Fast Proton Generation from Ultrashort Laser Pulse Interaction with Double-Layer Foil Targets

The results of studies of fast-proton generation from foil targets irradiated by 1-ps laser pulse at 10¹⁷0ex0exW/cm² are presented. It is shown that a considerable increase in proton energy and current is possible when a double-layer foil target containing a high- Z layer and a low- Z hydrogen-rich layer is used instead of a single-layer target. Proton energies and current increase with the Z of the high- Z layer and depend essentially on the target and the layer thicknesses. Above 10⁹ forward-emitted protons of energy >1000ex0exkeV have been recorded within a cone angle <3^∘.