Design and calibration of the fast ion diagnostic experiment detector on the poloidal divertor experiment

A special purpose charge-exchange analyzer was constructed to measure the spatial distribution of hot-plasma ions, as a function of energy and time, in the poloidal divertor experiment (PDX). The fast neutrals produced by charge exchange within the tokamak are reionized as they pass through a helium stripping cell in the detector. The energies of these ions are determined by the trajectories they follow between cylindrical deflection plates which are set at known electrostatic potentials. We describe the technique used to calibrate the response of this system as it depends on the energies and the masses of the particles which are being detected.