Digirad Corporation

Other

F Patrick Doty

Clinton LaMar Lingren

Stanley J Friesenhahn

Boris Apotovsky

Jack F Butler

Frank L Augustine

William L Ashburn

Richard Louis Conwell

Bo Pi

Ashot Oganesyan

A radiation detector for detecting ionizing radiation. The detector includes a semiconductor having at least two sides. A bias electrode is formed on one side of the semiconductor. A signal electrode is formed on a side of the semiconductor and is used to detect the energy level of the ionizing radiation. A third electrode (the control electrode) is also formed on the semiconductor. The control electrode shares charges induced by the ionizing radiation with the signal electrode, shielding the signal electrode until the charge clouds are close to the signal electrode. The control electrode also alters the electric field within the semiconductor, such that the field guides the charge clouds toward the signal electrode when the clouds closely approach the signal electrode. As a result, signal loss due to trapped charge carriers (i.e., electrons or holes) is minimized, and low-energy tailing is virtually eliminated. A fourth electrode can be added to separate the charge-shielding and field shaping functions of the control electrode. More electrodes can be added to further enhance both functions. The invention can be used in several cross-strip detector configurations, in a side-entry radiation detector, and with liquid/gas ionization detectors.

Semiconductor radiation detector with enhanced charge collection

A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector including a plurality of closely-packed detection modules. Each detection module includes a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold. The fall-through circuit searches for the next detection element and associated channel having a valid event. The signal processor performs diagnostics, gain normalization, and response efficiency normalization functions. The data acquisition system controls the acquisition and processing of data received from the conditioning and processing channels, produces image data based upon the data in a format that is compatible with existing imaging cameras, and transmits the data to the image processing computer. The image processing computer formulates images based upon the processed signals and displays the formulated images on a display device.

Semiconductor gamma-ray camera and medical imaging system

A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector including a plurality of closely-packed detection modules. Each detection module includes a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements.

A high-energy photon imaging system including an imaging head, a signal processor, a data acquisition system and an image processing computer. The imaging head includes a detector comprising a plurality of closely-packed detection modules. Each detection module comprises a plurality of detection elements mounted to a circuit carrier. The detection elements produce electrical pulses having amplitudes indicative of the magnitude of radiation absorbed by the detection elements. The circuit carrier includes channels for conditioning and processing the signals generated by corresponding detection elements and for preparing the processed signals for further processing by a signal processor. Each conditioning and processing channel stores the amplitudes of the detection element electrical pulses exceeding a predetermined threshold. The detection modules employ a fall-through circuit which automatically finds only those detection elements that have a stored pulse amplitude exceeding the threshold. The fall-through circuit searches for the next detection element and associated channel having a valid event. The signal processor performs diagnostics, gain normalization, and response efficiency normalization functions. The data acquisition system controls the acquisition and processing of data received from the conditioning and processing channels, produces image data based upon the data in a format that is compatible with existing imaging cameras, and transmits the data to the image processing computer. The image processing computer formulates images based upon the processed signals and displays the formulated images on a display device.

Semiconductor gamma- ray camera and medical imaging system

A radiation detector for detecting ionizing radiation. The detector includes a semiconductor having at least two sides. A bias electrode is formed on one side of the semiconductor. A signal electrode is formed on a side of the semiconductor and is used to detect the energy level of the ionizing radiation. A third electrode (the control electrode) is also formed on the semiconductor. The control electrode shares charges induced by the ionizing radiation with the signal electrode, until the charge clouds are close to the signal electrode. The control electrode also alters the electric field within the semiconductor, such that the field guides the charge clouds toward the signal electrode when the clouds closely approach the signal electrode. As a result, trapping of charge carrying radiation (i.e., electrons or holes) is minimized, and low-energy tailing is virtually eliminated.

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San Diego, CA, United States of America

F Patrick Doty