JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - CONF AU - Yamamoto, N. AU - Gamelin, A. AU - Marchand, P. AU - Naito, D. AU - Sakanaka, S. AU - Yamaguchi, T. ED - Braun, Hans-Heinrich ED - Chrin, Jan ED - Ganter, Romain ED - Hiller, Nicole ED - Schaa, Volker RW TI - Bunch-lengthening RF System Using Active Normal-conducting Cavities J2 - Proc. of FLS2023, Luzern, Switzerland, 27 August-01 September 2023 CY - Luzern, Switzerland T2 - ICFA Advanced Beam Dynamics Workshop T3 - 67 LA - english AB - Bunch lengthening using a double RF system (fundamental + harmonic cavities) is essential in preserving the extremely low emittance in fourth and future generation synchrotron light rings. Recent studies have revealed that, in many cases, unstable beam motions, as so-called "mode-0" and "periodic transient beam loading" instabilities, prevent from reaching the optimum bunch lengthening condition with low and high beam current, respectively, even in symmetric filling patterns. While reducing the R/Q is beneficial for the latter, it will worsen the former. To achieve an efficient bunch lengthening system, we proposed a promising solution based on a powered TM020-type harmonic cavity with RF feedbacks (RF-FBs)*, as reported at FLS2018. Based on this concept, we are developing both fundamental and harmonic cavities using the TM020 resonant mode**, a kicker cavity having a bandwidth >5MHz***, bunch-phase monitor (BPhM) and RF-FBs. In this presentation, we describe our overall bunch lengthening system including cavity and BPhM designs. We also present particle tracking simulation results demonstrating that the bunch lengthening limitations can be alleviated by means of direct RF-FBs****. PB - JACoW Publishing CP - Geneva, Switzerland SP - 18 EP - 21 KW - cavity KW - kicker KW - synchrotron KW - beam-loading KW - controls DA - 2024/01 PY - 2024 SN - 2673-7035 SN - 978-3-95450-224-0 DO - doi:10.18429/JACoW-FLS2023-MO3B3 UR - http://jacow.org/fls2023/papers/mo3b3.pdf ER -