[Neutron] J-PARC Newsletter No.40 May 2010
fujio maekawa
maekawa.fujio at jaea.go.jp
Thu Jun 3 03:16:50 CEST 2010
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J-PARC Project Newsletter
No. 40, May 2010
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]
SUPER-KAMIOKANDE DETECTED THE FIRST NEUTRINO EVENT.
THE FIRST MLF SYMPOSIUM HELD AT THE END OF MARCH.
IAC, A-TAC, NIAC, AND MUSAC WERE HELD.
USERS STEERING COMMITTEE JOINS DISCUSSION ON JFY22 AND
JFY23 BUDGETS.
LIQUID HYDROGEN PROBLEM SOLVED.
2. [Accelerator Division]
AVAILABILITY EXCEEDS 92 % IN 120 KW OPERATION FOR THE
COMMON USE OF MLF (MATERIAL AND LIFE SCIENCE FACILITY).
RECOVERY OF RFQ LINAC AND HIGH AVAILABILITY IN MLF
COMMON USE OPERATION.
ATAC 2010.
3. [Nuclear and Particle Physics Division]
INSTALLATION OF THE K1.1BR IN THE HADRON EXPERIMENTAL HALL.
WORKSHOP ON "PHYSICS WITH THE EXTENDED HADRON HALL".
T2K IS ACCUMULATING PHYSICS DATA WITH INCREASING BEAM
POWER TO SEARCH FOR ELECTRON NEUTRINO APPEARANCE.
4. [Materials and Life Science Division]
THE USER OPERATION IN FEBRUARY AND MARCH WAS CANCELLED
DUE TO A TROUBLE IN THE CRYOGENIC HYDROGEN SYSTEM, AND
RESUMED ON MAY 9.
THE FIRST MLF SYMPOSIUM WAS HELD ON MARCH 29-31, 2010.
A CLEAR EVIDENCE FOR THE MAGNETIC ORDERING IN CeRu_2Al_10
WAS OBSERVED BY MUON SPIN ROTATION MEASUREMENTS.
5. [Exotic Nuclear Science Group]
FIRST MEASUREMENT OF SINGLE PARTICLE STATES IN NEUTRON
RICH NUCLEUS 35SI.
6. [Nuclear Transmutation Section]
JOINT WORKSHOP EUROTRANS-JAEA ON ACCELERATOR DRIVEN-
SYSTEM (ADS) ACTIVITIES
7. [Safety Division]
APPLICATION FOR OPERATION OF K1.1 BEAM LINE IN HADRON
EXPERIMENTAL HALL WAS GRANTED BY MEXT (MINISTRY OF
EDUCATION, CULTURE, SPORTS, SCIENCE AND TECHNOLOGY).
8. [Editorial Note]
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1. [Overview] by Shoji NAGAMIYA
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SUPER-KAMIOKANDE DETECTED THE FIRST NEUTRINO EVENT
Although it was already reported, Super-Kamiokande
detected the first neutrino event on February 24th.
This proved that the neutrino detector system is now working
very well. Presently an effort to increase the beam power
is underway. See the accelerator section in this Newsletter.
THE FIRST MLF SYMPOSIUM HELD AT THE END OF MARCH
At the end of March the first domestic MLF Symposium
was held. At this meeting many new results were reported.
Currently 12 neutron beam lines are working, 9 of them are
for open usage and 3 of them are at the commissioning stage.
See the neutron and muon sections in this Newsletter for
the exciting results presented at this symposium. Note that
6 additional neutron beam lines were budgeted so that a total
of 18 beam lines are either working or budgeted out of 23
available ports.
IAC, ATAC, NIAC, AND MUSAC WERE HELD
From the end of February a series of committee meetings
were held. First, the Neutron International Advisory Committee
(NIAC) meeting was held, followed by Muon Science Advisory
Committee (MUSAC) and Accelerator Technical Advisory Committee
(ATAC) meetings. Finally, on March 15 and 16 the J-PARC
International Advisory Committee (IAC) meetings were held
including new members.
Since this year was the first year for J-PARC to run
for the users program, the main discussion was on how to move
into the operational stage efficiently. Many useful
recommendations came to the J-PARC Center as well as to KEK
and JAEA.
USERS STEERING COMMITTEE JOINS DISCUSSION ON JFY22 AND
JFY23 BUDGETS
The Users Steering Committee for which the members are
elected by the communities has recently joined discussions
on the usage of JFY22 budget and the proposed JFY23 budget.
On the latter, the ultra slow muon channel and high momentum
beam line, together with a neutron beam line have been
discussed. Also, the completion of the 400 MeV linac as well
as the request of lodging were proposed.
Concerning the operational budget, the J-PARC Center
proposed an 8 cycle operation for JFY23 (note 9 cycles are
a full 200 days). This request was endorsed by the Users
Steering Committee. The final budget proposal was agreed
also by the J-PARC Steering Committee which was held at the
end of April.
LIQUID HYDROGEN PROBLEM SOLVED
In late February helium was leaked into liquid hydrogen
and the entire neutron source operation had to be stopped.
However, this problem has been solved. It took about two
months to fix it. See the report for neutrons.
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2. [Accelerator Division] by Ainosuke ANDO
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AVAILABILITY EXCEEDS 92 % IN 120 KW OPERATION FOR THE
COMMON USE OF MLF (MATERIAL AND LIFE SCIENCE FACILITY)
RECOVERY OF RFQ LINAC AND HIGH AVAILABILITY IN MLF COMMON
USE OPERATION
The RFQ LINAC has almost recovered from the discharge
problem and the 120 kW operation for the MLF common use has
stably been successful from November 2009 (Run #27). The
availability was ~ 92.4 % for the total operation time of 842.3
hours by January 2010 (Run #29). In particular, we are very
proud of the stable operation of the DC power supplies of high
voltage for the LINAC klystrons (HV -DC). The time lost due to
troubles of the HV-DC was only ~ 2.5 hours. The dominant part
of troubles (~ 32.5 hours) was caused by the power supplies of
the RCS (3 GeV Synchrotron, Rapid Cycling Synchrotron)
extraction kickers. But this problem has been steadily improved
as deepening understanding of the system and the conditioning
method of Thyratrons; the loss times in each run were ~16 hours
in Run #27, ~10 hours in Run #28 and ~6 hours in Run #29.
Unfortunately the progress stopped because of the suspension
of the MLF common use due to the leakage problems of hydrogen
gas in the modulator system.
40 KW OPERATION FOR THE NEUTRINO EXPERIMENT
The user run for the neutrino experiment started from
January 2009 and 40 kW beam of MR (50 GeV synchrotron) is now
delivered to the neutrino target by the fast extraction with
six bunches and the repetition period of 3.52 seconds.
The beam loss ratio at injection was drastically improved to
less than 0.2 % by adjusting the excitation timing of the
injection kicker. There are no serious problems in injection
and acceleration for power higher than 40 kW, say, 65 kW. But
when operated with the beam power larger than 40 kW, a drift
of the horizontal position of the extracted beam at the neutrino
target appears. This drift is corrected by increasing the
excitation current of kickers. The strength of magnetic field
in the extraction kickers is reduced by heating due to the wake
field. An increase of vacuum pressure is also observed. On the
other hand, there is no such a problem in the injection kickers.
There is a difference of circuit type and matching; lumped
constant without a matched load for extraction and distributed
constant with a matched load for injection. An intensive study
and analysis has just started to avoid this problem in new
kickers, which will be installed in this summer shut down
referring to the preceding study in the LHC (Large Hadron
Collider) injection system.
ATAC 2010
The ninth meeting of ATAC (Accelerator Technical
Advisory Committee) was held from 11 to 13 March 2010. Thomas
Roser of BNL succeeds Stephen Holmes of FNAL as the chair.
The other members are David Findlay (RAL), John Galambos
(SNS), Roland Garoby (CERN), Akira Noda (Kyoto U.), Peter
Ostroumov (ANL) and Jie Wei (Tsinghua U.). Uli Ratzinger
(U. Frankfurt) could not attend. Following the presentations
by the accelerator members, enthusiastic and frank
discussions were made, in particular, towards a steady and
fast realization of 1 MW (RCS) and 0.75 MW (MR fast extraction).
The importance of a comprehensive scheduling was also
pointed out because the common use of both MLF and MR must
proceed with an approval of machine time for users consistent
with the construction and the beam commissioning of the LINAC
energy upgrade to 400 MeV.
-----------------------------------------------------------
3. [Nuclear and Particle Physics Division]
by K.TANAKA and J.IMAZATO / by T.TSUKAMOTO
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INSTALLATION OF THE K1.1BR IN THE HADRON EXPERIMENTAL HALL
(by K.TANAKA and J.IMAZATO )
The Installation of the K1.1BR beam line has been
started in the Hadron Experimental Hall. The K1.1BR is a
low momentum separated beam line up to 0.8 GeV/c taken off
the production target T1, and was designed as a short branch
line of the future extension to K1.1 for stopped kaon beam
experiments. Although K1.1BR is equipped with only one stage
of electrostatic separation, as the upstream part of the
K1.1 beam line, a considerably good K/pi separation can be
expected due to the presence of an intermediate vertical
focus before the single-stage separation. Particle physics
experiments are planned there using a stopped K+ beam. In
order to reduce the cost of the beam line, most elements
of K1.1BR are recycled ones from the old beam lines of
KEK-PS except for the very upstream part of the beam line.
However, those recycled magnets, power supplies and an
electrostatic separator are "combat proven" soldiers. The
most upstream part of the beam line is constructed with new
"radiation resistant" elements since they experience very
high radiation generated at the production target. The beam
commissioning of K1.1BR will start in the autumn run of the
Hadron Experimental Hall allocated in upcoming October.
Following the first beam commissioning the beam will be
used for the moment for "test experiments". The first
experiment approved is the test of a small prototype for
the large scale liquid argon detector for the next generation
neutrino detector.
WORKSHOP ON "PHYSICS WITH THE EXTENDED HADRON HALL"
The workshop on "Physics with the Extension of the
Hadron Hall" was held on March 6 and 7 at KEK Tsukuba. The
workshop was hosted by Hadron Hall Users Association (HUA)
and co-hosted by the J-PARC Center, the IPNS of KEK, and
the Nishina Center of RIKEN. The participants from
universities and the research institutions (mainly users)
were more than 70 people, and active discussions were
undertaken. The current Hadron Hall is just half in its
size of the original plan, where there is only one production
target and the number of the beam lines is limited. It will
take at least a few years to complete the already approved
experiments with the current number of the beam lines. The
workshop was intended to focus on physics programs in the 5
or 10 year range, which can be realized in the extended
experimental hall. Physics in the present Hadron Hall was
also be discussed to have a perspective from the current
Hadron Hall to the extended one. This kind of a bottom-up
discussion by users who aim to make fruits of physics at the
Hadron Hall is indispensable. The slides of the talks are
available on the web. Please contact HUA secretariats at
hua-sec at rcnp.osaka-u.ac.jp.
T2K IS ACCUMULATING PHYSICS DATA WITH INCREASING BEAM
POWER TO SEARCH FOR ELECTRON NEUTRINO APPEARANCE
(by T.TSUKAMOTO)
For high beam power operation, several projects in
the neutrino beam line were done such as installation of the
beam collimator, beam tuning etc. Following the neutrino beam
line operation with 20kW beam power last year, T2K is
accumulating physics data with increasing beam power, about
60kW has been achieved until now, and accumulated beam by
T2K is 1.37e+19 PTO (protons on target).
The T2K near detector ND280 is complete except for
the barrel ECAL(electromagnetic calorimeter) of the off-axis
detector, which will be installed during this summer
shutdown, and commissioning of the detector was finished
last year. Physics data are being collected by ND280 and
also SK (Super-Kamiokande). T2K detected neutrinos at
ND280 in Nov. 2009, and on Feb.24, 2010 detected the first
neutrino interaction at
SK ( http://www.kek.jp/ja/news/press/2010
/T2KfirstEvent.html , http://www.kek.jp/intra-e/press
/2010/T2KfirstEvent.html ).
A T2K collaboration meeting is being held every
4months. Recently it was held in Apr. (Apr.21-24) where
there were discussions about data analysis to get physics
results for conferences in this summer.
-----------------------------------------------------------
4. [Materials and Life Science Division] by Masatoshi ARAI
-----------------------------------------------------------
THE USER OPERATION IN FEBRUARY AND MARCH WAS CANCELLED
DUE TO A TROUBLE IN THE CRYOGENIC HYDROGEN SYSTEM, AND
RESUMED ON MAY 9
THE FIRST MLF SYMPOSIUM WAS HELD ON MARCH 29-31, 2010
A CLEAR EVIDENCE FOR THE MAGNETIC ORDERING IN CeRu_2Al_10
WAS OBSERVED BY MUON SPIN ROTATION MEASUREMENTS
1. Neutron International Advisory Committee (NIAC)
The NIAC meeting was held on February 24-26, which is
lead by Dr. Dan Neumann (National Institute of Standards
and Technology,US). Previously this was a technical advisory
committee for the neutron target technology/engineering.
Because MLF has started the user program since 2008, the
mission of the committee has been changed so that it gives
advice on organization, operation, safety, instrumentation
and target station.
2. Neutron Source
During starting up the cryogenic hydrogen system for
the Run#30 on February 10, a trouble was found in the
accumulator, which is one of important components to absorb
the pressure fluctuation in the super-critical hydrogen due
to proton beam injection. The user service operation in
February and March was cancelled to take emergency measures
against the trouble for restarting the operation as quick
as possible. On-beam commissioning of the cryogenic hydrogen
system without the function of the accumulator was completed
in April, and the user service operation was resumed on
May 9. Replacement of the accumulator with a new one is planned
in the summer maintenance period.
New spares of the proton beam window assembly and
the target vessel were manufactured and set on-site.
The new proton beam window has a non-destructive beam
profile monitor, which detects secondary electrons from the
interactions of the proton beam with the helium gas in the
helium vessel. The replacement procedures for the spares were
examined carefully and confirmed respectively.
3. Neutron Science
Since the MLF user operation stopped due to the trouble
in the cryogenic hydrogen system in February, some of the
remaining experimental proposals in the 2009B term (the
second half of FY2009) were rescheduled, and are being
carried out in May.
The first MLF symposium was held on March 29-31 at
IQBRC (Ibaraki Quantum Beam Research Center). Over 220
participants from universities, academic institutes, and
companies attended and discussed many topics, such as
superconductivity, Li-ion batteries, mechanical engineering,
protein structures, etc.
A completion ceremony for the High Resolution Chopper
Spectrometer (HRC, BL12) was held at the MLF on March 26,
with the Institute for Solid State Physics (ISSP), University
of Tokyo, who oversees the construction and operation of
HRC under the contract between KEK-ISSP. The features,
construction process, software development, and scientific
goals were explained in the ceremony. The ceremony was
finished with a group photograph of over 50 participants
standing on the shield of the HRC.
4. Muon Science
At the Muon Science Facility (MUSE), we had several
user's programs during the beamtime of January, 2010.
Among them, Dr. Kambe discovered clear evidence for the
magnetic ordering in CeRu_2Al_10, in the zero field muon
spin rotation measurements, in spite of the fact that no
evidence of the internal field was observed by the nuclear
quadrupole resonance (NQR) measurement under zero field.
The 8th Muon Science Advisory Committee (MUSAC VIII)
was held at Tokai on March 11 and 12, 2010, just as MUSE
became the world's most intense pulsed muon beam facility
and demonstrated that unprecedented fluxes of 10^7-10^8
surface muons per second will be available when the
ultimate design value of 1 MW beam power is achieved.
The main overall recommendation was that the highest
priority should be to secure funding for fully developing
the ultra slow muon beam line, as it promises to be a
unique tool for novel experiments in nano-materials
research.
-----------------------------------------------------------
5. [Exotic Nuclear Science Group] by Hiroari MIYATAKE
-----------------------------------------------------------
FIRST MEASUREMENT OF SINGLE PARTICLE STATES IN NEUTRON
RICH NUCLEUS 35SI
A neutron-rich nucleus 35Si is located in the transition
region from normal to anomalous shell structure. Single
particle states of 35Si, which were key quantities to
disentangle the anomaly, were sought by measuring proton
resonance elastic scattering in inverse kinematics with
around 4 MeV/nucleon 34Si beams at the RIKEN Nishina center.
Isospin-different single particle states called isobaric
analog resonances (IARs) were clearly observed. This was
the world first measurement for IARs of bound states in
neutron-rich nuclei.
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6. [Nuclear Transmutation Section] by Hirofumi TSUJIMOTO
-----------------------------------------------------------
JOINT WORKSHOP EUROTRANS-JAEA ON ADS ACTIVITIES
The joint workshop between a European project called
"EUROTRANS" and JAEA on Accelerator-Driven System (ADS) was
held in Karlsruhe, Germany on March 18-19. The EUROTRANS
project was launched in 2005 under the EURATOM 6th Framework
Programme. The objective of the project is the design and the
feasibility assessment of an industrial ADS dedicated to
transmutation. A wide range of R&D activity has been carried
out by a consortium consisting of 29 partners from 14 countries.
The JAEA also joined the project in 2007. This workshop was
the second one with EUROTRANS. In the workshop, the design
study for an experimental and a demonstration ADS, and
experimental results for coupling of a subcritical system
with an external neutron source were discussed. Moreover,
research results for associated technologies, such as fuels,
heavy liquid metal technologies and nuclear data, were
presented and discussed.
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7. [Safety Division] by Taichi MIURA and Hiroshi NAKASHIMA
-----------------------------------------------------------
APPLICATION FOR OPERATION OF K1.1 BEAM LINE IN HADRON
EXPERIMENTAL HALL WAS GRANTED BY MEXT
The application for the operation of a secondary beam
line (K1.1) at the Hadron Experimental Hall in Nuclear and
Particle Physics Facility was granted by the Ministry of
Education, Culture, Sports, Science and Technology (MEXT)
on April 1.
The 9th Radiation Safety Committee of J-PARC will meet
on May 27,2010 to discuss the alterative application of
all J-PARC facilities. The main topics are the power-up for
the whole facilities (except Hadron Facility(HD)), the new
secondary beam lines in Materials and Life Science Facility,
and shielding reinforcement for a primary-beam dump and
the shielding re-arrangement procedure for the experimental
areas in HD.
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8. [Editorial Note]
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+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Editorial Board:
Toshifumi TSUKAMOTO (Chair): toshifumi.tsukamoto at kek.jp
Fujio MAEKAWA: maekawa.fujio at jaea.go.jp
Takashi ITO: itou.takashi at jaea.go.jp
Dick MISCHKE (English Editor): mischke at triumf.ca
Chikako KAIBARA (Secretary): kaibara.chikako at jaea.go.jp
++++++++++++++++End of Letter+++++++++++++++++++++++++++++++
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