Flashbox Compact Beam Spectometer and its Application to the High-Gradient Acceleration Study

A Flashbox compact spectrometer has been developed for the Two-beam Test Stand (TBTS), which is a part of the CLIC test facility CTF3 at CERN. It is used to study RF breakdown currents emitted from high gradient X-band accelerating structures being prototyped in the TBTS. The Flashbox is built around the beam tube such that an electron beam can pass to be accelerated in the accelerating structure while charged particles emitted from the structure can be intercepted on the spectrometer consisting of detector plates aligned along the beam axis in combination with magnetic and electric fields. The Flashbox has made it possible to identify electrons and ions emitted by the accelerating structure during RF breakdowns. We describe the Flashbox and first results.