Characterization of MeV proton acceleration from double pulse irradiation of foil targets
Abstract
We report on the experimental characterization of proton acceleration from double-pulse irradiation of um-scale foil targets. Temporally separated sub-picosecond pulses have been shown to increase the conversion efficiency of laser energy to MeV protons. Here, two 700 fs, 1 ω pulses were separated by 1 to 5 ps; total beam energy was 100 J, with 5-20% of the total energy contained within the first pulse. In contrast to the ultraclean beams used in previous experiments, prepulse energies on the order of 10 mJ were present in the current experiments which appear to have a moderating effect on the enhancement. Proton beam measurements were made with radiochromic film stacks, as well as magnetic spectrometers. The effect on electron generation was measured using Kα emission from buried Cu tracer layers, while specular light diagnostics (FROG, reflection spectralon) indicated the laser coupling efficiency into the target. The results obtained will be presented and compared to PIC simulations.
Work by LLNL was performed under the auspices of U.S. DOE under contract DE-AC52-07NA27344.- Publication:
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APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2014
- Bibcode:
- 2014APS..DPPCP8072K