COMBINED SIMULATION METHODOLOGY FOR A COMPLETE CHARACTERIZATION OF IONIZING RADIATION EFECTS IN DETECTION DEVICES

Abstract

Ionizing radiation detection devices have been widely used in recent years in various applications and experimental
fields, such as high energy physics, nuclear physics, and medical imaging. Detailed description of their operational
properties and their characterization by means of numerical modelling, as simulations, are key issue to understand
the characteristics of radiation detectors in terms of efficiency, resolution and signal-to-noise ratio, since they allow
optimizing parameters that will be further used. The modelling processes, as the simulations, are routinely carried out
using various tools, like Monte Carlo approaches, for instance: PENELOPE, FLUKA or GEANT4 are used to study
the interaction of the radiation with the detector accounting for the whole physical processes. However, transporting
electron/hole pairs, as generated through the device sensor to conform the corresponding electronic signals uses tools
based on the finite element method, such as TCAD (Technology Computer Aided Design), which are developed
mainly to help the microelectronics industry to design products. Usually, modelling approaches for radiation transport
and electonic signal production are not integrated, thus performing the simulation process by splitting the problem into
sucessive independent phases. Within this framework, the present study proposes, implements, and reports on a novel
methodology that allows combining the two approaches aimed at integrating the complete simulation, thus achieving a
step-by-step integrated modelling flow to describe the interaction of ionizing radiation with the sensor along with the
transport of the generated charge to the photodiodes and, finally, to the generation of electronic signals.