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 methods and devices for reducing the scanning time for an X-ray diffraction scanner system by increasing the count rate or efficiency of the energy discriminating X-ray detector. In a first embodiment, the count rate of the energy discriminating X-ray detector is increased by increasing the number of detectors counting X-ray scatter photon in particular energy bins by configuring individual pixel detectors within a 2-D X-ray detector array to count photons within specific energy bins. In a second embodiment, the gain of amplifier components in the detector processing circuitry is increased in order to increase the energy resolution of the detector. In a third embodiment, the individual pixel detectors within a 2-D X-ray detector array are configured to count photons within specific energy bins and the gain of amplifier components in the detector processing circuitry is increased in order to increase the energy resolution of the detector.

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.

Abstract: A radiation detector unit includes an interposer, at least one radiation sensor bonded to a front side of an interposer, an application-specific integrated chip (ASIC) bonded to a backside of the interposer, a carrier board bonded to the backside of the interposer and located on a backside of the ASIC, and at least one flex cable assembly attached to a respective side of the carrier board.

Abstract: An electro-optic modulator includes a doped semiconductor crystal having a crystallographic surface having an amplitude modulation orientation, a first metal electrode located on a first surface of the doped semiconductor crystal, a second metal electrode located on a second surface of the doped semiconductor crystal, and accumulation space charge regions located within surface regions of the doped semiconductor crystal that are proximal to the first metal electrode and the second metal electrode and including excess charge carriers of a same type as majority charge carriers of the doped semiconductor crystal.

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: A detector element circuit for a CT imaging system may include a plurality of sensors for detecting photons passing through an object and a first electronic component configured to determine an energy of photons detected by the plurality of sensors and generate photon count data, which may be a count of detected photons in one or more energy bins. The detector element circuit may further include a second electronic component configured to receive the photon count data from the first electronic component and is clocked at a first clock rate; a local memory storage configured to receive the photon count data from the second electronic component at the first clock rate and to output the photon count data at a second clock rate.

Abstract: Various embodiments described herein may include a detector array for a CT imaging system. The detector array includes a pixel array in which each pair of adjacent pixels in the pixel array may be separated by a collimator (e.g., located between each row and column of the pixel array) that absorbs photons and each pixel in the pixel array includes a sub-pixel array. The collimator absorbs photons that strike at a boundary between adjacent pixels. Each sub-pixel may have an anode that is connected to an ASIC channel. When a sub-pixel in a pixel detects a photon, signals of a plurality of sub-pixels in the pixel are automatically summed, including the sub-pixel that detected the photon.

Abstract: A method of fabricating a solid state radiation detector method includes mechanically lapping and polishing the first and the second surfaces of a semiconductor wafer using a plurality of lapping and polishing steps. The method also includes growing passivation oxide layers by use of oxygen plasma on the top of the polished first and second surfaces in order to passivate the semiconductor wafer. Anode contacts are deposited and patterned on top of the first passivation oxide layer, which is on top of the first surface. Cathode contacts, which are either monolithic or patterned, are deposited on top of the second passivation oxide layer, which is on the second surface. Aluminum nitride encapsulation layer can be deposited over the anode contacts and patterned to encapsulate the first passivation oxide layer, while physically exposing a center portion of each anode contact to electrically connect the anode contacts.

Abstract: A cathode conductive strip can be attached to a semiconductor radiation sensor by using a double sided dual adhesive electrically conductive tape in a sensor assembly or a detector module to provide reliable electrical connection between the semiconductor radiation sensor and the cathode conductive strip. The double sided dual adhesive electrically conductive tape includes an electrically conductive backing with two different adhesion strength adhesives on both sides. The high adhesion strength side is bonded to the cathode electrode of the semiconductor radiation sensor. The lower adhesion strength side is bonded to the conductive face of the cathode conductive strip.

Abstract: A method of fabricating a solid state radiation detector method includes mechanically lapping and polishing the first and the second surfaces of a semiconductor wafer using a plurality of lapping and polishing steps. The method also includes growing passivation oxide layers by use of oxygen plasma on the top of the polished first and second surfaces in order to passivate the semiconductor wafer. Anode contacts are deposited and patterned on top of the first passivation oxide layer, which is on top of the first surface. Cathode contacts, which are either monolithic or patterned, are deposited on top of the second passivation oxide layer, which is on the second surface. Aluminum nitride encapsulation layer can be deposited over the anode contacts and patterned to encapsulate the first passivation oxide layer, while physically exposing a center portion of each anode contact to electrically connect the anode contacts.