Prepulse effect on laser-induced water-window radiation from a liquid nitrogen jet

Abstract

The authors show the prepulse effect on the conversion efficiency of a visible laser into water-window (lambda=2.3-4.4 nm) x ray from a liquid nitrogen jet. It is observed that a prepulse of only 2 mJ enhances the conversion efficiency by 10-15 times for the main pulse of 15-60 mJ at a delay of 3-6 ns. The photon flux is similar to 1.2x10(12) photons/pulse sr at a delay of 4 ns for a main pulse of 60 mJ with a prepulse of 4-8 mJ. It is noticed that the conversion efficiency increases with the delay up to 3 ns and is then saturated. (c) 2007 American Institute of Physics.