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TY - CONF AU - Aoyagi, H. AU - Furukawa, Y. AU - Takahashi, S. ED - Tavares, Daniel ED - Picoreti, Renan ED - Bruno, Gustavo ED - Marques, Sergio ED - Schaa, Volker R.W. TI - Inclined X-ray Beam Position Monitors to Reduce Influence of Filling Pattern for the SPring-8 Photon Beamlines J2 - Proc. of IBIC2020, Santos, Brazil, 14-18 September 2020 CY - Santos, Brazil T2 - International Beam Instrumentation Conference T3 - 9 LA - english AB - The X-ray beam position monitors (XBPMs) equipped with blade-type detector heads in SPring-8, which operate in photoemission mode, are required to withstand severe high heat loads. In addition, they must work in a variety of several-bunch mode operations. However, as bunch current in the storage ring increased, influence of bunch filling patterns on XBPM performance increased year by year. We have performed a systematic evaluation of the influence of the filling patterns. We found that the cause of the influence is suppression of the XBPM current signal due to the space charge effect, and that it can be quantified by observing the behavior of the current signal while changing the voltage of a photoelectron collection electrode*. We have designed and manufactured new blade-type detector heads in inclined configuration for the purpose of mitigation the space charge effect**. It has been demonstrated that the influence of filling patterns is reduced to a few um. We also report that, as a result of a series of efforts against existing XBPMs for all ID beamlines, the influence has been reduced to about 5 um RMS. PB - JACoW Publishing CP - Geneva, Switzerland SP - 37 EP - 40 KW - operation KW - space-charge KW - storage-ring KW - electron KW - photon DA - 2020/10 PY - 2020 SN - 2673-5350 SN - 978-3-95450-222-6 DO - doi:10.18429/JACoW-IBIC2020-TUPP06 UR - https://www.jacow.org/ibic2020/papers/tupp06.pdf ER -