Correction of some diagnostic x-ray spectra measured using CdZnTe detector

X-ray spectra have been directly measured using a low-efficiency CdZnTe (CZT) detector. Photon spectra produced by a single-phase 2-pulse diagnostic X-ray unit driven at 50-100kV and a few mA, mammographic X-ray unit at 25-32kV and 80mAs, and X-ray computed tomography scanner at 120kV and 3mA, have been analyzed. Since detected spectra do not coincide with a true photon spectra, a correction is applied. Monoenergetic response function and full energy peak efficiency for the CZT detector have been determined by an evaluation of spurious effects such as K-escape, coherent scattering and incoherent (Compton) scattering, using Monte Carlo method. The results obtained using the CZT detector agree with X-ray spectral data published by Bureau of Radiological Health (BRH) which was measured by using a Ge detector, and also agree with those obtained by an ionization chamber. Therefor CZT detector would be able to use for quality control and quality assurance of some diagnostic X-ray units. (J.P.N.)