Characterization of a picosecond laser generated 4.5keV TiK-alpha source for pulsed radiography

Abstract

K α radiation generated by interaction of an ultrashort (1ps) laser with thin (25μm) Ti foils at high intensity (2×1016W∕cm2) is analyzed using data from a spherical Bragg crystal imager and a single hit charge-coupled device spectrometer together with Monte Carlo simulations of Kα brightness. Laser to Kα and electron conversion efficiencies have been determined. We have also measured an effective crystal reflectivity of 3.75±2%. Comparison of imager data with data from the relatively broadband single hit spectrometer has revealed a reduction in crystal collection efficiency for high Kα yield. This is attributed to a shift in the K-shell spectrum due to Ti ionization.