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US 5,306,907 AGranted
X-ray and gamma ray electron beam imaging tube having a sensor-target layer composed of a lead mixture
AssigneeUniversity of Connecticut
InventorsSol Nudelman, Donald R. Ouimette
Life of this patent
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Abstract
A large area video camera is suitable for high energy imaging applications. The sensor-target of the camera tube is composed of TlBr, TlI, PbI.sub.2, or PbBr.sub.2 or a two layer structure comprising CsI and a photoconductive layer of materials such as amorphous silicon, amorphous selenium, cadmium sulphide, antimony trisulfide or antimony sulphide oxysulphide. A disclosed tube incorporates various modifications for dealing with problems associated with stray capacitance, premature electron leakage and secondary electron emission.
Claims20
An imaging tube comprising:
- sensor-target means comprising signal plate means for detecting irradiating high energy photons and providing storage capacity to hold electrons on the surface of said sensor-target means, said sensor-target means comprising a layer substantially composed of material selected from the group consisting of PbI.sub.2, PbBr.sub.2 and a PbI.sub.2 and PbBr.sub.2 mixture, which layer receives incident high energy radiation and causes the generation of internal electronic positive carriers in quantities which are greater than the number of incident photons of said radiation;
- electron optics means for generating a low velocity electron beam and directing said beam at said sensor-target means to deposit a uniform layer of charge;
- so that high energy radiation directed at said sensor-target means produces a charge redistribution at said sensor-target means surface for generating a signal for transmittal to a read-out circuit.
An imaging tube comprising:
- sensor-target means comprising signal plate means for detecting irradiating high energy photons and providing storage capacity to hold electrons on the surface of said sensor-target means, said sensor-target means comprising a photoconductive layer substantially composed of material selected from the group consisting of TlBr, TlI, PbI.sub.2, PbBr.sub.2 a TlBr and TlI mixture and a PbI.sub.2 and PbBr.sub.2 mixture, which layer receives incident high energy radiation and causes the generation of internal electronic positive carriers in quantities which are greater than the number of incident photons of said radiation;
- electron optics means for generating a low velocity electron beam and directing said beam at said sensor-target means to deposit a uniform layer of charge;
- blocking means comprising a blocking layer disposed between said signal plate means and said photoconductive layer for blocking the injection of holes from said signal plate means into said photoconductive layer,
- so that high energy radiation directed at said sensor-target means produces a charge redistribution at said sensor-target means surface for generating a signal for transmittal to a read-out circuit.
1 more element
An imaging tube comprising:
- sensor-target means comprising signal plate means for detecting irradiating high energy photons and providing storage capacity to hold electrons on the surface of said sensor-target means comprising a photoconductive layer substantially composed of material selected from a group of TlBr, TlI, PbI.sub.2, PbBr.sub.2 a TlBr and a TlI mixture, and a PbI.sub.2 and a PbBr.sub.2 mixture, which layer receives incident high energy radiation and causes the generation of internal electronic positive charge carriers in quantities which are greater than the incident number of photons of said radiation, said sensor-target means having an input side surface and an opposite vacuum side surface;
- electron optics means for generating a low velocity beam and directing said beam at said sensor-target means to deposit a uniform layer of charge;
- reduction means for reducing secondary electron emissions in said sensor-target means comprising a beam landing layer disposed between the vacuum side surface of the sensor-target means and said electron optics means,
- so that high energy radiation directed at said sensor-target means incident side surface produces a charge redistribution at said sensor-target means surface for generating a signal for transmittal to a readout circuit.
1 more element
Dependencies are inferred from the claim text.