Spectrum method to measure compositions of diagnostic 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 of diagnostic neutral beam(DNB) on HT-7 Tokamak.According to the Doppler effect,the multi-peak H_α spectra 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 component are 15%,42%,35% and 8% respectively.