Multi-channel neutral analyzer-system

Abstract

This is an informal report intended primarily for internal or lim ited external distribution. ThP. opinion~ and conclus ions stated are those of the author and may or may not be those of the laboratory.

Evidence for neutral-beam-injected oxygen impurities in 2XIIB

“…This could result from beam injection of high-energy oxygen, but is unlikely to result from slow collisional heating [7]; the life-time of low-energy impurities is too short. Further evidence that the oxygen is injected by the neutral beams comes from the charge-exchange analyser [8], which is able to resolve the energy components of the neutral beam when the beams are fired into low-pressure neutral gas. A one-tenth energy deuterium component is observed at such times which is consistent with the break-up of D 2 O from the neutral beam [9].…”

Contemporary Instrumentation and Application of Charge Exchange Neutral Particle Diagnostics in Magnetic Fusion Experiments

“…In early devices, to provide both mass and energy analysis capability for charge exchange spectrometers the initial approach was to utilize a magnetic field region for momentum analysis followed by an electrostatic system (typically cylindrical [33] or parallel plate [34] condensers) for energy analysis. In such configurations, the magnetic and electric fields were orthogonal to each other and the resulting instrument had several disadvantages: a) the cylindrical condensers were complicated to fabricate and align, b) the spatially separated magnetic and electrostatic field regions led to relatively large spectrometer dimensions, and c) typically only a single ion species was detected at a time because there were too few channels (~ 5-7) to provide useful measurements of more than one ion species.…”

“…A variation of the superimposed E||B concept in which the parallel magnetic and electric fields were spatially separated was developed for the charge exchange analyzers on the Poloidal Divertor Experiment (PDX) [13], replacing an earlier design based on cylindrical electrostatic plates [33]. Since then, additional variations have improved on the PDX the design [34,35]. A schematic illustrating the concept is shown in Fig.…”