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Title: Simulation of non-linear rf losses derived from characteristic Nb topography

A simplified model has been developed to simulate non-linear RF losses on Nb surfaces exclusively due to topographical enhancement of surface magnetic fields. If local sharp edges are small enough, at locations where local surface fields exceed Hc, small volumes of material may become normal conducting without thermal leading to quench. These small volumes of normal material yield increases in the effective surface resistance of the Nb. Using topographic data from typical BCP?d and EP?d fine grain niobium surfaces, we have simulated field-dependent losses and found that when extrapolated to resulting cavity performance, these losses correspond well to characteristic BCP/EP high field Q0 performance differences for fine grain Nb. We describe the structure of the model, its limitations, and the effects of this type of non-linear loss contribution on SRF cavities.
 [1] ; ;  [2]
  1. JLAB
  2. W&M. JLAB
Publication Date:
OSTI Identifier:
Report Number(s):
JLAB-ACC-13-1800; DOE/OR/23177-2769
DOE Contract Number:
Resource Type:
Resource Relation:
Conference: SRF 2013, 23-27 Sept 2013. Paris, France
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States