[Neutron] J-PARC newsletter #13
Masatoshi ARAI
masatoshi.arai at kek.jp
Mon Jul 28 20:33:50 CDT 2003
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J-PARC Project Newsletter
_______ No. 13 July, 2003 _______
High Intensity Proton Accelerator Project proposed jointly
by the Japan Atomic Energy Research Institute (JAERI)
and the High Energy Accelerator Research Organization (KEK)
http://j-parc.jp/
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HEADLINES AND CONTENTS
1. <<Overview>>
.CONSTRUCTION IS MAKING STEADY PROGRESS.
.NEGOTIATION FOR THE JFY2004 BUDGET IS IN PROGRESS.
.TWO IMPORTANT COMMITTEE MEETINGS WERE HELD IN MARCH.
.STATUS OF LETTERS OF INTENT.
.OTHER ACTIVITIES.
2. <<Accelerator Group>>
.FULL HIGH POWER TEST OF THE RCS RF CAVITY.
3. <<Exotic Nuclear Science Group>>
.MODIFICATION OF THE RNB-ACCELERATORS SUCCESSFULLY FINISHED.
.CONSTRUCTION OF THE ION-SOURCES WITH UC-TARGETS IS PROCEEDING.
4. <<Nuclear and Particle Physics Group>>
.THE 2ND NUCLEAR AND PARTICLE PHYSICS FACILITY COMMITTEE
(NPFC) MEETING.
5. <<Neutron Science Group>>
.RE-DESIGN OF THE MLF CONVENTIONAL FACILITY BUILDING IS
UNDERWAY TO MEET RATIONAL COST REDUCTION REQUIREMENT.
6. <<Muon Science Group>>
.A PROTOTYPE EDGE-COOLED NON-ROTATING GRAPHITE TARGET
WAS MADE AND IS UNDER HEATING TEST.
7. <<Radiation Safety Group>>
.THE EXAMINATION OF THE REGULATIONS ON PREVENTION FROM
RADIATION HAZARDS FOR J-PARC WAS STARTED.
8. <<Integrated Control Group>>
.CONTROL SYSTEM PREPARATION FOR THE 60 MeV LINAC COMMISSIONING.
9. <<Facility Construction Group>>
.CONSTRUCTION BEGAN AT MOST OF THE JAERI CONSTRUCTION SITE.
.FIRST KEK BUILDING WAS COMPLETED AT JAERI SITE.
10. <<Announcement of Symposia and Meetings>>
11. <<Editorial Note>>
.Subscribe or Unsubscribe
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1. <<Overview>> By Shoji NAGAMIYA
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.CONSTRUCTION IS MAKING STEADY PROGRESS.
FY2003 started on April 1, 2003. The project entered into
the third year for construction. During the first 3 years including
this year, 46% of the total KEK budget has been awarded, whereas
only 30% of the total JAERI budget has been funded. A sharp increase
in the JAERI budget is needed for the next fiscal year, FY2004.
A good news is that the creation of a new research center called the
Neutron Science Research Center was approved for JAERI, and this
Center started its operation on April 1, 2003, by inviting Professor
Y. Fujii from University of Tokyo as the Director of this Center.
In general, the construction work is moving steadily.
Contracts with companies on the accelerator components have been
completed at the 80% level for the Linac, 50% for 3 GeV and 60% for 50 GeV.
Building construction is also moving smoothly. The main control
office building was completed at the end of June. The scenery of
the construction site is changing everyday.
As reported before, remains of ancient salt farms were
discovered at the construction site of 50 GeV. Extensive
archeological studies are presently in progress over the area of
about 6 ha. About 100 people were hired for the studies. Coins,
human remains, pottery, remains of residential areas, etc. have
been discovered so far. Although a certain delay for the project
is anticipated, it is expected that the completion date of the 50 GeV
building is unchanged. The project team is also trying to make the
delay of installation of the accelerator components to a minimum.
.NEGOTIATION FOR THE JFY2004 BUDGET IS IN PROGRESS.
In JFY2004 the project will enter into the latter half for
construction. On this occasion we propose seriously the initiation of
funding for the neutrino experiment. Also, we started to negotiate an
additional fund to allow an early recovery of the linac energy to the
original 400 MeV (which is now reduced due to the design change of the
entire accelerator system). Furthermore, the important negotiation
this time is to increase the JAERI construction budget sharply for
JFY2004 in order to complete the project in a timely manner.
.TWO IMPORTANT COMMITTEE MEETINGS WERE HELD IN MARCH.
The International Advisory Committee meeting was held on March
10 and 11. An early start of the neutrino program, a quick recovery
of the linac energy to the original design value, the creation of a
simple and clear organization at the operational stage, etc. were
recommended. Preceding this meeting, the Accelerator Technical
Advisory Committee meeting was held on March 7 and 8. Technical
discussions on an improved design of the 3 GeV ring, a realistic
scenario on the recovery of the linac energy to the original design
value, etc. were discussed. The project team will take these comments
and advice seriously.
.STATUS OF LETTERS OF INTENT.
Last year the Project Office called for two types of Letters
of Intent, one for neutron instruments at 3 GeV and the other for
nuclear and particle physics experiments at 50 GeV. For neutron
instruments the selection was made for the 18 LoIs. About a half of
LoIs were recommended to move to the next stage for more detailed
proposals. On the other hand, for nuclear and particle physics
experiments the presentations of 30 LoIs were made at two meetings
in March and June. The recommendation will be sent to the Project
Director soon.
Concerning the LoIs for nuclear and particle physics
experiments, the total number of authors was 478 and the author
distribution was 1/3 in Japan, 1/3 in the US, 1/4 in Europe and the
remainder in Asia. This geographical distribution indicates that the
J-PARC will become a truly international facility.
.OTHER ACTIVITIES.
1) The Accelerator Driven Transmutation System (ADS) International Symposium
was held on March 24 and 25.
B. Richter reported the status from the US and B. Frois that from Europe.
Representatives from the Asian countries were invited also. The
need for international coordination and collaboration was discussed.
This meeting was the first ADS international meeting for the project.
2) The Ibaraki Prefecture held the final meeting of the
Science Frontier 21 on March 27. Recommended at this meeting was
the usage of the prefecture's budget primarily for the construction
of a few neutron beam lines.
3) On May 17 about 900 volunteers planted 9000 trees along the new
road near the linac. The instructor was Professor Miyawaki,
a well-known researcher on the forest.
4) The neutrino group proposed the need of a third detector located
at 2 km from the J-PARC site. Accordingly, the geological studies were
initiated by the U. Tokyo. Discussions with the local community, the
village and the Prefecture were held. The Tokai Village intends to
loan the land to us with no rental fees. A cost estimate of this
detector construction was made and it was shown to the Government
along with the budget request of the entire neutrino facilities.
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2. <<Accelerator Group>> by Yoshisige YAMAZAKI
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.FULL HIGH POWER TEST OF THE RCS RF CAVITY.
In addition to the RF system for the 50-GeV Main Ring (MR),
the cavity for the 3-GeV Rapid-Cycling Synchrotron (RCS) was
successfully tested with full peak RF power and full duty factor.
J-PARC will be the first machine that will extensively use cavities
loaded with Magnetic Alloy (MA), which was first developed at KEK.
In particular, the rapid-cycling, high-energy acceleration requires
a very high field gradient, which is, in the J-PARC case, several
times as high as what conventional ferrite-loaded cavities can
generate. This high field gradient can be only realized with the MA
cavities. Also, MA cavities are immune to coupled-bunch
instabilities, and a complicated tuning control system, which follows the
frequency increase during acceleration, is not necessary, since their
Q-value is extremely low, being down to 0.9. However, the extremely
high R/Q with an extremely low Q value, which keeps the shunt
impedance (acceleration efficiency) reasonably high, implies that
the beam loading should be compensated for the wide range of
frequencies. In order to keep the range within a practical band
width for the high-power RF amplifier, the Q value should be
optimized. It was found by J-PARC group that the Q value can be
controlled by adjusting the gap width between the radially cut MA
cores. The MA core is made of MA tapes impregnated with
resin, being too soft to machine with the necessary accuracy. This
problem was finally solved after several attempts, making the
high power test successful. Further development will continue
to ensure reliable mass production.
.THE 4TH J-PARC ACCELERATOR GROUP TECHNOLOGICAL MEETING.
All the accelerator group members from both KEK and JAERI
meet together to report the construction status, the R&D results and
the technological issues and to discuss them. The meeting is
held every six months. This time it was held on July 1st and 2nd in KEK.
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3. <<Exotic Nuclear Science Group>> by Hiroari MIYATAKE
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.MODIFICATION OF THE RNB-ACCELERATORS SUCCESSFULLY FINISHED.
The cavities of the KEK linacs (SCRFQ: split coaxial RFQ and
IH: interdigital-H) have been modified to increase the resonant
frequencies by about 2%, i.e. 25.5 MHz to 25.96 MHz and 51 MHz to 51.92
MHz, respectively, for further acceleration with the JAERI 129.8 MHz
superconducting linac. These KEK linacs together with the 18 GHz
charge breeding ECRIS (Electron Cyclotron Resonance Ion Source) will
be installed at the KEK-JAERI joint RNB(radioactive nuclear beam)
facility and will be operational at the end of this year. After the beam
conditioning schedule, a pilot experiment with 1.1 MeV/u RNB will be
started in the next year, FY2004.
.CONSTRUCTION OF THE ION-SOURCES WITH UC-TARGETS IS
PROCEEDING.
Two kinds of ion sources, the surface ionization type and the
FEBIAD (Forced Electron Beam Induced Arc Discharge) type, have been
improved to produce heavy neutron-rich RNBs with proton-induced
fission of 238U. In the present FEBIAD type ion source, a 2.6
mg/cm2 uranium-carbide target is directly attached to a plasma
chamber, while the surface ionization type one, a 2.6 mg/cm2
uranium-carbide target is located inside the ion source.
A self-contained unit of the ion source is coupled to the
acceleration chamber of the separator through a simple transport
device. For the safe maintenance of the target/ion-source, a
compact remote-handling system and a storage section are under design.
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4. <<Nuclear and Particle Physics Group>> by Tomofumi NAGAE
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.THE 2ND NUCLEAR AND PARTICLE PHYSICS FACILITY COMMITTEE
(NPFC) MEETING.
The second meeting of Nuclear and Particle physics Facility
Committee (NPFC) was held at KEK from June 26 to June 28, 2003.
All the LOI's, except the L12(neutrino oscillation experiment) which
was considered in the first meeting, were presented in the first two
days. There were 25 talks including 10 by those from abroad.
The Committee considered each LOI from the view-points of
physics impact, beam schedule, and technical feasibility, etc.
As for the beam schedule, a few LOI's have been classified as
"Day-1". The comments for each LOI will be submitted to the Project
Director in a short time. Also, the current scheme of the primary
beam configuration, having one line A with a production target T1,
has been approved by the Committee. The Committee expects that the
Project Team will prepare the initial design of the secondary beam
line configuration at "Day-1" and its extension options in Phase-1
based on the recommendations.
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5. <<Neutron Science Group>> by Yujiro IKEDA
(Materials & Life Science Experimental Facility Group)
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.RE-DESIGN OF THE MLF CONVENTIONAL FACILITY BUILDING IS
UNDERWAY TO MEET RATIONAL COST REDUCTION REQUIREMENT.
Nine neutron instruments out of 18, which were proposed in
the first framework of LOI call, have been recommended by the review
committee to proceed to the next step of review process. The second
call for letters of intent (LOI) of neutron instruments has been
submitted to potential users worldwide, for which the deadline is October
15, 2003.
Incident proton beam peak power density to be directed on
the mercury target has been recognized as critical due to the
mechanical stress of the target window. According to the mitigation
request, we have investigated possible reduction of the power by
expanding the beam profile. Though it seems very effective, it
imposes a change in the dimension of the beam entrance of the
reflector region, which results in an increase of the area of the
target to accept the beam. For this change, the heating profile of
the structure, e.g., blades for Hg flow, and edge of the target
container has been analyzed. As a result, we concluded that there
is no serious effect for the expansion of the beam entrance region.
The building design of the MLF conventional facility has been
reviewed for changes that could reduce the cost. Although
it will result in a delayed start for construction, we decided to
make a considerable change in the structure by eliminating a
intermediate radioactive storage area. To meet this change, an
extensive investigation of utilizing existing facilities in the
JAERI Tokai site for storage was made.
Specifications of a mercury target container, a mercury
circulation system, a cryogenic cold moderator system, etc. are
being finalized. They are close to call for tender.
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6. <<Muon Science Group>> by Yasuhiro MIYAKE
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.A PROTOTYPE EDGE-COOLED NON-ROTATING GRAPHITE TARGET
WAS MADE AND IS UNDER HEATING TEST.
As a production target at the muon science facility, we are
planning to install a 20 mm graphite target for phase 1, where a heat
loss as much as 3.3 kW is calculated to be deposited into the region
of 25 mm in diameter by the 3GeV, 1 MW proton beam.
At present, we are investigating whether we can adopt an
edge-cooled non-rotating graphite target, because of its ease of
handling and maintenance. Calculations, done so far, for the heat
and stress induced by the heat deposit of 3.3 kW are showing that we
are able to use it for the 3GeV 1MW proton beam, even considering
the neutron irradiation effect.
Recently, a prototype target was made according to the
following design. For the cooling pipe, SUS tube with O.D. 3/8 inch
tube was adopted. In order to bury the 3 turns of SUS tube in the
copper holder, hot isostatic press (HIP) was adopted. A Titanium layer
with a thickness of 1 mm was placed as a buffer material to release
stress. The copper holder, the titanium layer and the isotropic
graphite with a taper of 3 degrees were silver-brazed in vacuum.
We are now performing heating tests on the graphite target by
two sets of electron guns.
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7. <<Radiation Safety Group>> by Tokushi SHIBATA
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.THE EXAMINATION OF THE REGULATIONS ON PREVENTION FROM
RADIATION HAZARDS FOR J-PARC WAS STARTED.
With the completion of the J-PARC construction, it is
necessary to receive an approval from the Ministry of Education,
Culture, Sports, Science and Technology (MEXT) for the radiation
facilities in order to operate J-PARC. At the application stage,
it is compulsory to prepare the regulations on
prevention from radiation hazards for J-PARC. In the first step,
a radiation controlled area must be applied to MEXT for installing
activated apparatus such as magnets and shielding in order to
construct beam lines. After the construction, the beam lines will
be applied to get an approval for the operation.
Currently the LINAC facility is planning to carry
activated beam-line components into the LINAC beam-line tunnel
from KEK. This will be the first application to MEXT for a
radiation controlled area in the J-PARC facilities and is scheduled
to be completed in the last quarter of the fiscal year of 2004.
Hence, at the end of fiscal year 2003 or at the beginning
of fiscal year 2004, the safety system of J-PARC must be
proposed to the safety deliberative committee on Radiation Safety
of J-PARC and then to the radiation safety committees of JEARI and
KEK. In these committees, the regulations and radiation safety
control system of J-PARC must be presented. The study of the
regulations and the system has commenced in the working group
formed in the radiation safety group: every text in the regulations
has been examined word by word from various points of view.
The first draft is expected to be completed within the fiscal year
of 2003.
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8. <<Integrated Control Group>> by Tadahiko KATOH
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.CONTROL SYSTEM PREPARATION FOR THE 60 MeV LINAC COMMISSIONING.
Extensive work has been done for providing software
required for the commissioning of the 60 MeV linac scheduled in July
at the KEK site. The driver software and support software on
IOCs (Input/Output Controllers) used in the EPICS based system has been
developed for PLCs and WE7000 measuring stations. PLCs are used for
monitoring and controlling ion source, drift-tube linac tank and RF
power sources.
WE7000 measuring stations are used to collect waveform data
of the linac, e.g. RF pulse waveforms, beam current monitor signals,
and so on. The EPICS software development environment has been moved
from kek.jp domain to a new j-parc.jp domain so that the staff of
both sites can have a common environment.
The noise problem of the MPS (Machine Protection System)
units (reported in the previous News Letter) has been fixed by putting a
noise filter on the DC power supply line. A prototype model of the optical
fan-out module for the timing signal distribution system has been
developed and tested recently. Construction of the Central Control
Building has been finished, but it cannot be used as offices because the
water
supply works are not yet completed.
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9. <<Facility Construction Group>>
by Hideo NARUSE and Takashi NANBU
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.CONSTRUCTION BEGAN AT MOST OF THE JAERI CONSTRUCTION SITE.
Construction of the Linac Building and 3GeV Synchrotron
Building are progressing satisfactory. The construction of the linac
accelerator tunnel started in June. Detailed design of the Material
and Life Science Facility Building, which was completed last March,
is being modified now.
.FIRST KEK BUILDING WAS COMPLETED AT JAERI SITE.
Construction of the Central Control Building, which started
last December, was completed at the end of June. In this building,
central control for the operation and the maintenance of the whole
accelerator facility will be carried out, which includes control and
monitoring of the accelerator and utility system in order to maximize
the operating efficiency. The building is located at the center of
the whole site. Exterior of the building is exposed concrete finish
and tiling, which is similar to the other buildings being constructed
by JAERI.
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10. Announcement of Symposia and Meetings
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1) International Symposium on Pulsed Neutron Science and Instruments
(IPN2003)
Oct 27 - 30, 2003 in Tsukuba, Japan.
http://neutron-www.kek.jp/Symposia/index.html
2) UK-Japan Neutron Science Workshop (UKJ2003)
Oct 31 - Nov 1, 2003 in Izura SPA (Pacific seaside), Japan.
http://neutron-www.kek.jp/Symposia/index.html
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11. Editorial Note
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In case you do not wish to receive this Newsletter in the
future, please send an email to
majordomo at jkj.tokai.jaeri.go.jp
and simply write one sentence in the body of the message as
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If you wish to receive, write one sentence in the body of the message
as
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You can get a help with a sentence of "help" in the body.
Information on the project can be also obtained at the Web site:
http://j-parc.jp/
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Editorial Board:
Masatoshi ARAI (chair): masatoshi.arai at kek.jp
Koji YOSHIMURA koji.yoshimura at kek.jp
Yujiro IKEDA: ikeda at cens.tokai.jaeri.go.jp
Nobuo OUCHI ouchi at linac.tokai.jaeri.go.jp
Shinya SAWADA: shinya.sawada at kek.jp
English Editor:
Dick Mischke mischke at lanl.gov
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