[Neutron] J-PARC Newsletter No. 70
shibata.kaoru
shibata.kaoru at jaea.go.jp
Mon May 21 04:00:59 CEST 2018
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J-PARC Project Newsletter
No.70, April 2018 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]
NEW FISCAL YEAR STARTED TOWARDS NEW STAGE OF FACILITY OPERATION.
2. [Accelerator Division]
OPERATION STATUS OF THE ACCELERATORS.
ACCELERATOR TECHNICAL ADVISORY COMMITTEE (A-TAC) MEETING.
3. [Particle and Nuclear Physics Division]
SUCCESSFUL BEAM TIME WITH 50 KW BEAM POWER.
J-PARC NEUTRINO FACILITY CONTINUES TO ACCUMULATE T2K DATA IN ANTI- NEUTRINO
MODE.
STATUS OF THE MUON G-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34).
STATUS OF THE COHERENT MUON TO ELECTRON TRANSITION (COMET).
PROGRAMS OF ADVISORY COMMITTEE MEETINGS.
4. [Materials and Life Science Division]
STEADY NEUTRON PRODUCTION OPERATION CONTINUES WITH PROTON BEAM POWER OF 400
KW.
SCHEDULED NEUTRON BEAM DELIVERY FOR 8-RUN CYCLES WAS ACHIEVED IN FY 2017.
GENERAL USER AND NEW USER PROMOTION NEUTRON PROPOSALS APPROVED FOR THE
2018A PERIOD.
QUANTUM BEAM SCIENCE FESTA WAS HELD ON MARCH 2 TO 4.
COMING OF THE SEASON FOR MEETINGS.
5. [Nuclear Transmutation Division]
MATERIALIZATION OF ACCELERATOR-DRIVEN SYSTEM IN COLD LIQUID METAL LOOP.
6. [Safety Division]
5TH SYMPOSIUM ON SAFETY IN ACCELERATOR FACILITIES.
THE APPLICATION FOR A LICENSE OF THE OPERATION WAS GRANTED.
7. [Editorial Note]
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1. [Overview] by Naohito SAITO
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NEW FISCAL YEAR STARTED TOWARDS NEW STAGE OF FACILITY OPERATION
We have just started the new Japanese fiscal year. I am now reappointed
as the director of J-PARC for three more years, which is the end of the
terms under the regulation. In the last three years, I believe that we went
through a phase change in the J-PARC operation from the construction and
initial production stage to a full production stage as a research facility.
The changes are not complete yet, therefore the goal of the next three years
is to continue the phase change to accelerate the science production and
innovations.
The beam power at the Material and Life Science Facility (MLF) is now
brought up to 500 kW, which is 50% of the design. This represents the third
trial to operate the facility at 500 kW, the previous two efforts were cut
short due to a water leak in the protection layer of the mercury target
vessel. As was reported in the previous newsletter, we went through a
thorough investigation of the cause and careful production of the new
target, a.k.a. target#8, and careful operation of that target at 300 kW in
the beginning, then 400 kW from the beginning of the year. Through this
process, we have built our confidence to operate the target at 500 kW based
on various measurements and model calculations. We really hope that all MLF
users will be able to enjoy the higher power beam until the summer shutdown.
We plan to install an even more robust target, target#10, to achieve higher
beam power for more science production and innovations with users.
The Main Ring is approaching 500 kW for the fast extraction (FX), which
is 67% of the design. The slow extraction (SX) also achieved the 50 kW
representing 50% of the expected maximal beam power for SX. The accelerator
team never stops improvements of the beam power and quality even before the
installation of the new power supply. The new power supply is being prepared
for further exploitation of the high intensity frontiers in particle and
nuclear physics. While we are still waiting for the main funding, the
management is working together with the project team to minimize the delay
of the implementation of the power supply, especially considering the power
supply is an important prerequisite of world leading physics program at the
neutrino and hadron experimental facilities.
All these facility improvements are for more science and innovations to
be produced with the users at J-PARC. We are looking forward to working with
more users for more excitements!
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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 7
as a new operation run: Run#78. The user program resumed for the Materials
and Life Science experimental facility (MLF) on January 10. The beam power
was increased to 400 kW, while it was 300 kW as of December.
A cooling water pump had a failure and was replaced on January 16.
Therefore, the user program for the hadron experimental facility
(HD) was delayed from January 15 to 17. The beam power was 10 kW at the
start-up, but thanks to the beam tuning, the beam power achieved
50 kW, which was a long-desired power level. The other highlights in this
run were a successful slow extraction and delivery test at 8 GeV for the
Coherent Muon to Electron Transition (COMET) experiment. The delivery to the
HD ended on February 26 as scheduled.
The accelerators had a beam study time from March 1 to 7, and then the
beam delivery resumed to the MLF. The main ring operation switched to the
fast extraction mode and delivered beam to the neutrino experimental
facility from March 9 at the beam power of 470 kW.
The availability in the Japanese Fiscal Year 2017 (from April
2017 to March 2018) was high: about 93 percent for the MLF since we had no
serious troubles at the linear accelerator (linac), the Rapid Cycling
Synchrotron (RCS) and the MLF. The availability for the Neutrino
Experimental Facility (NU) and HD facility users was 89% and 66%,
respectively. The cause of the low availability for the HD was an
electro-static septum trouble in April 2017.
ACCELERATOR TECHNICAL ADVISORY COMMITTEE (A-TAC) MEETING
The 17th A-TAC meeting was held at the J-PARC Research Building from
March 1 to 3. Eight 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, K.
OZAWA, T. ISHIDA, T. MIBE, S. MIHARA, AND T. KOMATSUBARA
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SUCCESSFUL BEAM TIME WITH 50 KW BEAM POWER (by T. TAKAHASHI, T. NOMURA, K.
OZAWA)
Slow extraction (SX) beams from the Main Ring were delivered for user
operation from Jan. 13 to Feb. 26 in the beam time. We achieved the beam
power of 50 kW, and it was the important milestone in the beam power
development of the SX beam.
In the beam time, several experiments were conducted. The E14/KOTO
experiment continued taking physics data. KOTO accumulated about 1e19 POT
for physics data, which roughly doubled the total data amount in 2017. For
the operation at 50 kW beam, the experiment implemented a new feature in the
trigger scheme. To judge the existence of associated extra hits in the
detector, the information of individual channels, each of which was energy
calibrated, was utilized in the new scheme. This scheme provided a sharper
cut in energy deposit distribution and thus enabled setting a tighter cut
condition and control of the trigger rate.
At the K1.8BR beamline, the E31 experiment was conducted to accumulate
three times larger statistics data than previously obtained. The E31
experiment aims to study the structure of the Lambda (1405) hyperon
resonance using K- beam and a deuteron target.
The internal structure of the Lambda (1405) resonance is a long- standing
problem in hadron physics and the E31 experiment can provide important
information about a molecular-like structure of the Lambda
(1405) resonance.
At the K1.8 beamline, a new experiment E40 started to study hyperon
proton interactions by direct measurements of Sigma-hyperon proton
scatterings. In the experiment, Sigma hyperons are produced by the (pi, K+)
reaction on a liquid hydrogen target and are scattered by protons in the
same target. The released K+ is detected by the rearranged KURAMA
spectrometer, and a Sigma-hyperon proton scattering is reconstructed with a
newly installed detector. In this beam time, the spectrometer and the
detector were commissioned.
J-PARC NEUTRINO FACILITY CONTINUES TO ACCUMULATE T2K DATA IN ANTI- NEUTRINO
MODE (by T. ISHIDA)
The neutrino experimental facility at J-PARC has continued its
operation since last October for the T2K experiment. The beam is stable with
anti-neutrino mode at about 485 kW beam power.
Accumulated protons-on-target (POT) in last March has reached 1.5x10^20,
which is to be added to the data already accumulated until last December,
3.8x10^20.
We plan to continue the operation two more months towards the end of
May, in order to double the statistics of anti-neutrino mode data until 2017
(7.6x10^20). Our primary interest is to see if electron antineutrino
"appears" as electron neutrino does in the neutrino mode data, which was
confirmed by T2K in 2013. With doubled statistics, T2K has a sensitivity of
2.7 sigma on the electron antineutrino appearance signal.
STATUS OF THE MUON G-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34) (by T. MIBE)
The E34 collaboration prepares for precision measurements of muon
anomalous magnetic moment and electric dipole moment.
An international workshop on hadronic vacuum polarization contribution to
muon g-2 was organized at KEK Tsukuba campus on Feb
12-14 (http://www-conf.kek.jp/muonHVPws/index.html). New theoretical and
experimental developments towards precise calculation of the muon
g-2 were presented. A white paper will be prepared from the outcomes of this
workshop and following ones.
A new muon beam profile monitor was tested at the Materials and Life
Science Experimental Facility (MLF). A small-scale prototype of the positron
tracking detector was used in the measurement of muonium hyperfine splitting
at MLF. A paper on magnetic design and method of a superconducting magnet in
a cylindrical volume with homogeneous magnetic field was published.
STATUS OF THE COHERENT MUON TO ELECTRON TRANSITION (COMET) (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 COMET experiment requires a specially prepared proton beam for
producing the pulsed-muon beam as the beam timing information is utilized to
reduce the beam induced background well below the target sensitivity; the
proton beam of 8 GeV should have minimum leakage from acceleration buckets
to in-between pulses. The ratio of the number of protons in-between two
consecutive beam pulses to that in a pulse, called extinction factor, should
be less than 10^-10 to achieve the target sensitivity of the experiment.
In January and February 2018, the first test of acceleration and
extraction of 8 GeV in this pulsed mode was executed by the accelerator and
beam transport groups, and the beam extinction measurement was successfully
carried out with help of the K1.8 group.
The preliminary result shows that the extinction level satisfies the
requirement by adopting a beam time window selection. It will further
continue the study to understand the details of the pulse time structure.
PROGRAMS OF ADVISORY COMMITTEE MEETINGS (by T. KOMATSUBARA)
The 25th Program Advisory Committee (PAC) meeting was held at Tokai on
January 15-17. Status of the experiments was reported, and proposals and
near-term machine time allocation were discussed.
https://kds.kek.jp/indico/event/26624/
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 18-20, 2018.
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4. [Materials and Life Science Division] by Toshiji KANAYA
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STEADY NEUTRON PRODUCTION OPERATION CONTINUES WITH PROTON BEAM POWER OF 400
KW
SCHEDULED NEUTRON BEAM DELIVERY FOR 8-RUN CYCLES WAS ACHIEVED IN FY2017
1) Neutron Source
The proton beam power delivered to the neutron production mercury
target vessel has been increased up to 400 kW from January, 2018. The
mercury target vessel, which is equipped with mechanically coupled structure
between the inner mercury vessel and outer water shroud in the forward part
has been running stably since last October.
In March 20 2018, accumulated neutron beam delivery time reached
176 days (8-run-cycles), the operational goal of the fiscal year, since
April 2017. Resultant availability of the neutron source become as high as
92 percent. Furthermore, fabrication of the spare target vessel in the same
structure as for current one was completed. The current target vessel has a
narrow channel mercury flow channel at the front end of the target and
equips a gas micro-bubbles generation system as a measure of suppressing
pitting damage induced by high power pulsed proton beam injection.
GENERAL USER AND NEW USER PROMOTION NEUTRON PROPOSALS APPROVED FOR THE
2018A PERIOD
QUANTUM BEAM SCIENCE FESTA WAS HELD ON MARCH 2 TO 4
2) Neutron Instruments and Science
From January 10, we resumed the last half of the user program for the
2017B period, which continues until April 1. The 2018A user program will
start from April 4.
Proposals for 2018A were reviewed by the joint meeting between Neutron
Science Proposal Review Committee (NSPRC) and Proposal Evaluation Committee
(PEC) which was held on January 29. 174 general user proposals for neutron
instruments and five new user promotion proposals for public beamlines were
approved. The result was authorized by the Materials and Life Science
Experimental Facility
(MLF) Advisory Board and the Selection Committee in the joint meeting on
February 7. MLF also accepted one proprietary proposal. In this period, the
competition rate of general user proposals was 1.5.
Besides, urgent proposals are welcomed anytime.
Quantum Beam Science Festa, which is a conference for mainly domestic
users of J-PARC MLF and Institute of Materials Structure Science (IMSS) of
High Energy Accelerator Research Organization (KEK) was held in Mito,
Ibaraki Pref. on March 2 to 4 with 524 participants. In this Festa, MLF
symposium was held on March 2 in which MLF facility status, scientific
results and developments were reported. A meeting for MLF future planning,
jointly organized by the Japanese Society for Neutron Science and Society of
Muon and Meson Science of Japan, was also held on March 4, and a future
planning for the second target station of MLF was discussed.
COMING OF THE SEASON FOR MEETINGS
3) Muon Science Facility (MUSE)
The New Year started with a series of meetings for reviewing 2018A
experimental proposals and the international advisory committees over every
level of J-PARC activities. Following the IMSS Muon Program Advisory
Committee for reviewing S-type proposals (long- term projects), the Muon
Science Proposal Review Committee was held in the late January 2018 to
review 27 general use proposals. The committee approved 23 proposals for
D1/2 and S1 instruments, while three proposals that exclusively needed D1/2
instruments were set priorities and put in the queue. The relatively sharp
decline in the number of submitted proposals in this round brought mild
concern among committee members to call for careful analysis, which was also
shared by the Muon Advisory Committee meeting held by order of J-PARC
director in late February.
In the meantime, the proton beam power ramped up to 400 kW while
keeping single bunch mode since January, and muon users enjoy the
world-highest flux for both positive and negative muons. It also makes those
comfortable who are working at the ultra-slow muon (USM) commissioning on
the U-line. While waiting for good news on the laser ceramics for the UV
laser final amplifier, they recently achieved 95 percent USM beam transport
efficiency.
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5. [Nuclear Transmutation Division] by Toshinobu SASA
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MATERIALIZATION OF ACCELERATOR-DRIVEN SYSTEM IN COLD LIQUID METAL LOOP
Lead-bismuth eutectic alloy (LBE), a typical liquid metal coolant for
fast reactor development, is adopted for the Accelerator- driven System
(ADS) proposed by JAEA to reduce the environmental impact from minor
actinides (MA). In the ADS, LBE acts both a spallation target to produce
spallation neutrons to drive the ADS and a coolant of subcritical core to
transmute MA by fission chain reaction. The operation parameter for
LBE-cooled ADS is specified to maximize the MA transmutation efficiency and
recovery of consumed energy for ADS operation including high-current proton
accelerator.
In the current design, maximum LBE temperature set to 450°C and 100°C
of temperature difference are considered to transfer the generated heat from
the fission reaction of MAs loaded in subcritical core. The spallation
target, which will be installed in ADS Target Test Facility (TEF-T), planned
in J-PARC project, adopts the same operation parameter to reproduce the
operation environment of future ADS in small spallation target and obtain
irradiation data of candidate structural materials for ADS components. The
target is bombarded by 250 kW proton beam from LINAC to irradiate various
materials, and deposited heat is taken out through the heat exchanger. The
secondary coolant of the heat exchanger is pressurized water to miniaturize
the heat exchanger mounted on movable trolley.
To gain the experience of entire LBE spallation target in J-PARC,
mockup loop IMMORTAL (Integrated Multi-functional MOckup for TEF-T
Real-scale TArget Loop) was built and has just started the operation since
the beginning of 2017. Operation tests progressed steadily, by increasing
flow amount of LBE, maximum operation temperature up to 500°C, and finally,
set a temperature difference of 50°C by running pressurized water heat
exchanger. Each operation test was succeeded in equable condition. Further
tests reflecting rated operation condition of future ADS will be performed
in fiscal year 2018.
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6. [Safety Division] by Yukihiro MIYAMOTO and Kotaro BESSHO
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5TH SYMPOSIUM ON SAFETY IN ACCELERATOR FACILITIES
After the accident at the Hadron Experimental Facility in 2013, J-PARC
Center holds a safety symposium every year in order to share information on
safety at accelerator facilities. The 5th Symposium on Safety in Accelerator
Facilities was held on January 25-26 at Ibaraki Quantum Beam Research Center
(IQBRC), and 124 participants exchanged information on various safety issues
at accelerator facilities. The featured topics this time were radiation
safety education and safety in heavy load transportation works. Nine talks
and eighteen posters were presented by various institutions and universities
in Japan. In addition, two invited speakers from overseas gave talks on
safety training service at CERN by Mr. Christoph Balle and talks on ensuring
safety in the experiment using a tritium target by Mr. Albert Manzlak,
Jefferson Lab, USA. Domestic and international cooperation between
accelerator facilities is important for improving safety status and
continuing stable operations 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. 26. The topics were the increase
of beam intensity for the Neutrino Experimental Facility
(NU) and the annex of the Materials and Life Science Experimental Facility
(MLF) for storing Radio-Activated Materials (RAM).
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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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