LASER PLASMA X-RAY-EMISSION STUDIES USING A PINHOLE TRANSMISSION GRATING SPECTROMETER

The powerful diagnostic capabilities of the pinhole transmission grating spectrometer (PTGS) have been utilized in studying laser plasma soft x-ray (SXR) emission and the following results are presented: (1) Studies of the SXR emission from C, Al, SiO2, Cu, Se, Mo, Sn, Er, W, and Au targets irradiated by a 1.06-mu-m laser beam with average power density 5 x 10(14) W/cm2 and 300 ps duration indicate the strong dependence of the SXR emission on the atomic number Z. (2) Comparative experiments of Al or Au plasma SXR emission show that changes of the laser intensity have a more remarkable influence on low-Z plasma SXR emission than on high Z's. (3) Experiments on target configurations (foil, multilayer, and half-cylindrical-groove target) reveal that the foil target is least effective for short-wavelength SXR emission, while the half-cylindrical target not only converges the plasma in the groove region, but also most effectively enhances the short-wavelength SXR emission or increases the electron temperature therein. (4) The PTGS is also complementarily used with the grazing incidence grating spectrograph in the SXR lasing experiments to determine the essential parameters of the line-focused laser-produced plasmas.