Peter Fischer - ASICs for Photon Detection integrating Avalanche Diodes and CMOS Readout

The detection of optical photons with high sensitivity is required in a wide range of applications (fluorescence, scintillation, Cherenkov photons,…). The classical photomultiplier tubes have been mostly replaced by solid state avalanche diodes and silicon photomultipliers. Unfortunately, the latters only produce small signals so that sensitive, often fast, amplifiers are required. These readout ASICs (which we also develop in our group) consume significant power and are an additional mechanical component, complicating system design.

An alternative approach uses Single Photon sensitive Avalanche Diodes (SPADs) integrated into a CMOS technology, so that detection and readout can be combined on a single chip. The large signals of the individual SPADs enable low noise and low power solutions. After gaining initial experience with small test chips, we have submitted an engineering run with several very different readout architectures to fit different needs. The architectures and possible applications will be described and some first results will be presented.