Determination of the energy response of dosimeters with a Bragg-monochromatized beam

Abstract

In the energy region below 50 keV the energy response of dosimeters is usually determined by means of filtered Bremsstrahlung radiation. The “monochromatic” radiation produced by filtering the continuous X-ray spectrum of an X-ray tube shows a broad energy distribution for the maximum of the intensity and a considerable “tailing” to low energies. To avoid this disadvantage we used a Bragg monochromator for the energy region between 10 keV and 50 keV. The Bragg monochromator, a commercially available X-ray spectrometer, reflects selectively monochromatic X-rays from a continuous bremsspectrum of a tungsten X-ray tube. The angle of reflection and the energy are determined by the Bragg condition. The energy resolution obtained was 2%. The photon flux density at the place of the dosimeter was measured with an efficiency calibrated Ge(Li) semiconductor detector. From this photon flux density the actual exposure of the dosimeter under examination can be calculated.