Simulation of thin-film detectors of ionizing radiation and thermal neutrons based on CdTe

Abstract

The article is dedicated to the numerical simulations of thin-layer structures based on CdTe semiconductors, which can be fabricated by using low-cost technologies. Structures Mo/Au/CdS/CdTe/Au, and their modifications, with different thicknesses of the main layers are investigated. The possibility of creating a detector of ionizing radiation based on these structures, which has selective properties with respect to the radiation type, and very low operation voltage, is shown. The detection efficiencies of α-, β-, and γ-radiation in different energy ranges were calculated based on the obtained values of energy losses of ionizing particles, which are proportional to the output signal of the detector. The use of such detectors, together with a solid-state converter made of boron carbide containing either natural boron natB or boron enriched with the 10B isotope up to 95%, for the detection of thermal neutrons was also studied. It was shown that the structures could be used to create α-particle spectrometers, given that the CdTe thickness is tailored to the highest expected α-particle energy. Detectors with thin CdTe (1–5 μm) can be successfully used in the counting mode. For neutron detection, stacking multiple single structures into sandwich structures was proposed and investigated. In such a configuration, the detector qualities were markedly improved: the efficiency of neutron detection reached ∼60%, while the sensitivity to the background γ- and β-radiation was ∼100 times lower than that for neutrons. The very low sensitivity of the simulated neutron detectors to the neutron incidence angle was shown.