Abstract: Disclosed herein is radiation detector, comprising a first photodiode comprising a first junction; and a first scintillator, wherein a first point in a first plane and inside the first scintillator is essentially completely surrounded in the first plane by an intersection of the first plane and the first junction. The first junction is a p-n junction, a p-i-n junction, a heterojunction, or a Schottky junction. The radiation detector further comprises a first reflector configured to guide essentially all photons emitted by the first scintillator into the first photodiode. The first scintillator is essentially completely enclosed by the first reflector and the first photodiode.

Abstract: Disclosed herein are apparatuses for detecting radiation and methods of making them. The method comprises forming a recess into a semiconductor substrate, wherein a portion of the semiconductor substrate extends into the recess and is surrounded by the recess; depositing semiconductor nanocrystals into the recess, the semiconductor nanocrystals having a different composition from the semiconductor substrate; forming a first doped semiconductor region in the semiconductor substrate; forming a second doped semiconductor region in the semiconductor substrate; wherein the first doped semiconductor region and the second doped semiconductor region form a p-n junction that separates the portion from the rest of the semiconductor substrate.

Abstract: An apparatus for detecting X-ray, comprising an X-ray absorption layer comprising an electrode, an electronics layer and a wall sealing a space among electrical connections between the X-ray absorption layer and the electronics layer. The electronics layer comprises: a first and second voltage comparators configured to compare a voltage of an electrode to a first and second thresholds respectively; a counter configured to register a number of X-ray photons absorbed by the X-ray absorption layer; and a controller configured to: start a time delay from a time at which an absolute value of the voltage equals or exceeds an absolute value of the first threshold; activate the second voltage comparator during the time delay; cause the number registered by the counter to increase by one, if, during the time delay, an absolute value of the voltage equals or exceeds an absolute value of the second threshold.

Abstract: Disclosed herein is a method comprising: aligning a collimator and a plurality of radiation detectors of an image sensor by: moving the radiation detectors along a first direction; moving the collimator along a second direction perpendicular to the first direction; rotating the collimator about an axis perpendicular to the first direction and the second direction; wherein the plurality of radiation detectors are configured to capture images of portions of a scene at different image capturing positions, respectively, and to form an image of the scene by stitching the images of the portions.

Abstract: Disclosed herein is a method comprising: capturing a first image of a portion of a human using an image sensor inside the human with a first beam of radiation from a radiation source outside the human, while the radiation source is at a first position relative to the image sensor; capturing a second image of the portion of the human using the image sensor with a second beam of radiation from the radiation source outside the human, while the radiation source is at a second position relative to the image sensor; wherein the first position and the second position are different, or the first beam of radiation and the second beam of radiation are different; determining a three-dimensional structure of the portion based on the first image and the second image.

Abstract: Disclosed herein is a detector, comprising: a plurality of strip pixels, wherein each of the strip pixel is configured to count numbers of radiation photons incident thereon whose energy falls in a plurality of bins, within a period of time.

Abstract: Disclosed herein is a system suitable for X-ray detection. The system comprises a detector and cooling system configured to control temperature of the detector and prevent condensation of water vapor on the detector. The detector comprises an X-ray absorption layer and electronics layer. The X-ray absorption layer comprises a plurality of pixels, each pixel configured to count numbers of X-ray photons incident thereon whose energy falls in a plurality of bins, within a period of time. The electronics layer comprises an electronic system configured to add the numbers of X-ray photons for the bins of the same energy range counted by all the pixels. The cooling system comprises a chiller configured to lower temperature and moisture level of air, and a fan configured to blow the air that is cooled and dried to the detector.

Abstract: Disclosed herein is radiation detector comprising: a radiation absorption layer configured to generate electric signals by absorbing radiation particles; an electronics layer comprising an electronic system configured to process or interpret the signals; a flexible PCB configured to receive output from the electronic system; wherein the radiation absorption layer and the flexible PCB are mounted on a same side of the electronics layer.

Abstract: Disclosed herein is an image sensor comprising: a plurality of packages arranged in a plurality of layers; wherein each of the packages comprises an X-ray detector mounted on a printed circuit board (PCB); wherein the packages are mounted on one or more system PCBs; wherein within an area encompassing a plurality of the X-ray detectors in the plurality of packages, a dead zone of the packages in each of the plurality of layers is shadowed by the packages in the other layers.

Abstract: Disclosed herein is a system, comprising: a first X-ray source comprising a plurality of X-ray generators configured to respectively emit a plurality of X-rays toward an object; and a first X-ray detector configured to detect images of the object formed respectively by the plurality of X-rays from the first X-ray source.

Abstract: The present teaching relates to methods, systems, and apparatus for X-ray imaging with a detector capable of resolving photon energy. In one example, an X-ray microscope is disclosed. The X-ray microscope comprises an X-ray source and a detector. The X-ray source is configured for irradiating X-ray to a sample. The detector is configured for: detecting X-ray photons from the irradiated X-ray, determining energy of each of the detected X-ray photons, and generating an image of the sample based on detected X-ray photons that have energies in a predetermined range.

Abstract: Disclosed herein is an apparatus suitable for radiation detection. The apparatus may comprise a radiation absorption layer and a first electrode on the radiation absorption layer. The radiation absorption layer may be configured to generate charge carriers therein from a radiation particle absorbed by the radiation absorption layer. The first electrode may be configured to generate an electric field in the radiation absorption layer. The first electrode may have a geometry shaping the electric field so that the electric field in an amplification region of the radiation absorption layer has a field strength sufficient to cause an avalanche of the charge carriers in the amplification region.

Abstract: Disclosed herein is an apparatus suitable for detecting X-ray. The apparatus may comprise an X-ray absorption layer, an electronics layer and a distribution layer. The X-ray absorption layer may comprise a first plurality of electric contacts and configured to generate electrical signals on the first plurality of electric contacts from X-ray incident on the X-ray absorption layer. The electronics layer may comprise a second plurality of electric contacts and an electronic system, wherein the electric system electrically connects to the second plurality of electric contacts and is configured to process or interpret the electrical signals. The first plurality of electric contacts and the second plurality of electric contacts have different spatial distributions. The distribution layer is configured to electrically connect the first plurality of electric contacts to the second plurality of electric contacts.

Abstract: Disclosed herein are methods of making and using an absorption-unit array suitable for X-ray detection and a detector comprising such an absorption-unit array. The methods of making the absorption-unit array may include forming the absorption-unit array on a substrate and forming a guard ring encompassing more than one absorption units of the absorption-unit array after separating the absorption-unit array from the substrate; or may include forming a plurality of absorption units and a guard ring encompassing more than one of the absorption units on a portion of a substrate after separating the portion from the substrate. The method of using an absorption-unit array may include using some of the absorption units of the absorption-unit array as a guard ring by applying an electrical voltage. A detector suitable for X-ray detection comprises an absorption layer and an electronics layer, wherein the absorption layer comprises an absorption-unit array.

Abstract: Disclosed herein is a method comprising: obtaining a third image from a first X-ray detector when the first X-ray detector and a second X-ray detector are misaligned; determining, based on a shift between a first image and the third image, a misalignment between the first X-ray detector and the second X-ray detector when the first and second detectors are misaligned; wherein the first image is an image the first X-ray detector should capture if the first and the second detectors are aligned.

Abstract: Disclosed herein is a radiation detector system, comprising a radiation detector, the radiation detector comprising a semiconductor substrate and a pixel array in the semiconductor substrate, wherein the pixel array comprises (a) M first-row pixels, and (b) N second-row pixels, both M and N being positive integers and greater than 1, and wherein each pixel of the N second-row pixels is larger than any pixel of the M first-row pixels in a radiation direction perpendicular to a straight line segment having a first end in a first-row end pixel of the M first-row pixels and a second end in a second-row end pixel of the M first-row pixels.

Abstract: Disclosed herein is a system comprising: an avalanche photodiode (APD); a bias source configured to supply a reverse bias to the APD; a current meter configured to measure electric current through the APD; a controller configured to reduce the reverse bias to a value below a breakdown voltage of the APD from a value above the breakdown voltage when an intensity of light incident on the APD is above a threshold, and configured to determine the intensity of the light above the threshold based on the electric current through the APD when the reverse bias is below the breakdown voltage.

Abstract: Disclosed herein is a method and apparatus for determining time of arrival of incident photons. The time of arrival may be determined with high time accuracy based on characteristics of the rate of change of a voltage across a capacitor being charged by charge carriers generated from the incident photons.

Abstract: Disclosed herein is a method comprising: forming electrical contacts on a first surface of an epitaxial layer supported on a substrate, the first surface being opposite from the substrate; bonding the epitaxial layer to an electronics layer, wherein the first surface faces the electronics layer and the electrical contacts on the first surface are bonded to electrical contacts of the electronics layer; exposing a second surface opposite the first surface by removing the substrate; and forming a common electrode on the second surface.

Abstract: Disclosed herein is a radiation detector comprising: an electronics layer comprising a first set of electric contacts and a second set of electric contacts; a radiation absorption layer configured to absorb radiation; a first set of electrodes and a second set of electrodes, wherein the first set of electrodes and the second set of electrodes are interdigitated and extend into the radiation absorption layer in a direction of thickness thereof; wherein the electronics layer and the radiation absorption layer are bonded such that the first set of electrodes are electrically connected to the first set of electric contacts and the second set of electrodes are electrically connected to the second set of electric contacts.