Determination of X-ray tubes radiation beam characteristics with semiconductor pixel detectors

Abstract

X-ray tubes belong among the most important sources of ionizing radiation and are used in various applications and methods, i.e. investigation of materials, diagnostics in medicine, irradiation, etc. For such applications, the exact properties of X-ray sources or their X-ray beams need to be known, as well as when Monte Carlo simulations of experimental setups are considered with the aim of optimization or calibration of X-ray systems. These properties include X-ray spectra, beam profiles, divergence and homogeneity of beams. Properties of low power X-ray tubes with the maximum voltage up to 50 kV were investigated in this study. These devices included a small laboratory X-ray tube with collimated X-ray beam and a microfocus X-ray tube with polycapillary focusing optics. Beam shape features were reconstructed using a silicon pixel detector. The pixel detector was inserted into X-ray beams at different distances from X-ray sources. Beam 2D profiles were obtained and since the pixel detector worked in a single event detection mode, approximate energy of individual photons could be measured as well as their position. In this way, detailed information about the beam properties was obtained. • X-ray beam parameters are mapped by a pixel detector. • The beam shape and energy distribution of the emitted photons are assessed. • The size of the irradiated point and the quality of the collimators are determined.