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

作者：Gonnella D^*; Eichhorn R; Furuta F; Ge M; Hall D; Ho V; Hoffstaetter G; Liepe M; O'Connell T; Posen S; Quigley P; Sears J; Veshcherevich V; Grassellino A; Romanenko A; Sergatskov D A

来源：Journal of Applied Physics, 2015, 117(2): 023908.

DOI：10.1063/1.4905681

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(0) of 2.7 x 10(10) at 2.0K 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(0) of 3 x 10(10). The sensitivity of the cavities' residual resistance to ambient magnetic field was determined to be 0.5 n Omega/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.

• 出版日期2015-1-14