Recent developments in the domain of standard CMOS imagers for visible light, mainly in the reduction of the pixel size due to the scaling of the technological node, have led us to investigate the suitability of some of these devices as ionizing radiation detectors.
A standard VGA imager with 5.6x5.6 micrometer pixel size has been chosen.
It has been characterized using laboratory sources and charged particles beams. The main results obtained are: small average pixel multiplicity (4-5) for the detection of charged particles, S/N value about 30, intrinsic spatial resolution at 620 nanometers, efficiency close to 100% with small fake hit rate..
The GBT project aims at designing, in a commercial CMOS 130 nm technology, a fast and radiation tolerant optical transceiver providing a bidirectional connection between the frontend electronics and the DAQ, trigger and DCS systems. A chip named Giga Bit Laser Driver (GBLD) for data transmission at high data-rates has been developed in this framework as part of the GBT project.
L. Servoli et al., “Use of a standard CMOS imager as position detector for charged particles” Nuclear Physics B Proceedings Supplements, Volume 215, Issue 1, p. 228-231, DOI: 10.1016/j.nuclphysbps.2011.04.016