Operating experiences with the TFTR escaping alpha detectors

Abstract

This paper reviews the operating experiences obtained with a set of scintillator-based escaping fast ion detectors which have been used successfully for several years on the TFTR tokamak. There have been several operational problems which need to be resolved before these detectors are used to measure 3.5 MeV DT alphas in 1993. The main problem has been overheating by edge plasma heat flux for large major radius plasmas, when the detectors were not shadowed by the adjacent limiter. Other problems have been due to runaway electron-induced x-ray flux and scintillator and foil damage.