Characteristics of hard x‐ray emission from subpicosecond laser‐produced plasmas

Calibrated thermoluminescence dosimeters have been used to measure the angular and spectral dependence of hard x‐ray emission produced from intense subpicosecond laser irradiation of solid targets. A dosimeter detector set with nine filter channels (13.5–400 keV) has been tested successfully. Total bremsstrahlung conversion up to 0.23% and conversion of 8×10−5 from laser energy to Ta Kα line emission (photon energy ≊57 keV) was determined. The scaling of the hard x‐ray yield with laser intensities ranging from 3×1016 to 3×1018 W/cm2 was investigated.