5-20 KEV LASER-INDUCED X-RAY GENERATION AT 1 KHZ FROM A LIQUID-JET TARGET

We report ultrashort pulse, 1 kHz repetition rate x-ray generation in. the 5-20 keV spectral region, induced by the interaction of laser rad iation with copper nitrate solution and ethylene glycol liquid-jet tar gets. The characteristics of the copper nitrate source are relevant fo r application to time-resolved x-ray diffraction studies as well as fo r spectroscopic x-ray absorption studies. The x-ray sources were opera ted uninterrupted for in excess of 5 h with no detectable buildup of d ebris on the associated optics. The x-ray flux generated by both sourc es is estimated to be of the order of 10(6) photons s(-1) sr(-1) in th e 5-20 keV region. The spectra have been measured with both a PIN phot odiode, and with transmission measurements taken using aluminum filter s. We find that the plasma emission has a broadband component attribut ed to bremsstrahlung emission, with the bulk of the x-ray emission emi tted from the chamber lying between 5 and 20 keV for both sources. The copper nitrate emission, however, delivers a dominant emission peak a t 9 keV, attributed to the characteristic K emission of copper. (C) 19 98 American Institute of Physics. [S0034-6748(98)01009-0]