17th KEKB Accelerator Review Report
Andrew Hu*on
for theAccelerator Review Commi*ee

Committee Members• Andrew Hu*on, Chair JLab

• Bob RimmerJLab• Yunhai Cai
SLAC(replacing John Seeman)• Kem Robinson

LBNLSLAC• Alexander Chao

SLAC

• John T. Seeman(unable to a*end)• Oswald GröbnerCERN• Zhao Zhentang

SINAP• John Fox(a*ended via EVO)SLAC

• Frank Zimmermann

CERN• Stuart Henderson(unable to a*end)

FNAL• Gwo‐Huei Luo

NSRRC• Won Namkung

POSTECH• Evgeny Perevedentsev BINP
• David RiceCornellUniversity (unable to a*end)

Ex Oﬃcio Members• Katsunobu OideKEK• Kazunori Akai

KEK• Atsushi EnomotoKEK• Haruyo Koiso

KEKIntroduction• The Seventeenth KEKB Accelerator Review Commi*ee mee[ngwas held on February 20‐22, 2012
• The mee[ng followed the standard format, with two days of oralpresenta[ons by the KEKB staﬀ members, followed by discussion
between the Commi*ee members• The Commi*ee was impressed by the high standard of thepresenta[ons, which dealt with the earthquake recovery as wellas the design of SuperKEKB• It was par[cularly pleasing to have several presenta[ons givenby recently hired junior staﬀ members• The Commi*ee evaluated the present status of the project andprepared recommenda[ons, which were presented to the KEKBstaﬀ members before the close of the mee[ngContents of Report••

KEK Roadmap
Recovery of Linac aber the Earthquake••

Beam diagnos[cs, Feedback systems
Photon Monitors••

Overview of Design Issues
Overview of Construc[on Status••

Beam Background
Development of New LLRF System•

Belle II Construc[on andCommissioning•

Improvement of Superconduc[ngCavi[es•Dynamic aperture and IR modeling•

Cavity for Damping Ring••

Error Tolerance and Op[cs Correc[onIR Magnets•

Produc[on Status of VacuumComponents•

Beam Background•••

IR Vacuum Chamber and Assembly
Collision Feedback

Baking equipment and coa[ngequipment•

RF Gun and Low Emi*ance Transport••MagnetBeam diagnos[cs, Feedback systems••

Positron Source
CSR in Damping Ring•

Photon Monitors•

Synchrotron Injec[on•Beam Background•

Beam Abort System•

Magnet•Control and Timing SystemExecutive Summary• The SuperKEKB Project has made considerable progress since last year
despite the massive earthquake that did considerable damage tobuildings and equipment• However, the eﬀort applied to a rapid recovery of the linac and Photon
Factory was not available to make progress on the project, so all theschedule ﬂoat has already been used up• There has been rapid progress in some areas, for example the vacuum
system, with large quan[[es of components being delivered; this has
overloaded the staﬀ assigned to inspec[on and quality assurance• In other areas, notably the Interac[on Region components, the very
specialized components are s[ll being designed, and should be
prototyped before going out for ﬁnal order• The schedule is extremely 0ght to complete everything in the 0me
available

Executive Summary (cont)• The progress in the linac area is impressive; the earthquake caused
considerable damage to the linac, but the linac group managed toresume beam opera[ons within two months• In addi[on, the new linac is designed and components are on order• Magnet refurbishment is proceeding; the wiggler magnets survived
being banged together in the storage area, but it is feared that the LER
Magnets did not fare as well
• Progress in the design and beam dynamics of the rings has beensteady, but this is an extremely diﬃcult machine and there are s[llunanswered ques[onsExecutive Summary (cont)• Overall, the Commi*ee rated the cost risk to be low for theen[re Project• The technical risk and the schedule risk to be low for theInjector chain, facili[es and the ring components• The technical risk and the schedule risk to be high for theInterac[on Region• The Commi*ee therefore believes that a mi[ga[on strategy
should be developed, modifying the commissioning plan toenable the project to reach T=0 on [me and to advance the startof physics opera[on as much as possible

Recommendation 1• Develop a back‐up plan to commission the collider rings
without the Interac[on Region components toestablish the required beam current, to carry out low
emi*ance tuning and to approach the required vacuum
by beam scrubbing of the ring
• This plan would be ac[vated in case of delays in delivery of
the interac[on region components to minimize the impact
to the start of the physics program

Recommendation 2• KEK management should con[nue to do everything possible
to ensure that the staﬃng needed for SuperKEKB is madeavailable as soon as possible• Some progress has been made by short‐term and somepermanent hiring, and through collabora[ons withuniversi[es and other ins[tutes, but shortage of qualiﬁed
staﬀ con[nues to be a major risk to successful comple[onof the project, the commissioning and opera[onRecommendations 3 & 4• Develop a clear set of milestones for the produc[on of theIR SC magnets and cryostats so that progress can be
carefully tracked, because the Commi*ee is concerned
about the schedule risk
• Re‐examine the IR Vacuum design to ensure that thevacuum required for the experiment can be obtained in a
reliable way. It is also necessary to ﬁnd suﬃcient space andaccessibility for vital machine elements

Recommendation 5• Develop, with benchmarking, the necessary simula[ontools to study the various cri[cal path beam dynamics
eﬀects aﬀec[ng the SuperKEKB performance• These simula[ons should include at least the 3D IR
modeling, the error eﬀects, dynamic aperture, beam‐beaminterac[on, intrabeam sca*ering, and the outcome ﬁguresof merit will include the achieved luminosity, detector
background, and Touschek life[meRecommendation 6• Con[nue to aggressively pursue the [mely comple[on ofthe components of the injector chain while maintaining theability to simultaneously inject into the PF and AR• Complete hardware demonstra[ons of key components
and simula[ons with the goal of a self‐consistent end‐to‐end descrip[on of the injec[on system that meets all of therequirements