Characterisation of a MeV Bremsstrahlung x-ray source produced from a high intensity laser for high areal density object radiography

摘要

Results of an experiment to characterise a MeV Bremsstrahlung x-ray emission created by a short (<10 ps) pulse, high intensity (1.4×10~(19) W/cm~2) laser are presented. X-ray emission is characterized using several diagnostics; nuclear activation measurements, a calibrated hard x-ray spectrometer, and dosimeters. Results from the reconstructed x-ray energy spectra are consistent with numerical simulations using the PIC and Monte Carlo codes between 0.3 and 30 MeV. The intense Bremsstrahlung x-ray source is used to radiograph an image quality indicator (IQI) heavily filtered with thick tungsten absorbers. Observations suggest that internal features of the IQI can be resolved up to an external areal density of 85 g/cm~2. The x-ray source size, inferred by the radiography of a thick resolution grid, is estimated to be approximately 400 lm (full width half maximum of the x-ray source Point Spread Function).