Keyword: data-analysis
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WEPFDV004 A New Model for Q-Slope in SRF Cavities: RF Heating at Multiple Josephson Junctions at Weakly Linked Grain Boundaries or Dislocations cavity, SRF, ECR, electron 556
  • K. Saito
    KEK, Ibaraki, Japan
  • K. Saito
    FRIB, East Lansing, Michigan, USA
  Several models are already proposed for Q-slopes in SRF cavity performance, medium field Q-slope (MFQS), high field Q-slope (HFQS). However, these does not explain both in a way unified. Here, a new model by multiple Josephson junctions on weakly linked grain boundaries or dislocations is proposed for the unified explanation. This model suggests two kind of junctions: ceramic like one and weak superconductor one. If plotted the field vs. RF power dissipation, an increase of RF loss is remarkably observed in proportional to the cube of fields, on both BCP’ed and EP’ed cavity (MFQS). An exponential RF dissipation is often observed at high fields for BCP’ed cavity (HFQS). If supposed the number of J-junctions linearly increases with the fields (this is explained by the flux quantum penetration condition), these behaviors are easily explained. In addition, this model has a potential to explain the anti-Q slope behavior observed in Nitrogen doped or mid-temperature baked cavity. In this paper, this model will be explained, then several data analysis results will be presented.  
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About • Received ※ 21 June 2021 — Accepted ※ 11 November 2021 — Issue date; ※ 16 May 2022  
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