Author: Venturini Delsolaro, W.
Paper Title Page
TU1A05 Seamless Quarter Wave Resonators for HIE ISOLDE 292
 
  • W. Venturini Delsolaro, A. Miyazaki
    CERN, Geneva, Switzerland
 
  The HIE-ISOLDE post accelerator consists of 4 cryomodules with 5 niobium-coated Quarter Wave Reso-nators (QWR) each. The standard manufacturing tech-nique was to machine the inner and outer conductor sepa-rately, to shrink-fit the 2 pieces and to apply an electron beam welding at the interface. Due toμcracks, ob-served on some of the cavities around the welds, we took the decision to explore the possibility of a seamless de-sign. First cavities became available in late 2017 and were then cold-tested in the vertical cryostat. These seam-less coated quarter wave resonators have shown some of the highest Q-values of all HIE-ISOLDE cavities in the acceptance tests. Furthermore, we studied the cavity per-formance with different compensations of the earth mag-netic field and different temperature gradients upon cool down. These tests have demonstrated record-breaking RF surface fields for the Nb/Cu technology. This paper re-views the design and fabrication and reports on the cold tests results of seamless quarter wave resonators, and of possible future applications  
slides icon Slides TU1A05 [30.518 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1A05  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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