Research On Spectrum Method To Measure Compositions Of Diagnostic Neutral Beam For HT-7

Diagnostic neutral beam (DNB) is an important diagnostic tool for Tokamak physics. It could get the operation parameter of the plasma through the interaction between beam produced by diagnostic neutral device and plasma from Tokamak . In order to reach the best state of plasma, it is readjusted to the operation parameter of Tokamak.This paper has introduced the systemaic device of Diagnostic Neutral Bean and overall analyzed the function of G-M refrigeration in DNB system . At the same time, it has explained the principle of spectrum-measurement. Through the spectrometer to measure the reliable data ,using the procedure to analyse those data would obtain the composition of the neutral beam.An optical spectroscopy based on Doppler shift is applied to measuring energy and the percentages of the four energy component-the full energy , half energy ,third energy and the eighteenth energy (E,E/2,E/3 and E/18) of diagnostic neutral beam(DNB)on HT-7 Tokamak. According to the Doppler effect, the multi-peak H_αspectra is obtained, which are emitted by the neutral beam and separated from the unshifted H_α. Both the measurement principle and the data processing algorithm are presented in this paper. The experimental results of DNB show the percentages of the four energy components are 15%,42%,35%and8% respectively.