The detection of single photons within the visible and near infrared spectrum became a key requirement for future space-based observations. Examples are the direct detection of exo-planets, multi object observation of high z-shift objects or high-cadence searches for short duration transients. One option to achieve photon number resolved measurements at non-cryogenic temperatures with a high quantum efficiency are silicon detectors with deep sub-electron noise. Such highly sensitive devices are especially prone to radiation damage, which presents a crucial parameter for space applications.
In this context, RNDR-DEPFET detectors offer complement properties to established technologies. The active pixel concept enables a high time resolution and good radiation hardness, while the fully depleted bulk of high purity silicon wafers ensure a high quantum efficiency and low dark count rate.
We will demonstrate the capability of a kilo-pixel RNDR-DEPFET sensor to detect signals as small as single electrons with a high time resolution, by continuously repeating a non-destructive readout. To evaluate the radiation hardness of this technology, we irradiated conventional DEPFET detectors – without repetitive readout – with 60 MeV protons. The results of this campaign provide information on the radiation hardness of DEPFETs in particular and of scientific silicon detectors with high-resistivity material in general.