Characterization of an x-ray-flux source for the production of high-energy-density plasmas

Abstract

The results from a series of experiments that characterize the x-ray flux transmitted through a laserirradiated Au foil are presented. The purpose of the experiments was to develop a working model for anx-ray source that will create hot, dense plasmas with controllable gradients. These plasmas will be used as a test bed for the study of the complex radiative processes that are intrinsic to the evolution of moderateand high-Z matter. The experiments quantitatively measured the timeand frequencydependent energy transferred to the back of the foil. Angular information and the characterization of the flux as a function of foil thickness are also presented. Tables of the time-dependent flux are given.PACS number(s): 52.25.Nr, 52.50.Jm plasmas [5]. Further, the qualities of the emission spectra, i.e. , the quasicontinuous spectral nature and the controllable duration, have proved extremely useful in the development of absorption sources in the x-ray region [6]. Second, the plasma produced by the interaction of the laser with a high-Z material is of interest in the study of laser-rnatter coupling. The formation of gradients, coronal heating, and parametric processes are still the subjects of ongoing investigations [7].Of these studies, a few have been devoted to the x-ray radiation that is transmitted through the back of thin high-Z foils. Investigations were instigated to further understand the energy coupling of the laser to the high-Z 46 7853

Optimization of x-ray sources for proximity lithography produced by a high average power Nd:glass laser

“…Early experiments with 8 ns Nd:glass laser pulses indicated that efficiencies around 8%/27c sr could be achieved;l however, experiments with 30 ns KrF pulses focused to more than 1014 W/cm2 failed to achieve yields comparable to X-ray yields from laser-produced plasmas also depend on measurements with shorter pulses at the same ~ave1ength.l~ A practical limit on the pulse duration of less than about 5 ns was suggested by Chaker et although this conclusion was tentative in the absence of experimental data. The requirements of high average power with high focused intensities and moderate pulse duration are potentially in conflict with the pulse parameters of current high average power laser technology, which operate more reliably with rather long pulse durations in the range of 10 -15 ns duration for Nd:glass technology and 25 -30 ns for excimer lasers.…”

M-L band x-rays (3–3.5 KeV) from palladium coated targets for isochoric radiative heating of thin foil samples

“…In line with the processing method of Phillion and Hailey, the emission is assumed to be uniformly emitted into 4π for calculating conversion efficiency. In reality, the opacity variation of the plasma plume and target as a function of angle should be considered, but for keV x-rays these should be small corrections in the immediate vicinity of the target normal [14,15]. Processes which can lead to anisotropic emission of hard x-rays require laser intensities several orders of magnitude higher than those used here [16].…”

High Energy Density Science at the Linac Coherent Light Source

“…In addition, in Fig. V.D.1 we show lines of constant scattering parameter α = 2 for 180° backscattering, for three probe wavelengths of 60,190, and 5000 Å. Stated differently, for a given plasma temperature, we should be able to access a density that is 6-7 orders of magnitude higher than previously attempted.…”

“…The Au foil is irradiated by a single 1 ns, temporally square-shaped pulse of 0.52 µm light at an intensity of 1.6x10 14 W/cm 2 . [60,61,62] Fig. V.D.4.…”