Profile correction to electron temperature and enhancement factor in soft x-ray pulse-height-analysis measurements in tokamaks

Because soft x-ray pulse-height-analysis (PHA) spectra contain chordal information, the electron temperature and the radiation intensity (enhancement factor) measurements do not represent the local values. Assuming that the profile Ansatz for the electron temperature and density is of the form n/sub eo/[1-(ra)2]/sup α/ and kT/sub eo/[1--(ra)2]/sup β/, we obtain the correction factors for the electron temperature and the enhancement factor as a function of the profile coefficients α and β and the energy at which the evaluation was made. The corrected values of the temperature are typically between 1 to 10% higher than the values derived from the raw chordal spectra. We also correct the measured radiation intensity for the profile effects. Finally, the spectrum distortion due to pulse pile-up effects is evaluated. A set of curves is given from which the distortion of the spectrum can be obtained, if the electron temperature, the Be or Al filter thickness, and the electronic parameters of the acquisition system are known. 7 refs., 23 figs