Reduction of Radiation Effects in Biomedical Imaging Detectors by Technology Change

Abstract

Silicon is a preferred material in the design of medical imaging detectors. It enables reliable and inexpensive detectors to be produced. However, the operation of this material is compromised when irradiated with high radiation of more than 5 &times;10¹⁴ particles/cm²of high energy neutrons. The defects caused transform the electrical properties. Therefore, this loss of information compromises the reconstruction of important events. This research paper aims to make a scientific contribution to the reduction of this radiation effects. The proposed solution is obtained by changing the silicon material generally used to design the detectors by a carbon nanotube material. The use of carbon nanotube material allows the detector to reduce the effects of radiation and leakage currents. A particular observation was made on the linear attenuation coefficient μ, the radiation length X₀ and the width of the forbidden band Eg. Our results show the best characteristics for a carbon nanotube material compared to silicon. For a cross thermal section equal to &sigma;_Si = &sigma;_c = 2 &times;10^-3b ,the carbon linear attenuation coefficient is great her than the silicon (&mu;_Si = 9.979 &times;10^-5cm^-1 <&mu;_C = 3.533 &times;10^-4cm^-1), For a maximum effective cross section of equal diffusion &sigma;_C = 1009 &times;10^-3b, (&mu;_Si = 0.503 &times;10^-3 cm^-1 <&mu;_C = 1.732 &times;10^-3 cm^-1), for a minimum effective cross section of equal diffusion &sigma;_Si = &sigma;_C = 10.09 &times;10^-3b, &mu;_Si = 0.503 &times;10^-3 cm^-1 <&mu;_C = 1.732 &times;10^-3 cm^-1. X_0si = 22.009 g/cm2 and  X_0c= 42.969 g/cm²,  E_gsi= 1.2e.V and  E_gsi= 5.5e.V. From these results, the carbon material has an attenuation coefficient at least three times higher than that of the silicon material.