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2023.01.27

J-PARC Project Newsletter No.89, January 2023 dispatch

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     J-PARC Project Newsletter

                                No.89, January 2023
Japan Proton Accelerator Research Complex under joint operation 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]

* WE HOPE EVERYBODY COULD HAVE A HAPPY NEW YEAR AND WE WISH TO HAVE
ANOTHER FRUITFUL YEAR WITH MANY SCIENTIFIC OUTPUTS.
* UK MINISTER FOR SCIENCE, RESEARCH AND INNOVATION VISITS J-PARC.
* THE CEREMONY TO CELEBRATE THE RENEWAL OF COOPERATION AGREEMENT
IN THE FIELD OF SPALLATION NEUTRON SOURCE DEVELOPMENT BETWEEN J-PARC
AND ESS ERIC (EUROPEAN SPALLATION SOURCE ERIC) WAS HELD AT ESS.

 2. [Accelerator Division]

STABLE OPERATION OF THE ACCELERATORS FOR MLF USERS FROM NOVEMBER TO
DECEMBER. BEAM COMMISSIONING IN THE MR HAS STARTED AT HIGH REPETITION
RATE WITH NEW POWER SUPPLIES.

 3. [Particle and Nuclear Physics Division]

*FIRST XI ATOMIC X-RAY MEASUREMENT USING A COUNTER-EMULSION HYBRID
METHOD.
*FINISHING TOUCHES TO THE START OF THE NEUTRINO BEAM OPERATION.
*STATUS OF THE JSNS2 / JSNS2-II (SEARCHING FOR STERILE NEUTRINOS AT
J-PARC MLF, E56 / E82).
*STATUS OF THE COHERENT MUON TO ELECTRON TRANSITION (COMET).
*STATUS OF THE MUON g-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34).

 4. [Materials and Life Science Division]

*EXTENDED MLF OPERATION SCHEDULE IN THE 2022B PERIOD.
*MAINTENANCE WORKS DURING THE SUMMER OUTAGE WERE COMPLETED AND THE
BEAM OPERATION STARTED ON SCHEDULE.
*PROPOSALS FOR 2023A PERIOD WERE RECEIVED.
*THE NEUTRON AND MUON SCHOOL WAS HELD IN A HYBRID STYLE.
*THE PLANNED MUSE MAINTENANCE WORKS WERE COMPLETED AND THE MUON
TARGET AND ALL BEAMLINES OPERATED SMOOTHLY.

 5. [Nuclear Transmutation Division

THIRD CAMPAIGN OF CORROSION EXPERIMENT SUCCESSFULLY COMPLETED.

 6. [Safety Division]

AN EMERGENCY DRILL WAS HELD ASSUMING RADIATION EXPOSURE ACCIDENT

 7. [Information]

 8. [Editorial Note]

BEAM COMMISSIONING OF THE MAIN RING WAS FURTHER POSTPONED

 

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1. [Overview] by Takashi KOBAYASHI
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WE HOPE EVERYBODY COULD HAVE A HAPPY NEW YEAR AND WE WISH TO HAVE
ANOTHER FRUITFUL YEAR WITH MANY SCIENTIFIC OUTPUTS.

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  Recently, although the COVID pandemic doesn't show signs of
subsidence yet, social/research activities are getting back to normal
with appropriate preventive measures against COVID spread.
  International researchers are coming back to J-PARC, for example,
for construction work of the T2K near neutrino detector upgrade. We
are thrilled to welcome our international friends back to J-PARC.
Face-to-face meetings/workshops/conferences restarted also at J-PARC.
An example is the workshop on "Development of fundamental physics
using neutron" (https://kds.kek.jp/event/43680/).
  Also, around J-PARC, face-to-face PR activities have restarted in
various local events for the general public, for example, in "Ozora
Marche" https://ozoramarche.com/ (sorry, but only in Japanese) in
front of Muramatsu shrine.
  We realized the impact and importance of direct face-to-face
communication.

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UK MINISTER FOR SCIENCE, RESEARCH AND INNOVATION VISITS J-PARC.

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https://www.kek.jp/en/topics-en/202212161205/
  On December 14th, George Freeman MP, UK Minister for Science,
Research and Innovation, Department for Business, Energy and
Industrial Strategy, and his delegation visited J-PARC. Minister
Freeman gave a short speech in front of the staff and users at
J-PARC: "This kind of research is not only hugely inspiring to
people, but also goes to the heart of our humanity. It also brings
technological developments to a new generation. I am delighted to
announce that the UK has decided to allocate extra funding for the HK
project."

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THE CEREMONY TO CELEBRATE THE RENEWAL OF COOPERATION AGREEMENT IN
THE FIELD OF SPALLATION NEUTRON SOURCE DEVELOPMENT BETWEEN J-PARC AND
ESS ERIC (EUROPEAN SPALLATION SOURCE ERIC) WAS HELD AT ESS

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https://j-parc.jp/c/en/topics/2022/12/16001087.html
  The renewed cooperation agreement between the J-PARC Center and ESS
in spallation neutron source development was signed on June 8, 2022.
On October 10, a ceremony was held in Lund, Sweden, where ESS is
located, in the presence of the Japanese Ambassador to Sweden,
Mr. Noke Masaki, to mark the extension of the agreement. At that
time, the signed agreement was handed over between Dr. Kobayashi,
Director of the J-PARC Center, and Dr. Schober, Director General of
the ESS.
  In conjunction with the ceremony, a Commissioning Workshop of the
ESS-J-PARC collaboration was held, face-to-face, at ESS. ESS is
entering the commissioning phase, and the J-PARC experiences could be
useful for ESS commissioning. On the other hand, the J-PARC
commissioning took place more than 10 years ago so that many young
researchers at J-PARC never experienced any of its commissioning
activities. Therefore, this kind of international workshop to share
experiences and information is beneficial for both sides. Very active
discussions were held during the workshop.
https://indico.esss.lu.se/event/3079/overview

 

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2. [Accelerator Division] by Michikazu KINSHO
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STABLE OPERATION OF THE ACCELERATORS FOR MLF USERS FROM NOVEMBER TO
DECEMBER. BEAM COMMISSIONING IN THE MR HAS STARTED AT HIGH REPETITION
RATE WITH NEW POWER SUPPLIES.

  A new operation run was started in November after the summer
shutdown. Accelerator studies at the beam current of 50 mA were
carried out at the linac. The studies were also performed at the 3
GeV Rapid Cycling Synchrotron (RCS) with a linac beam current of
50 mA for user operation. The main purposes of the studies were to
startup the machine, reproduce the accelerator parameters, to confirm
the performance of some new components installed during the summer
shutdown, to survey new parameters for lower beam loss, etc. Beam
studies of linac and RCS studies have been performed until November
18th.
  Beam user operation for the MLF users was started on 21st November
as scheduled with beam power of 780kW, which was smaller than the
power before summer shutdown. Then, on 30th November, the frontend of
the linac was retuned and the beam power was restored to 800 kW to
the MLF. The user operation could be continued with high availability
  of more than 90%.
  Beam commissioning of the Main Ring (MR) was postponed to 12th
December from original schedule of 19th November due to the delay of
tunning of new power supplies. There is currently no change to the
scheduled start of the neutrino user operation in middle January.
[schedule is postponed further, see the editorial note.]

 

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3. [Particle and Nuclear Physics Division]
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THE FIRST Xi ATOMIC X-RAY MEASUREMENT USING A COUNTER-EMULSION HYBRID
METHOD (Mamami FUJITA)

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  Study of nuclei containing an Xi- hyperon, which contains two
strange quarks, is important to understand general baryon
interactions and the equation of state of neutron star. The X-rays
from Xi atoms have fruitful information about interactions between Xi
and nucleus, since the energy levels of an Xi atom and their widths
are modified by the strong interactions between Xi and nucleus.
Historically, the study has been performed using missing-mass
spectroscopy and nuclear emulsion experiments, but their interactions
are still unclear, since the information of existing data is very
limited. Thus, we developed a new approach using measurements of
X-rays from Xi atoms.
  The J-PARC E07 experiment was conducted at J-PARC K1.8 beam line,
which provides the K- beam necessary for Xi production via the
p(K-, K+)Xi- reaction. The experimental difficulty is that most of
Xi-s decay before stopping and such decays make a significant
background in the X-ray spectrum. To reject these background photons,
we developed a hybrid method using three detector systems: magnetic
spectrometers for identification of the (K-, K+) reaction, nuclear
emulsion for Xi tracking, and Ge detectors for X-ray measurement.
The background level was drastically reduced to a level of 1/170 by
applying this triple coincidence measurement. Unfortunately, no X-ray
peak was observed with the current statistics. We found that five
times larger statistics are needed. Such statistics will be obtained
in a future experiment.
(DOI)
https://doi.org/10.1093/ptep/ptac156

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FINISHING TOUCHES TO THE START OF THE NEUTRINO BEAM OPERATION
(by Yoshiaki FUJII)
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  Beam operation is scheduled to start-up on January 12, 2023.
[schedule is postponed further, see the editorial note.] The beam
group of the neutrino experimental facility is doing the last work to
finish up the system.
  The primary beamline had installation of the last beamline component
on 10/24. The super-conducting system is now under cooling, and the
whole of the primary beamline system will establish beam-ready by
1/10, 2023.
  The major work at the secondary beamline is the installation of a
new target and new horns #1 and #2. Their installation was completed,
and excitation tests of the new horns at 320kA were successfully done
on 12/9. All works in the helium vessel were completed, and the
vessel was closed for evacuation to fill it up with helium.
  In the ND280 facility, new detectors SFGD, HATPC, and ToF counters
will be installed to reduce the uncertainty of the neutrino
interaction. Assembly work of the SFGD (Super Fine-Grained Detector)
is in progress at J-PARC. SFGD is an array of two million
scintillator cubes with sizes of 1cm x 1cm x1cm. The stacking process
of two-million cubes was completed, and people are working on
assembling the enclosure box. Presently two-million cubes are
supported in place with fishing lines. These will be replaced with
WLS fibers in January.
  Hyper-K had a collaboration meeting from 10/17 to 10/28 online and
had HK-PAC from 11/11-11/17 also online.

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STATUS OF THE JSNS2 / JSNS2-II (SEARCHIING FOR STERILE NEUTRINOS AT
J-PARC MLF, E56 / E82) ( by Takasumi MARUYAMA )
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  The JSNS2 (E56) / JSNS2-II (E82) collaboration searches for the
neutrino oscillation over a short distance with the sterile neutrinos
at J-PARC MLF.
  For the JSNS2, the new electronics developed by University of
Michigan are being tested using the LED calibration system at the
near detector storage area in J-PARC on Dec-2022. The new electronics
are working and seeing the LED light well. Immediately after the
reinstallation of the near detector on the 3rd floor of MLF in 2023,
the new electronics will be tested with the real liquid scintillator.
For the JSNS2-II, the approval of Japanese fire law to construct the
new far detector, located outside of MLF at a baseline of 48 m, was
obtained. There have been two J-PARC wide safety committee meetings
on JSNS2-II from September to November in 2022. The safety on the PMT
installation was discussed extensively so far, and the work was
approved after several countermeasures were made. The other hardware
such as the production of the acrylic tank has been progressing as
well. JSNS2-II aims to start the data taking within FY2023.

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STATUS OF THE COHERENT MUON TO ELECTRON TRANSITION (COMET)
(by Satoshi MIHARA)
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  The COMET experiment aims to search for the lepton-flavor violating
muon reaction, mu-e conversion, with a sensitivity better than 10-14
in Phase I. Facility and detector construction work continues; after
installing the primary proton beamline apparatus including a target
chamber and mask system for beam transport study of the curved
solenoid magnet, the shieling of the primary proton beamline was
closed with shielding blocks in December as part of the radiation
protection from the target and beam dump. Air lock shielding above
the shielding blocks was also prepared for preventing radioactive air
diffusion from the primary beamline area.
  The COMET collaboration is making intensive efforts to prepare the
beam studying system for the COMET Phase-alpha, the engineering run,
scheduled in JFY 2023. The system is composed of charged particle
trackers and range counter to measure the beam profile and particle
contents in the secondary beam. Beam extinction monitor based on a
new semiconductor technology will also be tested in Phase-alpha. It
is also an important issue to survey environmental radiation such as
neutrons and gammas to clarify the detector operating conditions.

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STATUS OF THE MUON g-2/ ELECTRIC DIPOLE MOMENT (EDM) (E34)
(by Tsutomu MIBE)
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  The E34 collaboration aims for precision measurements of the muon
anomalous magnetic moment and electric dipole moment.
  The radiation shielding blocks and walls were fabricated and
installed at the H-line. For the preparation for extension beyond the
MLF building, the re-location of the buried cables was completed. The
relocation of drainage water piping in the area of the H-line of the
experimental building is in preparation. The areal plan for the
building is refined in the working group under the J-PARC center. The
collaboration continues to develop the experimental apparatus.
There are two publications,
  1) Modeling the diffusion of muonium in silica aerogel
   (C. Zhang et al., NIM A 1042 167443(2022))
  2) High-power test of an interdigital H-mode drift tube linac
   (Y. Nakazawa et al., PRAB 25, 110101 (2022)).

 

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4. [Materials and Life Science Division] by Toshiya OTOMO
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EXTENDED MLF OPERATION SCHEDULE FOR THE 2022B PERIOD
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  Upon the approval of supplementary budget, J-PARC has reviewed its
operation schedule and decided to extend the MLF user operation until
the middle of March.
(https://mlfinfo.jp/en/announce/221209.html)

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MAINTENANCE WORKS DURING THE SUMMER OUTAGE WERE COMPLETED AND THE
BEAM OPERATION STARTED ON SCHEDULE
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1) Neutron Source
  On September 26th, specimens were cut out from the fore front wall
of the used target vessel which was operated with 836 kW at maximum.
This time, the specimen of the inner wall of the mercury vessel,
which was protected against the pitting damage by micro-bubble
injection into mercury flow, could not be obtained, because the
specimen fell into the mercury vessel. But, the damage on the
specimen of the outer wall of the mercury vessel, the mercury
boundary wall, was negligibly small, which was a promising result for
the stable beam operation with greater beam power. On October 11th,
the used mercury target vessel was replaced with a new one which had
the same structure of the mercury flow channel.
  On November 21th, the user program started with 780 kW, which was a
little bit less than the former power due to the trouble of the
accelerator component, and the stable beam operation has continued
with the availability of over 90 %.

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PROPOSALS FOR 2023A PERIOD WERE RECEIVED
THE NEUTRON AND MUON SCHOOL WAS HELD IN A HYBRID STYLE
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2) Neutron Instruments and Science
  The MLF 2023A call for proposal on general use (short-term and
one-year) was closed on November 7th. We have received 277 neutron
proposals including 4 new user promotion proposals and 1 one-year
proposal. All the proposals are now under review process, whose
results will be announced around February 2023.
( https://mlfinfo.jp/en/user/proposals/2023A/)
  The 6th Neutron and Muon School (NM-school) was held December
12th-16th in a hybrid style, with lectures online/on-site and
hands-on training on-site. The school provides lectures and practical
training for newcomers to neutron and muon beam research. The 18
on-site participants experienced beam-on experimental practices and
data analyses on neutron/muon instruments at J-PARC MLF or JRR-3 (a
research reactor of JAEA in operation at 20 MW), where two facilities
are located adjacent to the JAEA Tokai area.
(https://mlfinfo.jp/sp/school/6th-nms/index.html)
The recent scientific press releases at MLF from neutron instruments
were issued as follows:
(1) "Magnon mode transition in real space"
https://doi.org/10.1038/s41598-022-22555-9
(2) "Partial breakdown of translation symmetry at a structural
quantum critical point associated with a ferroelectric soft mode"
https://doi.org/10.1103/PhysRevB.106.134111
(3) "Non-Hookean large elastic deformation in bulk crystalline
metals"
https://doi.org/10.1038/s41467-022-32930-9
It was selected as one of the featured articles by the editor.

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THE PLANNED MUSE MAINTENANCE WORKS WERE COMPLETED AND THE MUON TARGET
AND ALL BEAMLINES OPERATED SMOOTHLY
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3) Muon Science Facility (MUSE)
  After the summer shutdown in 2022, MUSE resumed operation on
November 21st, 2022, as scheduled. The planned maintenance works were
completed and the muon target and all the beamlines operated smoothly
to conduct the user experiments.
  The rotating feeder unit of the muon production target was replaced
in the summer maintenance. The old unit had trouble with the rotating
torque turbulence due to the high accuracy requirement between two
rotating shafts, and a more flexible one was newly adopted. With this
replacement work, the interlock of the target was reviewed, and the
new way could reliably find the signs of failure by monitoring the
increase in the motor torque overlong periods. So far, the target has
been operating smoothly up to the present.
  In the D line, the final focusing magnets of the quadrupole triplet
and their power supplies for the D1 area were replaced with new ones
to provide a higher momentum beam. The commissioning was performed
just after the beam resumption and confirmed the beam transport. This
will extend the muon use.
  The results in D2 were presented to the press: "Volatile analysis of
the Hayabusa2 asteroid Ryugu sample revealing volatile sources and
recent surface evolution" has been published in "Science"
(https://www.science.org/doi/10.1126/science.abo0431), and
"Muon experiment reveals more detail of asteroid Ryugu" especially
about the elemental analysis by a negative muon beam.
(https://doi.org/10.1126/science.abn8671)
  The result in D1 was presented to the press: "Direct Measurement of
the Evolution of Magnetism and Superconductivity toward the Quantum
Critical Point" (https://doi.org/10.1073/pnas.2209549119).
  The 7th symposium on research on arts and sciences integration was
held at the KEK Tsukuba campus on October 2nd-3rd.
  MUSE received 41 muon proposals for the 2023A periods, and the
review process for these proposals is now underway.

 

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5. [Nuclear Transmutation Division] by Hironari OBAYASHI
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THIRD CAMPAIGN OF CORROSION EXPERIMENT SUCCESSFULLY COMPLETED

  Accelerator-driven transmutation system (ADS) proposed by JAEA uses
a lead-bismuth eutectic alloy (LBE) for spallation target and reactor
coolant for the good neutronic performance for ADS. However, LBE has
an issue of compatibility with standard reactor materials. LBE has
the specific characteristic to dissolve out elements from steels and
that drastically decreases the lifetime of the structural materials.
A recommended method to solve this issue is to suppress the
dissolution of elements in steel by controlling the oxygen
concentration (OC) in LBE, which is studied worldwide. In this
approach, an oxide film is formed on the steel surface by controlling
OC to an appropriate range, thus avoiding direct contact between
LBE and the steel. Under conditions where high-temperature LBE (400℃
or higher) flows, oxygen is consumed by the growth of oxide film
hence OC is constantly decreasing. OC in LBE is managed by
intermittently supplying a mixture gas containing trace amounts of
oxygen to a pure argon carrier gas to compensate for the consumed
oxygen. The control sequence of OC was automated and installed into
"OLLOCHI", a corrosion test loop with high-temperature LBE. Since
November 2020, the corrosion test campaign has been performed by
using OLLOCHI.
  The planned annual operation time of JAEA's ADS is around 7,000
hours, however, the duration of previous two campaigns for the
purpose of functional test of OLLOCHI was shorter than that. The
third campaign started in October, 2021 as a substantial corrosion
experiment for LBE application to ADS. Flow velocity at the test
section was 1 m/s. The temperatures of the hot and cold legs of the
LBE flow channel are 450℃ and 350℃, respectively. A target control
value of OC was set to one micro wt%. Three specimen holders, which
stored 26 corrosion test specimens in one holder, were prepared to
perform time dependent corrosion tests by changing exposure time for
2,000 hours, 5,000 hours, and 7,000 hours. During the campaign, the
control system of OC worked well, and as a result, the OC was
maintained around one micro wt% for more than 7,000 hours. Hence the
third campaign of corrosion experiment was successfully completed.
The post examinations of the obtained specimens including those of
previous campaigns are being performed in parallel to check the
compatibility of materials exposed to flowing high-temperature LBE.

 

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6. [Safety Division] by Yoshihiro NAKANE and Kotaro BESSHO
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AN EMERGENCY DRILL WAS HELD ASSUMING RADIATION EXPOSURE ACCIDENT
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  An emergency drill was held on Oct. 25 at the Materials and Life
Science Experimental Facility (MLF).
  It was assumed that the beam operation was started without
evacuating a worker in an experimental area of MLF and he was exposed
to radiation. The drill included contamination survey and
transportation of the exposed worker, estimation of exposure dose,
setup of the command post and communication with accidental site,
report to headquarters via TV conference, and simulated press
release.

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FISCAL 2022 J-PARC SAFETY AUDIT
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  The fiscal 2022 J-PARC safety audit was conducted by two auditors on
Nov. 28th. They reviewed the points: 1) Organizational structure for
safety management, 2) Safety management in works, 3) Emergency
responses, and 4) Fostering and maintaining safety education and
safety culture. The auditors gave us valuable recommendations, such
as importance of looking back at completed works, thinking about
margin for work schedules, and classification of acceptable minor
troubles and accidents that must not happen.

 

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7. [Information]
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8. [Editorial Note]
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BEAM COMMISSIONING OF THE MAIN RING WAS FURTHER POSTPONED
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  Beam commissioning of the Main Ring (MR) was postponed to late
January 2023 from 12th December due to the failure of the beam
extraction magnet which occurred after the article compilation date
(middle of December). The scheduled start of user operation of the MR
will be determined according to the results of the beam commissioning
and it is decided there will be no neutrino beam operation until the
end of March.

Past issues are available from the link below.
http://j-parc.jp/c/en/topics/project-newsletter/index.html

 

┏----…----…----…----…----…----…----…----…----…----…----…----…☆
Editorial Board:
Toshifumi TSUKAMOTO (Chair): toshifumi.tsukamoto@kek.jp
Kaoru SHIBATA: shibata.kaoru@jaea.go.jp
Takatoshi MORISHITA: morishita.takatoshi@jaea.go.jp
Jean-Michel POUTISSOU (English Editor): jmp@triumf.ca
Chiaki SHIRAISHI (Secretary): shiraishi.chiaki@jaea.go.jp
★----…----…----…----…End of Letter…----…----…----…----…----