Report of the SPring-8/SACLA AC and RSACGeneral comments•

RSAC really appreciates the organization of the review.

•RSAC recognizes the world class status of the SPring-8/SACLA complex.

•We appreciate the thoughtful response to the 2019 RSAC recommendations. We again
appreciate the joint review of RSC and JASRI affording the opportunity to understandthe SPring-8/SACLA facilities as a whole.

•The continuous progress in the technical areas highlighted by the Citius detector
development and the world leading optics is impressive.

•The collaborative development of accelerator-based x-ray sources, NanoTerasu andSPring-8-II, is a significant step towards a coordinated approach to SR in Japan.

Terms of Reference
1. comments and/or recommendations regarding the management and operation of theSPring-8/SACLA facilities
2. comments and/or recommendations regarding the revised accelerator/beamline
upgrade plan for the SPring-8-II project (including scrap & build)
3. comments and/or recommendations regarding the role of SPring-8 in synchrotron
radiation facilities in Japan and around the world
4. comments and/or recommendations regarding the progress of SPring-8/SACLA toward
their mission to set the direction for the future of science⚫

Terms of Reference (TOR1)

1. comments and/or recommendations regarding the management and operation of theSPring-8/SACLA facilities
Comments:•RSAC is in awe of the 99.5% uptime and ~ 230 hrs. MTBF for SPring-8. This is worldleading.

•The reliability and new operating modes of SACLA continues to provide newopportunities for the user community.

•The transition to the use of SACLA as the SPring-8 injector has already had significant
impact, reducing electric consumption by 5 MW and demonstrating a critical capabilityfor SPring-8-II•

The continued attention to a coherent approach to the management of the entire
Harima site is important to the operations, development and growth of the x-ray

facilities. In times of fixed budgets and increases in electricity costs and inflation ashared vision and responsibility by RSC and JASRI is critical.
•RSAC recognizes steps toward a coherent management system as recommended by
RSAC in 2019, but there is still more that can be accomplished.

Recommendations:•RSAC notes that the Pohang Accelerator Laboratory in Pohang Korea has similar
staffing levels, and both an FEL and a storage ring, and is providing accelerator physics
support to a next generation SR source as is true for the combination of RSC and JASRI
on the Harima site. RSAC recommends that RSC/JASRI consider the organizational
structure at PAL as an example of how a coherent management system can optimize
outcomes with very limited staff. This can become critical in times of fixed budgets andincreases in electricity costs and inflation.

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Terms of Reference (TOR2)

2. comments and/or recommendations regarding the revised accelerator/beamline
upgrade plan for the SPring-8-II project (including scrap & build)
Comments:
Accelerator upgrade:•The news that SPring-8-II is slated to begin installation with the 2027 summer
shutdown is wonderful news for the Japanese synchrotron user community as well as
the international users of SPring-8. The design of the storage ring has optimized theuse of permanent magnets to reduce electricity usage. The target emittance of 50 pm
will place SPring-8-II amongst the world leading facilities, ESRF and APS.

•RSAC takes note of the ‘short time’ between now and the planned start of installationof the new ring components at the start of the 2027 summer shutdown.

•RSAC endorses the updated lattice for Spring-8-II reaching an emittance of 50 pm. radthanks to the effective use of damping wigglers in two of the four 30m-long straightsections and to the use of reverse bends (shifted quadrupoles). This performance,
combined with an increase of the beam current from 100 to 200 mA, will enable a verysignificant increase in photon brightness.

Recommendations:•At a later stage of the project, RSAC recommends to evaluate the following detailed
recommendations which are summarized at the end of this presentation (pages 23-25)
to reach a step further in terms of performance and to fully exploit the potential of thisnew source. In consideration of the short time before the start of installation RSAC
recommends considering our detailed recommendations in a timely fashion withemphasis on the injection approach.
Comments:
Beamline upgrades:•The transition from multi-technique beamlines to focused beamlines in a continuous
way enhancing the SPring-8 capabilities with new optics, new detectors and impressive
automation and the SPring-8 data center will prepare the beamline suite for the start ofSPring-8-II. Further the synergy with the Fugaku Supercomputer will be critical to theDigital Transformation. Categorizing beamlines by measurement, experiment andR&D is well matched to the needs of a diverse user community.

Recommendations:
Beamline upgrades:•The progress on the scrap and rebuild approach to beamline upgrades is going well.
The definition of measurement, experiment, and R&D is a positive approach. The
measurement capability will become ever more important as the domain scientists see
the unique potential that SR results can deliver in answering complex questions. RSAC
recognizes a missing component: the link between the domain scientist and the facility.
RSAC recommends that RSC/JASRI look for a solution to this challenge. RSAC notes
the discussions at NanoTerasu regarding the creation of a third party to address thisneed.

•The RSAC recommends a continuation of the transition of contract beamlines toRIKEN ownership. This has several advantages:
1)

RIKEN has the expertise to upgrade and manage the beamline in the SPring-8-IIera⚫

2)

Block access is afforded to the ‘contract institution’3)

Increased access for the public to SPring-8-II beamlines.

Terms of Reference (TOR3)

3. comments and/or recommendations regarding the role of SPring-8 in synchrotron
radiation facilities in Japan and around the world.
Comments:•There are 5 sites worldwide that have both an FEL and a storage ring x-ray source with
common management: Among these the combination of SPring-8 (soon to be SPring-8-II) and SACLA is world leading. The cooperation and parallel developments of optics
and detectors is of particular note and contributes to world leading capabilities on theHarima site.
•The SPring-8 accelerator team designed the NanoTerasu accelerator complex andplayed a critical role in its construction and the commissioning which has alreadyshown impressive results with RF capture and stored beam in just 8 days from theinitial injection into the storage ring.

•The coordination of beamline capabilities between NanoTerasu and SPring-8 has
begun.We note that NanoTerasu also addresses, in part, the dark period during theinstallation and restart of SPring-8-II.We recognize that NanoTerasu will not provide
the breadth and in particular the hard x-ray facilities available at SPring-8 but manyusers will have access to important capabilities.

Recommendations:•RSAC takes note of he impending start of the user program at NanoTerasu. RSAC
suggests that RSC/JASRI in collaboration with NanoTerasu consider establishing asingle point of entry for users of SPring-8 and NanoTerasu. There are several
advantages that RSAC sees in this approach:1.

Remove redundancy in the facility-user interface.

2.

Users of SPring-8 are familiar with the existing system and this eliminates any
barrier to proposing experiments at NanoTerasu.

•RSAC strongly supports continued developments of synchrotron technologies that areworld leading such as state of the art reflecting optics. Communicating thedevelopments beyond SPring-8 and Japan to the world community in a timely fashion isvery important.

Terms of Reference (TOR4)
4. comments and/or recommendations regarding the progress of SPring-8/SACLA toward
their mission to set the direction for the future of science.
•X-ray facilities have in the past, and will for the foreseeable future, provide uniqueinformation necessary to better understand forefront science problems. It has alreadybeen documented that research using accelerator-based x-ray sources has contributed
to solutions addressing societal challenges. The energy, time and length scales
accessible with x-rays, in combination with their elemental specificity, on the Harima
site, are ideally matched to problems in chemistry, biology, medicine and materials
science. Further, x-ray results guide developments of technological importance that

directly impact society as evidenced by the continued leadership in industrial use atSPring-8. Continued development of x-ray research capabilities with SPring-8-II and in
the future with SACLA-II will ensure the importance of x-rays will continue.
•

From Prof. John Etchemendy, Provost (2000-2017), Sanford University at the LCLS
Ground Breaking: “Instruments have a life of their own. They do not merely follow
theory; often they determine theory, because instruments determine what is possible,
and what is possible determines to a large extent what can be thought.”

Recommendation:•RSAC urges RSC to begin now to consider all possibilities afforded by the installed
infrastructure to make SACLA-II unique worldwide. With a unique tool, new science
will be possible and can change the way people think about important questions in
fundamental science and their impact on societal challenges.

Requested by the RIKEN President
1.

Evaluate the responses to the 2019 AC recommendations.

2.

Based on the results of the Center's self-analysis, evaluate operations and R&D
activities for the 4th Mid- to Long- Term Plan period (FY2018-2024).

3.

Evaluate the policies of the 5th Mid- to Long-Term Plan period (FY2025-2031) andrecommend new directions for operations and R&D that should be implemented andpromoted.

⚫

Request of the RIKEN President (TOR1)

1. Evaluate the responses to the 2019 AC recommendations.
•RSAC is very pleased with the response to our 2019 recommendations. In particular, asa committee, we are encouraged to continue helping RSC/JASRI drive world leading
science and technology with accelerator-based x-ray sources.

⚫

Request of the RIKEN President (TOR2)

2. Based on the results of the Center's self-analysis, evaluate operations and R&D activities
for the 4th Mid- to Long-Term Plan period (FY2018-2024).
•RSAC recognizes the strengths of the Center as world leading in the development ofadvanced beamline components that in turn lead to cutting edge research by RSC staff,JASRI staff and users.

•Both SPring-8 and SACLA are exceptionally reliable, stable, and well managed, despiteminimal staffing levels.
•RSC staff have world leading impact in several areas, highlighted, for example, byresults from SACLA in non-linear x-ray science and inelastic x-ray scattering at SPring8 and the High Energy Density science platform at SACLA.

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Request of the RIKEN President (TOR3)

3. Evaluate the policies of the 5th Mid- to Long-Term Plan period (FY2025-2031) andrecommend new directions for operations and R&D that should be implemented andpromoted.
•RSAC emphasizes the importance of the generation of reliable, robust data as the basisfor scientific advances. The SPring-8-II Upgrade (2025-2028) is an opportunity toreach this goal as a better ‘Data Creation Platform’. Generating the data is necessary
but not sufficient. Analysis, visualization, and interpretation is also critical. It is the data
generation aspect of TRIP that is the strength of SPring-8 (SPring-8-II) and SACLA.
RSC has also established the direct link to Fugaku which provides the othercomponents that will make TRIP successful.

•RSAC recognizes the need for top down as well as bottoms up approaches for the use ofSPring-8 and SACLA. The top-down approach is well matched to use inspired researchfor example with the Semiconductor Device Characterization Platform and theNational Resilience Platform. RSAC takes note that the existing strategy of RSC tocreate data, use the unique capabilities of the Fugaku supercomputer and thebioscience capabilities matches exactly the TRIP concept.

•SPring-8 has world leading use by industry and this naturally resonates with a topdown approach.

•RSAC strongly recommends RSC start considering SACLA-II with a focus ondeveloping worldwide unique capabilities.

•There is always a need to train and develop the next generation of leaders for the RSC.
This is a continuing need, not just for RSC but for large facilities in general. This will
ensure a continuity of vision for the development of the capabilities on the Harima site.

⚫

Accelerator upgrade recommendations (1)•In addition to the reduction of the electron beam emittance, it is necessary to optimize
other parameters such as the proper matching of the electron and photon phase-spaces.
This will maximize the intensity of the coherent flux. A first objective could be having
both horizontal and vertical beta functions of about 2m in 24 of the available 48 straightsections.

•In these straight sections, the horizontal beam-stay-clear is then reduced which willallow the installation of small vertical as well as horizontal gap insertion devices. In
addition, RSAC suggests comparing the performances of the undulators (and inparticular in-vacuum undulators) with variable parameters of length, gap and local betafunctions.

⚫

Accelerator upgrade recommendations (2)•RSAC recommends evaluating the replacement of the short and normal bending
magnet sources or at least a few of them by longitudinal gradient permanent magnet
material bending magnets targeting a sharp peak field of about 3T as has been
constructed and successfully used in operation at Sirius and planned for the SLS 2.0and SOLEIL II projects. This will bring the critical photon energy from 22.5 keV to 71
keV which will tremendously increase the photon flux at higher photon energies. RSAC
believes that with such a shape of the longitudinal magnetic field and a very small
dispersion in its center, the contribution to the total energy loss per turn should be low.

⚫

Accelerator upgrade recommendations (3)•As is the case for Spring-8, Spring-8-II will run in Top-up mode for stable operation. A
conventional scheme with pulsed bump magnets is considered for a transparent
injection into Spring-8-II. RSAC believes that the ultralow emittance of the new source
will enhance the sensitivity of the electron beam position and beam size to even verysmall errors in the injection system. RSAC recommends the team evaluate an injection
scheme using a single Non-linear Kicker taking advantage of the very low emittancebeam from the LINAC. The first fourth generation storage ring (MAX IV) is runningwith such a system and has achieved sub-micrometer levels of residual perturbations tothe stored beam size, well below the nominal beam size in both horizontal and verticalplanes.