Abstract:
An ultra-violet/visible/infra-red gamma-insensitive gas avalanche focal plane array comprising a planar photocathode and a planar anode pad array separated by a gas-filled gap and across which is applied an electric potential. Electrons ejected from the photocathode are accelerated sufficiently between collisions with the gas molecules to ionize them, forming an electron avalanche. The gap acts like a proportional counter. The array of anode pad are mounted on the front of an anode plate and are connected to matching contact pads on the back of the anode via feed through wires. Connection of the anode to signal processing electronics is made from the contact pads using standard indium bump techniques, for example.
Abstract:
A highly sensitive and compactly structured radiation measuring instrument for detecting ionizing radiation, in particular for measuring dose rates and contamination.The laminar structure of the associated counter tube, using only a few, simple plastic parts (1, 8, 9) and a highly elastic counter wire (2), makes it possible to use the simplest manufacturing techniques. The service life of the counter tube construction, which is completely and permanently sealed and filled with gas, is expected to be more than 12 years.The described counter tube can be adapted in optimal fashion to the available space in a pocket instrument if it is used in combination with a specialized high-voltage generator which is low in interference voltage and with a pulse evaluation circuit having a means of compensating for interference voltage.
Abstract:
This invention provides a high-resolution, position-sensitive, proportional-counter for ionizing radiation emanating from a surface source of ionizing radiation. There is provided a counting chamber means having an open entrance window on one side of and spaced from the source of ionizing radiation, and an anode counting wire on the other side of the open entrance window. Also, there is provided a counter wall cathode, having a delay line read-out opposite to the entrance window and spaced from the anode. A means, including several orifices for flushing a counting gas through the counting chamber means and out of the open entrance window between the source and the open entrance window, produces a stabilizing counting gas layer that does not mix with the surrounding air. This prevents the sample from being completely surrounding air. This prevents the sample from being completely enclosed so as to be charged up electrostatically. An electronic means is connected to the delay line for providing the read out of the desired high-resolution, position-sensitive, proportional-counter information corresponding to the ionizing radiation emanating from outside the open entrance window.
Abstract:
A curved location- or positionally-sensitive proportional counter tube having a trough-shaped cathode in a counting chamber. A curved resiliently elastic wire forming the anode extends longitudinally through the curved counting chamber in conformance with the curvature of the latter. Suitable fastening arrangements engage the ends of the wire so as to mount the wire in asymmetrical relationship to a counter tube window and equidistantly from the side walls of the cathode trough.
Abstract:
A fan-shaped beam of penetrating radiation, such as X-ray or .gamma.-ray radiation, is directed through a slice of the body to be analyzed to a position sensitive detector for deriving a shadowgraph of transmission or absorption of the penetrating radiation by the body. A number of shadowgraphs are obtained for different angles of rotation of the fan-shaped beam relative to the center of the slice being analyzed. The detected fan beam shadowgraph data is reordered into shadowgraph data corresponding to sets of parallel paths of radiation through the body. The reordered parallel path shadowgraph data is then convoluted in accordance with a 3-D reconstruction method by convolution in a computer to derive a 3-D reconstructed tomograph of the body under analysis. In a preferred embodiment, the position sensitive detector comprises a multiwire detector wherein the wires are arrayed parallel to the direction of the divergent penetrating rays to be detected. A focussed grid collimator is interposed between the body and the position sensitive detector for collimating the penetrating rays to be detected. The source of penetrating radiation is preferably a monochromatic source.
Abstract:
A method and apparatus designed for the purpose of determining quickly and with high resolution the spatial distribution of radioactivity within an object emitting radioactive particles, especially those of low energy. A gas-filled position sensitive detector is used having an elongated electrode wire enclosed inside of and running the length of the detector. The object is placed inside the detector in close proximity to the wire. An electric circuit means is operably connected to the wire to determine the point along the wire at which an emitted particle is sensed. A two-or three-dimensional spatial distribution can be obtained by using a plurality of such wires.
Abstract:
A proportional detector for the localization of particles comprises a leak-tight chamber filled with fluid and fitted with an electrode of a fisrt type consisting of one or more conducting wires and with an electrode of a second type consisting of one or more conducting plates having the shape of a portion of cylindrical surface and a contour which provides a one-to-one correspondence between the position of a point of the wires and the solid angle which subtends the plate at that point, means being provided for collecting the electrical signal which appears on the plates.
Abstract:
A set of proportional counters has been arranged into an array which can detect and indicate the position of an X-ray interaction within the array, in the X-Y plane.
Abstract:
A radio-active radiation counter is provided with a counter chamber having a diaphragm-less open window, and two collecting electodes are disposed in said chamber and separated from each other. A gas to be ionized is injected in a pulse into the chamber intermittently to create a gas cloud for a short duration in the space where the electrodes are disposed, and a voltage pulse is applied across the electrodes during the presence of said gas cloud between the electrodes to operate the counter in order to measure the radiation coming into the chamber during the voltage being applied to the electrodes. Because of the absence of a diaphragm in the ray entrance window of the counter chamber, the absorption of radiation energy in a diaphragm is avoided and thereby it is possible to measure radiations of energy less than 1 Kev.