The Sandia Laser Plasma Extreme Ultraviolet And Soft X-Ray (XUV) Light Source

Abstract

Laser produced plasmas have been shown to be extremely bright sources of extreme ultra-violet and soft x-ray (XUV) radiation; however, certain practical difficulties have hindered the development of this source as a routinely usable laboratory device. To explore solutions to these difficulties, Sandia has constructed an XUV laser plasma source (LASPS) with the intention of developing an instrument that can be used for experiments requiring intense XUV radiation from 50-300 eV. The driving laser for this source is a KrF excimer with a wavelength of 248 nm, divergence of 200 jtrad, pulse width of 23 ns at 20 Hz and typical pulH energy of 500 mJ which allows for good energy coupling to the plasma at mgderate (10¹² W/cm²) power densities. This source has been pulsed approximately 2 x 10⁵ times, demonstrating good tolerance to plasma debris. The source radiates from the visible to well above 1000 eV, however, to date attention has been concentrated on the 50-300 eV region. In this paper, spectral data and plasma images for both stainless steel and gold targets are presented with the gold target yielding a 200 μ, plasma and reradiating 3.9% of the pump energy into 15-73 eV band, a flux of 1.22 x 10 photons/pulse/eV into 2n sr. Further efforts will expand these measurements to rare earth targets and to higher spectralenergies. A special high throughput wide angle XUV (50-300 eV) monochromator and associated optics is being concurrently developed to collect the plasma radiation, perform energy dispersion and focus the radiation onto the experimental area.