Abstract: An apparatus (208) includes a plurality of photosensors (310). Photon trigger signals produced in response to signals from the sensors are received by a trigger line network that includes segment (302), intermediate (304), and master (306) lines. The trigger network is configured to reduce a temporal skew introduced by the trigger line network. Validation logic (324) provides a trigger validation output signal (610).

Abstract: A photon-counting Geiger-mode avalanche photodiode intensity imaging array includes an array of pixels (200), each having an avalanche photodiode (250). A pixel senses an avalanche event and stores, in response to the sensed avalanche event, a single bit digital value therein. An array of accumulators (320) are provided such that each accumulator is associated with a pixel. A row decoder circuit (310) addresses a pixel row within the array of pixels. A bit sensing circuit (300) converts a precharged capacitance into a digital value during read operations.

Abstract: The invention relates to a radiation detector (100) that is particularly suited for energy resolved single X-ray photon detection in a CT scanner. In a preferred embodiment, the detector (100) comprises an array of scintillator elements (S k) in which incident X-ray photons (X) are converted into bursts of optical photons (hn). Pixels (P k) associated to the scintillator elements (S k) determine the numbers of optical photons they receive within predetermined acquisition intervals. These numbers can then be digitally processed to detect single X-ray photons (X) and to determine their energy. The pixels may particularly be realized by avalanche photodiodes with associated digital electronic circuits for data processing.

Abstract: A photodetector array (142) includes a plurality of photodetector cells (202) such as avalanche photodiodes (208) and readout circuits (210). An array self-tester (226) tests a dark count or other performance characteristic of the cells (202). The test is performed in connection with the manufacture of the array (142) or following the installation of the array (142) in a detection system (100).