Enhanced fluorescence from x-ray line coincidence pumping of K-pumped Cl and Mg-pumped Ge plasmas

Abstract

Many resonant photo-pumped X-ray laser schemes that use a strong pump line such as Ly-a or He-a to populate the upper laser state of a separate lasing material have been proposed over the last four decades but none have been demonstrated. As a first step to creating a photo-pumped X-ray laser we have decided to reinvestigate some of these schemes at the Orion laser facility with the goal to show enhanced fluorescence. In particular we look at using the Ly-a or He-a K lines to pump the 1s-3p and 4p transitions in H-like Cl and see fluorescence on the 4f-3d line at 65 Å and the 3d-2p line at 23 Å. Preliminary experiments are presented that show a modest enhancement. As an alternative we also look at enhancing the 2p-2s line in Ne-like Ge at 65Å using the Ly-a Mg line to photo-pump the 2s-3p line of Ne-like Ge. Calculations are presented that suggest modest enhancements of 2.5.

X-ray-line coincidence photopumping in a potassium-chlorine mixed plasma

“…This will occur when the emission lines are resonant, i.e., close enough in energy. LCP was one of the original mechanisms proposed for demonstrating lasing at x-ray wavelengths [1,2]. Strong Ly α or He α emission from a laser produced plasma was sought to efficiently force a population inversion in a lasing ion, which then decays via intermediary states to the ground.…”