The DIII-D E∥B charge exchange diagnostic
Published Web Locationhttps://doi.org/10.1063/1.1140131
One of the neutral-particle spectrometers used on the Doublet III tokamak has been improved and modified for use as an active charge exchange diagnostic on the DIII-D tokamak. The spectrometer employs a He stripping cell, parallel E and B analyzer fields, and a microchannel-plate detector with 60 energy channels for each of two neutral-particle masses. Improvements to the diagnostic include better radio frequency and γ-ray shielding and complete instrumentation of all energy channels. Calibration results for H and D are similar to those reported previously. The instrument views across one of the DIII-D heating beams which can be modulated to provide local neutral doping. The analyzer is scanned shot to shot to measure neutrals with pitch angles between ∼5° and ∼110°.