[Neutron] J-PARC Newsletter No.38
arai (J-PARC)
masaarai at hotmail.co.jp
Thu Nov 12 11:10:22 CET 2009
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J-PARC Project Newsletter
No. 38, Nov. 2009
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
===============================================================
Hot news from J-PARC:
We have started a 120kW-operation since 10 November after serious
improvements on the RFQ linac as described below. This is a big step
for us from the 20kW-operation in the previous stages. The accelerators
are working successfully with higher reliability now.
===
HEADLINES AND CONTENTS
1. [Overview]
LODGING WILL BE CONSTRUCTED BY KEK
OPEN HOUSE FOR J-PARC
ACCELERATOR REVIEW WAS CONDUCTED
FEE FOR PROPRIETARY EXPERIMENTS
2. [Accelerator Division]
BEAM COMMISSIONING RESTARTED WITH STEADY IMPROVEMENT OF
RFQ (RADIO-FREQUENCY QUADRUPOLE) LINAC
THE IMPREGNATED RESIN IS THE MAIN REASON FOR BUCKLING OF MA
(MAGNETIC ALLOY) CORE FOR RF CAVITIES
THE REPETITION CYCLE TIME OF MR (50-GeV Synchrotron) WAS
SHORTENED TO 3.52 SEC
3. [Nuclear and Particle Physics Division]
BEAMLINE AND DETECTOR INSTALLATION IS MAKING PROGRESS
IN THE HADRON HALL
STATUS OF NEUTRINO FACILITY
4. [Materials and Life Science Division]
5. [Exotic Nuclear Science Group]
THE INTERNATIONAL REVIEW COMMITTEE WAS HELD FOR A NEW
EXPERIMENTAL RESEARCH PROJECT PROPOSED BY RNB GROUP
STRUCTURE OF 11Be WAS STUDIED BY USING 9Li RADIOACTIVE
NUCLEAR BEAMS AT TOKAI RADIOACTIVE ION ACCELERATOR
COMPLEX (TRIAC)
SELF-DIFFUSION COEFFICIENTS IN ELECTROLYTE FOR LITHIUM ION
BATTERY WERE DIRECTLY MEASURED AT TRIAC
6. [Nuclear Transmutation Section]
NEEDS OF R&D FACILITIES IN NUCLEAR SCIENCE
7. [Safety Division]
APPLICATION FOR OPERATION LICENCES WERE SUBMITTED TO MEXT
8. [Announcement of Symposia and Meetings]
9. [Editorial Note]
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1. [Overview] by Shoji NAGAMIYA
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LOGDING WILL BE CONSTRUCTED BY KEK
For a long time, we have requested "lodging" for users. Very
recently KEK decided to construct 52 rooms for users on the site of
the Ibaraki Quantum Beam Research Center, where the Users Office
and office space for users are currently located. The anticipated
completion of this lodging will be sometime near the end of 2010 or,
at the latest, the beginning of 2011. We have also requested
construction of a hotel by Tokai Village. We were told that the effort
to construct a new hotel will still continue, even if the lodging is
constructed by KEK.
OPEN HOUSE FOR J-PARC
On August 1 we had an open house for J-PARC. This year, the
open house was hosted by both J-PARC and Tokai Research Center.
We had 4600 visitors among which 3700 were J-PARC visitors. Last
year we had 2600 visitors for the J-PARC, so the number increased
substantially this year. We shall have an open house once a year
in coming years.
ACCELERATOR REVIEW WAS CONDUCTED
On July 29 an accelerator review was conducted (chair is
Professor Oide from KEK). This time, the main purposes of the
review are on 1) technical feasibility of approaching 1 MW, 2)
financial constraints to achieve it, and 3) the best strategy for
the future. Based on this review, the next stage is to discuss with
the user communities if the current strategy presented by the
accelerator group is agreeable to the communities. I will
report the results of these discussions in the next issue of
the Newsletter.
FEE FOR PROPRIETARY EXPERIMENTS
Since last December the beam time has been open for neutron
users. Recently, an industrial usage started to come, though
we have not yet settled how much the actual charge is for
proprietary experiments without any publications. The Government
started to agree with the fee which is comparable to SPring-8.
For any work for which the results are published, the beam time
charge is free at J-PARC.
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2. [Accelerator Division] by Ainosuke ANDO
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BEAM COMMISSIONING RESTARTED WITH STEADY IMPROVEMENT
OF RFQ (RADIO-FREQUENCY QUADRUPOLE) LINAC
Beam Commissioning restarted on October 1 after the summer
shutdown for the maintenance of the accelerators and the improvement
of the RFQ linac. In the improvement, two cryopumps of 4000 L/s each
and two SIP's (Sputtering Ion Pumps) of 800 and 400 L/s were added
to the existing evacuation-pumping system, and a mass separator to
obtain clear information of outgassing was installed. An additional TMP
(Turbo Molecular Pump) of 500 L/s was also installed in the LEBT (Low
Energy Beam Transport between the ion source and the RFQ), which was
replaced by a new one with orifices at both ends to reduce the
unnecessary flow of H- ions and hydrogen. The operation of RCS (3-GeV
Rapid Cycling Synchrotron) has been restarted with the LINAC beam at
first of 5 mA in peak current and 0.1 msec pulse width to ensure the
stable beam output of 20 kW from RCS in October. In the next stage,
the pulse width will be expanded to 0.5 msec for 100 kW of RCS, and
then the peak current will be raised to 15 mA for 300 kW of RCS.
The demonstrated operation with the RCS beam output of 200 kW in
70 seconds and equivalent 310 kW in one shot in September 2008 will
be routine if there are no troubles in hardware and the beam loss
issues are solved.
THE IMPREGNATED RESIN IS THE MAIN REASON FOR BUCKLING OF
MA (MAGNETIC ALLOY) CORE FOR RF CAVITIES
Buckling or stress deformation has been found in many MA cores
for the RF cavities of RCS as reported in Newsletter #36.
Investigation for the correlation between the damaged cores and their
manufacturing processes clarifies that the existence of the impregnated
resin, of which the coefficient of linear expansion is larger than that
of the MA alloy by about 8 times, prevents any room for expansion of
MA alloy ribbons. Although the impregnation of the resin with light
viscosity was adopted in R&D to make a core more rigid, the original
process without impregnation is re-adopted to restore only the
original purpose.
THE REPETITION CYCLE TIME OF MR (50-GeV Synchrotron) WAS
SHORTENED TO 3.52 SEC
As the improvement of the power supplies for the main magnets
(bending and quadrupole magnets) resulted in the shorter rise and fall
time (still not enough for the design values), the cycle time of MR is
shortened to 3.52 sec for the FX mode (Fast Extraction for the neutrino
target). MR is operated in the two modes of FX and SX (Slow Extraction
for the hadron target) from October. In the SX mode, the cycle time
is still 6 sec with the 30-GeV flat-top of 2 ~ 3 sec; enough for favorite
beam manipulation or gymnastics.
-----------------------------------------------------------
3. [Nuclear and Particle Physics Division]
by Toshiyuki TAKAHASHI and Hiroaki WATANABE
by Masahiro SHIBATA, Yoshiaki YAMADA and Toshifumi TSUKAMOTO
-----------------------------------------------------------
BEAMLINE AND DETECTOR INSTALLATION IS MAKING
PROGRESS IN THE HADRON HALL
Preceding the further commissioning of the accelerator MR and
the eventual slow beam delivery to the Hadron Hall in this autumn,
the installation of beamlines is making progress. Following the
completion of K1.8BR in January 2009, the K1.8 beamline will be
completed soon as the extension of K1.8BR. K1.8 delivers
separated charged meson beams up to 2.0 GeV/c, at which primarily
hypernuclear spectroscopy will be performed. In particular,
the study of the double strangeness system will be a topic in Day-1
experiments. The beamline has already been tested for all
the magnets and equipped with a second electrostatic separator
in the extended section. In the experimental area the high-resolution
Superconducting Kaon Spectrometer (SKS) is now being set up.
The magnet had already been moved from KEK-PS with some
modifications in the cryogenic system. The magnet has been
successfully cooled down and excited. Detector mounting is
also ongoing by the user group.
On the other side of the primary beamline, the construction of
the neutral kaon line KL has been also finished. The beamline
consists of two sets of movable collimators and a sweeping magnet
between them and should deliver a K_L beam with very suppressed
halo-neutron background. The E14 KOTO experiment (the rare decay
experiment KL-> pi0nu nu-bar) will be performed with an
international collaboration. In this autumn, the beam survey
is scheduled, in terms of the K_L yield measurement as well as
the beam quality study.
STATUS OF NEUTRINO FACILITY
The primary proton beam line of the neutrino facility has four
types of proton beam monitors, namely intensity, position, profile and
beam loss monitors. Five CTs (Current Transformers) are installed as
intensity monitors. 2% precision was achieved in the previous
commissioning. Twenty one ESMs (ElectroStatic Monitors) are installed
to measure beam position. Present typical resolution is 0.6 mm and
we are working to improve the resolution by understanding the
background to the signal. Nineteen SSEMs (Segmented Secondary
Emission monitors) are installed as profile monitors. Obtained resolution
is 0.2 mm for position and width. Fifty BLMs (Beam Loss Monitors) are
placed around the beam line. No significant beam loss was observed in
the previous commissioning except for beam loss from foils of the
SSEMs. This indicates that the total beam loss was less than 0.1
percent. In the summer shutdown, ESM and SSEM re-alignment work
was carried out and software was upgraded to deal with multi-bunch
beam in addition to analysis of obtained data. Now we are ready for
beam commissioning from October.
For the beam run with higher beam power in Autumn, the second
and third horns were installed into the Helium vessel on July 10th
and August 6th, respectively. Then, simultaneous test operation with
1st, 2nd and 3rd horns successfully finished in September. The helium
vessel is now under an evacuation test, and will be filled with 1500m3
of helium gas soon. The Autumn beam run will start after the final
test operation of horns in He gas.
The installation work of the T2K near detectors is ongoing
at the NM (Neutrino Monitor) building. A neutrino beam monitor,
INGRID (Interactive Neutrino GRID detectors), was successfully
installed in August. The commissioning and calibration of INGRID is
being carried out to be ready for the neutrino beam in October.
As a part of the off-axis neutrino detectors, the P0D(Pi-zero
Detector), the FGD (Fine Grained Detector), and the DSECAL
(DownStream Electromagnetic CALorimeter) were tested on surface
and were installed in the detector support structure, called BASKET.
Two TPC (Time Projection Chamber) modules will be shortly
installed this October. The work of cabling and piping is being
carried out, and the commissioning of the detectors will follow.
The T2K off-axis neutrino detector is scheduled to be ready for
operation in December.
-----------------------------------------------------------
4. [Materials and Life Science Division] by Yujiro IKEDA
-----------------------------------------------------------
1. Neutron Source
In the summer maintenance period, annual voluntary inspection
of the cryogenic hydrogen system was completed successfully.
A vibration measuring system for the hydrogen circulation pump
was installed to evaluate abnormal pump rotating conditions.
Some remote-controlled cameras in the hot cell were modified
to move on rails for better visibility in replacement work
of activated components such as moderators.
The tunnel of the proton beam transport line was surveyed and
the uneven subsidence was found to be a maximum of 1 mm for the
last year. The magnets and the beam monitors were realigned
in this summer shutdown period with the accuracy better
than 0.1 mm.
The fabrication of the spare of target vessel was continued
to fix the safety hull on the mercury vessel. As for R&D on the
pressure wave mitigation, the micro-bubble distribution in the
target vessel was measured at the tetrathiafulvalene (TTF)
mercury loop of Oak Ridge National Laboratory (ORNL)
under collaboration with the Spallation Neutron Source (SNS).
2. Neutron Science
Various maintenance and improvements have been carried out in
twelve BL's during the Summer shutdown. A large vacuum tank with a
volume of 50 m3 (the weight of 40t) for the High Resolution Chopper
Spectrometer (HRC) was installed at BL12. A small vacuum tank and
six gas-filled tanks with a total volume of 20 m3 for the super high
resolution powder diffractometer (SuperHRPD) was installed at BL08
after the removal of the second-hand chamber. The installation of
3He detectors for both BL08 and BL12 are now underway.
Disk choppers maintenance and the confirmation of the guide tube
alignment were carried out in the Disk-Chopper Spectrometer
(AMATERAS) at BL14, and in the Engineering diffractometer (Takumi)
at BL19. Maintenance of detectors and electronics etc. were carried
out in most of the BL's.
User operation for the 2009A period (the first half of FY2009)
has been re-started on Oct. 12. 105 accepted experiments out of
116 proposals will be carried out during the period of 2009A.
The first result of the High Intensity Chopper Spectrometer
(4Seasons, BL01) utilizing the new technique of "the Multiple Incident
Energies" has been published and selected as the Editor's choice of
the Journal of the Physical Society of Japan (J. Phys. Soc. Jpn. 78
(2009) 093002).
3. Neutron Optics and Detectors
A neutron focusing device consisting of a spheroidal supermirror
(m=2) has been developed by using an ion beam sputtering instrument.
Elliptical mirror optics, which have no chromatic aberration, can be
effectively used for manipulating a wide range of wavelengths of
neutrons especially at pulsed neutron sources. The performance of
this optical system can be increased by using a spheroidal geometry
which increases the aperture ratio, and by using supermirrors which
increase the critical angle of total reflection.
4. Muon Science
The designs of the muon production target and the two sets of
scrapers are such that they are both placed in one large vacuum
chamber in order to make remote handling simple during maintenance
work. Particular care was given to the means of mounting the target,
moving and inserting the target with the required precision, as well
as cooling, monitoring, and changing the target in the hot cell,
assuming that all of the work is intended to be done from the top of
the maintenance area. Also we fabricated a dedicated muon cask,
together with a stand to position it on top of the target chamber
with good precision, for the maintenance of the muon target assembly,
the scraper assembly, and the profile monitor assembly.
During the summer shutdown of 2009, we have had a commissioning
test of exchanging the irradiated muon target assembly having about
50 mSv/h of dose on its surface. The irradiated target assembly was
lifted into the cask, and moved into the hot cell. In the hot cell, the
target assembly was successfully transferred into the dedicated stand
for the muon target assembly. After several measurements such as
dose and dimensions, the target assembly was put back into the target
chamber in the proton beam line.
-----------------------------------------------------------
5. [Exotic Nuclear Science Group] by Hiroari MIYATAKE
-----------------------------------------------------------
THE INTERNATIONAL REVIEW COMMITTEE WAS HELD FOR A NEW
EXPERIMENTAL RESEARCH PROJECT PROPOSED BY RNB GROUP
A new experimental research project is proposed by a research
group of the radioactive nuclear beams (RNB group) to understand the
rapid neutron capture process nucleosynthesis by an intensive study
on the decay nature of N = 126 waiting point isotones and nearby nuclei.
An international review committee for the proposal was held on July 16.
The committee appreciates a new initiative of RNB group in this
research region.
STRUCTURE OF 11Be WAS STUDIED BY USING 9Li RADIOACTIVE
NUCLEAR BEAMS AT TOKAI RADIOACTIVE ION ACCELERATOR
COMPLEX (TRIAC)
The elastic resonance scattering experiment of 9Li and deuteron
was successfully performed to study the structure of 11Be during
1-4, Oct. The radioactive nuclear beam (RNB) of 9Li, whose half-life
is 0.178 second, was accelerated with the energy of 0.85 MeV/u,
purity of almost 100% and intensity of 5*104 particles per second.
SELF-DIFFUSION COEFFICIENTS IN ELECTROLYTE FOR LITHIUM
ION BATTERY WERE DIRECTLY MEASURED AT TRIAC
LLTO (Li3xLa2/3-xTiO3) and LVSO (Li3VO4/Li4SiO4) are
candidates for the electrolyte of a solid-state lithium ion battery.
Self-diffusion coefficients for Li in those materials were directly
measured for the first time, using 8Li RNB from TRIAC during
19-23, Sept. The detailed analysis is in progress.
-----------------------------------------------------------
6. [Nuclear Transmutation Section] by Hirofumi TSUJIMOTO
-----------------------------------------------------------
NEEDS OF R&D FACILITIES IN NUCLEAR SCIENCE
A report on "Research & Test Facilities Required in Nuclear
Science & Technology" was published by the Organization for Economic
Cooperation and Development (OECD) Nuclear Energy Agency.
The report says that the Transmutation Experimental Facility under
the J-PARC project is expected to play important roles in
establishment of the technical basis to deal with minor actinide (MA)
in nuclear energy systems and to couple a proton accelerator with
a fast spectrum reactor.
(http://www.nea.fr/html/science/reports/2009/6293
-Research-Test-Facilities.pdf)
The first meeting of the expert group on Integral Experiments
for Minor Actinide Management was held in September at
the headquarters of OECD/NEA. This expert group was established
by the Nuclear Science Committee to review integral experiments
for validating MA nuclear data critically, as well as to recommend
additional integral experiments needed for validating MA nuclear
data and to investigate the possibility of establishing an international
framework for facilitating integral experiments for MA management.
The Expert Group will complete and document their activities within
two years.
-----------------------------------------------------------
7. [Safety Division] by Taichi MIURA and Hiroshi NAKASHIMA
-----------------------------------------------------------
APPLICATION FOR OPERATION LICENSES WERE SUBMITTED TO MEXT
Applications for licenses for the operation of the Nuclear and
Particle Physics Facility (HD) and the Materials and Life Science
Facility (MLF), 50GeV proton synchrotron (MR), the Neutrino
Experimental Facility (NU) were submitted to the Ministry of Education,
Culture, Sports, Science and Technology (MEXT) on June 24.
The main change points are the enlargement of a secondary beam
line in HD :K1.1, the collimator installation in the secondary beam line
BL10 in MLF, and the beam-intensity upgrade in HD, MR and NU.
The application for the operation of HD, MLF, MR and NU was
granted by MEXT on September 25.
-----------------------------------------------------------
8. [Announcement of Symposia and Meetings]
-----------------------------------------------------------
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9. [Editorial Note]
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+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Editorial Board:
Masatoshi ARAI (chair): masatoshi.arai at j-parc.jp
Fujio MAEKAWA: maekawa.fujio at jaea.go.jp
Nobuo OUCHI: ouchi.nobuo at jaea.go.jp
Shinya SAWADA: shinya.sawada at kek.jp
Toshifumi TSUKAMOTO: toshifumi.tsukamoto at kek.jp
English Editor: Dick MISCHKE mischke at triumf.ca
Secretary: Chikako KAIBARA kaibara.chikako at jaea.go.jp
++++++++++++++++End of Letter+++++++++++++++++++++++++++++++++
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