A Compton scattering spectrometer for determining X-ray photon energy spectra.

With the use of more sophisticated diagnostic technologies it is becoming increasingly important to know the energy spectra of the primary photons from clinical x-ray tubes. At the high fluence rates used under working conditions, it is necessary to greatly reduce the number of photons to the detector per unit time in order to avoid pulse pile-up. The Compton scattering method is very suitable for this reduction and hence it has been further developed in this work in the primary-photon energy range 20-200 keV. The movement of the electrons in the scattering target causes an energy broadening of the Compton scattered photons. This broadening results in a decreased energy resolution, which is particularly seen as a smearing out of the characteristic x-ray peaks of the anode material. Comparison between the spectrum obtained using a Compton spectrometer and unfolded with our reconstruction and the spectrum measured directly in the primary beam shows very good agreement even though relatively simple reconstruction algorithms have been used.