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 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: 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 fabricating radiation sensor dies includes forming a plurality of radiation-sensitive detector elements and a plurality of visible identifiers on at least some of the radiation-sensitive detector elements on a substrate, where each visible identifier is located in a different sub-region of the substrate containing a subset of the radiation-sensitive detector elements, and separating the sub-regions of the substrate from one another to provide a plurality of radiation sensor dies, where the visible identifier on each radiation sensor die uniquely identifies the radiation sensor die with respect to the other radiation sensor dies of the plurality of radiation sensor dies.

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: 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: 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: 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 radiation detector tile includes a single crystal compound semiconductor tile having a zinc blende crystal structure, a (111) plane first major (i.e. prominent) surface and four side surfaces which are rotated by an angle of 13° to 17° to a {110} family of planes. The tile may be formed by dicing a (111) oriented wafer at directions which are rotated by an angle of 13° to 17° from <110> in-plane slipping directions to reduce or eliminate the side surface chipping and sub surface dislocation defects.

Abstract: An ionizing radiation detector, such as a photon counting computed tomography detector, includes a semiconductor material plate, a plurality of anodes located on a first side of the semiconductor material plate, where the gaps (i.e., streets) between adjacent anodes are less than 15 ?m in width, and at least one cathode located on a second side of the semiconductor material plate. Ionizing radiation detectors according to various embodiments may have improved count rate stability (CRS) characteristics and a reduced number of Non-Conforming Pixels (NCPs) relative to conventional detectors.

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 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: 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: A radiation detector module includes a frame, a module circuit board connected to the frame, detector units that each include radiation sensors disposed above the frame and electrically connected to the module circuit board, and an optically and infrared radiation opaque, X-ray transparent, electrically insulating detector shield covering a top surface and at least one side surface of the radiation sensors.

Abstract: A radiation sensor includes a radiation-sensitive semiconductor layer, a cathode electrode disposed over a front side of the radiation-sensitive semiconductor layer that is configured to be exposed to radiation, at least one anode electrode disposed over a backside of the radiation-sensitive semiconductor layer, and a potential barrier layer located between the cathode electrode and the front side of the radiation-sensitive semiconductor layer.

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.

Abstract: Various aspects include circuits and methods for use in X-ray detectors for obtaining time information regarding when an indication of an X-ray photon's energy, such as a CSA output voltage, and using the time information to obtain temporal-spectral data regarding an X-ray photon detection. The temporal-spectral data may be used to determine the X-ray photon's energy, to detect and account for multiple X-ray photon detection events (“pile ups”), and/or accommodating detection events in which charge is shared between two pixel detectors.