THE INTERNATIONAL ADVISORY COMMITTEE

ON THE J-PARC PROJECTREPORT
4 June 2010Blossom at J-PARC Center March 2010

Meeting 15 -16 March 2010
Tokai, Japan

1

CONTENTS
EXECUTIVE SUMMARY
Developing a Strategy with KEK and JAEA

35RECOMMENDATIONSStrategy
BudgetAccelerator Systems
Scientific Programs
Particle and nuclear/hadron physics
Material and Life Sciences
Neutrons
Muons
Nuclear transmutation

6
6
6
6
7
7
7
7
8
8

GENERAL STATUS OF THE PROJECT10ACCELERATOR SYSTEM STATUS
PARTICLE AND NUCLEAR PHYSICS
Hadron Experiments
Neutrino Experiments

11
14
14
16

MATERIAL AND LIFE SCIENCES
Neutron scattering
MLF Muon Facility

18
18
22

USER INTERFACE, SAFETY and COMPUTING
User Interface
Computing and Networking
SafetyCryogenics

24
24
25
25
26

NUCLEAR TRANSMUTATION

26

APPENDIX I Agenda 8th International Advisory Committee J-PARC 30
APPENDIX II IAC Committee Members

32

APPENDIX III A-TAC Report 2009

33

2

EXECUTIVE SUMMARY
The International Advisory Committee (IAC) for the J-PARC joint project of theJapanese Atomic Energy Agency (JAEA) and the High Energy Accelerator
Research Organisation (KEK) met between 15 and 16 March 2010 at J-PARC
Centre, Tokai and toured the construction site of J-PARC.

The IAC had reports from the Accelerator Technical Advisory Committee (ATAC), the Muon Science Experimental Facilities Advisory Committee (MUSAC),
the Neutron Instrument Advisory Committee (N-IAC) and the Program Advisory
Committee for Particle and Nuclear Physics (KEK/J-PARC) which met in thepreceding two months. The agenda of the IAC meeting is attached as Appendix I
and the membership at Appendix II.

The year 2009-2010 was a year of great achievement for the whole project. The
IAC has seen results from all sectors using initially 20kW and finally 100kW
Linac power. Some of these have indicated truly world-leading status at present
or in the near future for the facility.

The IAC strongly commends thecommitment of the Director and all of the staff at J-PARC Center for an amazing
effort in recognizing 'teething' troubles in some areas and rapidly solving the
problems so as to explore as soon as possible the potential of this, alreadyremarkable facility. The reports from the various sections in this document will
give the detail of these achievements.

The morale of the J-PARC Center staff has been greatly sustained by the strong
commitment from both the JAEA and the KEK. The maintenance of sufficientbudget flexibility to allow problems in this first phase of the operation to be3

addressed expeditiously has been very valuable. If close cooperation and sharedcredit in the achievements with J-PARC 'parents' can be enhanced as the energy
recovery project proceeds, and if the necessary new staff are recruited as
instruments in the MLF facility achieve full productivity J-PARC will become aworld leading facility in materials and life sciences as well as nuclear and particle
physics.

The IAC has the perception that the B-factory upgrade is now the top priority for
KEK and that outsourcing funds and personnel from J-PARC might be an option
to meet this priority. The IAC is clear that a strong commitment must be
maintained by both partners to reach the design goals for operation andexperiments in a timely manner.

The position of the Director of J-PARC Center and his relationship to the parent
organizations as well as to the broader science organization of Japan is of thehighest importance.

At this important stage, the intersection between the

directors of J-PARC and the directorates of JAEA and KEK must be very good.

The IAC foresees complete success of the experiment by the Japanese
Government in melding together in J-PARC Center, the complementary
scientific and engineering cultures of KEK and JAEA. J-PARC Center is now
reaching the strength where our primary recommendation in 2009 of setting
priorities with the partners, while still a necessity, is now surpassed.

We

recommend that suitable steps be taken for the partners and J-PARC Center
together to identify future goals and ways in which the complementary culturesof KEK and JAEA can further contribute to outcomes of the highest quality.

4

Developing a Strategy with KEK and JAEA
With the successful extraction of four different kinds of beam last year theconstruction stage of J-PARC is basically over. It is time to develop a strategy
to exploit the full capacity of this precious facility for scientific activities. In
this strategy, the efficiency and co-operation with which the J-PARC Centercan operate with its own, and personnel attached from both KEK and JAEA,
is crucially important. It becomes the responsibility of the partners working
with the J-PARC Center Director to cope with this in a smooth way. The“mirror” structure, which has been so successful in the construction stage
should be kept in the J-PARC Center during the next few years.

For this strategy to work it is necessary to have the key administrative
members of J-PARC Center involved in the administration of KEK as well as
JAEA. The establishment of this organizational structure is crucial tosuccessful scientific activities in years to come for both JAEA but also KEK as promised to the government and scientific communities. The National aswell as international mission J-PARC depends on this.

5

IAC Recommendations
STRATEGY
The IAC commends the success of the established J-PARC management
structure. The principal recommendation of the IAC is that for J-PARC. JAEA
and KEK should have a mirror image management structure to co-operate
seamlessly at financial, management and scientific levels - especially for themost expeditious achievement of the Linac energy recovery program in parallelwith growth of the whole user program.
BUDGET
The IAC has requested the J-PARC study all means for meeting the present planand speeding the increase of intensity in the Main Ring if possible. This should
be done without sacrificing a proper understanding and long term operation of theaccelerator system. There will be budgetary consequences of this and the parallel
fast growth of the user program in the 2010-2013 period.
Recommendation: The IAC recommends that both KEK and JAEA work
closely with J-PARC to ensure success of proposals to the Japanese
Government for an increased operational budget in 2011 and 2012.

ACCELERATOR SYSTEMS
Recommendations: The IAC recommends that J-PARC set up a task force
with the goal of mapping a strategy to get beam losses under control as soon as
possible and to make sure that the Linac upgrade project does not eclipse thebeam losses mitigation priority.

6

In particular the IAC and A-TAC recommend that accelerator studies be
pursued that aim at characterizing and understanding losses observed in the
RCS and MR at the highest beam intensities possible. Strategies should also be
developed that could substantially increase the MR fast extracted beam power
as soon as possible and even before the completion of the 400 MeV Linac
upgrade to satisfy the urgent need to maximize the beam power delivered by theMain Ring to the neutrino target.
SCIENTIFIC PROGRAMS
Particle And Nuclear/Hadron Physics
Recommendation: The IAC urges that a clear strategy for maximizing theimpact of T2K be a critical component of an overall J-PARC strategic plan in
the face of strong international competition. The strategy should include
identification of appropriate resources to realize timely delivery of the 5-year
beam plan.

Recommendation: The IAC recognizes the need for short term physics returns,
and recommends that J-PARC should concentrate its efforts on improving thepower and, especially, the duty factor of the slow extraction beams from theMain Ring.
Materials And Life Sciences
Neutrons
Recommendation: The IAC recommends that JPARC adopts a coordinatedand coherent approach to the operations and future development of the
MLF, embraced by all partners.
This will require7an organizational structure that enables both the scientific andtechnical development to be owned equally by all partners.
a process which ensures that the evolution of the detector suite delivers
world leading instruments fitting into a coherent strategy agreed upon by
all stakeholders

Muons
Recommendation: The highest priority is to secure funding for ultra slow
muon beam line for SR and to involve the condensed matter community inthis unique opportunity (workshop, scientific case). To secure the operationof a strong user program on the existing D1 and D2 beam lines and torealize the construction of the new ultra slow muon beam line on a shorttime scale, the IAC recommends to strengthen the research and technicalstaffs of the Muon Science Section of the J-PARC Center.

NUCLEAR TRANSMUTATION
Recommendation: The IAC recommends that J-PARC should propose incollaboration with JAEA a coherent strategy on nuclear wastes associating
ADS, P/T and FBR in collaboration with University research.

Recommendation: J-PARC should increase the efforts in the preparation of
ADS experiments and develop a roadmap to the completion of the TEF II
facility.

8

Recommendation: The IAC recommends that experimental results should
be presented to the IAC meeting next year.
Recommendation: J-PARC should continue to contribute to education andtraining in Japan to build a new generation of scientists and engineers.

9GENERAL STATUS OF THE PROJECT
The beginning of the operation phase of J-PARC has been spectacular.
Highlights have been an almost complete solution to the problems identified
early in 2009 which limited the power of the proton accelerator to 20kW with"frequent conditioning", the demonstration at this power that calculations of
instrument performance were fulfilled in experiments both in the MLF andthe neutrino areas.

In the former, world leading performance has been achieved in high resolution
powder diffraction and new, highly innovative, techniques in time of flight
spectroscopy have been demonstrated and published. For muons, a similar worldclass performance has been demonstrated and published. The observation of thefirst neutrino events, first in the near neutrino detector, and then across Japan in
the far detector at SuperKamiokande (on 24 February 2010) were milestone
events.

The IAC also notes that good care is being taken by the direction to manage
generational change in the staff while retaining the expertise of some who havemade unique contributions, and can still do so, to accelerator, neutron target,
beam line and instrument development. All of this is a good indication for the
future. The intersections between staff of KEK, J-PARC and JAEA will continue
to be vital to maintaining the momentum of the project. The rare qualities ineach organization, and their budget provisions, must cohere to this end. The IAC
already commends the harmonious inclusion of former and actual KEK and
JAEA employees as well as new recruits into the J-PARC operational structures.

10

For future appointments, this intentional blending of cultures should be an
administrative priority for KEK and JAEA as well as J-PARC.

The IAC was pleased to see the steps taken by J-PARC to use the new J-PARC
building and our meeting was held there. The description of plans for student andvisitor accommodation in proximity to the J-PARC building was encouraging as
was the interest of the Tokai Mura village in the project. A highlight was thereception given to the IAC and J-PARC members by Tatsuya Murakami, Mayorof Tokai Muraon the evening of 15 March 2010. It is apparent to the IAC that as
the J-PARC operation phase grows, there will be much greater needs for local
accommodation by national and international visitors as well as social and mealfacilities nearer the J-PARC facilities and easy access between them and the JPARC center building.
ACCELERATOR SYSTEM STATUS

The J-PARC accelerator complex has been developed to be the highest intensity
machine in its category.

A compromise was made during phase 1 by limiting the injector LINAC to 180
MeV. Now funding has been secured to increase the energy of the linac to400MeV as originally intended. This is one of the requirements for achieving thepredicted 1MW power level in the RCS or 0.75MW in the MR. This upgrade partis well in hand and the installation is planned for the summer shutdown 2012.

11

Even with lower RCS injection energy, both the RCS and Main Ring have been
operated with significant beam power, but the beam intensities are still quite low
and space charge effects are difficult to identify. Consequently beam loss
mechanisms in the RCS and MR are not well understood at the moment.
However, it is critical to understand the loss mechanisms at every stage ofacceleration, as these present the largest degree of uncertainty in planning for
mitigation strategies and upgrades.

Recommendation: Set up a task force with the goal of mapping a strategy to
get beam losses under control as soon as possible and to make sure that the
Linac upgrade project doesn’t eclipse the beam losses mitigation priority. In
particular the IAC and A-TAC recommend that accelerator studies be pursuedthat aim at characterizing and understanding losses observed in the RCS and
MR at the highest beam intensities possible.

There is an urgent need to maximize the beam power delivered by the Main Ringto the neutrino target. Strategies should be developed that could substantially
increase the MR fast extracted beam power as soon as possible and even before
the completion of the 400 MeV Linac upgrade.
As part of its deliberations, the IAC enquired of the Accelerator team about thepossibility of significantly increasing the intensity in the main ring by expediting
the Linac energy recovery program without sacrificing the development ofknowledge of the operation of the accelerators and the monitoring and reductionof beam loss in all accelerator components.

The combination of these two

objectives and particularly funding and manpower limitations make this not12possible. In the process of these deliberations, the IAC became aware of thefunding shortfall against an optimum profile for the energy recovery process.
Recommendation: The IAC recommends that a very high priority be given to
the proposed funding requirements for bringing the accelerators and target
systems to their designed performance.

A detailed appraisal of the Accelerator program was made by the accelerator
technical Advisory Committee. Its report- presented to the IAC is attached. The
report has recommendations for the next phase of the accelerator development
and the IAC endorses these.

13PARTICLE AND NUCLEAR PHYSICSThe J-PARC program of particle and nuclear physics is supported primarily by
the operation of the 30 GeV Main Ring (MR). The hadron program uses slow
extraction to a number of beam lines in the hadron hall. The neutrino beam uses
fast extraction and sends an off-axis neutrino beam in the direction of theunderground water Cerenkov detector Super-Kamiokande at Kamioka nearly 300
kilometers from Tokai. For the former experiments the quality and duty factor of
the beams are important. For both hadron and neutrino experiments, beam poweris important.
HADRON EXPERIMENTS

Currently there are two charged particle beams K1.8 and K1.8BR, which will
support a number of experiments using charged pion and kaon beams to search
for and examine nuclear structure and nuclear matter to study QCD under somespecific and extreme conditions. Some are hypernuclear experiments which
provide information on the forces inside the nucleus. Another searches for an
exotic bound state called a pentaquark. J-PARC is to be congratulated for theconsiderable progress has been made in commissioning the two programs
associated with these beam lines and establishing good pion-kaon separation.

Also being developed is a rare kaon decay installation, which will search for the
decay of the K0L into a pizero and neutrino-anti neutrino pair. The current state of
the art suggests that this mode offers a window on new physics. Development of
the beam line, which is being operated in test mode, and the experiment, will takeplace over the next couple of years. Progress has been made on each.

14

Future facilities in preparation are another low energy beam, K1.1BR and an
extracted high momentum, primary, proton beam. The K1.1BR beam line is
expected to begin its beam commissioning in FY2010 and will be used initiallyfor test beam work. Funding for the high p beam line has been requested in the
FY2010 budget. This would complete the complement of beamlines intended forthe first phase of hadron experimentation. In this context and expecting that there
will be little conflict with the program to improve the existing slow extraction
performance, the IAC supports this initiative.

Eventually to fully exploit the capabilities of the machine it is expected that thelarge hadron hall be extended. At present the funding for the extension is not in
the planning although we heard an intriguing thought that the RIKEN
organization might take on this task. The IAC encourages the J-PARC
management to explore further this possibility.

In the very recent commissioning work, there have been difficulties, somepartially understood and mitigated, which have resulted in a low duty factor forthe slow extraction beam. Improvement to a level of order 80% at high beam
power, which would be needed to support the full program, will requireconsiderable attention, time and resources but is mandatory for the program. It
should also be noted that there is more than one path to achieve acceptable yields
in the two operating beam lines. It is necessary to optimize the yield, notnecessarily the beam power. This might be achieved using a higher Z production
target. An optimum approach should be developed.
Planning for operation for the next year reflects the tensions in play. Given thepriority of the neutrino beam, it is likely that 60 days or less of hadron beam
15

operation will be available in the next fifteen months. In this context, the PAC
has offered a set of priorities. This committee endorses those priorities, which
could support the completion of about two of the experiments in the K1.8 andK1.8BR complex and could provide short exposures for the neutral kaon beamline. However, this committee would not like to see the laboratory sacrifice its
longer-term needs for the beam duty factor and power to improve to an extended
run of experiments for which the beam conditions fall short.

While recognizing the importance of moving continuously to flesh out thefacilities supported by the MR, the IAC believes that investment in the new highmomentum proton beam should be balanced against the resources needed to
improve the beam quality.

If new, creative methods arise to provide funding for extensions to the facilities,
for example, extending the hall, the committee encourages the laboratory to
explore them.
NEUTRINO EXPERIMENTS
The T2K experiment, directing a muon neutrino beam from the Main Ring
toward the Super-Kamiokande detector, is the centerpiece of the particle andnuclear physics program at J-PARC. There has been impressive progress inthe past few years: Beamline completion in 2008; the first beam to neutrino
beamline and beam commissioning in April-May 2009; the installation of thesecond and third horns and the completion and commissioning of the on-axis
near detector (INGRID) in June-October 2009; the completion of the off-axis
near detector and the first neutrino event in both near detectors in November-

16

December 2009; the start of physics data taking in January 2010; and the first
J-PARC neutrino event in the Super-Kamiokande detector on February 2010.
The IAC whole-heartedly congratulates the J-PARC / KEK team and the T2K
collaboration for this incredible progress and success. The T2K collaboration
with about 500 members from 62 institutions in 12 countries is a strong
international collaboration. The collaboration has started analysis activities
and plans to produce the first oscillation result by Summer 2010. Besides
relatively minor work envisaged during the 2010 Summer shutdown and newhorn power supplies needed for higher current running, the experiment is fully
ready for physics data taking with higher power beams.

The T2K has strong international competitors in other reactor- andaccelerator-based neutrino oscillation experiments with a similar goal of
improving sensitivity to the unknown mixing angle sin2(213) to a level of0.01 or beyond. In order for T2K to remain competitive or to observe electron
neutrino appearance implying, a finite sin2(213) first, J-PARC will have toimprove beam power rapidly. The IAC was presented with a viable 5-year
Main-Ring beam plan. Assuming this is delivered, the T2K will becompetitive because the reactor experiments have been delayed. The NOvA
experiment must be taken into account since it is back on track in the U.S. andis likely to start earlier than anticipated.

Recommendation: The IAC urges that a clear strategy for maximizing theimpact of T2K be a critical component of an overall J-PARC strategic planin the face of strong international competition. The strategy should include
identification of appropriate resources to realize timely delivery of the 5year beam power plan.
17

MATERIALS AND LIFE SCIENCES
NEUTRON SCATTERINGThe staff of J-PARC and the Materials and Life Sciences Facility (MLF) is tobe congratulated for the impressive progress seen over the last year. Amongthe many achievements to be highlighted areStable operation at 120 kW with very high reliabilitynine instruments are now operating in a user program, three areundergoing commissioning, three more instruments are under construction,and funding has been secured for an additional three instruments – this is
an impressive feat by any standards and could not have been achieved
without the tireless efforts of a relatively small staff.

An innovative early publication with the first scientific results
demonstrating repetition rate multiplication

Demonstration of energy-dispersive imaging



Outstanding new developments in scintillator detectors

MLF staff are also dealing with, and learning from, the normal teethingproblems encountered during the commissioning of a new facility.
Nevertheless the facility is already delivering top quality scientific results.

Target and moderators systems are performing well and will not be stressed atcurrent power levels. An impressive number of instruments now exists on theexperimental floor, but with limited (although adequate for initial scientificcommissioning) detector complements. Completing instrument detector
coverage will be essential to realize the full potential of J-PARC, but is not a
critical issue at this stage.

Commissioning this diverse instrument suite,18

developing coherent across-the-board operational procedures and attracting,sustaining and inspiring a growing user community are the prime challenges
at this stage in this sector of J-PARC’s development.

The MLF is now facing the common concern that all major user facilities ofthis nature face, namely a transition from a construction project to a reliable,
operating facility which can support a vibrant user program, delivering bothscience and innovation. This transition is difficult at the best of times but
somewhat exacerbated in the case of the MLF by the diversity of stakeholders
and funding sources - JAEA, KEK, Ibaraki Prefecture. It is critical at thisstage to consolidate and stabilize the operation of the facility to support thedemands of the rapidly growing user community. In this context, stabilizationmeans the following:

Increasing the staff for instrument support, including both staff dedicatedto specific instruments as well as those needed for core support groups
such as data acquisition, sample environment, and detectors. We note thatinternational best practice for operating a neutron user facility is at leastsix staff per instrument. A coherent staffing plan should be developed
across organizational boundaries allowing the MLF to take advantage ofthe skill sets available in all participating institutions to fully support theuser program.

In order to maximize the efficiency and the cost effectiveness of the user
support organization it is crucial that the MLF adopt a high level ofstandardization across instrument operations of all stakeholders such that
support functions for the instruments (detectors, sample environment,
instrument control, data analysis software) can be maintained through19

centralized groups. All institutions operating instruments at the MLF
should contribute to, and be partners in, a unified instrument operations
support organization. The essential point is that user support must be
essentially equal for all instruments, regardless of the source of funding
and all of the institutions building and operating instruments at the MLF
should work to achieve this goal.
It is essential to make available a suite of facilities that includes sample
handling capabilities, science support laboratories incorporating standard
laboratory

equipment

andanalysistechniques,

restaurants,

accommodation, and reasonable office and meeting space.
The operational focus should be to increase the number of instrument days,
and the reliability of the source at a reasonable power level – 300kW issufficient and at this power level the MLF will produce the most intense
peak pulse intensities in the world. Pushing the source power to 1 MW,with increasing likelihood of lower reliability, is less important at thisstage.

It is neither critical, nor advisable, at this stage for the MLF to actively
seek funding for new instrumentation. There are only a few beam lines
left unallocated. It is important to define a process which ensures that only
world leading instruments, those that fit into a coherent long term strategy,
are approved for future construction. Any long term planning for future
instrumentation should take into consideration the operation of the JRR3M, and include input from all stakeholders, especially the user
community.

In parallel to stabilizing and expanding the user operations, MLF management
must turn to developing and enabling a world class internal science program.

20

The creation of a strong in-house research program will be critical to the longterm success of JPARC/MLF, and will act as an intelligent customer base topromote and develop sophisticated user support and science-led instrument
development.

In this case the multiple ownership of J-PARC/MLF provides a unique
opportunity to attract the best scientific staff to the facility. It is essential that acommon, coherent recruitment policy be established that leverages to a
maximum the distinct capabilities, and collaborating networks, of the
stakeholder institutions. A broad portfolio of recruiting mechanisms should beconsidered including joint university appointments, fellowships, postdoctoraland student programs and sabbaticals. Strong links to the academic communitythat forms the base of the user program is essential. The recruiting activities
should be closely coupled to outreach programs such as workshops, schools,
and training activities. The IAC strongly recommends that a comprehensive
communications and outreach plan be developed that incorporates all the above
activities.
Recommendation: The IAC recommends that JPARC adopts a coordinatedand coherent approach to the operations and future development of the MLF,
embraced by all partners.
This will require an organizational structure that enables both the scientific and technicaldevelopment to be owned equally by all partners.
 a process which ensures that the evolution of the instrument suite delivers
world leading instruments fitting into a coherent strategy agreed upon by all
stakeholders
21

MLF MUON FACILITY
The IAC heard a presentation by Dr. Miyake on the status of the MUSE
facility and plans for the future development of a user program. The
observations and recommendations from the Muon science advisorycommittee (MUSAC) which had met just two days prior were given by Dr.
Poutissou (replacing Dr. E. Morenzoni, chair of MUSAC who could notattend).

The IAC was pleased to hear about the success of the initial beam
delivery campaign which led to the first publication of J-PARC in
Physical Review Letters. It showed, that even under trying circumstances,
the facility is able to deliver top results and is already providing theworld’s best pulsed muon intensities. The first muon beamline and its
spectrometer are being optimized in a collaboration between JAEA andKEK to service a more versatile and competitive program.

By far the highest priority should be to secure funding for developing the
Ultra Slow Muon beamline which promises to be the unique facility thatwill attract users worldwide. Through a strong synergy with the R/D
program initiated by the G-2 collaboration, KEK and RIKEN

aredeveloping a state of the art laser ionization system which will be ideallysuited for the J-PARC pulse muon beam and would provide anenhancement of two orders of magnitude in the yield of ultra slow muons(USM) produced per incident surface muon delivered to the muonium
target compared to what has been demonstrated at ISIS by the RIKEN-

22

RAL collaboration. The J-PARC USM source would be truly unique andtailored to pulsed excitation of many classes of nano-materials.

For the longer term plans, adding a couple of surface muon experimental
stations on the S line would allow the MUSE facility to service a large
community of users, both nationally and internationally. The remaining
port ( H-Line) could be reserved for a more specialized, very highacceptance line that could service the G-2

experiment , very highluminosity micro beams , negative muon based programs etc. It is urgent
to come to a consensus on the kind of front end that needs to be installed
before the activation in the target region makes

the task too dose

intensive.

The MUSE team has been extremely successful .However maintaining
and operating

the present infrastructure, completing the three otherbeamlines while running a user program will be a challenge for thecurrent level of personnel.
Recommendation: The highest priority is to secure funding for ultra
slow muon beam line for SR and to involve the condensed matter
community in this unique opportunity (workshop, scientific case). To
secure the operation of a strong user program on the existing D1 andD2 beam lines and to realize the construction of the new ultra slow
muon beam line on a short time scale, we recommend to strengthen the
research and technical staffs of the Muon Science Section of the JPARC Center.

23

USER INTERFACE, SAFETY and COMPUTING
User Interface
The creation of the J-PARC User Office is now a reality. For the first time the
IAC met on ‘J-PARC Premises’ - a notable step.

The User Office defines the culture of many aspects of life for the J-PARC user
community and has the potential to develop harmony with the wider user
community at Tokai, including, for example, users of JRR3-M. The IAC ispleased to see that progress continues to be made in developing a pro-active userinterface at J-PARC.

The IAC noted many favorable developments:

thefeedback to the J-PARC center from the Users Steering Committee was seen as
an essential engagement for shaping the future directions of the facility; IUC
welcomed the opportunity to interact with local political figures (the Mayor of
Tokai attended the Monday evening reception) and impress on them theimportance of J-PARC internationally; outreach to the local community throughTV exposure, open days etc is strong and outreach to industry (including theefforts of Ibaraki Province) is pioneering and has already achieved an
engagement unsurpassed elsewhere.

Much remains to be done both locally - accommodation for users; a user building
including rest areas, discussion space, and laboratories; easier access to the JPARC site; and globally - strengthening membership of JSNS; developing
outreach in the Asia-Oceania region and increasing visibility of J-PARC
internationally through the internet and focused intentions.

But an impressive

start has been made towards the realization of a “TOKAI campus” which will24

provide an active intellectual forum for researchers, post-doctoral fellows andstudents across the J-PARC enterprise and for the community at large.
SafetyThe IAC again emphasizes the importance of safety and risk evaluation. It
reiterates its comments from the 2009 IAC report: "As the community of users
grows at J-PARC, the opportunity must be taken to create the strongest safety
culture with respect to operations and radioprotection. A highly safe-conscious
user group is a foundation for success and an asset to the institution. The
induction processes, the refresher courses and the public awareness of the carefor safety in the whole organization are important.

The IAC is aware that

attention is being paid to these matters and commends this. As J-PARC moves tooperations in an international context, an explicit rather than implicit approach tosafety needs to be established.
Recommendation: Report explicitly on safety and risk evaluation proceduresat future IACs."
Computing and Networking
The progress in computing and networking for the J-PARC facility as seen by
the IAC was developing well. The attention being paid to future needs andthe openness of communication is highly desirable as is the provision - withstrong input from instrument scientists of "user friendly" software for
immediate processing of data at the instrument as results are taken. This isimportant for the MLF Facility where it may be necessary to assess whether
the biological and other fragile samples have not deteriorated before or during
the experiment. The provision of "user friendly" software as "freeware" to theuser community and the standardization of its use among the users will
promote scientific communication and publication.
25

Cryogenics
Sample environment cryogenics for the MLF are a separate issue from the
major cryogenic systems required for the accelerator. Delivery of this service
is user driven and should be part of a developing Sample Environment(SE)capability in MLF and not tied – on a day to day basis – to a central
cryogenics service. As the facility ramps up in both operational days, power
and variety of instrumentation, an service essential to deliver science will be
the development of both sophisticated sample environment infrastructure anda competent coherent team to deliver, operate and develops the SE kit. ISIS
currently supports some 200 pieces of SE kit with a team of some 25 staff.

NUCLEAR TRANSMUTATIONThe recent report of the AEC committee composed of high-level representativesof academic, public organizations and industry, chaired by Professor Yamana
strongly supports partitioning and transmutation (P&T) technology. The IAC
fully agrees with the recommendations of the AEC Committee that R&D should
not aim only at the improvement of the P&T performance, but at the achievementof the whole performance including safety, economy, environmental-friendliness,saving resource, and non-proliferation.

The IAC was pleased to hear the presentation of the Transmutation group. The
recommendations of the IAC have been carefully addressed. The group has also
well taken into account the conclusions of the AEC report. The IAC endorses theplanned activities that will be included in the new 5-year plan (FY 2010-2014) of
JAEA.

26

Nuclear Power is an essential component of the Japanese energy portfolio.
Research on nuclear wastes is essential. The IAC appreciates the efforts of the JPARC team to build a strong R&D community bridging academic and industry
technology research, in particular the collaboration with Kyoto University on the
FFAG- KUCA experiments. The IAC reiterates that fruitful collaborations
between J-PARC and academic R&D in Japan are essential for the developmentof future nuclear reactors. Confidence of the public needs coherent informationfrom universities, public organisations and industry research. This is one of theessential keys for continuing to use nuclear power in Japan in the long term. The
difficulties observed in recovering from the sodium leak that occurred in the
Monju fast breeder reactor, 14 years ago, are emblematic of the public need forreliable information. The IAC was pleased to learn that the procedures forresuming the test operations of the Monju reactor have entered their final phaseand that JAEA is hoping to resume the test operation by the end of March thisyear.

Recommendation: The IAC recommends that J-PARC should propose incollaboration with JAEA a coherent strategy on nuclear wastes associating
ADS, P/T and FBR in collaboration with University research.

The group has an active participation in EU major collaborative experimental
programs: R&D on transmutation of Minor Actinides (MA) with the fast breeder
PHENIX (sodium cooled (similar to Monju) in France, PSI in Switzerland andpreparation of the MYRRHA project under development at Mol in Belgium inassociation with the EUROTRANS collaboration. MYRRHA is the mostambitious ADS project in Europe. It is the basis for a future European XT-ADS

27

(eXperimental demonstration of Transmutation in an ADS and for various R&D
applications. It consists in a proton accelerator delivering a 600 MeV - 2.5 mA(or 350 MeV - 5 mA proton beam) to a liquid Pb-Bi spallation target that in turncouples to a Pb-Bi cooled, subcritical fast nuclear core. On March 4th 2010, theBelgian government has decided to finance about 40% of the MYRRHA project(1000 M€). This project is expected to be completed in 13 to 15 years. A memberof the J-PARC group is now staying at Mol to join the Central Design Team
(CDT) of the European 7th Framework Program (FP7). The IAC is pleased by
the important role of the J-PARC group in international R&D on transmutation.
Recommendation: J-PARC should increase the efforts in the preparation of
ADS experiments and develop a roadmap to the completion of the TEF II
facility.

Dr.Oigawa’s presentation briefly described the many areas in which the group is
involved, in particular nuclear data on minor actinides (MA) and long-lived
fission products (LLFP), irradiation of MA, and the experimental preparation of
the TEF facility including spallation target design, beam trip effects, material
corrosion, thermal hydraulics of the spallation target.

Recommendation: The IAC recommends that experimental results should bepresented to the IAC meeting next year.

The IAC reiterates that the considerable knowledge of Japan in accelerator
development, design and safety studies in ADS, fuel studies, materials science,and nuclear data is fundamental to expand the frontier of knowledge in safe andreliable nuclear waste management.

28

Education and training in JAEA’s facilities in Tokai, advanced reactors and JPARC offers unique opportunities to strengthen a unique combination of researchand engineering.
Recommendation: The IAC recommends that J-PARC should continue tocontribute to education and training in Japan to build a new generation ofscientists and engineers.

29

APPENDIX IAgenda for the 9th International Advisory Committee Meeting
J-PARC

Agenda for the International Advisory Committee Meeting of J-PARC(Preliminary)
Date: March 15 (Mon) and March 16 (Tue), 2010
Place: J-PARC Center – Tokai
March 15 (Mon)8:50 - 9:10

Executive Session (Closed)
Committee + S. Nagamiya, H. Kobayashi, Y. Ikeda

9:10 - 9:30
9:30 - 9:50

Overview of KEK (+ J-PARC)
Overview of the JAEA (+ J-PRC)

9:50 – 10:10-- Coffee Break –10:10 – 11:10
11:10 – 12:20
11:10 – 11:50
11:50 – 12:20
12:20 – 12:40

Status of J-PARC
Accelerators
J-PARC Accelerator Progress Report
A-TAC Report
Closed Session

12:40 – 13:30-- Lunch –13:30 – 15:30(13:30-13:55)
Y. Ikeda(13:55-14:20)(14:20-14:35)(14:35-15:00)

Material and Life Science Experimental Facility- Status of MLF and Topical Progress Report of Neutrons(15:00-15:15)(15:15-15:30)
15:30 – 15:50

A. Suzuki
H. Yokomizo

S. Nagamiya
A. AndoT. Roser- Experimental Results from Neutrons
M. Arai- N-TAC Repor
Y. Ikeda for D. Newmann- Current Status and One year progress of MUSE
Y. Miyake- Competition/Coexistence of Magnetism in Iron Pnictides
Probed by Muon Spin Rotation
R. Kadono- MuSAC report
J.-M. Poutissou for E. Morenzoni-- Coffee Break –15:50 – 17:40 Nuclear and Particle Physics Experimental Facility(15:50-16:20)- T2K experiment
T. Kobayashi(16:20-16:55)- Nuclear physics experiments (mainly for K1.8/K1.8BR)
T. Takahashi(16:55-17:20)- Particle physics experiments (mainly for KL)
T. Komatsubara(17:20-17:40)- Plan of particle and nuclear physics experiments(PAC/JPNC, Hadron hall plan, R&D for future exps.,...)
K. Nishikawa
17:40 – 18:20

Closed Session30

18:30 -Reception

March 16 (Tue)8:50 - 9:10

Executive Session (Closed)

9:10 – 9:40
9:40 – 10:00

Nuclear Transmutation
Network and Computing at J-PARC

10:00 – 10:25-- Coffee Break –10:20 – 11:40
11:40 – 12:00

Closed Session & Working
Summary Session

12:00 – 13:00-- Lunch –13:00 – 15:00
Adjourn-- Site Tour --31

H. Oigawa
A. ManabeAPPENDIX II

IAC COMMITTEE MEMBERS

Jean-Michel A
Poutissou

TRIUMF

Associate Director
Emeritus

jmp@triumf.ca

John William White

Australian National
University

Professor

jww@rsc.anu.edu.au

Andrew Dawson Taylor

ISIS,Rutherford Appleton
Laboratory,STFC

Director Facility
Development andOperations; Head of
ISIS

andrew.taylor@stfc.ac.uk

Bernard Frois

CEA

Directorbernard.frois@cea.fr

Stuart Douglas
Henderson

Oak Ridge National
Laboratory (ORNL)

Director

shenderson@ornl.gov

Satoru Tanaka

University of Tokyo

Professor

s-tanaka@n.t.u-tokyo.ac.jp

Hidetoshi Fukuyama

Tokyo University of
ScienceIan Anderson

NScD/ORNL

Sergio Bertolucci

CERN

Young-Kee Kim

FNAL

Vice President andProfessor
Associate Laboratory
Director for NScD
Director for Researchand Computing
DeputyDirector/Professor of
Physics

Hugh Montgomery

Thomas Jefferson
National Accelerator
Laboratory

Laboratory Director

mont@jlab.org

Thomas Roser

Brookhaven National
Laboratory

Accelerator Division
Head, ColliderAccelerator Dept.

roser@bnl.gov

Hoerst Stoecker

GSI Helmholtzzentrum
fuer
Schwerionenforschung

Scientific Director andCEO

H.Stoecker@gsi.de

Eiko Torikai

University of Yamanashi

Professor

et@yamanashi.ac.jp

Tsumoru Shintake

SPring-8, RIKEN

Principal Researcher

shintake@spring8.or.jp

Shoji Nagamiya

J-PARC Center

Director

shoji.nagamiya@j-parc.jp

Yujiro Ikeda

J-PARC Center

Deputy Director

ikeda.yujiro@jaea.go.jp

Hitoshi Kobayashi

J-PARC Center

Deputy Director

hitoshi.kobayashi@kek.jp

32

fukuyama@rs.kagu.tus.ac.jp
andersonian@ornl.gov
sergio.bertolucci@cern.ch
ykkim@fnal.gov

APPENDIX III

Report from the
9th Meeting of the Accelerator Technical Advisory
Committee for the Japan Proton Accelerator ResearchComplex (J-PARC)

March 11 - 13, 2010
J-PARC Center
Tokai, Japan33

Table of Contents
Overview.................................................................................................................. 1
Transition to Operations & Power Projections......................................................... 2
Linac Status.............................................................................................................. 5
3 GeV Rapid Cycling Synchrotron .......................................................................... 6
Main Ring Synchrotron............................................................................................ 8
RF Systems for the Synchrotrons ............................................................................. 9
Linac Energy Upgrade Plan ................................................................................... 11
Impedance and Instabilities .................................................................................... 12
Appendix I: Meeting Agenda ................................................................................. 1334

Overview
The Accelerator Technical Advisory Committee (ATAC) for the J-PARC Project held its
ninth meeting over the period March 11-13, 2010 at the J-PARC Center in Tokai, Japan.
This report of ATAC was presented to the Meeting of the International Advisory
Committee (IAC) on March 14, 2010.
ATAC members in attendance at this meeting included: J. Galambos (SNS), D. Findlay(RAL) R. Garoby (CERN), S. Holmes (Fermilab), A. Noda (Kyoto), P. Ostroumov (ANL),
T. Roser (BNL, chair), J. Wei (Tsinghua Univ.)
U. Ratzinger (U. Frankfurt) was unable to attend.

The ATAC wish to express its appreciation to JAEA and KEK management and support
staff for their hospitality during this meeting, and to the J-PARC staff for their excellent
and comprehensive presentations. The Committee also greatly appreciates that the J-PARC
team has carefully addressed all recommendations from the last review.



J-PARC completed the construction of phase 1 in 2008 and, since then, steadily
increased its performance and delivered beams for a growing user community:o The construction schedule and performance ramp-up followed plan from2005 quite accurately. This is a great success.
o Many firsts during the last year: first Kaon and neutrino production, first300 kW beam power from RCS for 1 hour, first neutrino event at
SuperKamiokandeo After resolving RFQ break-down issue continuous operation with 120 kW
beam power to MLF; 9 neutron beam lines in operation and, 3 in beamcommissioning, 3 under construction, and 3 more are funded from a total of
23 possible beam lines.
o About 10 hadron experiments have been approved serving about 200 users--Beam power achieved:o RCS: 120 kW; 300 kW for 1 hour testo MR: ~ 30 kW for fast extraction; ~ 2 kW for slow extractionBeam power plan for the future:o By 2012: 300 kW for RCS, 400 kW for MR FX, 20 kW for MR SXo Linac Energy Recovery construction completed and installed by the end of2012 (65 Oku Yen in hand, need additional 30 Oku Yen)o Request 90 Oku Yen equipment funding for Linac, RCS and MR to reachdesign performance (1 MW @ RCS, 750 kW @ MR) by 2014 (2 year delay
for RCS)

Plan to increase operation to more than 200 days and pursue more beam lines foro Muon facility (1/4 funded)o MLF neutron facility (18/23 funded)
o Hadron facility (several Kaon beam lines and primary beam line)o Available funding is 71% of 200 day operations

Comments and recommendations:

J-PARC is now serving four user groups: muon, neutron, neutrino, and hadronbeams. At the same time extensive machine commissioning is required and there isan ambitious upgrade program.

Continuing commissioning and operation of J-PARC Phase 1 as well as completingthe upgrade plans over the next few years will be very challenging.
Rec. #1: A detailed schedule should be developed to coordinate thecommissioning and upgrade efforts with the user requirements andexpectations for machine operations. The schedule for some of theperformance improvement and upgrade plans may need to be extended
to accommodate the steady production periods requested by the users.

Operations and Power Projections

36

--

The entire J-PARC complex is now in an operational state. Beam is being provided
routinely to the Materials and Life Sciences Facility from the RCS at a level of 120 kW,
and from the MR to the neutrino target at 30 kW, and to the hadron experimental area at 2
kW. Planning has been initiated for a program to achieve the full Phase I goals for the JPARC facility.

Primary Achievements

120 kW of beam to the MLF on a routine basiso 12 neutron and 1 muon beamline in operationo 300 kW of beam from the RCS demonstrated for one hour30 kW of beam at 30 GeV to the neutrino target on a routine basiso First observed neutrino events in near and far T2K detectors
o Single pulses accelerated and extracted from MR at intensities
corresponding to 100 kW



2 kW beam at 30 GeV slow extracted beam to the Hadron Area (6-bunch
operation)o Three beamlines commissionedo 98.5% efficiency, 11% duty factorMany technical issues either resolved or significantly mitigated in last year
o RFQ
o Ring RF systems
o MR power supply systemo MR slow extraction systemAccelerator availability of 92% over last three month

Planning initiated on multi-year program to achieve, and then exceed, original JPARC goals

Comments and Recommendations
User priority over next five years is identified as stable operations



Goals for JFY2010
o RCS: 200 kW operations (routine)

37

--

o MR Fast Extraction: 100 kW (routine)o MR Slow Extraction: 5 kW (routine)o 200 days of machine operations including accelerator studies


Residual activation is being monitored in all machines and beamlines
o Measurements are being done periodically, and all presented measurements
are on contact
R2: Establish an activation-monitoring plan that provides theinformation required to connect with beam loss simulations, provide
projections into the future, and assure that equipment can be
maintained without unacceptable dose to workers.

Spares queues are being built up per prior ATAC recommendationso Spare RFQ
o Spare klystronso Spare ring rf cavities
o Still no overall strategy on spares
R3: Establish a spares strategy based on a risk analysis incorporating
mean time between failure (MTBF), performance impacts of failures,
fabrication/procurement lead times, costs, etc. Such a strategy should
be used as a basis for establishing the spares component of theoperations budget.

Beam loss mechanisms in the RCS and MR are not well understood at the moment.
It is critical to understand these mechanisms, as these will form the basis for the
upgrade plans.
Rec. #4: Pursue studies aimed at characterizing and understanding
losses observed in the RCS and MR at the highest beam intensities
possible.

Projected performance goals for RCS and MR are now available through JFY2014

38

--

o Achieves original J-PARC Phase 1 goals: RCS=1.0 MW, MR=0.72 MW
o MR performance goal is dependent upon RCS achieving its performancegoalo Slow extracted beam power exceeds 30 kW
o Assumes linac upgrade to 400 MeV completed in JFY2012
o Continues operations of MR at 30 GeV through the periodo Upgrade to 50 GeV is not strongly motivated at this point, and appears to bedifficult due to magnet saturationPrimary elements of the upgrade plano Ion source to 60 mAo RFQ to 50 mA
o Linac to 400 MeV/50 mAo Upgrade of the RCS injection to 400 MeV
o Improvements to MR power supply system to support shorter cycle timeo Second harmonic cavities in MR
o Aperture improvements in the MR injection and fast extraction areao Collimator upgrades in 3-50 BT and MR to multiple kWs



The ATAC finds the overall approach to achieving Phase I goals as generally
plausible, and offer the following comments and recommendations to establish thisplan on a firmer footing:

The Linac Energy Upgrade is well underway, but 30 Oku-yen of funding still to be
secured

The MR slow extraction goal is less than user expectations.
Rec. #5: Continue simulations of slow extraction in the MR including all
known beam intensity dependent effects.
Rec. #6: Prepare a strategy for managing losses in excess of a few kW inthe extraction region.

39

--



Planning for operation of the RCS with 400 MeV injection has been focused almost
entirely on the upgrade to the injection area. There is a need to analyze all aspects of
the RCS in terms of the increased beam intensityPlanning for the MR 720 kW upgrade is based on a preliminary concept andsupporting simulations have been initiated. Plans are being made to upgrade thecollimators for a 10% beam loss at injection (~ 7kW). This is based on space charge
simulation and also is reasonable, based on scaling from similar machines.

Preliminary concepts for 1.7 MW from MR are based on reduction of cycle time to
1.0 sec. In addition to power supply and RF upgrades this would likely also requirea further upgrade of the collimators.

The plan for the MR relies on success in achieving 1 MW in the RCS. However, if
this achievement were to be delayed there may be other options for providing 720
kW from the MR including: further reduction of the MR cycle time, increasing the
MR operating energy, and stacking of more than four RCS cycles in the MR. The
committee suggests continuing consideration of such options.



The upcoming five year period will involve accelerator operations, accelerator
studies aimed at providing short term improvements and to support longer term
improvement strategies, installation and commissioning of the linac energy upgrade,
and a number of further installations required to support the final goals. Carefulplanning will be required in order to deliver the maximum integrated beam power tothe users over this period.



A complete operations plan is desirable including the following elements:
o Estimates of peak performance in the RCS and MR by yearo Estimates of the integrated beam power delivered from the RCS and MR byyear
o Estimates of the integrated hours of beam on target for users and accelerator
studies by year.
o Estimates of commissioning time required following the linac upgrade.
o Estimates of the expected availability by year.
o Estimates of required resources to support the plan by year.

40

--

Rec. #7: The existing operations plan should be further developed toinclude the above-mentioned elements. This plan should include input
from the user community.


A complete upgrade plan is needed, incorporating the following elements:o Parameter tables for each ring, including all relevant beam and machine
operational parameters. These parameter tables should be modified as
operational or development activities indicate the need for changes.
o Complete beam simulations should be pursued to guide the evolution of theabove parameter table.
o Complete consideration of potential beam instabilities.
Rec. #8: The operations plan should be augmented by a technicalupgrade plan that describes the configuration of the complex, andassociated performance goals through the upgrade period.

Linac Status

Primary achievements
Successful RFQ recovery program.



Successful support of RCS and MR beam operations

Compared to one year ago, the linac team has made tremendous progress, and thelinac is able to supply adequate beam to support operations and beam studies ofdownstream accelerator systems.

Comments and recommendations


Attention has been given to the issues highlighted by the ATAC-09 review.



The RFQ conditioning issue has been attacked on many fronts, and the results show
dramatic improvement in the ability for the RFQ to run for extended periods. Many
modifications have been applied (additional pumping, restricted aperture,

41

--

elimination of oil contamination sources, etc.), and there is a better understanding of
the problem provided by monitoring of vacuum and RGA measurements.
Rec. #9: Consider trying to operate the RFQ longer than the one-weekperiod successfully demonstrated to date. This could possibly be done
during beam study time. If successful, this will allow more freedom inscheduling production hours for the user facilities.


A number of operational hardware issues have arisen and are being dealt withappropriately (e.g. vacuum seals, water flow balancing). This is a natural part of amachine operation power ramp-up.

The klystron lifetime of 25,000 hours is being approached (~ half) and someevidence of RF performance change was presented. The quoted klystron lifetime
seems short as compared to the experience at other installations, but an active
monitoring of the RF performance system is being done and should be continued.

A new spare RFQ with similar beam performance specifications as the present RFQ
is being prepared. This is an important effort to ensure reliable beam production andto enable higher intensity beams for RCS studies. However, the suggested
completion date of Nov. 2010 is optimistic.
Rec. #10: Develop a more detailed resource loaded schedule for the new
RFQ, including testing. One particular concern is the proposed
horizontal brazing scheme. Care should be taken to maintaining highvane tip positioning accuracy for horizontal brazing.

The ion source capability is adequate for present day operation and has been
demonstrated to support 300 kW operation (15 mA at 0.5 ms). Nonetheless, there isa need to demonstrate higher capability for the ultimate 1 MW scenario (up to 60
mA). More aggressive efforts with test stand ion source studies should be pursued.
Also, the rather long source changeover time of 3 days was identified as a limitation.
This will impact the hours one can supply beam to users eventually and should be
addressed.

42

--

Rec. #11: Have the ion source test stand operation be monitored by thecentral control room to facilitate 24/7 operation for extended tests, as isdone at other facilities.
Rec. #12: Investigate means to reduce the source changeover time
(examine techniques at other facility).
A primary machine activation mechanism was identified as H+ production in the
LEBT, which was fully accelerated and lost at the first bend. A clever chicane
scheme with appropriate scraping has remedied the problem and clearly identified
the issue.

Beam losses measurements in the ACS upgrade area of the Linac have been
performed for two different vacuum pressures. These experiments clearly
demonstrate beam loss increase in the ACS area when the pumps are off in the
SDTL linac.
Rec. #13: Additional studies are required to understand whether thiseffect is a dominant source of the losses in the ACS area. Measure thebeam loss as the vacuum pressure is progressively increased.

Extensive beam studies were presented. There is an un-identified RMS emittance
growth in the DTL, but no apparent halo is generated. In the SDTL no further RMS
emittance growth is observed but beam halo is generated. A matching scheme has
been developed that uses empirical MEBT RF adjustment to minimize halo at theend of the SDTL. Model comparisons suggest this is due to a longitudinal missmatch and coupling to the transverse plane. Interestingly, beam loss at the end of
the SDTL is insensitive to the reduction of the observable beam halo.

Beam loss is sufficiently low for present day operation, but the loss at the future
ACS upgrade region is a concern for higher power operation. This loss appears to
be insensitive to normal tuning adjustments.
Rec. #14: Continue both theoretical and experimental studies towards
the reduction of beam losses in the ACS area: study longitudinal beam
parameters with available equipment (e.g. consider acceptance scans)

43

--

and consider implementing additional longitudinal measurement
techniques.
Rec. #15: Consider implementing an RF subtraction scheme with the
BLMs in the linac.

3 GeV Rapid Cycling Synchrotron

Primary achievements
Running the RCS routinely at 120 kW.

Demonstrating operation at 300 kW.

Carrying out an extended programme of machine physics measurements.

Establishing the extent to which the synchrotron and its systems are becoming
activated due to beam losses.

RF systems are adequately supporting operations.



The RCS team are to be thoroughly congratulated on making the operationally
important transition to a régime of routine running.

Comments and recommendations


The RCS team have addressed the issues highlighted by the ATAC-09 review.



Although several significant issues have been highlighted by the RCS team, most of
RCS systems must have run well, e.g. the power supplies for the main magnets andthe high-power RF drivers, and this success certainly deserves recognition.



Operation for 1 hour at 300 kW was achieved, which is good for demonstration of
the beam stability at this intensity. However 1 hour is a rather short time to run atsuch powers.
Rec. #16: The RCS should be carefully run at 300 kW for periods
longer than 1 hour to help reveal any latent problems and weaknesses.

44

--

It could also be worthwhile to increase incrementally the beam power
above the nominal level on some run cycles by ~ 10%, if possible, and tonote any resultant changing trends in activation.
While the RCS team have successfully carried out effective and extended
programmes of machine physics measurements, both for themselves and forcomparison with beam dynamics simulations, much remains to be done.
Rec. #17:

Sufficient time should always be made available forcomprehensive programmes of machine physics measurements.
Work remains to be done to optimise settings of trim quadrupoles and othercorrectors to compensate for inevitable imperfections in the lattice, and also toenhance performance by suitably varying the tunes throughout the acceleration
cycle. Such work inevitably depends on the availability of extended periods ofrunning at the higher power settings.
Much effort has been devoted to measurement of dose rates from radioactivity
induced in machine structures by beam losses. No doubt, in view of the relatively
short time the machine has been running, there are day-to-day and cycle-to-cycle
variations in the measured dose rates, but gradually over time the systematics of thedose rates should become apparent. It should be remembered that it is radiation
doses to personnel, not radiation dose rates per se, that are important, and that often
appropriate engineering design can be used to partially offset effects of radiationdose rates.
Rec. #18: Systematics for dose rates at 30 cm from contact should beestablished as well as for dose rates on contact.
Eventually it may become worthwhile to install a set of long beam loss monitors allaround the ring some ~1–2 metres from the beam line to provide a consistentmeasure of radiation dose rates in practical working environments.



It is clear that there are substantial uncertainties at injection into the RCS, and thatmuch work remains to be done over optimising injection schemes, particularly with

45

--

regard to stripping foil configurations, to help make progress towards higher beam
powers.
Rec. #19: The proposed programme of measurements for different
painting regimes and for different geometries and thicknesses ofstripping foils is encouraged. A range of foil sizes, rather than just twosizes, should be considered for installation and testing at the next foilchange opportunity. Also considered should be a diagnostic system toprovide direct information of the linac beam spot on the foil (e.g. athermal imaging camera for high power operation, or a phosphor
screen “foil” for low intensity usage).
Rec. #20: Further measurements should be made to provide a moredetailed picture of beam loss mechanisms at injection (e.g. by making
measurements using a fast local beam loss monitor to distinguishbetween losses arising directly from the injected H– beam and thecirculating H+ beam).


It is especially important to understand thoroughly the beam dynamics at injection if
the full benefits of injection at 400 MeV from an upgraded linac are to be gained.



The acceptances of the beam lines to the neutron producing target and to the Main
Ring (MR) are different. Could a scheme be devised to “vary” collimation on apulse-by-pulse basis, perhaps by incorporating beam bumps?

Problems have been encountered with the RCS extraction kickers; electricalbreakdown has occurred in the plugs connecting the coaxial cables from the kicker
drivers to the kicker vacuum vessels. The committee supports measures that are
being taken to resolve the breakdown problems.

Main Ring Synchrotron

Primary Achievements

46

--



Successful beam delivery to neutrino (NU) beam line (up to 32 kW) and hadron(HD) beam line (2-3kW) has been accomplished. Operation with the beam
power up to 100 kW for NU was also demonstrated.

First neutrino event has already been detected on site on November 22nd, 2009,
and at SuperKamiokande on February 24th, 2010.



Beam is delivered to Hadron Experimental Hall

Congratulation to all members of the MR team and related groups

Comments and recommendations


Total injection beam loss amounts to 105 W for 100 kW MR operation.
Rec. #21: The beam halo development just after transfer from RCS to
MR should be carefully studied up to highest beam intensity achievable.

Beam loss at the slow extraction equipment area is observed together with avacuum pressure rise when operating with higher beam intensity. The
vacuum pressure rise is reduced after some hours of beam operation.
Rec. #22: The beam loss during acceleration might be due to electron
cloud. This should be investigated with appropriate diagnostics.



Slow beam extraction has been achieved with beam power up to 3 kW andwith duty factor up to 11 % using spill feedback and shorted trim coils of thering quadrupoles. The duty factor is further increased to 15 % by applicationof RF noise, which increases the horizontal transverse motion. The
extraction efficiency is estimated to be 98.5 %.
Rec. #23: To raise the available beam power with slow extraction andimprove the duty factor to larger than 50 %, other possible schemes
such as RF knockout to increase horizontal beam emittance or the slow
extraction scheme used at the BNL/AGS should be investigated.

A new main magnet power supply is being designed to increase the

47

--

repetition rate of the MR. This offers the opportunity to incorporate further
measures to reduce ripple at flat top.
Rec. #24: Consider a dedicated low voltage supply for improved current
regulation at flat top and flat base.
Rec. #25: The beam loss during slow beam extraction should be
carefully investigated and compared to reliable simulation codesthat include high intensity effects.
Realization of 0.72 MW beam power for fast extraction with 30 GeV is to berealized by the supply of 1MW beam from RCS with the 400 MeV linac
beam energy upgrade by the end of 2014.
Rec. #26: For the purpose of beam loss reduction, the beamcharacteristics near the end of 3-50 BT line should be evaluated withmeasurements of beam profile and momentum spread.

RF Systems for the Synchrotrons

Primary Achievements

The performance of the FineMet loaded cavities in both synchrotrons is still a
subject of concern. Large efforts are being invested to understand and cure theobserved problems in the short term.



For the long term, alternative solutions are studied, and preliminary ideas forincreasing the gradient are investigated.



As a matter of fact, the present difficulties do not impact on the operation of the
J-PARC complex. The reliability of the synchrotrons RF systems is continuously
improving and contributes clearly to the regular progress in performance of thewhole J-PARC complex.

48

--

Comments and recommendations


Status of investigation on the degradation of RCS uncut FineMet cores:o Impedance reduction in the RCS cavities has been intensively studied: out of
the 90 cores analyzed, 25 showed buckling with 2 having degraded
impedance.
o Buckling is clearly correlated with a specific preparation process, based on
impregnation with low viscosity epoxy resin.
o A “flawless” preparation process is identified (“type C”). New cores arebeing built to replace the ones prepared with other techniques.



Recently observed degradation of MR cut cores:o Impedance reduction has been observed in all cavities since the summer of2009.
o This effect is understood as related to a degradation of the surface of the cuts.
Initial characteristics can be recovered by exposure to air and/or polishing.
o In the short term, cavities will be systematically opened and core cuts
polished during ordinary shutdowns.
o For the longer term, silica coating is being studied.
Rec. #27 (for RCS and MR): The ATAC fully agrees with theprocedure and with the high priority given to this work by the JPARC management. Moreover, the Committee underlines thatsystematic monitoring of the characteristics of the cavities
remains essential to detect as early as possible any futuresource of trouble.



Independent analysis of FineMet loaded cavities and search for alternative
solutions:o Computations and mechanical tests can largely explain buckling.
o The use of “raw FineMet” immersed in a chemically inert cooling fluid is
advocated.
o A test set-up is being assembled to demonstrate performance of such asolution on a single core assembly.

49

--

Rec.

#28:

The

committee

confirms

its

supportoftheinvestigation of this alternative scheme. If the test is successful
it should be considered whether a complete cavity that uses thealternate cooling fluid is built and installed in the ring.
Possibility to increase the accelerating gradient:o More voltage will be necessary to reduce significantly the MR cycling timeand reach beam power beyond 0.72 MW. A new FineMet preparation
scheme is proposed that could increase the impedance of the cores.
o Preliminary development proceeds without interfering with the more urgent
work programs.
Rec. #29: This proposal has a high potential interest, either toincrease the voltage for a given RF power, or to reduce
dissipation for a given voltage. The ATAC encourages thisdevelopment.

Linac Energy Upgrade

Primary Achievements


Procurement and fabrication of major components of the 400 MeV Energy
Upgrade are being performed according to the original schedule:o Contract has been placed for fabrication of all accelerating modules except
the debuncher modules.
o Procurement of 972 MHz klystrons is on schedule and 16 klystrons will bedelivered by the end of 2010.

The R&D module consisting of accelerating and coupling segments with tuners
has been built and successfully tested at design power level.

All recommendations of the ATAC-2009 sub-committee on Linac Energy
Upgrade are being implemented:
o 3 BSMs will be ordered,

50

--

o BPMs are being modified for the TOF measurements,
o BLM detectors are being developed,
o Extensive beam dynamics simulations are in progress.


Development of the beam diagnostics system for the 400 MeV energy upgrade
is well advanced and all components of this system will be delivered by the endof 2011.



A high-power test area of the ACS modules is being prepared and a few
accelerator modules will be ready for the tests by the fall of 2010.

Comments and Recommendations
Off-line high-power tests of the ACS module have been successfully performed.
These tests validated fabrication technology based on simplified machining of
the accelerating cells developed for the mass production of the ACS accelerating
cells.

In addition, operation of the tuners at high-power level has beensuccessfully demonstrated.
Rec. #30: Additional measurements are recommended during highpower tests of each ACS module prior to beam commissioning:i. Take measurements of the frequencies of nearest two modes at
high-power level with the goal to confirm correct tuning of thedispersion curve. For some modules it may require fine-tuning to
avoid accelerating field distortions at high-power level.
ii. High-power conditioning should be continued until the design
value of the residual gas pressure at full RF power level will beachieved. It is reasonable to estimate the residual gas pressure in
the accelerating cell aperture from its relationship to the vacuum
gauge reading. This will help to control H-minus stripping by theinteraction with the residual gas.


There is progress in end-to-end beam dynamics simulations including the 400
MeV upgrade section and beam transport to the RCS. Following therecommendation of the ATAC-2009, the effect of various machine errors on 5051

--mA beam parameters has just begun to be investigated. Simulations with very
low statistics have already revealed significant increase of the emittancecontaining 99% particles in the transverse phase space even though the input
emittance was lower than the measured beam emittance. The study of beamlosses in the high-energy section is the part of the beam dynamics simulations.
Current operation of the linac reveals appreciable beam halo formation after the
DTL-SDTL. There is a unique opportunity at the J-PARC linac to implement
beam collimators at the MEBT-2 due to the fact that sufficient space is available.
Rec. #31: Continue high-statistics simulations with all machine errors
with the goal to deliver high-current beam parameters to the RCS
stripping foil according to the design specifications. Following thepositive SNS experience, consider implementation of a beam collimation
system between the SDTL and ACS. Include the effect of collimators
into the computer simulations.


Tentative plan for procurement and installation of the Energy Upgrade
equipment has been developed, which shows that the final installation and beamcommissioning will take place within 6 months during the second half of 2012.
This schedule is ambitious and could be implemented if appropriate funding isprovided.

Impedance and Instabilities

Primary Achievements

Vacuum pressure rise was observed in the MR.

Transverse damping system was developed for the MR.

Comments and recommendations:

Like many other high-intensity accelerators, the performance of J-PARC
accelerators is eventually limited by beam loss and instabilities. It is important to

52

--

find out as early as possible bottlenecks of the machine so that mitigations can beplanned and implemented. Implementations of remedies like nonlinear correctors
and ramping power supplies, ramping trim quadrupoles, coating of component
surfaces of high secondary-electron yield take time. In many aspects, the J-PARC
RCS resembles the RAL/ISIS ring, and the MR resembles the BNL/AGS. It is
important to carefully study the experience at these machines.
Rec. #32: Test the beam at highest possible single-pulse intensity todetermine performance limitation at RCS and MR; refer to theoperational experience of accelerators like RAL/ISIS, BNL/AGS,
CERN/PS, and ORNL/SNS pertaining to beam loss, instabilities andtheir remedies.
Beam diagnostics with sufficient speed and dynamic range is needed inunderstanding the mechanisms of beam loss and the nature of possible instabilities.
Detailed analysis and planned machine studies are crucial in the understanding ofmachine features.
Rec. #33: Enhance beam diagnostics and analysis capabilities, including
e.g. fast beam loss measurements, high-frequency beam position
measurements in RCS and MR, fast transverse beam profile
measurements, and longitudinal wall-current-monitor measurements.



Most of the time, computer simulations only provide qualitative indications of theactual machine conditions. It is risky to quantitatively base the design of e.g.
collimation systems and device coating decisions on the simulation results. Even for
qualitative comparison purposes, the model, the approach, and the coding ofcomputer simulations need to be benchmarked with machine study results undersimple and known machine conditions. It is also helpful to benchmark with othersimilar machines. For example, thresholds and growth of several types of
instabilities were predicted and simulated for the SNS accumulator. Such results
could be closely compared and referenced for RCS. Slow-extraction experience at
BNL/AGS could also be closely referenced.

53

--

Rec. #34: Benchmark simulation models and codes using machine study
results of J-PARC accelerators; benchmark with results of otheraccelerators like RAL/ISIS, BNL/AGS, CERN/PS, and ORNL/SNS.


At early stages of machine commissioning and operation, extensive machine studies
are needed to assess the equipment reliability and accuracy, machine aperture,single-particle versus collective effects, instability threshold and growth rate, andbeam loss mechanisms. Even at intensities much lower than the full design value,
instabilities can be enhanced by adjusting the machine lattice conditions like thetunes and the chromaticity, and the beam conditions like bunch intensity, length,size, and momentum spread.
Rec. #35: Perform extensive, dedicated beam studies on beam loss andinstability by varying machine conditions like transverse tunes andchromaticity, and beam parameters; benchmark with computer
simulation and theoretical estimations on instability threshold, growths,
and beam loss.

Vacuum pressure rise in a ring could be the effect of an electron cloud. The effect islikely to be enhanced as the beam intensity is raised in future. In RHIC, vacuum
pressure rise and signals in the electron detectors are the clear signatures of electron
cloud, even though electron-cloud may not cause instabilities in the beam.
Rec. #36: Look for possible signatures of electron-cloud effects in bothMR and RCS; prepare corresponding diagnostics and potential
remedies.

Maneuver of the transverse tunes along the ramping cycle and resonance correction
with nonlinear correctors is crucial in avoiding resonances and instabilities at highintensity machines.
Rec. #37: Study the potential benefits of tune maneuver and nonlinear
corrections during the ramping cycle in RCS and MR; consider possible
implementations.

54

--

Appendix: Meeting Agenda

55