Abe Tetsuo
MOPL072
Observation of sudden beam loss in SuperKEKB
716
SuperKEKB suffers from sudden beam loss(SBL) during operation. It causes collimator damage, QCS quench and large beam background to the Bell-II detector. Beam aborts triggered by SBL hinder us from storing large beam current. Since cause of SLB is unclear, we launched an effort to investigate it and consider measures to be taken. In this paper, we discuss phenomena of SBL and various hypotheses to explain SBL.
  • H. Ikeda, T. Abe, H. Fukuma, T. Ishibashi, T. Koga, H. Kaji, H. Nakayama, Y. Suetsugu, S. Terui, M. Tobiyama
    High Energy Accelerator Research Organization
  • M. Aversano, K. Yoshihara
    Nagoya University
  • Y. Funakoshi, G. Mitsuka
    KEK
  • Y. Liu
    Sokendai, the Graduate University for Advanced Studies (Sokendai)
Paper: MOPL072
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-MOPL072
About:  Received: 03 May 2023 — Revised: 12 May 2023 — Accepted: 20 Jun 2023 — Issue date: 26 Sep 2023
Cite: reference for this paper using: BibTeX, LaTeX, Text/Word, RIS, EndNote
WEPA118
Upgrades of S-band Accelerating Structures and Pulse Compressors in the Electron and Positron Injector Linac of KEK
2932
New S-band disk-loaded TM01-2pi/3-travelling-wave structures and pulse compressors have been developed for upgrades of the injector linac for SuperKEKB and Photon-factory storage rings in KEK. The structures 2-m long have ingenious disk irises with oval fillets reducing discharge in high-power operation and modulations in radius suppressing beam break-up instabilities arising from HEM11 wakefields. The pulse compressors are of compact spherical-cavity-type resonating at the degenerate TE112 dipole modes with a high Q-value of 98,000 and yield a peak power gain of 6.2. The structures generate an acceleration gradient of 25.9 MV/m in power operation of 40 MW by using the pulse compressor and stably accelerate a two-bunch beam with a bunch charge of 4 nC.
  • H. Ego, T. Abe, Y. Higashi, T. Higo, T. Yoshimoto
    High Energy Accelerator Research Organization
  • Y. Bando
    Sokendai, the Graduate University for Advanced Studies
Paper: WEPA118
DOI: reference for this paper: 10.18429/JACoW-IPAC2023-WEPA118
About:  Received: 02 May 2023 — Revised: 10 May 2023 — Accepted: 16 Jun 2023 — Issue date: 26 Sep 2023
Cite: reference for this paper using: BibTeX, LaTeX, Text/Word, RIS, EndNote