Bench measurements of low frequency transverse impedance

Abstract

For frequencies below 10 MHz the classical two wire transmission line method is subject to difficulties in sensitivity and measurement uncertainties. Thus for evaluation of the low frequency transverse impedance properties of the LHC dump kicker a modified version of the two wire transmission line has been used. It consists, in the present case, of a 10 turn loop of approximately 1 meter length and 2 cm width. The change of input impedance of the loop is measured as a function of the surroundings and by using a proper reference (metallic beampipe) these changes are converted into a meaningful transverse beam coupling impedance. Measurements of several calibration objects have shown close agreement with theoretical results. For frequencies below 10 MHz the classical two wire transmission line method is subject to difficulties in sensitivity and measurement uncertainties. Thus for evaluation of the low frequency transverse impedance properties of the LHC dump kicker a modified version of the two wire transmission line has been used. It consists, in the present case, of a 10 turn loop of approximately 1 meter length and 2 cm width. The change of input impedance of the loop is measured as a function of the surroundings and by using a proper reference (metallic beam pipe) these changes are converted into a meaningful transverse beam coupling impedance. Measurements of several calibration objects have shown close agreement with theoretical results. EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH CERN -AB Division

Impedance measurements of the extraction kicker system for the rapid cycling synchrotron of China Spallation Neutron Source

“…9. With the measured input impedances for DUT and REF, the transverse impedance can be expressed as [33]…”