摘要:
A method for treatment of the surface of a CdZnTe (CZT) crystal that provides a native dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals. A two step process is disclosed, etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and after attachment of electrical contacts, passivating the CZT crystal surface with a solution of 10 w/o NH4F and 10 w/o H2O2 in water.
摘要:
A method for treatment of the surface of a CdZnTe (CZT) crystal that provides a native dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals. A two step process is disclosed, etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and after attachment of electrical contacts, passivating the CZT crystal surface with a solution of 10 w/o NH4F and 10 w/o H2O2 in water.
摘要翻译:一种用于处理CdZnTe(CZT)晶体表面的方法,其提供天然电介质涂层以减少表面泄漏电流,从而提高使用CZT晶体的检测器的分辨率。 公开了两步法,用常规溴/甲醇蚀刻处理的溶液蚀刻CZT晶体的表面,并且在电接触附着之后,用10w / o NH 3溶液钝化CZT晶体表面, 4°F和10w / o 2 H 2 O 2在水中。
摘要:
A CdZnTe (CZT) crystal provided with a native CdO dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals is disclosed. A two step process is provided for forming the dielectric coating which includes etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and passivating the CZT crystal surface with a solution of 10 w/o NH4F and 10 w/o H2O2 in water after attaching electrical contacts to the crystal surface.
摘要翻译:公开了一种CdZnTe(CZT)晶体,其具有天然CdO介电涂层以减少表面漏电流,从而提高使用CZT晶体的检测器的分辨率。 提供用于形成电介质涂层的两步法,其包括用常规溴/甲醇蚀刻处理的溶液蚀刻CZT晶体的表面,并用10w / o NH4F和10w的溶液钝化CZT晶体表面 / o H2O2在水中,将电触点连接到晶体表面。
摘要:
A method for reducing the leakage current in CZT crystals, particularly Cd.sub.1-x Zn.sub.x Te crystals (where x is greater than equal to zero and less than or equal to 0.5), and preferably Cd.sub.0.9 Zn.sub.0.1 Te crystals, thereby enhancing the ability of these crystal to spectrally resolve radiological emissions from a wide variety of radionuclides. Two processes are disclosed. The first method provides for depositing, via reactive sputtering, a silicon nitride hard-coat overlayer which provides significant reduction in surface leakage currents. The second method enhances the passivation by oxidizing the CZT surface with an oxygen plasma prior to silicon nitride deposition without breaking the vacuum state.
摘要:
A radiation detector device is provided that is capable of distinguishing between full charge collection (FCC) events and incomplete charge collection (ICC) events based upon a correlation value comparison algorithm that compares correlation values calculated for individually sensed radiation detection events with a calibrated FCC event correlation function. The calibrated FCC event correlation function serves as a reference curve utilized by a correlation value comparison algorithm to determine whether a sensed radiation detection event fits the profile of the FCC event correlation function within the noise tolerances of the radiation detector device. If the radiation detection event is determined to be an ICC event, then the spectrum for the ICC event is rejected and excluded from inclusion in the radiation detector device spectral analyses. The radiation detector device also can calculate a performance factor to determine the efficacy of distinguishing between FCC and ICC events.
摘要:
An interwoven multi-aperture collimator for three-dimension radiation imaging applications is disclosed. The collimator comprises a collimator body including a plurality of apertures disposed in a two-dimensional grid. The collimator body is configured to absorb and collimate radiation beams emitted from a radiation source within a field of view of said collimator. The collimator body has a surface plane disposed closest to the radiation source. The two-dimensional grid is selectively divided into at least a first and a second group of apertures, respectively defining at least a first view and a second view of an object to be imaged. The first group of apertures is formed by interleaving or alternating rows of the grid, and the second group of apertures is formed by the rows of apertures adjacent to the rows of the first group. Each aperture in the first group is arranged in a first orientation angle with respect to the surface plane of said collimator body, and each aperture in the second group is arranged in a second orientation angle with respect to the surface plane of said collimator body such that the apertures of the first group are interwoven with the apertures of the second group.
摘要:
An electron gas grid semiconductor radiation detector (EGGSRAD) useful for gamma-ray and x-ray spectrometers and imaging systems is described. The radiation detector employs doping of the semiconductor and variation of the semiconductor detector material to form a two-dimensional electron gas, and to allow transistor action within the detector. This radiation detector provides superior energy resolution and radiation detection sensitivity over the conventional semiconductor radiation detector and the “electron-only” semiconductor radiation detectors which utilize a grid electrode near the anode. In a first embodiment, the EGGSRAD incorporates delta-doped layers adjacent the anode which produce an internal free electron grid well to which an external grid electrode can be attached. In a second embodiment, a quantum well is formed between two of the delta-doped layers, and the quantum well forms the internal free electron gas grid to which an external grid electrode can be attached. Two other embodiments which are similar to the first and second embodiment involve a graded bandgap formed by changing the composition of the semiconductor material near the first and last of the delta-doped layers to increase or decrease the conduction band energy adjacent to the delta-doped layers.
摘要:
The present invention relates to a novel hybrid anode configuration for a radiation detector that effectively reduces the edge effect of surface defects on the internal electric field in compound semiconductor detectors by focusing the internal electric field of the detector and redirecting drifting carriers away from the side surfaces of the semiconductor toward the collection electrode(s).
摘要:
The present disclosure provides systems and methods for crystal growth of cadmium zinc tellurium (CZT) and cadmium tellurium (CdTe) crystals with an inverted growth reactor chamber. The inverted growth reactor chamber enables growth of single, large, high purity CZT and CdTe crystals that can be used, for example, in X-ray and gamma detection, substrates for infrared detectors, or the like. The inverted growth reactor chamber enables reductions in the presence of Te inclusions, which are recognized as an important limiting factor in using CZT or CdTe as radiation detectors. The inverted growth reactor chamber can be utilized with existing crystal growth techniques such as the Bridgman crystal growth mechanism and the like. In an exemplary embodiment, the inverted growth reactor chamber is a U-shaped ampoule.
摘要:
A photolithographic process forms patterns on HgI2 surfaces and defines metal sublimation masks and electrodes to substantially improve device performance by increasing the realizable design space. Techniques for smoothing HgI2 surfaces and for producing trenches in HgI2 are provided. A sublimation process is described which produces etched-trench devices with enhanced electron-transport-only behavior.