[Neutron] J-PARC Newsletter No.42 Oct 2010

[fujio maekawa]

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      J-PARC Project Newsletter
                                          No. 42, Oct 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]

BUDGET PROPOSAL SUBMITTED TO FINANCE DEPARTMENT.
MANY ELEMENTS IMPROVED DURING SUMMER SHUTDOWN.
CENTER FOR KOREAN J-PARC USERS STARTED.
J-PARC OPEN HOUSE.
FOREIGN WORKERS AND VISITORS DISCUSSION WITH THE MAYOR.

2. [Accelerator Division]

THE SCHEDULED MAINTENANCE AND IMPROVEMENTS WERE SUCCESSFULLY FINISHED

3. [Nuclear and Particle Physics Division]

K1.1BR COMMISSIONED SOON.
T2K STATUS DURING SUMMER SHUTDOWN.

4. [Materials and Life Science Division]

OPERATION IN AUTUMN HAS BEEN STARTED AS SCHEDULED.
CONSTRUCTION OF SIX NEW INSTRUMENTS IS CONTINUING.
DEVELOPMENT OF SCINTILLATION DETECTORS FOR THE HE-3 SUPPLY PROBLEM.
MODIFICATION OF THE D-LINE DURING THE SHUT-DOWN PERIOD IN SUMMER 2010.

5. [Nuclear Transmutation Section]

IRRADIATION EFFECTS ON THE AUSTENITIC STEELS FOR THE BEAM WINDOW
OF ADS

6. [Safety Division]

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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  BUDGET PROPOSAL SUBMITTED TO FINANCE DEPARTMENT

      The budget request from our funding agency, Ministry of Education
etc. (MEXT), to the Finance Department was announced at the end of
August. For JAEA an 8 cycle operation was submitted (9 cycles, which
is 200 days, is our ultimate goal).  Also, the 400 MeV upgrade and
neutron beamline are in the budget request.  Furthermore, a budget
associated with a new third party operation is included.
In addition, an improvement of the Linac and 3 GeV toward 1 MW
operation was requested under the new frontier special budget
framework.  For KEK a 6 cycle operation, together with construction of
the ultra slow muon channel, is included in the budget request. Final
results for the JFY2011 funding will be announced at the end of
December.  Everything added together amounts to about 190 Oku Yen at
this moment.

  MANY ELEMENTS IMPROVED DURING SUMMER SHUTDOWN

      During the summer shutdown many repairs and improvements were
completed.  For the neutron source a He leakage problem into liquid
hydrogen was fixed.  By doing this, a higher intensity beam can be
taken for neutrons.  Various elements at the Main Ring were fixed,
in particular, in relation to the fast extraction line.  We hope
that from the fall much higher flux will be realized for neutrons.
The K1.1BR line was installed in the Hadron Hall, so that a new
experiment to study T-violation can be started.  These are just
examples that have been done during the summer shutdown.

  CENTER FOR KOREAN J-PARC USERS STARTED

      About 200 Korean physicists have decided to participate in
J-PARC.  The new organization called the "Center for Korean J-PARC
Users" started officially.  Agreement between this Center and the
J-PARC Center was signed on October 1, 2010.  The Korean Office
will be open at Ibaraki Quantum Beam Research Center.  This is an
excellent opportunity for all of us.

  J-PARC OPEN HOUSE

      On August 28, the third J-PARC Open House was held.  This year,
3,800 people visited Tokai.  This number is agreeable to us,
since visitors were able to go around most of the J-PARC
facilities without waiting too long.  Also, the capacity of
cafeteria fits perfectly to this number.

  FOREIGN WORKERS AND VISITORS DISCUSSION WITH THE MAYOR

      On August 17, the discussion meeting was held between
non-Japanese workers and visitors, on many issues such as a need for
lodging, an improvement of education, an improvement of local
transportation services, etc.  Also, many foreign visitors had
a nice party after the discussion meeting with the Mayor,
Mr.Tatsuya Murakami and other village people.


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2. [Accelerator Division] by Ainosuke ANDO
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  THE SCHEDULED MAINTENANCE AND IMPROVEMENTS WERE SUCCESSFULLY FINISHED

1. MR (30-GeV Synchrotron)
      (1) As mentioned in the previous newsletter, MR is now ready for
the 8-bunch operation without problems of beam-heating up to the beam
power of 750 kW.
      (2) The collimator in 3-50BT ; Beam Transfer line from RCS
(3-GeV synchrotron) to the MR, has been improved to permit a 2-kW beam
loss, which makes the active forming of the beam shape possible.
This will gives us an advantage to understand and to reduce the beam
losses in the MR.

2. RCS
      (1) Many different types of charge exchange foils have been
mounted to obtain an optimum thickness and shape from the viewpoint
of the minimum beam loss in the accumulation stage where the loss is
dominated by large angle Rutherford scattering due to multi-passage
of the foil.
      (2) The chromaticity correction will be done during the full
acceleration period by AC power supplies for sextupole magnets. This
would contribute to the reduction of beam loss at dispersive points
in the acceleration.

3. MPS (Machine Protection System)
      There are concurrent beam supplies from RCS to MLF (Materials
and Life science Facility) and MR. Previously when an MPS
interlock in one side activated, the supplies to both sides were
interrupted for maximum protection. After operational experience,
this system has been updated so as to suspend only the corresponding
supply to the source facility of an interlock.


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3. [Nuclear and Particle Physics Division] by J.IMAZATO and T.TSUKAMOTO
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  K1.1BR COMMISSIONED SOON (by J.IMAZATO)
  -the progress in the summer shutdown -

      During this summer shutdown further progress was made in the
Hadron Experimental Hall. The construction of the K1.1BR beam line,
which started this spring, has been completed, and the experimental
area of the KL neutral kaon line has been extended. K1.1BR should
deliver a separated charged kaon beam up to 1.0 GeV/c and will be used
for particle physics experiments using stopped kaons in the future.
The beam line is now waiting for commissioning and beam tuning
starting on October 12. For some period after the start of operations,
the beamline will provide beams for detector test experiments. The KL
area is now completed in the final form. The KOTO (E14) group is now
piling up CsI crystals at the detector end-cap for their rare decay
experiment aiming for an engineering run in the coming beam cycle.
       Two nuclear physics experiments (E19 and E17) are waiting for
the beam at K1.8 and K1.8BR, respectively, in the coming cycle. They
had already started an engineering run before, and E19 is now ready
for the physics run.


  T2K STATUS DURING SUMMER SHUTDOWN (by T.TSUKAMOTO)

      T2K accumulated neutrino beam data until June 26 as reported in
the previous J-PARC newsletter #41. The analysis is being continued
and it was reported at international conferences such as ICHEP 2010
(http://www.ichep2010.fr/ ) that 33 neutrino events have been observed
by Super-Kamiokande with the accumulated data corresponding to
3.23e+19 POT(protons on target), in which there are 23 neutrino events
satisfying event selection cuts such as vertex point and measured
energy.

      Many projects are being carried out for the neutrino beam
facility and the near detector ND280 for the beam operation with higher
power than 100kW from the middle of November.

      The T2K logo was selected through a vote of all t2k members
in July 2010 as shown at
http://www.t2k.org/news/logo/t2k_logo_medium.png.


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4. [Materials and Life Science Division] by Masatoshi ARAI
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  OPERATION IN AUTUMN HAS BEEN STARTED AS SCHEDULED

  CONSTRUCTION OF SIX NEW INSTRUMENTS IS CONTINUING

  DEVELOPMENT OF SCINTILLATION DETECTORS FOR THE HE-3 SUPPLY PROBLEM

  MODIFICATION OF THE D-LINE DURING THE SHUT-DOWN PERIOD IN SUMMER 2010

1. Neutron Source

       During the summer shutdown period, the equipment was inspected
or overhauled thoroughly.  No serious faults or defects were
found and stable operation is expected for the coming beam
cycles.  The accumulator of the cryogenic hydrogen system was
replaced with a new one to recover a function of the system to
absorb hydrogen pressure fluctuations due to turning on/off of the
high power proton beam.  User operation has been started in middle
of October as scheduled.

       The beam optics of the proton beam transport line has been
intensively studied to reduce the beam current density onto the
mercury target. The beam profile can be made flat by introducing a
couple of octupole electromagnets in the most downstream part of the
proton beam transport line. The specifications of the octupole
electromagnets are being finalized for procurement.  The design
review meeting on the compact-type mercury target vessel and the
microbubble injection system for pressure wave mitigation was held.
The R&Ds on the seal performance of the compact target flange and
the analytical code to estimate qualitatively gas accumulation in
mercury circulation loop were required.

2. Neutron Science

       User operation for the 2010A period (from June to November 2010)
is continuing and 74 accepted general proposals called by J-PARC as
well as 20 general proposals called by Ibaraki prefecture (proposals
from industrial users to two Ibaraki prefecture beamlines)
are being carried out.  For the 2010B period (from December 2010 to
March 2011), 99 general proposals were submitted, reviewed by the
neutron science proposal review committee, and finally, adoption or
rejection of each proposal was decided by the MLF advisory board.
In total, 110-days beamtime will be available: 50 days for 2010A and
60 days for 2010B.  The call for the next term proposals (2011A) will
be started on November 17.

       The construction of six new instruments, DNA (BL02, Inverted
Geometry Spectrometer), SPICA (BL09, Powder), PLANET (BL11, High
Pressure Diffractometer), TAIKAN (BL15, Small Angle Neutron
Scattering), VNR (BL17, Vertical Reflectometer) and SENJU (BL18,
Single Crystal Diffractometer), are continuing. Beamline and
instrument shielding for TAIKAN, beamline shielding for DNA,
choppers, supermirror guide tubes and all the shielding for PLANET
were installed already.  The International Advisory Committees for
SENJU and VNR were held in August and September, respectively,
and valuable comments were obtained.

3. Neutron Instrument

       We also are faced with the world-wide Helium-3 supply problem
for building neutron detectors in J-PARC/MLF.  J-PARC center has
approved the "Collaboration Agreement Concerning the Development of
Alternative Techniques to He-3 Based Neutron Detectors for
Neutron Scattering", which was proposed at the time of International
Conference on Neutron Scattering 2009 held at Knoxville.  A joint
programme for development of scintillation detectors is under
discussion.

4. Muon Science

       During the shut-down period in summer 2010, we have been
working on the modification of the Decay-Surface Muon Line
(D-line) which is the only muon beam line at MUSE.

       So far, we have been using old quadruple magnets with a
small aperture of 200 mm in diameter for Q4 and Q7 in the D-line.
We are now replacing the old Q4 and Q7 with new quadruple magnets
with an aperture of 300 mm in diameter. These installations may
increase transmission efficiency as much as 1.5 times higher.

       In addition, in order to remove positron contamination
having the same momentum as the surface muons, a static E x B
filter, so called DC separator, has been developed. We are now
replacing the older separator having an electrode gap of 100 mm
(+-100kV), with a new separator having a gap of 200 mm (+-250kV),
and the muon beam loss by hitting the electrodes or the beam ducts
could be reduced significantly.

       Also, for extracting an intense surface muon beam of as much
as 4 x 10^8/s, which will be intended to generate intense ultra slow
muons, we just started fabrication of the superconducting curved
solenoid for the Ultra Slow Muon Beam Line (U-line).  In order to
finalize the specifications, we are now discussing details of the
design with TOSHIBA, which won an international bidding.


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5. [Nuclear Transmutation Section] by Hirofumi TSUJIMOTO
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  IRRADIATION EFFECTS ON THE AUSTENITIC STEELS FOR THE BEAM WINDOW
OF ADS

       The beam window for the spallation target of
ADS (Accelerator Drive System) will be subjected to high-energy proton
and spallation neutron irradiation. To evaluate the lifetime of the
beam window, post irradiation examination (PIE) of the STIP (SINQ
target irradiation program, SINQ; Swiss spallation neutron source)
specimens was carried out at Japan Atomic Energy Agency (JAEA).
The specimens were austenitic steels that are preferable as the
material for the beam window of ADS from the view point of
DBTT (Ductile- Brittle Transition Temperature)
shift, which should be taken into consideration for ferritic /
martensitic (F/M) steels.  The irradiation conditions of the
specimens were as follows: proton energy was 580 MeV, irradiation
temperatures ranged from 100 to 450 degrees C, and displacement
damage levels ranged from 6.5 to 19.5 dpa (displacements per atom).
All PIE work has been carried out in the hot laboratory at JAEA.

       Results of the tensile tests performed at room temperature
indicated that irradiation hardening occurred with increasing
displacement damage level up to 10 dpa.  At higher doses, irradiation
hardening seemed to tend to saturate.  Degradation of ductility was
bottomed around 10 dpa and specimens kept their ductility until
19.5 dpa.  The most of specimens fractured in ductile manner, however,
the specimens irradiated at the higher dose (>19 dpa) and higher
temperature (>400 degrees C) showed partially intergranular morphology.


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6. [Safety Division] by Taichi MIURA and Hiroshi NAKASHIMA
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  APPLICATION FOR OPERATION OF THE WHOLE FACILITY WAS GRANTED BY MEXT

      The application for the operation of all the facilities was
granted by the Ministry of Education, Culture, Sports, Science and
Technology (MEXT) on August 27.

      The main change topics are the power-up for all the 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.

     The inspection of the HD will be conducted on October 22 by the
Nuclear Safety Technology Center (NUSTEC).


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7. [Announcement of Symposia and Meetings]
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  2nd MLF Symposium, Jan. 17-18, 2011 at KEK, Tsukuba
(Language: Japanese)
http://j-parc.jp/MatLife/ja/meetings/MLFsympo/index.html


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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++++++++++++++++++++++++++++++++++++++++++