Abstract:
An X-ray detection system includes at least two electrodes constructed and cooperatively arranged at a photoconductive material to provide an electric field inside the material in a first direction, an X-ray shield and an X-ray window, a read-out circuitry, and a processing circuitry. The X-ray shield and the X-ray window are constructed and arranged to direct X-rays into the photoconductive material in a selected X-ray direction substantially different from the first direction, wherein the directed X-rays are absorbed at a location inside the photoconductive material at a depth corresponding to their energy. The read-out circuitry is constructed and arranged to receive electric signals corresponding to the absorption location inside the photoconductive material. The processing circuitry is constructed and arranged to determine the energy of the absorbed X-rays based on the electric signals.
Abstract:
A three-color QWIP focal plane array is based on a GaAs/AlGaAs material system. Three-color QWIPs (300) enable target recognition and discriminating systems to precisely obtain the temperature of two objects in the presence of a third unknown parameter. The QWIPs (300) are designed to reduce the normal reflection over a significant wavelength range. One aspect of the present invention involves two photon absorptions per transition in a double quantum well structure which is different from typical QWIP structures. This design is expected to significantly reduce the dark current as a result of higher thermionic barriers and therefore allow the devices to operate at elevated temperatures. The device is expected to be fabricated using a GaAs/AlxGa1-xAs material system on a semi-insulating GaAs substrate (340) by Molecular Beam Epitacy (MBE).
Abstract translation:三色QWIP焦平面阵列基于GaAs / AlGaAs材料系统。 三色QWIP(300)使得目标识别和识别系统在存在第三个未知参数的情况下精确获得两个物体的温度。 QWIP(300)设计用于减少有效波长范围内的正常反射。 本发明的一个方面涉及双重量子阱结构中每个跃迁的两个光子吸收,其不同于典型的QWIP结构。 由于较高的热离子屏障,预期这种设计将显着降低暗电流,因此允许器件在升高的温度下工作。 该器件预期将通过分子束表现(MBE)在半绝缘GaAs衬底(340)上使用GaAs / Al x Ga 1-x As材料体系制造。
Abstract:
The invention provides a millimeter wave and far-infrared detector of extreme sensitivity and shorter response time. The detector comprises an input (1) for introducing incident millimeter wave or far-infrared radiation (2) to a detector antenna; a semiconductor substrate (4) on which is formed a single-electron transistor (14) for controlling the current penetrating a semiconductor quantum dot (12); and bow tie antennas (6, 6a, 6b, 6c) for concentrating millimeter wave or far-infrared radiation (2) onto a semiconductor quantum dot that define a submicron space in the single-electron transistor (14). The quantum dot forming a two-dimensional electron system efficiently absorbs the concentrated radiation and maintains the resulting excitation state for more than 10 nanoseconds so that more than 1,000,000 electrons can be transported for a single photon absorbed.
Abstract:
A semiconductor radiation imaging assembly comprises a semiconductor imaging device including at least one image element detector. The imaging device is arranged to receive a bias for forming the at least one image element detector. The assembly also includes bias monitoring means for monitoring the bias for determining radiation incident on the image element detector. Preferably, the imaging device comprises a plurality of image element detectors the bias for at least some of which is monitored for determining incident radiation. More preferably, the bias for all the detector elements is monitored.
Abstract:
A shielding grid (44) constructed of a radiation absorbing material (46, 48) for use with an array of discreet, non-contiguous radiation sensors to protect such sensors from scattered radiation. The sensors each have a radiation sensitive area (11) with a width (Ws) and a length (W1). In designing the grid a prototile having a prototile width and a prototile length is developed. The prototile width is equal to the radiation sensitive area width divided by an integer, and the prototile length is also equal to the radiation sensitive area length divided by an integer. The prototile contains a motif contained solely within the prototile that forms a pattern when a plurality of prototiles sufficient to cover the array of discreet detector are arrayed contiguously. The grid is constructed with the radiation absorbing material in this pattern.
Abstract:
Radiation imaging apparatus includes a support structure for a number of modules which each in their turn support a number of imaging device tiles. An imaging device on each tile provides an array of radiation detector cells. With the modular construction, the apparatus can provide a large imaging array from a large number of individual tiles. The support structure may be located in or form part of an imaging cassette. The modules provide tile mounting locations in one or more rows for the imaging device tiles, whereby the tiles may be accurately mounted with respect the module and to each other prior to being mounted on the support structure. The tiles are mounted on the modules and the modules are mounted within the cassette in a removable manner to facilitate the replacement of faulty tiles when required and/or the replacement of tiles having different resolutions and/or specifications for different imaging applications. Various arrangements for electronically clustering tiles are provided.
Abstract:
An image detector (1, 1a) has an array (2) of sensors (3) formed from layers of material provided on a substrate (4) and separated from a biasing electrode (5) by a radiation conversion layer (6) in which charge carriers are generated in response to incident radiation. Each sensor has a collecting electrode (7a, 7b) for colecting charge carriers generated in the radiation conversion layer (6), a capacitor (c) for storing charge and a switching element (8) having at least first and second electrodes (9 and 10) with one (10) of the first and second electrodes being coupled to the collecting electrode (7a, 7b) for enabling charge carriers stored at the sensor (3) to be read out. Each collecting electrode (7a, 7b) extends laterally beyond the associated switching element (8) on an insulating layer (12a, 12b) provided over the switching elements to form the associated capacitor (c) with an underlying reference electrode (12a, 12b) separated from the collecting electrode (7a, 7b) by the insulating layer (11a, 11b).
Abstract:
A radiation imager includes a photodetector array having topographically patterned surface features, which include support islands disposed over the active portion of one or more photodetectors in the photodetector array. A structured scintillator array having individual columnar scintillator elements is disposed in fixed relation to the photodetector array so that the individual scintillator elements are disposed on scintillator support islands. A barrier layer is disposed between the support islands and the photodetector array to minimize chemical interactions between the material forming the support island and the underlying photodetector array during the fabrication process. After the support islands have been patterned, the scintillator elements are grown by selectively depositing scintillator material on the support islands.
Abstract:
A photodetector is provided for sensing radiation in middle and long wave infrared domain. The sensor has a sensor layer of a first material having a first conductivity type and a first permittivity in which the shortest distance of any point in the sensor layer to an adjacent layer having a second conductivity type and a second permittivity lower than the first permittivity is 20 nanometres or less. Conductivity type may be semiconductor n-type or p-type or insulator. If, for example, a silicon sensor layer is sandwiched between two silicon oxide layers, the sensor layer of preferably p-type semiconductor has a maximum thickness of 40 nanometres. If a p-type layer of a first material is sandwiched between a dielectric layer with the second permittivity and an n-type layer of the first material, the maximum thickness is 20 nanometres. Spaced apart, two contacts are provided in contact with the sensor layer.