MeV proton beams generated by 3 mJ ultrafast laser pulses at 0.5 kHz

Abstract

Well-collimated proton beams are generated from bulk glass along the target normal direction by tightly focused 55 fs, 3 mJ pulses from a laser operating at 0.5 kHz repetition rate. Proton beams with energies of >265 keV have an emission angle of about 16° full width at half maximum. Spectral measurements indicate proton energies exceeding 0.5 MeV with a flux of 3.2×109 s−1 sr−1 and the flux of measured protons with energies of greater than 90 keV is 8.5×1011 s−1 sr−1 on center.