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 - Posthuma de Boer, D.W. AU - Orton, B.A. AU - Warsop, C.M. AU - Williamson, R.E. ED - Cai, Yunhai ED - Nagaitsev, Sergei ED - Kim, Dong Eon ED - Marx, Michaela ED - Schaa, Volker R. W. TI - Development of an Impedance Model for the ISIS Synchrotron and Predictions for the Head-Tail Instability J2 - Proc. of HB2023, Geneva, Switzerland, 09-13 October 2023 CY - Geneva, Switzerland T2 - ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams T3 - 68 LA - english AB - ISIS is a pulsed, spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. The rapid cycling synchrotron which drives the facility accelerates 3·10¹³ protons-per-pulse from 70 to 800 MeV at 50 Hz, and delivers a mean beam power of 0.2 MW to two target stations. Beam-loss mechanisms must be understood to optimise performance and minimise equipment activation; and to develop mitigation methods for future operations and new accelerators. Substantial beam-losses are driven by a vertical head-tail instability, which has also limited beam intensity. Beam-based impedance measurements suggest the instability is driven by a low-frequency narrowband impedance, but its physical origin remains unknown. More generally, research into the nature of the instability is hindered without a detailed transverse impedance model. This paper presents a survey of vertical impedance estimates for ISIS equipment, using analytical methods, low frequency CST simulations and lab-based coil measurements. The final impedance estimate is then used as an input to a new linearised Vlasov solver, and predicted growth rates compared with previously obtained experimental results. PB - JACoW Publishing CP - Geneva, Switzerland SP - 170 EP - 177 KW - impedance KW - kicker KW - simulation KW - synchrotron KW - coupling DA - 2024/04 PY - 2024 SN - 2673-5571 SN - 978-3-95450-253-0 DO - doi:10.18429/JACoW-HB2023-TUC4I2 UR - https://jacow.org/hb2023/papers/tuc4i2.pdf ER -