Large Area, High Dynamic Range, Sold State Photomultiplier Array for Cherenkov Calorimetry

Existing solid state detectors, such as charge coupled device (CCD) and complimentary metal oxide silicon (CMOS) imagers do not have adequate ultraviolet (UV) sensitivity for Cherenkov radiation detection. Therefore, a new type of UV-optimized, high-gain, low-noise, solid state avalanche photodiode (APD) is needed for low-level light detection of Cherenkov radiation. In recent years, silicon, CMOS-compatible solid state photomultipliers (SiPM) detectors have been shown to be capable of registering low scintillating light, and consequently intensive studies have been carried out to qualify SiPM-like APDs as possible photosensors for scintillation detectors. The results of these studies have revealed encouraging performance characteristics. However, due to the SiPM circuit¿s architecture, the detector¿s sensitivity peaks in the `green¿ part of the optical spectrum and is not very sensitive to the UV. This project will develop a large area, pixilated SiPM detector architecture that is optimized for illumination from the backside, where, unencumbered by the individual detector¿s circuitry, high responsivity can be achieved over the entire spectral range of Cherenkov radiation. In Phase I, single photon sensitive APDs and two SiPM detector designs where characterized over a wide range of operating conditions. Based on the identification and characterization of those device performance attributes critical for Cherenkov detection applications, the design of a large area, tiled, silicon-on-insulator (SOI) CMOS SiPM focal plane array (FPA) was developed and on-chip readout electronics circuits designed. During Phase II, the back-illuminated SOI CMOS SiPM arrays will be fabricated, optimized, integrated and their performance evaluated. Commercial Applications and other Benefits as described by the awardee: Improved SiPM devices will support future experiments in nuclear physics, high-energy physics, and astroparticle physics, DNA-sequencing, fluorescence and luminescence detection, positron emission tomography and single photon emission computed tomography.