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TY - CONF AU - Fisher, A.S. AU - Balakrishnan, N. AU - Brown, G.W. AU - Chin, E.P. AU - Cobau, W.G. AU - Dusatko, J.E. AU - Jacobson, B.T. AU - Kwon, S. AU - Mock, J.A. AU - Park, J. AU - Pigula, J. AU - Rodriguez, E. AU - Rudolph, J.I.D. AU - Sanchez, D. AU - Sapozhnikov, L. AU - Welch, J.J. ED - Schaa, Volker R.W. ED - Batten, Tonia ED - Bree, Michael ED - Petit-Jean-Genaz, Christine ED - Hunter, Darren TI - Commissioning the Beam-Loss Monitoring System of the LCLS Superconducting Linac J2 - Proc. of IBIC2023, Saskatoon, Canada, 10-14 September 2023 CY - Saskatoon, Canada T2 - International Beam Instrumentation Conference T3 - 12 LA - english AB - A 4-GeV superconducting linac has been added to the LCLS x-ray FEL facility at SLAC. Its 120-kW, 1-MHz beam requires new beam-loss monitors (BLMs) for radiation protection, machine protection, and diagnostics. Long radiation-hard optical fibres span the full 4 km from the electron gun of the SC linac to the final beam dump. Diamond detectors at anticipated loss points provide local protection. Detector signals are continuously integrated with a 500-ms time constant and compared to a loss threshold. If crossed, the beam is halted within 0.1 ms. Commissioning began in March 2022 with the 100-MeV injector and with RF processing of the cryomodules. At IBIC 2022 last September, we presented commissioning results from the injector BLMs. In October, the beam passed through the full linac and the bypass transport line above the LCLS copper linac, stopping at an intermediate dump. In August it continued through the soft x-ray undulator and achieved first lasing. Here we present BLM commissioning at energies up to 4 GeV and rates up to 100 kHz. We discuss measurements and software using the fast diagnostic-waveform output to localize beam losses and to detect wire-scanner signals. PB - JACoW Publishing CP - Geneva, Switzerland SP - 187 EP - 190 KW - linac KW - gun KW - cryomodule KW - MMI KW - radiation DA - 2023/12 PY - 2023 SN - 2673-5350 SN - 978-3-95450-236-3 DO - doi:10.18429/JACoW-IBIC2023-TUP005 UR - https://jacow.org/ibic2023/papers/tup005.pdf ER -