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TY - CONF AU - Lumpkin, A.H. AU - Diaz Cruz, J.A. AU - Edelen, A.L. AU - Edstrom, D.R. AU - Jacobson, B.T. AU - Prieto, P.S. AU - Ruan, J. AU - Thurman-Keup, R.M. AU - Zhou, F. ED - Tavares, Daniel ED - Picoreti, Renan ED - Bruno, Gustavo ED - Marques, Sergio ED - Schaa, Volker R.W. TI - Direct Observations of Sub-micropulse Electron-beam Effects from Short-range Wakefields in TESLA-type Superconducting RF Cavities J2 - Proc. of IBIC2020, Santos, Brazil, 14-18 September 2020 CY - Santos, Brazil T2 - International Beam Instrumentation Conference T3 - 9 LA - english AB - The preservation of the low emittance of electron beams during transport in the accelerating structures of large facilities is an ongoing challenge. In the cases of the TESLA-type superconducting rf cavities currently used in the European X-ray Free-electron Laser (FEL) and the under construction Linac Coherent Light Source upgrade (LCLS-II), off-axis beam transport may result in emittance dilution due to transverse long-range and short-range wakefields (SRW)*. To investigate such effects, experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility with its unique two-cavity configuration after the photocathode rf gun. We used optical transition radiation (OTR) imaging with a UV-visible synchroscan streak camera to display sub-micropulse y-t effects in the 41-MeV beam. The head-tail transverse kicks within the 11-ps-long micropulses were observed at the 100-micron level for steering off-axis in one cavity and several 100 microns for two cavities. Since the SRW kick angles go inversely with energy, these results may inform the commissioning plans of the LCLS-II injector where beam will be injected at ~1 MeV into a cryomodule. PB - JACoW Publishing CP - Geneva, Switzerland SP - 56 EP - 60 KW - cavity KW - electron KW - wakefield KW - laser KW - HOM DA - 2020/10 PY - 2020 SN - 2673-5350 SN - 978-3-95450-222-6 DO - doi:10.18429/JACoW-IBIC2020-TUPP17 UR - https://www.jacow.org/ibic2020/papers/tupp17.pdf ER -