Investigation of XUV amplification with Ni-like xenon ions using laser-produced gas puff plasmas

This paper presents results of a study of a gas-puff plasma soft-X-ray amplifier using Ni-like xenon. The target was created by pulsed injection of xenon from a high-pressure solenoid valve through a nozzle in the form of a 2 cm long slit. The plasma was produced by irradiating the gas puff plume with six line-focused laser beams. The uniformity of the plasma column was monitored using a crossed-slit X-ray pinhole camera while the ionisation balance was assessed with the help of keV resonance spectra obtained by a crystal spectrometer. A modest amplification was seen at two J = 0-1 lasing lines allowing however the first precise measurement of their wavelengths. Comparison of the results with a previously reported amplification in the gas-puff system is made, indicating issues essential to the performance of these systems.