Ultrafast inner shell photo-ionization pumped X-ray emission in C

A new model employing five energy levels and a fit time-varying linear phot o-pumping rate of x-ray source is proposed to analyze the gain of inner-she ll photo-ionization (ISPI) x-ray laser. The deduced analytical expressions for the time of the onset of the peak gain and its peak value reveal the ef fects of Auger decay, electron impact ionization, the density of lasing med ium and the ratio of statistical weights on the duration and peak value of the laser gain, also the requirements on the intensity of the driving USP l aser can be estimated.