INCREASING THE EFFICIENCY OF LASER ACCELERATION OF PROTONS USING ULTRA-THIN TARGETS

The results of laser acceleration of protons from aluminum targets 6 μm thick and ultra-thin diamond-like carbon films 100 nm thick when they are irradiated with femtosecond laser pulses with a peak intensity of up to 5 × 1020 W/cm2 are presented. It is shown that decreasing the target thickness from 6 μm to 100 nm does not lead to a significant change in the maximum proton energies, but contributes to an increase in the angular yield and the laser energy conversion coefficient. This effect is due to an increase in the number of protons in the low-energy part of the spectra, which is reflected in a twofold increase in the conversion coefficient.