Wireless impedance measurements and fault location on ESRF vacuum chamber assemblies

The TM wave transmission method and a new fully dispersion compensated TE wave time domain reflectometry (TDR) were applied in order to detect and localize discontinuities on already installed subassemblies of the ESRF vacuum chamber. The use of waveguide modes which require no center conductor allowed in-situ inspection of 13 meter long vessels. The waveguide TDR was performed between 2.7 and 4 GHz, where only the fundamental TE wave propagates: the reflection profile was computed using the time domain facility and dispersion compensation of the network analyzer. With both methods, the obtained responses were similar for all comparable subassemblies. (author) 1 ref.; 2 figs