Abstract: A family of photodetectors includes at least first and second members. In one embodiment, the family includes members having different pixel sizes. In another, the family includes members having the same pixel size. The detection efficiency of the detectors is optimized to provide a desired energy resolution at one or more energies of interest.

Abstract: A radiation detector includes an array of detector pixels each including an array of detector cells. Each detector cell includes a photodiode biased in a breakdown region and digital circuitry coupled with the photodiode and configured to output a first digital value in a quiescent state and a second digital value responsive to photon detection by the photodiode. Digital triggering circuitry is configured to output a trigger signal indicative of a start of an integration time period responsive to a selected number of one or more of the detector cells transitioning from the first digital value to the second digital value. Readout digital circuitry accumulates a count of a number of transitions of detector cells of the array of detector cells from the first digital state to the second digital state over the integration time period.

Abstract: A radiation detector includes an array of detector pixels each including an array of detector cells. Each detector cell includes a photodiode biased in a breakdown region and digital circuitry coupled with the photodiode and configured to output a first digital value in a quiescent state and a second digital value responsive to photon detection by the photodiode. Digital triggering circuitry is configured to output a trigger signal indicative of a start of an integration time period responsive to a selected number of one or more of the detector cells transitioning from the first digital value to the second digital value. Readout digital circuitry accumulates a count of a number of transitions of detector cells of the array of detector cells from the first digital state to the second digital state over the integration time period.

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

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 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).

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

Abstract: A positron emission tomography apparatus (100) includes a plurality of radiation sensitive detector systems (106) and selective trigger systems (120). The selective trigger systems identify detector signals resulting from detected gamma radiation (310) while disregarding spurious detector signals (310). In one implementation, the apparatus (100) includes a time to digital converter which decomposes a measurement time interval (Tmax) according to a binary hierarchical decomposition of level H, where H is an integer greater than equal to one.

Abstract: A radiation detector module (10) for use in a time-of-flight positron emission tomography (TOF-PET) scanner (8) generates a trigger signal indicative of a detected radiation event. A timing circuit (22) including a first time-to-digital converter (TDC) (30) and a second TDC (31) is configured to output a corrected timestamp for the detected radiation event based on a first timestamp determined by the first TDC (30) and a second timestamp determined by the second TDC (31). The first TDC is synchronized to a first reference clock signal (40, 53) and the second TDC is synchronized to a second reference clock signal (42, 54), the first and second reference clock signals being asynchronous.

Abstract: A light transmitting element such as a scintillating element (50) or an optic fiber (50?) has side surfaces coated with a metamaterial (62) which has an index of refraction less than 1 and preferably close to zero to light transmitted in the light transmitting element. A photonic crystal (80) or metamaterial layer optically couples a light output face of the light transmitting element with a light sensitive element (52), such as a silicon photomultiplier (SiPM). A thin metal layer (64) blocks optical communication between adjacent scintillating elements (50) in a radiation detector (22), such as a radiation detector of a nuclear imaging system (10).

Abstract: A PET scanner (10) includes a ring of detector modules (16) encircling an imaging region (18). Each of the detector modules includes one or more sensor avalanche photodiodes (APDs) (34) that are biased in a breakdown region in a Geiger mode. The sensor APDs (34) output pulses in response to light from a scintillator corresponding to incident photons. A reference APD (36) also biased in a breakdown region in a Geiger mode is optically shielded from light and outputs a voltage that is measured by an analog to digital converter (44). Based on the measurement, a bias control feedback loop (42) directs a variable voltage generator (48) to adjust a bias voltage applied to the APDs (34, 36) such that a difference (86) between a voltage of a break-down pulse (68) and a preselected logic voltage level (70) is minimized.

Abstract: A radiation detector includes an array of detector pixels each including an array of detector cells. Each detector cell includes a photodiode biased in a breakdown region and digital circuitry coupled with the photodiode and configured to output a first digital value in a quiescent state and a second digital value responsive to photon detection by the photodiode. Digital triggering circuitry is configured to output a trigger signal indicative of a start of an integration time period responsive to a selected number of one or more of the detector cells transitioning from the first digital value to the second digital value. Readout digital circuitry accumulates a count of a number of transitions of detector cells of the array of detector cells from the first digital state to the second digital state over the integration time period.

Abstract: A color imaging device comprises: one or more arrays (10, RA, GA, BA) of color selective photodetectors (R, G, B) configured to acquire a color image of a subject; a set of avalanche photodiode photodetectors (APD) arranged to acquire a luminance image of the subject; and digital image processing circuitry (30) configured to process the acquired color image and the acquired luminance image to generate an output image of the subject. In some embodiments the avalanche photodiode photodetectors are configured to perform photon counting. In some embodiments, the one or more arrays comprise an imaging array (10) including the color-selective photodetectors (R, G, B) distributed across the imaging array with the set of avalanche photodiode photodetectors (APD) interspersed amongst the color-selective photodetectors.

Abstract: A PET scanner (8) includes a ring of detector modules (10) encircling an imaging region (12). Each of the detector modules includes at least one detector pixel (24,34). Each detector pixel includes a scintillator (20, 30) optically coupled to one or more sensor APDs (54) that are biased in a breakdown region in a Geiger mode. The sensor APDs output a pulse in response to the light from the scintillator corresponding to a single incident radiation photon. A reference APD (26, 36) also biased in a break-down down region in a Geiger mode is optically shielded from light and outputs a temperature dependent signal. At least one temperature compensation circuit (40) adjusts a bias voltage applied to the sensor APDs based on the temperature dependent signal.

Abstract: When detecting scintillation events in a nuclear imaging system, time-stamping and energy-gating processing is incorporated into autonomous detection modules (ADM) (14) to reduce downstream processing. Each ADM (14) is removably coupled to a detector fixture (13), and comprises a scintillation crystal array (66) and associated light detect or (s) (64), such as a silicon photomultiplier or the like. The light detector(s) (64) is coupled to a processing module (62) in or on the ADM (14), which performs the energy gating and time-stamping.

Abstract: When detecting photons in a computed tomography (CT) detector, a sensor (10, 38) includes a photodiode that is switchable between liner and Geiger operation modes to increase sensing range. When signal to noise ratio (SNR) is high, a large bias voltage is applied to the photodiode (12) to charge it beyond its breakdown voltage, which makes it sensitive to single photons and causes it to operate in Geiger mode. When a photon is received at the photodiode (12), a readout transistor (18) senses the voltage drop across the photodiode (12) to detect the photon. Alternatively, when SNR is low, a low bias voltage is applied to the photodiode (12) to cause it to operate in linear mode.

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 radiation detector includes an array of detector pixels each including an array of detector cells. Each detector cell includes a photodiode biased in a breakdown region and digital circuitry coupled with the photodiode and configured to output a first digital value in a quiescent state and a second digital value responsive to photon detection by the photodiode. Digital triggering circuitry is configured to output a trigger signal indicative of a start of an integration time period responsive to a selected number of one or more of the detector cells transitioning from the first digital value to the second digital value. Readout digital circuitry accumulates a count of a number of transitions of detector cells of the array of detector cells from the first digital state to the second digital state over the integration time period.

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.