DIFFERENTIAL ABSORPTION SPECTROMETER FOR PULSED BREMSSTRAHLUNG

We describe a differential absorption spectrometer that measures the energy spectrum (from 20 to 800 keV) of flash x rays whose intensity precludes pulse-height analysis methods. The spectrometer uses individually calibrated thermoluminescent dosimeters, each inside its own spherical absorber, to accommodate isotropic radiation from pulsed bremsstrahlung sources. An iterative perturbation unfolding code determines the spectrum from the detector responses and the computed energy response functions. Unfolding works best with a good guess for the initial spectrum, and data with less than a few percent error.