GENERATION OF INCOHERENT PICOSECOND X-RAY PULSES - RESONANT PRODUCTION AND ADVANTAGE OF USING THIN-FILMS

The feasibility of using thin, freely suspended films as a target in f emtosecond laser-produced plasma (FLP) experiments is discussed. The c onditions for producing a significant increase in the FLP temperature (as much as a few kilo-electron-volts) are determined by use of a simp le numerical code. An increase in temperature leads to an increase in x-ray yield as well as to a shift of the x-ray spectrum toward shorter wavelengths. The experimental results on soft-x-ray generation from F LP on resonance lines of highly stripped hydrogenlike and heliumlike b oron ions are supported by results obtained with this code. FLP is als o analyzed as a source of soft x-rays, particularly in the 2-4-nm regi on (the so-called water window). (C) 1996 Optical Society of America