Experimental demonstration of laser to x-ray conversion enhancements with low density gold targets

Abstract

The enhancement of laser to x-ray conversion efficiencies using low density gold targets [W. L. Shang, J. M. Yang, and Y. S. Dong, Appl. Phys. Lett. 102, 094105 (2013)] is demonstrated. Laser to x-ray conversion efficiencies with 6.3% and 12% increases are achieved with target densities of 1 and 0.25 g/cm3, when compared with that of a solid gold target (19.3 g/cm3). Experimental data and numerical simulations are in good agreement. The enhancement is caused by larger x-ray emission zone lengths formed in low density targets, which is in agreement with the simulation results.

Expected X-ray dose rates resulting from industrial ultrafast laser applications

“…As seen in [11,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] the plasma properties k B T h , Z i , and n h are complicated functions of space and time. However, for this work it is assumed that the predominant part of the Bremsstrahlung emission in the part of the spectrum of interest is produced by the hot electrons, during the laser pulse, and at a constant hot-electron temperature in…”

“…Such high laser irradiances lead to hot-electron temperatures in the plasma of up to several keV [11] that result in Bremsstrahlung, recombination and line emission in the keV X-ray region. X-ray emission from laser-produced plasma is well known and has been investigated since the early 1980ies [12][13][14][15][16][17][18][19][20][21][22][23]. X-rays emitted from laser-induced plasma were used, in particular, in indirect driven fusion and X-ray laser research, later also for X-ray lithography and X-ray spectroscopy.…”

“…The conversion efficiency was investigated and optimized in particular for laser irradiances in the range of 10 14 W/cm 2 up to more than 10 20 W/cm 2 , with the plasmas produced in a vacuum chamber, e.g. [18][19][20][21][22][23].…”

Detailed investigation on x-ray emission from laser driven high-Z foils in a wide intensity range : role of conversion layer and reemission zone

“…In the context of indirect drive ICF scheme, use of short wavelength laser [10][11][12][13][14][15] , high-Z targets 16,17 , long pulse duration 18,19 , mixture/cocktail [20][21][22][23][24][25] are proposed to enhance the conversion efficiency in the range of multi-eV to multi-keV. Recently, various other methods like CH foam coated gold targets 26 , low density high-Z foam target 27,28 , double foil (DF) target 29 , counter propagating (CP) laser beams irradiation 30 , sandwiched target [31][32][33] , multi-layer target 34 and DF target irradiated with CP laser beams 35 are considered to increase the conversion efficiency. In the field of multi-keV emission, different types of target geometries, including pre-exploded metallic thin foils 36,37 , high-Z liner 38 , mid-Z or high-Z doped aerogels 39,40 , etc.…”

Synthesis, Microstructure, and Catalytic Performance of Monolithic Low‐Density Porous Au

“…Among the porous materials, low‐density porous Au (LPG) has attracted the most attention, as it retains the advantages of noble metals . Particularly, both theoretical and experimental studies using laser‐plasma interactions have shown that LPG targets have higher laser energy absorption rates (≈6%), lower ion kinetic energy, and 1.34 times higher laser to X‐ray conversion efficiency (CE) than solid Au targets . Therefore, LPG bulks can be applied to many fields, in which X‐ray sources play important roles.…”