Gas Detector LCLS Engineering Specifications Document

摘要

There are two Gas Detectors, located upstream and downstream of the FEL attenuation materials, which provide a non-intrusive measure of the FEL pulse energy in the fundamental, in real-time, on a pulse-by-pulse basis. The FEL operators and the users will use this information to monitor the performance of the FEL and the Attenuator and to cross-calibrate other detectors. The Gas Detectors measure the FEL pulse energy by measuring the fluorescence induced in a small volume of N2 gas by the passage of the FEL.