Abstract: Application specific integrated circuits (ASICs) for direct attach radiation detector structures include an array of unit cells including signal processing channel circuitry and data transmission through-substrate vias (TSVs) with reduced cross-talk between the signal processing channel circuitry and the data transmission TSVs.

Abstract: Direct attach radiation detector structures include an application specific integrated circuit (ASIC) including an array of unit cells including signal processing channel circuitry and at least one radiation sensor including an array of pixel detectors located over a front surface of the ASIC. In various embodiments, an ASIC having a fixed layout of unit cells may accommodate different radiation sensors having varying layouts of pixel detectors. In some embodiments, a redistribution layer on the front surface of the ASIC may route detection signals from pixel detectors to the corresponding unit cells. Alternatively, or in addition, a subset of the unit cells of the ASIC may be active unit cells that are electrically coupled to a pixel detector. The remaining unit cells may be inactive unit cells that may be powered down.

Abstract: An ionizing radiation detector includes a p-type semiconductor single crystal substrate having first and second major planar opposing surfaces, where the p-type semiconductor single crystal substrate is doped with n-type dopant atoms, and where a concentration of deep level acceptor defects is greater than a concentration of the n-type dopant atoms in the p-type semiconductor single crystal substrate; a cathode electrode on the first major planar opposing surface of the p-type semiconductor single crystal substrate, and a plurality of anode electrodes on the second major planar opposing surface of the p-type semiconductor single crystal substrate.

Abstract: A method of calibrating a pixelated radiation detector containing a plurality of pixel detectors electrically connected to a plurality of respective read-out channels of detector read-out circuitry includes determining a sensor material deadtime, ?sensor, for each of the plurality of pixel detectors, and adjusting the respective read-out channel deadtime, ?ASIC, based on the determined sensor material deadtime, ?sensor, of the respective one of the plurality of pixel detectors, such that a total deadtime, ?total of each pixel detector including a sum of the respective sensor material deadtime, ?sensor, and the respective read-out channel deadtime, ?ASIC, varies by less than ±5% from each other.

Abstract: A radiation detector unit includes at least one radiation sensor having pixel detectors that generate event detection signals in response to photon interaction events, an application specific integrated circuit (ASIC) including circuit components on a substrate, the at least one radiation sensor mounted over the application specific integrated circuit via a plurality of bonding material portions such that event detection signals generated in each of the pixel detectors of the at least one radiation sensor are received at a respective pixel region of the ASIC, and the circuit components of the ASIC convert the event detection signals received at each of the pixel regions of the ASIC to digital detection signals, and a carrier board underlying the ASIC, where the ASIC includes a plurality of through-substrate vias (TSVs) electrically coupling the ASIC to the carrier board, each of the TSVs underlying an active pixel detector of the at least one radiation sensor.

Abstract: Direct attach radiation detector structures include an application specific integrated circuit (ASIC), at least one radiation sensor located over a front surface of the ASIC, and a carrier board located over a back surface of the ASIC. In various embodiments, the carrier board may include one or more thermal management features that may reduce temperature non-uniformities in the detector structure. In additional embodiments, the carrier board may include one or more features to improve the manufacturability of the radiation detector unit.

Abstract: A radiation detector unit including an interposer configured to electrically connect a pixelated radiation sensor positioned on a front side of the interposer to an application-specific integrated circuit (ASIC) positioned on a back side of the interposer, where the interposer has at least one feature which equalizes the energy resolution (ER) response of edge and center pixel detectors of the pixelated radiation sensor within 10% of one another.

Abstract: A radiation detector unit includes at least one radiation sensor having pixel detectors that generate event detection signals in response to photon interaction events, an application specific integrated circuit (ASIC) including circuit components on a substrate, the at least one radiation sensor mounted over the application specific integrated circuit via a plurality of bonding material portions such that event detection signals generated in each of the pixel detectors of the at least one radiation sensor are received at a respective pixel region of the ASIC, and the circuit components of the ASIC convert the event detection signals received at each of the pixel regions of the ASIC to digital detection signals, and a carrier board underlying the ASIC, where the ASIC includes a plurality of through-substrate vias (TSVs) electrically coupling the ASIC to the carrier board, each of the TSVs underlying an active pixel detector of the at least one radiation sensor.

Abstract: An X-ray detector module of a multi-module X-ray detector array having a local processing unit configured to provide real-time control and computational capabilities at the x-ray detector module. In various embodiments, by providing these capabilities in the detector module itself, as opposed to a component located downstream of the detector module, there may be an immediate cost reduction, opportunities to include additional features, and performance improvement opportunities not otherwise practical to implement in conventional X-ray imaging systems.

Abstract: A method of X-ray imaging includes determining energies of photons emitted by an X-ray source and attenuated by an object that are detected by an energy-discriminating radiation detector, generating photon count data by counting a number of detected photons in a plurality of energy bins of the energy-discriminating radiation detector that includes a first energy bin and an adjacent second energy bin, and generating an X-ray image of the object using the photon count data. Detected photons determined to have an energy within a gap region between a maximum energy threshold of the first energy bin and a minimum energy threshold of the second energy bin are not included in the photon count data used to generate the X-ray image of the object.

Abstract: An X-ray radiation detector includes a semiconductor material plate, at least one cathode located on a first side of the semiconductor material plate, and at least one anode located on a second side of the semiconductor material plate. The semiconductor material plate thickness is at least 1.9 mm. The X-ray radiation detector is configured to operate at an absolute value of applied bias voltage of 1050 VDC to 1500 VDC, such that an electric field of at least 550 VDC/mm is generated in the semiconductor material plate.

Abstract: A method for determining bone mass density (BMD) of a patient includes obtaining X-ray scan data of a region of interest (ROI) of the patient using an energy discriminating photon counting radiation detector, and calculating the bone mass density (BMD) of the region of interest of the patient based on detected X-ray photon counts within three or more energy bins.

Abstract: Various embodiments include methods of compensating for signal loss due to depth-of-interaction (DOI) effects in radiation detectors, thereby improving detector efficiency. Various embodiments may include detecting the amplitude of a primary charge signal in a first pixel of an array of detector pixels in response to a photon interaction event, detecting the amplitude of a secondary charge signal in a second pixel of the array, where the amplitude of the secondary charge signal has an opposite polarity than the polarity of the primary charge signal, and generating a corrected photon energy measurement of the photon interaction event by applying a correction to the detected amplitude of the primary charge signal based on the detected amplitude of the secondary charge signal. Further embodiments include methods of improving detector efficiency by compensating for both depth-of-interaction (DOI) and charge sharing effects.

Abstract: A radiation detector includes a semiconductor layer having opposing first and second surfaces, anodes disposed over the first surface of the semiconductor layer in a pixel pattern, a cathode disposed over the second surface of the semiconductor layer, and an electrically conductive pattern disposed over the first surface of the semiconductor layer in interpixel gaps between the anodes. At least a portion of the electrically conductive pattern is not electrically connected to an external bias source.

Abstract: A radiation detector unit includes a read-out integrated circuit (ROIC) including a plurality of core circuit blocks located on a continuous uninterrupted substrate adjacent to one another along a first direction, and a plurality of radiation sensors bonded to a front side surface of the ROIC, where each radiation sensor of the plurality of radiation sensors is bonded to a respective core circuit block of the plurality of core circuit blocks of the ROIC. Additional embodiments include detector modules and detector arrays formed by assembling the detector units, and methods of operating and manufacturing the same.

Abstract: Various aspects include methods compensating for Compton scattering effects in pixel radiation detectors. Various aspects may include determining whether gamma ray detection events occurred in two or more detector pixels within an event frame, determining whether the gamma ray detection events occurred in detector pixels within a threshold distance of each other in response to determining that gamma ray detection events occurred in two or more detector pixels within the event frame, and recording the two or more gamma ray detection events as a single gamma ray detection event having an energy equal to the sum of measured energies of the two or more gamma ray detection events located in a detector pixel having a highest measured energy in response to determining that the gamma ray detection events occurred in detector pixels within the threshold distance of each other.

Abstract: Various aspects include methods of compensating for issues caused by charge sharing between pixels in pixel radiation detectors. Various aspects may include measuring radiation energy spectra with circuitry capable of registering detection events occurring simultaneous or coincident in two or more pixels, adjusting energy measurements of simultaneous-multi-pixel detection events by a charge sharing correction factor, and determining a corrected energy spectrum by adding the adjusted energy measurements of simultaneous-multi-pixel detection events to energy spectra of detection events occurring in single pixels. Adjusting energy measurements of simultaneous-multi-pixel detection events may include multiplying measured energies of simultaneous-multi-pixel detection events by a factor of one plus the charge sharing correction factor.

Abstract: Various aspects include methods for use in X-ray detectors for adjusting count measurements from pixel detectors within a pixelated detector module to correct for the effects of pileup events that occur when more than one photon is absorbed in a pixel detector during a deadtime of the detector system. In various embodiments, count measurements may be obtained at two different X-ray tube currents, from which the detector system deadtime may be calculated based on the two count measurements and a ratio of the two X-ray tube currents. Using the calculated deadtime, a pileup correction factor may be determined appropriate for the behavior of the detector system in response to pileup events. The pileup correction factor may be applied to pixel detector count values after the counts have been corrected for pixel-to-pixel differences using a flat field correction.

Abstract: Various aspects include methods for compensating for the effects of charge sharing among pixelate detectors in X-ray detectors by applying a correspondence factor to counts of X-ray photons in energy bins to estimate incident X-ray photon energy bins. The correspondence factor may be determined by determining an incident X-ray photon energy spectrum, adjusting the incident X-ray photon energy spectrum to account for an energy resolution of the pixelated detector, generating a charge sharing model for the adjusted incident X-ray photon energy spectrum based on a percentage charge sharing parameter of the pixelated detector, applying the charge sharing model to energy bins of the pixelated detector to estimate counts in each of the energy bins, and determining the correspondence factor by comparing the estimated counts in each of the energy bins to counts in the energy bins that would be expected for the adjusting the incident X-ray photon energy spectrum.

Abstract: A set of N standard bin count distributions may be generated by irradiating a test radiation detector system with an X-ray beam attenuated by a respective one of N different K-edge filters for each of the at least one X-ray source energy setting. Energy bins of detectors of a target radiation detector system may be calibrated by generating measured bin count distributions for each calibration setting in which a respective one of the N different K-edge filters attenuates a source X-ray beam. Calibration parameters of the detectors of the target radiation detector system may be adjusted to match each of the measured bin count distributions to a corresponding standard bin count distribution. In addition, energy resolution of the radiation detectors can be measured and calibrated by fitting a portion of the measured X-ray spectrum near a K-edge to a fitting function.