Effect of gaunt factor correction in soft x-ray plasma diagnostics

The effect of Gaunt-factor correction on temperature estimation over the range from 100 to 1500 eV had been studied. Greene's (1959) analytical expression for the quantum-mechanical Gaunt factor averaged over a Maxwellian distribution is used. Transmission ratios are calculated with and without the Gaunt factor for various combinations of beryllium foils, taking into account X-ray emission due to free-free transitions. A significant difference (at least about 15%) is observed between the temperatures estimated from classical and quantum-mechanical curves above 600 eV. Selection of foil combinations useful for estimating higher temperatures is also discussed.