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TY - CPAPER AU - Marhauser, F. AU - Ament, L.J.P. AU - Benson, S.V. AU - Douglas, D. TI - Suppression of Upstream Field Emission in RF Accelerators J2 - Proc. of International Conference on RF Superconductivity (SRF2015), Whistler, BC, Canada, Sept. 13-18, 2015 AB - So-called electron loading is the primary cause for cavity performance limitations in modern RF accelerating cavities. In superconducting RF cavities in particular, the onset of parasitic electron effects may start at field levels as low as a few MV/m. Electron loading can be attributed to mainly three phenomena: field emission, multiple impact electron amplification, and RF electrical breakdown. Field emission has been a persistent issue despite advances in SRF technology, whereas RF electrical breakdown and multipacting can be controlled by appropriate cavity design choices. Field emission becomes a major concern when the electrons emitted are captured by the accelerating RF field and directed along the beam axis through a series of cavities or even entire cryomodules. Consequently, electrons can accumulate energy comparable to that of the main beam over similar distances. This can represent a considerable dark current, which can travel downstream or upstream depending on the field-emitting site of origin. In this paper, a method is presented that can significantly suppress the upstream field emission by design. PB - JACoW CY - Geneva, Switzerland SP - 246 EP - 249 KW - electron KW - cavity KW - cryomodule KW - SRF KW - site DA - 2015/12 PY - 2015 SN - 978-3-95450-178-6 DO - 10.18429/JACoW-SRF2015-MOPB061 UR - http://srf2015.vrws.de/papers/mopb061.pdf ER -