those are covered in the following articles.
We also worked hard on the budget negotiations with MEXT through KEK
and JAEA, and we hope to hear better news towards the end of the
calendar year.

In the end of this message, we announce the start of a series of
workshops, "J-PARC workshop", especially to stimulate more scientific
discussions under the J-PARC organization. There are already several
proposals for interesting topics of science. We hope that various
scientific outputs would emerge from the discussions in and after the
workshops.

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2. [Accelerator Division] by Kazuo HASEGAWA
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MAINTENANCE AND IMPROVEMENT WORK DURING SUMMER SHUTDOWN

Beam operation was suspended for maintenance during the summer
shutdown from July to September. Maintenance of the components and
various improvement work were made in the accelerator facilities.

At the linac, some multipacting regions, where the radio
frequency (RF) reflection is rather high, are observed at some of the
separated type drift tube linac (SDTL) cavities after the great
earthquake in 2011. In particular, the region of the SDTL5#B cavity
has been shifted to the operation point. We attempted vacuum property
improvement by degassing with warm water, etc., but they were not so
effective. In this maintenance period, we took more active measures
such as cleaning of the inside of the cavity with a cloth that was
dipped with an organic solvent. A certain improvement of the RF
characteristics is observed so far at the high-power conditioning and
beam tuning.

At the 3 GeV Rapid Cycling Synchrotron (RCS), we have several
items for improvement. One is to reinforce the Anode power supplies
for the acceleration cavity system. The cause of the insufficient
power supply capacity was revealed at the 1 MW trial study. This
improvement will lead to more stable acceleration at the higher power
beam operation. Another is to improve the power supplies of the
horizontal shift bump magnets. This will be expected to improve the
flatness of the bump magnetic fields and less beam loss during beam
injection.

In the Main Ring synchrotron (MR), we have a plan to have a
double accelerating voltage with approximately 1 second period for
the fast extraction. A high impedance metal magnetic alloy core
(FT3L) which has been newly developed is used for it.
In 2014, one prototype cavity was installed and has already been used
for user operation. Based on the operational results, we have made a
plan to replace 8 existing cavities in 2015 and 2016. In this summer,
we finished replacement of 4 of those cavities as scheduled.
We have studied and tested a shortening of the acceleration period at
the slow extraction for the hadron experiment facility. As a result,
it will be feasible to reduce the period from 6 seconds to 5.52
seconds.

The J-PARC accelerator facilities resumed beam operation on
September 29 as scheduled. After beam tuning and study of the
accelerator facilities, the user operation with the new period is
expected to start from middle of October 2015.

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3. [Particle and Nuclear Physics Division] by T. TAKAHASHI,
K. AOKI AND T. TSUKAMOTO
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BEAM TIME AND MAINTENANCE WORKS AT HADRON HALL (by T. TAKAHASHI and
K. AOKI)

Slow extraction (SX) beam was delivered for user operation
during April 24 to May 7 and June 5 to July 1. In the beam time,
several experiments were executed after the Hadron Hall renovations.
Measurement of neutral Kaon rare decays was successfully resumed. A
new experiment for testing muon-electron universality was started in
good shape.
In addition, an experiment to study energy levels of hypernuclei
by precise measurement of gamma-rays was successfully carried out.
Gamma-rays from 4-Lambda-He and 19-Lambda-F hypernuclei were measured
by a Ge-array detector, which is called Hyperball-J. The results were
reported at the HYP2015 conference. It is one of the major conferences
in this field and was held at Sendai in September (http://lambda.phys.tohoku.ac.jp/hyp2015).
During the summer shutdown, maintenance work in the hadron
primary beam line room was performed for the vacuum system of the
beam line and the cooling water line of the beam dump. In addition,
the emergency collection system was improved and no longer requires
frequent repumping during the beam operation. Thermo-switches were
installed to the beam dump and implemented as Machine Protection
System (MPS).
Before and after the maintenance work, the double layer gas-tight
sheets, which cover the primary beam line room, were successfully
removed and restored. They passed the airtight test and are ready to
accept the beam.

FIRST LOOK AT ANTINEUTRINO APPEARANCE FROM T2K (by T. TSUKAMOTO)

The T2K collaboration observed 3 candidate electron antineutrino
events in the muon antineutrino beam from J-PARC at Super-Kamiokande.
http://www2.kek.jp/ipns/articles/t2k-antinue-first-result/index.html
http://t2k-experiment.org/2015/07/first-look-at-antineutrino-appearance-from-t2k/
As reported in the last newsletter issue No.59, T2K started
antineutrino beam operation from May 2014 and accumulated about
4x10^20 POT (protons on target) so far, and released its first
measurement of muon-antineutrino disappearance in May. The result of
appearance of electron antineutrino was obtained with the same
antineutrino beam data set. T2K would expect to observe 3.8 events,
with 1.8 coming from backgrounds and 3 events were observed.
The search for electron antineutrino appearance with more antineutrino
beam data is the next step in the exploration of charge-parity (CP)
symmetry.
The result was presented at several international conferences etc. The
details are as follows:
https://indico.cern.ch/event/356420/session/10/contribution/322
https://www2.kek.jp/physics-seminar/files2015/20150724_T2K.pdf
https://indico.fnal.gov/getFile.py/access?contribId=60&sessionId=17&resId=0&materialId=slides&confId=9771
http://theory.fnal.gov/jetp/
http://www-conf.slac.stanford.edu/ssi/2015/
http://www.icas.ru/english/index.htm
https://indico.cern.ch/event/344173/

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4. [Materials and Life Science Division] by Toshiji KANAYA
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MERCURY TARGET VESSEL HAS BEEN REPLACED

1) Neutron Source
In July, we concluded the cause of the trouble on the target
vessel as follows. A part of the welded surface between two steel
plates which were used to form a shroud of the target vessel for the
cooling channel was incomplete in the fabrication process, and then a
crack occurred with repetitive thermal stress induced by beam trips
during the operating period. As a countermeasure against this defect,
we changed the welding method for the shroud of a spare target vessel.
The fabrication of the spare target vessel was completed in September
2015. We replaced the target vessel with new one from late September
to October 7.
Regular maintenance from the spallation neutron source components
to the 3-GeV proton beam transport facility was done. Periodic
inspection and an overhaul of a hydrogen pump were conducted for the
cryogenic hydrogen system. Survey and alignment of the 3-GeV proton
beam transport components were also carried out.
Pressure wave mitigation technology by using microbubbles, which
had been developed for improving the performance of the mercury
spallation target at J-PARC won the 2014 Japan Society of Mechanical
Engineers (JSME) Medal for New Technology, and the mercury target
vessel was displayed at the exhibition booth of the National Museum of
Nature and Science from July 28 to August 10, 2015.

CKORJ-PARC AND J-PARC HOSTED THE 1ST JAPAN-KOREAN JOINT WORKSHOP
CONSTRUCTION OF A NEW INSTRUMENT AND MAINTENANCE FOR EXISTING
INSTRUMENTS

2) Neutron Instruments and Science
The 1st Japan-Korean Joint Workshop on Polarized Neutron
Reflectometry was held at J-PARC on July 30, 2015. It was organized
by the Center for Korean J-PARC Users (CKorJ-PARC) and MLF. 18
participants (Japan: 11, Korea: 7) joined this workshop. In the
workshop, both Korea Atomic Energy Research Institute (KAERI) and
J-PARC sides reported the current status of neutron reflectometers and
development work on neutron optical devices including polarizing
supermirrors and He-3 polarizing filters. Also, extensive discussion
on future collaboration between Korea and Japan was held. The workshop
provided a good opportunity for information exchange on this field,
and hence CKorJ-PARC and J-PARC center agreed to enhance collaboration
continuously.

In this summer shutdown period, construction work of BL23
(POLANO, Polarized Neutron Spectrometer) was carried out. The beam-
transport section and a slow chopper are being installed and tested.
The existing instruments and auxiliary devices (choppers, optical
devices and vacuum pumps, etc.) are being maintained and upgraded.
Additional Si111 analyzer banks of BL02 (DNA, near-backscattering
spectrometer) have been installed.

BRAND-NEW SOLENOID AND SCRAPER ARE IN PLACE

3) Muon Science Facility (MUSE)
One of the major tasks for Muon staff in this summer shutdown
period was the replacement of superconducting solenoid coils (SSC) on
the D-line. The SSC and its cooling system were partially damaged in
the Great East Japan Earthquake that occurred in 2011 and were
temporally fixed for quick restoration. Since then, Muon staff have
been working in a stepwise fashion with the aim of the complete
recovery of the whole system. Following the replacement of the helium
compressor system in last summer, they proceeded to the final step of
replacing SSC. In last July, the cannon-shaped gigantic cryostat
containing old SSC (~6 m long) was pulled out from the channel on the
wall separating the experimental hall from the M2 tunnel, and the
brand-new SSC in an orange-colored cryostat was finally set up in the
fixed position and connected to the cooling system. The soundness of
the entire system was proven by the subsequent test operation for
cooling and magnet excitation conducted in collaboration with J-PARC
Cryogenics Section and thus is ready for beam operation this coming
fall.
Another major task was replacement of the beam scraper system on
the primary proton beamline. The scraper, consisting of a set of
water-cooled massive copper collimators, is placed just behind the
muon production target to clean up the beam halo induced by scattering
in the muon target.
It turned out that one of the thermometers monitoring the local
temperature was not operating properly, which led to the decision to
replace the entire system considering the scheduled beam power
increment towards the end of FY2015. The replacement work was
successfully conducted with special precaution to prevent the
radiation hazard early in September. The used scraper is now safely
stored in one of the storage pits for highly radioactive instruments.

CONCLUDED ARRANGEMENT ON COOPERATION WITH THE AUSTRALIAN NUCLEAR
SCIENCE AND TECHNOLOGY ORGANIZATION (ANSTO)

(4) International agreement
The High Energy Accelerator Research Organization (KEK), the
Japan Atomic Energy Agency (JAEA), and ANSTO concluded an arrangement
on cooperation in the field of neutron science at Manly, Sydney, on
20th July at the opening of the 2nd Asia-Oceania Conference on Neutron
Scattering.
Dr. Adi Paterson, the CEO of ANSTO, visited J-PARC on 18th August
and extensively discussed future cooperation with the Director of
J-PARC Center and MLF staff.

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5. [Nuclear Transmutation Division] by Toshinobu SASA
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NATIONAL REVIEW WORKING PARTY ENDORSED RESEARCH ACTIVITIES FOR
PARTITIONING AND TRANSMUTATION

In August 2015, the 8th and 9th meetings of national review
working party were held in Tokyo. The meetings were called to review
current research and development (R&D) activities for overall
partitioning and transmutation technologies for accelerator-driven
systems (ADS).
In the meeting, J-PARC Center introduced the latest result of
technology development for construction of Transmutation Experimental
Facility, specifically for the ADS Target Test Facility, TEF-T. R&D
activities for partitioning, minor actinide bearing fuel fabrication,
and Transmutation Physics Experimental Facility, TEF-P, were also
presented by Partitioning and Transmutation Technology Division of
JAEA.
Though official recommendation has not been issued, the working
party expressed its recognition of the proper progress in our
activities and had opinions to endorse the R&Ds to establish
transmutation technologies by ADS together with the technologies for
partitioning and handling of fuels for transmutation in the meetings.
From the technical point of view of the R&D for TEF-T, increasing
operation temperature, temperature gradient of target mockup loop and
management of oxygen potential control in flowing high temperature
liquid metal are identified as the most pressing concerns. The
preparation of mockup loop operation including refurbishment of the
loop components is underway.

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6. [Safety Division] by Yukihiro MIYAMOTO and Kotaro BESSHO
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THE FIRST MEETING OF THE LIAISON COMMITTEE ON SAFETY AND HEALTH FOR
CONTRACTORS WORKING AT J-PARC

The Liaison Committee on Safety and Health for Contractors
Working at J-PARC was established in order to share a common safety
mindset and information concerning safe work at J-PARC. The first
meeting of the committee was held on July 24 at an exhibition hall of
JAEA, Atom World, with 80 participants from 75 companies. At the
meeting, there were reports on recent accidents and troubles in
J-PARC, and also lessons learned from them and precautions were
presented. Based on these reports, some opinions were given by
contractors for ensuring a safe work environment. We believe that
these reports and discussions should be helpful to raising safety
awareness for the contractors working at J-PARC. Furthermore, the
latest safety information on J-PARC has been continuously shared
through e-mail after the meeting.

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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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