Behaviour of a Raytheon IRFPA (438×270) under High Energy Protons

Abstract

A Raytheon HgCdTe (cut-off 5 μm) 436×270 Infrared Focal Plane Array (IRFPA) is mounted at two of the three focal planes of an infrared imaging spectrometer, VIRTIS, on board the ESA/ROSETTA cometary mission. VIRTIS is comprised of a mapping spectrometer (-M) under Italian responsibility (Officine Galileo) and a high-resolution spectrometer (-H) under French responsibility (Observatoire de Paris, Meudon).

ROSETTA will be launched in 2003 to intercept the comet Wirtanen in 2011. Almost all the measurements of the instruments will be performed at the end of the mission, after 8 years irradiation of ionising particles (mainly high energy protons from solar wind) have degraded the instruments.

In order to simulate part of the ROSETTA detector’s radiation environment, we performed a set of irradiation tests under high energy protons (up to 50 MeV). This paper firstly describes the environmental conditions of the tests. As a second step, the characteristics we obtained before and after irradiation are given: detector dark current, readout noise, linearity, and operability. Those results are compared and discussed.

Centre National d’Etudes Spatiales (CNES)