Experimental study of proton emission from 60-fs, 200-mJ high-repetition-rate tabletop-laser pulses interacting with solid targets

Measurements of proton emission have been made from a variety of solid targets irradiated by a 60-fs, 200-mJ, 7 x 10(18)-W cm(-2) laser system operating at 2 Hz. Optimum target conditions were found in terms of target material and thickness. For Mylar targets of thickness 20-40 microm, a maximum proton energy of 1.5 MeV was measured. For aluminum targets, a maximum energy of 950 keV was measured for 12 microm, and for copper, 850 keV for 12.5 microm.