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J-PARC Project Newsletter
No. 44, April 2011
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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This issue covers topics before the Gigantic Earthquake on Mar 11.
The next issue will be released earlier than the standard interval for
the periodical issue to report the status after the earthquake.
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HEADLINES AND CONTENTS
1. [Overview]
ACCELERATOR IMPROVEMENT CONTINUED UNTIL THE EARTHQUAKE.
IAC, ATAC AND OTHER COMMITTEES WERE HELD.
ASIAN RELATIONS.
NEW APPOINTMENTS FOR J-PARC ORGANIZATION.
2. [Accelerator Division]
145 KW BEAM FOR THE NEUTRINO USER RUN
3. [Nuclear and Particle Physics Division]
EXPERIMENTS MADE PROGRESS.
T2K RESUMED DATA TAKING AFTER END YEAR/NEW YEAR SHUTDOWN.
4. [Materials and Life Science Division]
STABLE OPERATION AT 220 KW.
THE FIRST BEAM ON A SMALL ANGLE SCATTERING INSTRUMENT WAS RECORDED.
CONSTRUCTION OF NEW INSTRUMENTS IS CONTINUING.
5. [Nuclear Transmutation Section]
CAN BEAM TRIPS CAUSE THERMAL FATIGUE OF THE FUEL CLADDINGS FOR ADS?
6. [Safety Division]
THE PERIODICAL INSPECTION WAS CARRIED OUT BY NUSTEC AND THE
APPLICATION FOR OPERATION OF THE WHOLE FACILITY WAS GRANTED BY MEXT.
7. [Announcement of Symposia and Meetings]
8. [Editorial Note]
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1. [Overview] by Shoji NAGAMIYA
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ACCELERATOR IMPROVEMENT CONTINUED UNTIL THE EARTHQUAKE
Until the Gigantic Earthquake in Eastern Japan the accelerator
had been running very smoothly. The power has been increased
continuously to the level of 200 kW at 3 GeV (320 kW continuous
extraction already tested nicely) and 145 kW in the Main Ring. Also,
a preparation study to go up to 400 kW at 3 GeV was in progress.
Unfortunately, the big earthquake hit on March 11. The present issue
of the Newsletter is the summary before this earthquake.
IAC, ATAC AND OTHER COMMITTEES WERE HELD
On February 21 and 22 the annual IAC (International Advisory
Committee) was held. From this time Jean-Michel POUTISSOU took
over the chair after many years of service for the chair of John
WHITE. In association with this IAC, the Accelerator Technical
Advisory Committee (ATAC) was held on February 17-19. Also, the
annual Muon Science Advisory Committee (MuSAC) and the annual
Neutron International Advisory Committee (NIAC) were held on February
18-19 and February 28 to March 2, respectively. At the IAC, the
Ministry of Education, Culture, Sports, Science and Technology
(MEXT) also joined it and many experimental results were presented.
Also, users opinions were addressed. The report was about to be
sent to us. Many useful comments will be written there, while our
urgency has been changed since the IAC time, namely the recovery
of J-PARC is now the first priority as compared to the other
important issues written there. Of course, since this is an
important document, we shall read it carefully.
ASIAN RELATIONS
The J-PARC collaboration with Korea became stronger. In February
six Korean undergraduate students visited J-PARC for ten days in a
program called "J-PARC Internship". The J-PARC side prepared several
lecture courses and experimental courses. This is the first trial and
we shall continue this tradition. On the occasion of the Director's
visit to Taiwan, a new movement for collaboration started to be
generated with Taiwan as well.
NEW APPOINTMENTS FOR J-PARC ORGANIZATION
The J-PARC operation was changed as follows. The Head of the
Administration Division was changed from Michihiro MURASAWA to
Tetsuo TAKAHASHI as of January 1, 2011. From April 1 of 2011, one of
the deputy Directors (for KEK) will be changed from Hitoshi KOBAYASHI
to Koichiro NISHIKAWA. Also, the Head of the Accelerator Division
will be changed from Ainosuke ANDO to Kazuo HASEGAWA.
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2. [Accelerator Division] by Ainosuke ANDO
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145 KW BEAM FOR THE NEUTRINO USER RUN
1. Ion source
In Run #36, the accelerators were continuously operated for
two months (November and December, 2010). The total operation time of
the ion source was 1270 hours with the H-minus ion current of 17 mA.
Then from Run #37, i.e., from January, 2011, the operation cycle
became 1.5-months for beam service and 2-days for the ion source
exchange.
2. 145 kW Beam for User in Fast Extraction of MR
(50-GeV synchrotron)
145 kW beam has been served for the neutrino user run from
March 7, 2011. The accumulated proton numbers on the target reached
to almost one third of the first goal which is 3.1e20 by the end of
June, 2011.
3. ATAC (Accelerator Technical Advisory Committee)
The tenth meeting of ATAC was held from 17-19, February,
2011. The accelerator team frankly presented their achievements from
March, 2010 and issues to be improved and/or overcome and was greatly
encouraged through the discussion with and by the recommendations
of ATAC.
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3. [Nuclear and Particle Physics Division]
by T.KOMATSUBARA, T.TAKAHASHI and T.TSUKAMOTO
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EXPERIMENTS MADE PROGRESS
(T.KOMATSUBARA and T.TAKAHASHI)
The E14 KOTO collaboration has been working on the detector
construction for the KL -> pi0 nu nubar experiment. The goal is
to make the first observation of this very rare decay, whose branching
ratio is predicted to be 2.57 (37) (4) e-11 in the Standard Model.
The experiment moves the existing KEK-PS E391a detector to J-PARC
and applies necessary modifications. One major upgrade is to replace
the 7cm x 7cm x 30cm undoped CsI crystals in the E391a calorimeter
by the 2.5cm x 2.5cm x 50cm and 5cm x 5cm x 50cm crystals used
in the KTeV experiment at Fermilab in the US. Their improved energy
resolution is essential to detect the neutral pion in the final state
of the decay. All the crystals and phototubes were stored and tested
at Osaka University, and then moved to the J-PARC site for the
calorimeter construction. The KOTO collaborators installed a large
"dry room" in the experimental area of the Hadron Hall and started
the calorimeter construction in May 2010, and finished stacking the
2.7K CsI crystals on Tuesday, February 8th, 2011. They expect to
perform the commissioning of the calorimeter in the next beam time.
E19 (Search for Penta Quark, Theta+, via the p(pi-,K-)X Reaction)
reported the preliminary analysis results of the data obtained in
the Nov. RUN at the PAC11 held on Jan.14-16. -- No peak structure was
observed in the missing mass spectrum within the present sensitivity
of about 0.3 micro-barn/sr on the average from 2 to 15 degrees at the
incident momentum of 1.92GeV/c.
A large-size Aerogel Cherenkov Counter was newly constructed
and installed in the SKS spectrometer. The counter discriminates
pions and kaons both in online trigger and offline analysis. The
new counter has a larger effective area of 1950mm(H) x 1200mm(V)
than the previous one of 1350mm(H) x 1200mm(V), thus, the momentum
acceptance of the SKS will be enlarged.
T2K RESUMED DATA TAKING AFTER END YEAR/NEW YEAR SHUTDOWN
(by T. TSUKAMOTO)
In the end year/new year shutdown period, T2K ND280 magnet was
opened and closed to replace the TPC frontend board in which a
problem was found in last November.
T2K neutrino beam line resumed the operation from January, 2011.
Beam power of 145kW was achieved with a new operation condition 9e+13
proton/pulse and 3.04sec repetition without any problems in the T2K
neutrino beam line.
Accumulated POT (Protons On Target) is 7.0e+19 in this year 2011
until Mar.11 and 1.45e+20 in total.
T2K presented the results at winter conferences based on the
data from 3.23e19 POT, which was accumulated from January to June
in 2010.
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4. [Materials and Life Science Division] by Masatoshi ARAI
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STABLE OPERATION AT 220 KW
1. Neutron Source
Because of an effort to remove impurities in a helium refrigerator
for hydrogen provision to moderators even through the New Year's
holidays, operation of the neutron source at 220 kW from late January
to early March was generally stable.
A swirl bubbler with a complicated design, that will be able to
inject microbubbles into flowing mercury to mitigate the pressure
waves in the target vessel, was successfully machined from stainless
steel, and installed in the fabricated target vessel.
THE FIRST BEAM ON A SMALL ANGLE SCATTERING INSTRUMENT WAS RECORDED.
CONSTRUCTION OF NEW INSTRUMENTS IS CONTINUING.
2. Neutron Science
For the user operation of the 2011A period (the first half of
FY2011), 121 general proposals were submitted by Dec. 7. Each of the
proposals was pre-reviewed by four referees, and reviewed by eight
subcommittees (38 proposals to the crystal subcommittee, 8 to
liquid & amorphous, 5 to nanomaterials, 2 to biomaterials, 21 to
magnetism & strongly correlated systems, 19 to industrial application,
8 to R&D). Adoption/rejection and beamtime allocation for each
proposal was discussed in the neutron science proposal review committee
held on March 3. Although decisions by the MLF advisory board held on
March 11 were interrupted by the severe earthquake on that day, the
final results will be informed soon.
Commissioning of TAIKAN (BL15, Small Angle Scattering Instrument)
was started in March and the first beam profile was recorded.
Construction of an annex building for SPICA (BL09, Special Environment
Powder Diffractometer) was completed on Feb. 4. The first beam of
PLANET (BL11, High Pressure Diffractometer) was scheduled on March 11,
but the earthquake occurred on that day. The construction of DNA (BL02,
Inverted Geometry Spectrometer), VNR (BL17, Vertical Reflectometer)
and SENJU (BL18, Single Crystal Diffractometer) are also suspended.
Neutron International Advisory Committee (NIAC): Dan Neumann
(NIST), Rob Robinson (ANSTO), Kurt Clausen (PSI), John Haines (SNS),
Gunter Bauer (Julich), Kazu Yamada (Tohoku), Toshiji Kanaya (Kyoto),
and Yoshiaki Kiyanagi (Hokkaido), met on 28 Feb to 2 March.
The committee appreciated the good progress of the MLF facility in
these years. A report will come up soon.
International Workshop on Neutron Application on Strongly
Correlated Electron System (NASCES) was held on 23 to 25 February.
About 80 participants got together from all over the world and
enjoyed well prepared lectures and enthusiastic discussion on
scientific topics and newly emerged instruments and experimental
methods.
Two domestic workshops, high magnetic field applications and high
pressure applications, were also held on 8 and 9 March. More than 100
participants got together and discussed what kinds of equipment the
facility should supply for users and how we can have a collaborative
environment with university groups.
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5. [Nuclear Transmutation Section] by Hirofumi TSUJIMOTO
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CAN BEAM TRIPS CAUSE THERMAL FATIGUE OF THE FUEL CLADDINGS FOR ADS?
In addition to the development of the Transmutation Experimental
Facility (TEF), the Transmutation Section of the J-PARC Center is also
conducting a design study on the future Accelerator-Driven System
(ADS) for transmutation of long-lived nuclear wastes through
cooperation with the Research Group for Nuclear Transmutation
Technology of the Nuclear Science and Engineering Directorate, JAEA.
In the design study of ADS, one of the most important criteria is the
maximum temperature of the fuel cladding. In our design, the fuel
claddings are made of Mod.9Cr-1Mo steel, and their maximum temperature
is limited below 550 degrees C to mitigate the corrosion by lead-
bismuth eutectic (LBE). In addition, the integrity of the fuel
claddings should be evaluated not only for steady state but also for
transient state. Especially, frequent beam trips as experienced in
existing high-power proton accelerators are considered problematic
because they may cause thermal fatigue of the fuel claddings for ADS.
The evaluation results showed that the structural strength of fuel
claddings could be sufficiently kept under the conditions of both
steady and transient state, if we do not consider irradiation effects.
While irradiation effects on material properties are considered not so
serious under the practical condition of the ADS according to judgment
from existing irradiation data, it is of importance to accumulate
further experimental data for material irradiation by protons and
neutrons.
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6. [Safety Division] by Taichi MIURA and Hiroshi NAKASHIMA
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THE PERIODICAL INSPECTION WAS CARRIED OUT BY NUSTEC AND THE
APPLICATION FOR OPERATION OF THE WHOLE FACILITY WAS GRANTED BY MEXT
As five-years of radiation handling is approaching in J-PARC,
the first periodical inspection was carried out by the Nuclear Safety
Technology Center (NUSTEC) in Jan. 2011, to make sure that radiation
installations are maintained in compliance with technical standards
by the Radiation Hazards Prevention Law.
The application for the operation of all the facilities was
granted by the Ministry of Education, Culture, Sports, Science and
Technology (MEXT) on Feb. 25. The main topics are the abolition of
the injection dump in the 50GeV proton synchrotron, the power-up
and the shielding reinforcement for a primary beam line including
beam dump for the Hadron Facility, and the new secondary beam lines
in the Materials and Life Science Facility.
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7. [Announcement of Symposia and Meetings]
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1st Asia-Oceania Conference on Neutron Scattering, Nov. 20-24,
2011, Tsukuba, Ibaraki (Language: English)
http://j-parc.jp/MatLife/en/meetings/1stAOCNS
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8. [Editorial Note]
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Editorial Board:
Toshifumi TSUKAMOTO (Chair): toshifumi.tsukamoto@kek.jp
Fujio MAEKAWA: maekawa.fujio@jaea.go.jp
Takashi ITO: itou.takashi@jaea.go.jp
Dick MISCHKE (English Editor): mischke@triumf.ca
Chikako KAIBARA (Secretary): kaibara.chikako@jaea.go.jp
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