The effect of the instrument function on Doppler ion temperature measurements

Abstract The measurement of ion temperatures from the Doopler broadening of spectral lines is discussed. Calculations are used to show that the shape of the instrument function of the spectrometer can have a significant effect on the measured value, even when the broadening is large (∼10X) compared with the half-width of the instrument function. The discussion is illustrated by the optical example of measurements made using an XUV grating spectrometer.