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Title: Nitrogen-doped 9-cell cavity performance in a test cryomodule for LCLS-II

The superconducting RF linac for Linac Coherent Light Source-II calls for 1.3 GHz 9-cell cavities with an average intrinsic quality factor Q{sub 0} of 2.7 × 10{sup 10} at 2.0 K and 16 MV/m accelerating gradient. Two niobium 9 cell cavities, prepared with nitrogen-doping at Fermilab, were assembled into the Cornell Horizontal Test Cryomodule (HTC) to test cavity performance in a cryomodule that is very similar to a full LCLS-II cryomodule. The cavities met LCLS-II specifications with an average quench field of 17 MV/m and an average Q{sub 0} of 3 × 10{sup 10}. The sensitivity of the cavities' residual resistance to ambient magnetic field was determined to be 0.5 nΩ/mG during fast cool down. In two cool downs, a heater attached to one of the cavity beam tubes was used to induce large horizontal temperature gradients. Here, we report on the results of these first tests of nitrogen-doped cavities in a cryomodule, which provide critical information for the LCLS-II project.
Authors:
; ; ; ; ; ; ; ; ; ; ; ;  [1] ; ; ;  [2]
  1. CLASSE, Cornell University, Ithaca, New York 14853 (United States)
  2. FNAL, Batavia, Illinois 60510 (United States)
Publication Date:
OSTI Identifier:
22412823
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 2; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CAVITY RESONATORS; DOPED MATERIALS; FERMILAB; GHZ RANGE; LIGHT SOURCES; LINEAR ACCELERATORS; MAGNETIC FIELDS; NIOBIUM; NITROGEN; PERFORMANCE; PERFORMANCE TESTING; QUALITY FACTOR; SUPERCONDUCTING MAGNETS; TEMPERATURE GRADIENTS