Speaker
Description
The French Alternative Energies and Atomic Energy Commission (CEA) is deeply implied in the development of ALFA (Astronomical Large Format Arrays), a 2048x2048 short-wave infrared (SWIR) detector array with a 15 µm pixel pitch and a cutoff wavelength of 2.1 µm. The development is mainly funded by the European Space Agency (ESA), for the future space missions, and by the French national research agency. Since ALFA is dedicated to space applications, it has to be hardened against radiation effects. It is therefore essential to understand the effects of space radiations on these IR detectors. In particular, in addition to the study of energy deposition directly into the HgCdTe sensitive layer, it is mandatory to address the effects of particles energy deposition first in the CdZnTe substrate for detector structures where the substrate is not completely removed.
Here we present the model we have developed describing luminescence induced by proton energy deposition in the CdZnTe substrate of HgCdTe infrared detectors for space applications. The estimation of image pollution is performed with the use of GEANT4 Monte Carlo simulation and both analytical and numerical calculations of carrier diffusion inside the detector. Recombination processes are taken into account to modelled luminescence effect induced by proton irradiation.
Luminescence experiments and ellipsometry measurements are used as input parameters to model the response of the detector under irradiation. Simulated images have been confronted with real images acquired with real detectors during an irradiation campaign. During this experiment two detectors with different substrate thicknesses, 50 µm and 800 µm, have been irradiated with 62 MeV protons. The simulations are in good agreement with the results of the experiment, which validates the model we have developed. The comparison of the model with the experience will also be presented.
