Title :
Non quadratic RF losses in niobium sputter coated accelerating structures
Author :
Durand, C. ; Weingarten, W. ; Bosland, P. ; Mayer, J.
Author_Institution :
Eur. Organ. for Nucl. Res., CERN, Geneva, Switzerland
fDate :
6/1/1995 12:00:00 AM
Abstract :
Low field Q-values of more than 10/sup 10/ and maximum accelerating gradients E/sub a/ between 10 and 15 MV/m have been obtained in superconducting mono-cell and multi-cell accelerating cavities between 350 and 1500 MHz. The superconductor is niobium, which is magnetron-sputtered as a thin film (/spl sim/1-2 /spl mu/m) on a cavity made from copper sheet. The dependence of the slope of Q vs. E/sub a/ on temperature and frequency can be explained by RF magnetic flux trapped within intrinsic defects.<>
Keywords :
accelerator cavities; losses; magnetic flux; niobium; sputter deposition; sputtered coatings; superconducting cavity resonators; superconducting thin films; Cu; Nb; RF magnetic flux; intrinsic defects; low field Q-values; magnetron sputtered coating; nonquadratic RF losses; superconducting accelerating cavities; thin films; Acceleration; Copper; Dielectric losses; Magnetic fields; Magnetic flux; Magnetic losses; Niobium; Radio frequency; Superconducting magnets; Surface resistance;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
