Inner-shell photoionization-pumped x-ray lasers. Boron

A method of producing inversion by multistage x-ray pumping of low-Z elements is described. A detailed numerical model of the physical processes involved has been created and applied to boron. It is shown that significant inversion of the 255-eV Kα transition of hydrogen-like boron may be produced with an optical pump laser, producing on the order of 5 × 10¹⁶ W/cm². Demonstration of x-ray lasing will require a pump laser power of at least 20 TW and the solution of several technological problems which are briefly discussed.