CERN LHC Project Report 115 (1997),
presented at the IEEE Particle Accelerator Conference (session 2B-8), Vancouver, 1997
Surface Resistance Measurements for the LHC Beam Screen
F. Caspers, M. Morvillo and F. Ruggiero
May 1997
Abstract:
A critical review of resistive losses in the LHC beam screen, taking into
account anomalous skin effect and surface roughness, has triggered a
programme of surface resistance measurements at different temperatures,
frequencies and magnetic field intensities. The aim is to establish a realistic
heating budget for the LHC cryogenic system and to optimize
the fabrication process for the copper coating of the
beam screen. Preliminary results at cryogenic temperatures
(without magnetic field) indicate
a surface resistance about a factor two larger than previously estimated:
an absolute measurement precision of a few per cent is reached by comparing
the quality factors of even and odd TEM modes in a cylindrical
structure with two inner conductors.
F. Ruggiero
Wed May 21 17:11:35 1997