Two-filter soft x-ray spectrometer for plasma electron temperature measurement

摘要

The ratio of the intensity of continuum soft x-ray radiation in a selected wavelength region free from line radiation, measured by two different multiple-filter detectors, is used to estimate the electron temperature in a fusion plasma experiment. The detectors are silicon surface barrier diodes, each covered with different filters, selective for the same continuum interval but having different transmission dependencies on temperature. The ratio of the signal intensity is then temperature dependent but independent of plasma density. A criterion for the ratio method to be dependable is that the wave length region observed must be free from line radiation since the ratio of line radiation intensities would be dependent on species density as well as temperature. The wavelength region selected is 45-70 Aa which is free of oxygen and carbon line radiation, which are the dominant impurities in many fusion plasma experiments. The electron temperature range suitable for measurement is dependent on the filter parameters. Two cases have been developed which are suitable for temperature ranges of 50-150 eV and 100-300 eV. The electron temperature measurements are in good agreement with Thomson scattering measurements and measurements derived from line ratios in the vacuum ultraviolet wavelength region. (authors). (Atomindex citation 24:062806)