X-ray Spectrum Reconstruction by Diamond Detectors with Linear Response to Dose Rate

The absorbers method is here applied by interposing filters of variable thickness between the X-ray source and a detector so to attenuate the radiation intensity by using the attenuation coefficient as a selective photon energy operator. The analysis of the signal provided by a polycrystalline diamond thin film detector exposed to the energy-selectively-attenuated X-ray beam was used for the reconstruction of the radiation spectrum. The 50 mu m thick diamond detector achieves conditions of linear response to the dose rate of the incident radiation (linearity coefficient of 0.997 +/- 0.003) for a bias voltage >= 90 V, corresponding to an electric field >= 1.8 x 10(4) V/cm. Once the absorbers method is applied, only the detector signal linearity to dose rate allows reconstructing the source X-ray bremsstrahlung spectrum with sufficiently high accuracy.