Measurement of temporal durations of transient collisional excitation X-ray lasers

Abstract

We have measured temporal durations of Ni-like transient collisional excitation X-ray lasers (4d→4p, J=0→1) using a high-speed X-ray streak camera coupled with a flat field grating spectrometer. The pumping laser pulse consisted of a 400-ps prepulse and a 4.8-ps main pulse derived from a Nd:glass laser system with chirped pulse amplification. A quasi-traveling-wave pumping using a six-step mirror was adopted to synchronize the X-ray laser pulse and the onset of gain in a plasma medium. The X-ray laser outputs from three different materials, silver (Z=47), palladium (Z=46) and molybdenum (Z=42), showed that the X-ray laser duration became shorter as the atomic number decreased.