Beam Feedback System Challenges at SuperKEKB Injector Linac

The SuperKEKB electron/positron asymmetric collider, currently under construction, is designed to elucidate new physics beyond the standard model of elementary particle physics. This goal will only be achieved by precise measurements with a luminosity that is 40 times as high as that of the KEKB. The injector linac is to be upgraded to enable a beam size of 50 nm at the collision point, which is 20 times smaller than that of the KEKB, and a doubling of the stored beam current with a short lifetime of 10 min. At the same time, two light-source rings, the PF and PF-AR, will befilled in top-up injection mode. To this end, the linac will need to be operated with precise beam controls. Duallayer controls with EPICS and MRF event systems are being enhanced to support precise pulse-to-pulse beam modulation (PPM) at 50 Hz. A virtual accelerator (VA) concept is introduced here to enable a single linac to be modeled as four VAs switched by PPM, where each VA corresponds to one of the four top-up injections into the storage rings. Each VA is associated with independent beam orbit and energy feedback loops to maintain the required beam qualities. The requirements of the SuperKEKB HER and LER for the beam emittance, energy spread, and charge are especially challenging.

[1]  Noboru Yamamoto,et al.  Achievements of KEKB , 2013 .

[2]  Toshihiro Mimashi,et al.  Accelerator design at SuperKEKB , 2013 .

[3]  K. Mikawa,et al.  Accelerator control system at KEKB and the linac , 2012, 1211.5768.

[4]  Tsuyoshi Suwada,et al.  PULSE-TO-PULSE BEAM MODULATION AND EVENT-BASED BEAM FEEDBACK SYSTEM AT KEKB LINAC , 2010, 1006.2543.

[5]  Kazuro Furukawa,et al.  Beam-commissioning study of high-intensity accelerators using virtual accelerator model , 2009 .

[6]  Yukinori Kobayashi,et al.  The KEKB injector linac , 2003 .

[7]  J. Seeman.  SLC beam dynamics issues , 1991 .

[8]  J. Potier,et al.  Pulse to Pulse Modulation of the CERN PS Complex , 1977, IEEE Transactions on Nuclear Science.

[9]  T. Natsui,et al.  LONGITUDINAL MANIPULATION TO OBTAIN AND KEEP THE LOW EMITTANCE AND HIGH CHARGE ELECTRON BEAM FOR SUPERKEKB INJECTOR , 2013 .

[10]  M. Liu,et al.  DEVELOPMENT STATUS OF SINAP TIMING SYSTEM , 2013 .

[11]  Tsuyoshi Suwada,et al.  DEVELOPMENT AND APPLICATION OF THE TRIGGER TIMING WATCHDOG SYSTEM IN KEK ELECTRON/POSITRON LINAC , 2013 .

[12]  Yoshio Arakida,et al.  HIGH-INTENSITY AND LOW-EMITTANCE UPGRADE OF 7-GeV INJECTOR LINAC TOWARDS SuperKEKB , 2013 .

[13]  Kazuro Furukawa,et al.  DEVELOPMENT OF HIGH PRECISION BEAM POSITION MONITOR READOUT SYSTEM WITH NARROW BANDPASS FILTERS FOR THE KEKB INJECTOR LINAC TOWARDS THE SUPERKEKB , 2013 .

[14]  Makoto Tobiyama,et al.  Upgrade of Event Timing System at SuperKEKB , 2013 .

[15]  M. Iwasaki,et al.  Design and Status of the SuperKEKB Accelerator Control System , 2013 .

[16]  Kazuro Furukawa,et al.  Upgrade of BPM DAQ System for SuperKEKB Injector Linac , 2013 .

[17]  Yoshio Arakida,et al.  HIGH-INTENSITY AND LOW-EMITTANCE UPGRADE , 2013 .

[18]  Kazuro Furukawa,et al.  DEVELOPMENT OF FAST CONTROLS FOR BEAM WIRE SCANNER FOR SuperKEKB , 2012 .

[19]  Tsuyoshi Suwada,et al.  NEW EVENT-BASED CONTROL SYSTEM FOR SIMULTANEOUS TOP-UP OPERATION AT KEKB AND PF , 2009 .

[20]  XX International Linac Conference, Monterey, California BEAM SWITCHING AND BEAM FEEDBACK SYSTEMS AT KEKB LINAC , 2022 .