Abstract
A diagnostic for escaping charged fusion products is presently being tested on tokamak fusion test reactor (TFTR). It consists of a 1×1-in. ZnS scintillator screen located inside a movable probe at the bottom of the TFTR vacuum vessel. The alphas or tritons hit the scintillator screen where they create visible light pulses which are fiber-optically coupled to photomultiplier tubes and/or an intensified video camera for recording and analysis.