Abstract: A radiation detector arrangement for imaging of an object comprises multiple line detector units, each being arranged for one-dimensional imaging of the respective ray bundle. The detector units are arranged parallel in a two-dimensional array. The detector units are sited in rows and stacks, the rows being parallel with the detector unit and the stacks being orthogonal thereto, where the one-dimensional detector units in each row are together capable of detecting the object in one dimension. A device is provided for moving the detector units relative the object parallel with the stacks at least a distance corresponding to the distance between two adjacent detector units in the stacks.

Abstract: Ions produced by radioactive gases present in air impact on the sensitivity of contamination measuring instruments which detect ions generated by radioactive materials present on an item. Methods and apparatus address this issue by conducting a measurement of ions generated in a chamber by gaseous emitters and other background events in a volume of medium and deducting this from a measurement of ions generated in another chamber by the item as well as the gaseous emitters and background events. The variation of the gaseous emitters present within the medium is addressed by moving the medium about. An alternative solution uses a medium free of gaseous emitters having a significant level, for instance by sealed storage of air prior to its use in a method and instrument.

Abstract: An ionization chamber is provided for the detection of nuclear radiation. The chamber is a vessel which acts as a cathode wherein at least one anode is disposed within the chamber and off-set from a center axis of the chamber. The chamber can be made from variety of shapes but is cylindrical in the preferred embodiment. The device contains two anodes in the preferred embodiment which are both off-set from the center axis. One anode collects the free floating electrons which are produced in response to particle ionization and therefore has a collected charge applied thereto. The second anode has the charge induced by immobile ions. The induced charge is subtracted from the collected charge thereby providing an improved resolution for the ionization chamber which translates into a more accurate result. In the preferred embodiment, a pressurized noble gas, such as xenon, is used.

Abstract: A microstrip gas chamber (MSGC) comprises a gas volume, an electrically insulating substrate having a surface exposed to the gas volume. A set of alternating cathode strips and anode strips are provided on the surface of substrate, a high voltage source for establishing a potential difference between the anode and cathode strips is provide to produce an electric field sufficient for avalanche multiplication in said gas medium in a region near the anode strips. Grid electrodes are provided on the surface at each gap between the cathode strip and anode strip. The multi-grid type MSGC can offer very narrow gap between neighboring electrodes that might reduce a surface charge effect considerably. The multi-grid type MSGC may be applied to the field where both high gain and the stable operation are required.

Abstract: Radiation detector comprising one or more amplifying structures, each comprising an input electrode and an output grid which are kept separated by an insulating spacer. Each spacer defines amplification spaces for generating electrons by the avalanche effect. The dimensions of these amplification spaces are decorrelated with those of the mesh cells of the output grid.

Abstract: The invention concerns a device and method for two-dimensional imaging and timing of particles or electromagnetic radiation with improved pulse-pair resolution. A detector, e.g. a michrochannel plate detector with a delay-line anode with three or more conductive members is used as exemplary embodiment for achieving these requirements. Redundant position and timing information is used for uniquely determine the timing and position of two or more particles, even if they arrive at the same time at the detector.

Abstract: The present invention describes an apparatus for detection of ionizing radiation, wherein the incident radiation ionizes a substance, and the electrons released as a result thereof are accelerated in a dual parallel plate electrode arrangement. These electrons will interact with a scintillating substance to emit light, which is detected by a position sensitive light detector. Since the light is emitted isotropically in such scintillator measures are taken to achieve a good spatial resolution. Thus, the scintillating substance is either arranged in an array of separately located scintillating elements, wherein each scintillating element is separated from the other ones by means of a light impermeable wall, or has an extension in the direction of the accelerated electrons shorter than the absorption length of the light photons emitted in the scintillating substance.

Abstract: The present invention relates to a microstrip gas chamber and microstrip plate capable of reading signals from readout electrodes provided at a rear surface of the substrate in a superior manner while having a simple and compact configuration. The microstrip plate comprises an electrically insulating substrate 1, cathodes 2 and anodes 3 arranged alternately at the surface of the substrate 1, read-out electrodes 4 arranged so as to intersect the cathodes 2 and anodes 3 at the rear surface of the substrate 1, wherein a plurality of unitary regions 20 are provided at the surface of the substrate 1 and each unitary region 20 is electrically floated from the cathode via a resistance region 5.

Abstract: A radiation detector arrangement for imaging of an object comprises multiple line detector units, each being arranged for one-dimensional imaging of the respective ray bundle. The detector units are arranged parallel in a two-dimensional array. The detector units are sited in rows and stacks, the rows being parallel with the detector unit and the stacks being orthogonal thereto, where the one-dimensional detector units in each row are together capable of detecting the object in one dimension. A device is provided for moving the detector units relative the object parallel with the stacks at least a distance corresponding to the distance between two adjacent detector units in the stacks.

Abstract: A scanning-based radiation detector arrangement for two-dimensional imaging of an object comprises a plurality of one-dimensional detector units, each comprising an entrance slit, through which ionizing radiation as transmitted through the object is entered, and being arranged for one-dimensional imaging of the ionizing radiation, wherein the detector units are arranged in an array on a support with their respective entrance slits being parallel with each other and facing the source of the ionizing radiation. The detector arrangement further includes a rotating device for rotating the detector unit array in a plane perpendicular to the direction of the ionizing radiation, while the detector units are arranged to repeatedly detect, hence creating a series of two-dimensional images of the object.

Abstract: An ionizing radiation detector comprising a plurality of conductive tubes arranged in parallel fashion containing a gas mixture under pressure, a conductive wire being tensed at the center of each tube and adapted to being polarized with respect thereto, and comprising first and second tight enclosures each having a wall provided with openings in which are tightly inserted the first and second ends of each tube, the ends of each tube being open.

Abstract: A detector for detection of ionizing radiation comprises a first cathode and a first anode between which a first voltage is applicable; an ionizable gas arranged at least partly between the first cathode and the first anode; a radiation entrance arranged such that ionizing radiation can enter and ionize the ionizable gas; and a read-out arrangement. The detector further comprises a second cathode and a second anode between which a second voltage is applicable; and a solid state ionizable material arranged between the second cathode and the second anode such that part of the radiation entered into the ionizable gas can propagate through the gas, enter the solid state material and ionize it; wherein the read-out arrangement is arranged for detection of the electrons and/or holes drifted towards the second anode and/or cathode, respectively, separately of detection of the electrons drifted towards the first anode.

Abstract: A radiation detector comprises two electrode arrangements, each including a dielectric substrate and an electrically conducting layer formed on a first surface of respective dielectric substrate, wherein the electrodes are oriented such that the conducting layers are facing each other. A dielectric spacer is provided to hold the electrodes at a distance from each other to thereby define an inter-electrode space, which, during use, is filled with an ionizable gas. The electrodes are held at respective electric potentials to drift electrons released during ionization of the ionizable gas by external radiation towards one of the electrodes for detection.

Abstract: An apparatus for planar beam radiography comprises an ionizing radiation source and an ionizing radiation detector; the ionizing radiation source being line-like and extending substantially in a first direction; and the ionizing radiation comprising an elongated radiation slit entrance extending substantially in a second direction and being arranged for one-dimensional detection of radiation from the radiation source entering the detector through the radiation slit entrance. According to the present invention the radiation source and the radiation dectector are oriented such that the first and second directions are essentially perpendicular. Hereby,a facilitated alignment of the detector with respect to source is achieved.

Abstract: A method for detecting ionizing radiation, a detector (64) for detection of ionizing radiation, and an apparatus for use in planar beam radiography, including the detector. The detector includes: a chamber filled with an ionizable gas; first and second electrode arrangements (2, 1, 18, 19) provided in the chamber with a space between them, the space including a conversion volume (13); an electron avalanche amplification unit (17) arranged in the chamber; and, at least one arrangement of read-out elements (15) for detection of electron avalanches. Radiation enters the conversion volume between the first and second electrode arrangements via a radiation entrance. The distance between the first and second electrode arrangements is selected to achieve discrimination of fluorescent photons and/or long-range electrons, in order to achieve improved position resolution.

Abstract: A detector for detection of ionizing radiation comprises a chamber (13) filled with an ionizable gas, and including a first (17, 19) and a second (21) electrode arrangement between which a first voltage (U1, U2) is applicable, a radiation entrance (33) arranged such that radiation (1) can enter the chamber between and substantially in parallel with the first and second electrode arrangements, for ionization of the ionizable gas, an electron avalanche amplification arrangement (15) including an avalanche cathode arrangement (25) and an avalanche anode arrangement (27), between which a second voltage (Ua) is applicable, and a read-out arrangement (29), wherein the first voltage is applicable for drifting electrons created during ionization towards the electron avalanche amplification arrangement, the second voltage is applicable for avalanche amplification of said electrons, and the read-out arrangement is arranged for detection of the electron avalanches and/or correspondingly produced ions.

Abstract: An X-ray image detector includes a photoelectric conversion part providing electric charges in accordance with the received amount of light; a charge storage part (storage capacitor) having a first storage electrode, a dielectric layer deposited on the first storage electrode, a second storage electrode on the dielectric layer and a pixel electrode in contact with total surface of the second storage electrode and collecting electric charges produced in the photoelectric conversion part; and a switching part controlling release of the electric charges stored in the storage capacitor and a method for fabricating the same. The x-ray image detector has a reduced “off” electric current due to a reduced leakage current of the TFT, and the capacity of storage capacitor is increased. Also, the X-ray image detector may be manufactured with a higher yield, due to reduced electrical shorts between the first and second storage electrodes.

Abstract: A particle beam image detector employing gas amplification attained by pixel-type electrodes has high sensitivity and improved reliability of electrodes.

Abstract: A neutron flux measuring apparatus, adapted to a boiling-water reactor (BWR) of a nuclear power plant and an advanced boiling-water reactor (ABWR) of a nuclear power plant, for measuring a neutron flux in a reactor pressure vessel, comprises a neutron flux detector assembly incorporating a local power range monitor detector assembly and a start-up range neutron monitor detector, a preamplifier amplifying a detector signal obtained from said start-up range neutron monitor detector, a start-up range neutron monitor operation unit operating, indicating and monitoring the amplified signal of the start-up range neutron monitor detector, and a local power range monitor operation unit operating, indicating and monitoring a signal obtained from the local power range monitor detector.

Abstract: In order to obtain suitable absorption of the radiation to be detected in the detector gas of a radiation detector, in particular an X-ray detector, the detector is constructed in such a way that the radiation enters the detector parallel to the counting wire, thus offering an absorption path having any desired length. According to the invention, a number of avalanche chambers 50 is arranged adjacent the absorption chamber 46, said avalanche chambers having a comparatively small cross-section. The avalanche chambers are provided with grids 54 in such a way that charge multiplication by the grid voltage can occur only in the avalanche chamber. Due to the comparatively small cross-section of the avalanche chambers, broadening of the current impulses to be detected is prevented. Moreover, the comparatively long absorption chamber offers good radiation absorption and the presence of several avalanche chambers enables a favourable detection rate.

Abstract: A multiple cell radiation detector includes a central cell having a first cylindrical wall providing a stopping power less than an upper threshold; an anode wire suspended along a cylindrical axis of the central cell; a second cell having a second cylindrical wall providing a stopping power greater than a lower threshold, the second cylindrical wall being mounted coaxially outside of the first cylindrical wall; a first end cap forming a gas-tight seal at first ends of the first and second cylindrical walls; a second end cap forming a gas-tight seal at second ends of the first and second cylindrical walls; and a first group of anode wires suspended between the first and second cylindrical walls.

Abstract: The invention relates to an ionization chamber for ion beams and to a method of monitoring the intensity of an ion therapy beam by way of such an ionization chamber. For that purpose, the ionization chamber includes a chamber housing, a beam inlet window and a beam outlet window, a chamber volume filled with counting gas, a high-voltage anode and a high-voltage cathode, wherein the ionization chamber is constructed flat and sandwich-like from plate-shaped large-surface-area structures of the above-mentioned components, which are aligned orthogonally relative to the axis of the ion beam, and a centrally arranged large-surface-area orthogonally aligned plate-shaped counting anode is surrounded on both sides by a large-surface-area plate-shaped high-voltage cathode consisting of two parallel cathode plates, and the chamber housing consists of a housing frame, which frames a square ionization chamber volume, and on which frame the beam inlet window and the beam outlet window are mounted gas-impermeably.

Abstract: In a radiation image photographing apparatus using a radiation detection cassette containing an image memory, image data read from the image memory are properly related to a photographing menu used at the time of obtaining the image data. A counter value C of a photographing counter 57 in a cassette 50 is converted to radio data C′ and transferred to a display apparatus 21 while being stored in an image memory 45 as accompanying information of image data D. The display apparatus 21 relates the transferred counter value C to a photographing menu. When the image data D are read from the image memory 45, the counter value C is also read and the photographing menu corresponding to the image data D is identified by referring to the counter value C.

Abstract: A Geiger-Mueller triode directional sensor is provided to detect the direction of incident ionizing gamma radiation, comprising a housing divided into two subchambers, or GM counters, separated by a partition composed of a high Z layer of tungsten, the tungsten partition having an aperture for gas to freely communicate between the subchambers and maintain an identical gas mixture in both subchambers, radiation windows, external layers of a second material in the sidewall and a sensor. Incident gamma rays generate electrons within the tungsten partition, housing and the sidewall based on the photoelectric, Compton and pair effects. The electrons penetrate the radiation windows and are accelerated by an applied electric field in the housing, causing the electrons to ionize the gas within the housing and produce electrical discharges.

Abstract: A detector unit for detecting photons in the energy range 1 keV to 100 MeV, includes at least two converter layers adapted to interact with incident X-ray photons and to cause electrons to be emitted therefrom, at least one amplifier adapted to interact with the electrons emitted from the converters and adapted to produce a multiplicity of secondary electrons and photons representing a signal proportional to the incident fluence of X-ray photons, a connector connecting the detector to an electric field generator providing an electric drift field for secondary electrons in the detector, and a sensor device arranged to receive the signal and provide an input to electronic signal processor.

Abstract: A detector (64) for detection of ionizing radiation, an apparatus for use in planar beam radiography, comprising such a detector, and a method for detecting ionizing radiation. The detector comprises: a chamber filled with an ionizable gas; first and second electrode arrangements (2, 1, 18, 19) provided in said chamber with a space between them, said space including a conversion volume (13); means for electron avalanche amplification (17) arranged in said chamber; and, at least one arrangement of read-out elements (15) for detection of electron avalanches. A radiation entrance is provided so that radiation enters the conversion volume between the first and second electrode arrangements. In order to achieve well-defined avalanches the means for electron avalanche amplification includes a plurality of avalanche regions.

Abstract: A method and apparatus for radiography and also a detector for detecting incident radiation. In the method and the apparatus X-rays (9) are emitted from an X-ray source (60). The X-rays which have interfered with an object to be imaged are detected (62) in a detector (64). The detector (64), which detects incident radiation includes a gaseous avalanche chamber, including electrode arrangements between which a voltage is applied for creating an electrical field, which causes electron-ion avalanches of primary and secondary ionization electrons released by incident radiation.

Abstract: A detector for detection of ionizing radiation, and an apparatus for use in planar beam radiography, including such a detector. The detector includes a chamber filled with an ionizable gas. First and second electrode arrangements are provided in the chamber with a space therebetween. The space includes a conversion volume, an electron avalanche amplification unit arranged in the chamber, and at least one arrangement of read-out elements for detection of electron avalanches. To reduce the effect of possible spark discharges in the chamber, at least one of the first and second electrode arrangements includes a resistive material having a surface facing the other electrode arrangement.

Abstract: A radiation image detecting system includes a solid radiation detector made up of a plurality of solid radiation detecting elements which are two-dimensionally arranged and convert radiations bearing thereon image information to an image signal. An A/D convertor converts the image signal as output from the solid radiation detector to a digital image signal. The digital image signal is analyzed and a characteristic of standardization processing which is to be carried out on the digital image signal is determined. A standardization processing circuit carries out standardization processing on the digital image signal according to the characteristic of standardization processing determined.

Abstract: A detector (64) for detection of ionizing radiation, and an apparatus for use in planar beam radiography, including the detector (64). The detector (64) includes a chamber filled with an ionizable gas; first and second electrode arrangements (2, 1, 18, 19) provided in the chamber with a space between them, the space including a conversion volume (13); an electron avalanche amplification unit (17) arranged in the chamber; and, at least one arrangement of read-out elements (15) for detecting of electron avalanches. A radiation entrance is provided so that radiation enters the conversion volume between the first and second electrode arrangements. In order to achieve detectors which are simple to stack with each other, the first and second electrode arrangements exhibit a first and a second main plane, said planes being non-parallel. This permits stacked detectors to be manufactured simply and cost effectively.

Abstract: The invention relates to a device for digital subtraction angiography in an energy subtraction mode with a special electronic circuit.

Abstract: A device for determining the photon energy E1 and direction cone angle of incident gamma ray includes a radiation detector for receiving an incident gamma ray having an unknown photon energy E1 and an unknown direction and for scattering the gamma ray with two Compton scattering interactions and a subsequent scattering or absorption interaction. The detector provides three outputs, each output corresponding to one of the Compton scattering and the subsequent scattering or absorption interactions, to a processor, which is programmed to calculate the photon energy E1 and direction cone angle of the incident gamma ray based on these outputs.

Abstract: Spectrally resolved detection of ionizing radiation in a detector comprising a chamber (13) filled with an ionizable substance, a radiation entrance (33), an electron avalanche amplification means, and a read-out arrangement (29), comprises introducing a broadband radiation beam (1) into the chamber between and in parallel first and second electrode arrangements for ionization of the ionizable substance and avalanche amplifying said electrons. By means of the read-out arrangement (29) electron avalanches (SX1, SX2, . . . SXN), derivable mainly from ionization in sections (X1, H2, . . . , XN) of the chamber that are separated in the direction of the introduced radiation beam, are separately detected. From spectrally resolved absorption data, weighting factors (W11, W21, . . . , WM1, W12, W22, . . . , WM2, . . . , W1N, W2N, . . . , WMN) for different spectral components (E1, E2, . . . , EM) of the radiation (1) and for different sections (X1, X2, . . .

Abstract: The apparatus and method provide an improved technique for detecting ions as the area from which ions are attracted to a detector is increased, consequently increasing the number of ions detected. This is achieved by providing the outer electrodes of the detector connected to the electrical potential, together with alternate intermediate electrodes. The other intermediate electrodes and preferably the housing are grounded. The technique renders such detection techniques more sensitive and gives them a lower threshold at which they can function.

Abstract: A system for processing signals from a radiation detector with semiconductors. A plurality of elementary detectors are placed side-by-side along a detection surface or a detection volume in which radiation referred to as incident radiation is capable of giving up its energy in at least one interaction. The device includes the supplying in response to each incident ray, an amount of energy corresponding to the sum of the energies given up during each interaction induced by the incident radiation. This device may be used in medical imaging.

Abstract: The apparatus and method provide a technique for improving detection of alpha and/or beta emitting sources on items or in locations using indirect means. The emission forms generate ions in a medium surrounding the item or location and the medium is then moved to a detecting location where the ions are discharged to give a measure of the emission levels. To increase the level of ions generated and render the system particularly applicable for narrow pipes and other forms of conduits, the medium pressure is increased above atmospheric pressure.

Abstract: A multi-detector system receives incident radiation through a subject includes a gaseous microstrip detector, which has alternating anodes and cathodes on a substrate opposite a voltage source, is positioned adjacent a semiconductor detector. In a dual energy environment, electric fields are applied to both detectors as the incident radiation is directed therethrough. A gas electron multiplier is placed within the gas microstrip detector, and a potential is applied thereto to improve the generated signal. To further improve this signal, the anode and cathode may be operated as a Frisch Grid. Accordingly, the detectors generate corresponding signals which are compared to generate a contrasted signal of the subject. These signals may be generated for imaging, radiation monitoring, radiation measuring and the like. The direction of incident radiation and the orientation of the electric fields may be adjusted according to the particular application.

Abstract: A microstrip gas chamber comprises a gas volume, an electrically insulating substrate having a surface exposed to the gas volume, a set of alternating cathode strips and anode strips on the surface of substrate, a high voltage source for establishing a potential difference between the anode and cathode strips to thereby produce an electric field sufficient for avalanche multiplication in said gas medium in a region near the anode strips, and grid electrodes provided on the surface at each gap between the cathode strip and anode strip. The multi-grid type MSGC can offer very narrow gap between neighboring electrodes that might reduce a surface charge effect considerably. The present MSGC may be applied to the field where both the high gain and the stable operation are required.

Abstract: The invention relates to an ionization chamber which includes a plurality of measuring field electrodes (131 . . . 133) which are arranged on a substrate (120) at a distance from one another and are provided with supply leads (134), and at least one electrode (180) which is arranged at a distance from and faces the substrate and emits charge carriers under the influence of X-rays. An insulating layer (140; 190) provided on the supply leads and/or on the electrode, at least at the area of the supply leads, prevents the signals from the ionization chamber from being falsified by the charge carriers incident on the supply leads. The electrically insulating (layers) have such a high X-ray transparency that they are practically not reproduced in an X-ray image.

Abstract: The coplanar interdigitated grid technique with single electrode readout provides substantial spectral performance improvement over that of conventional full-area planar electrode detectors and over coplanar interdigitated grid detectors which measure the difference between the induced charge signals from two interdigitated coplanar grid electrodes. The signal from only one interdigitated grid electrode is read out. The signal response is optimized by changing the relative areas of the two grid electrodes and the bias applied across the detector. Only one preamplifier is needed and signal subtraction is not necessary. This eliminates the electronic noise contribution from the additional preamplifier used in the normal coplanar grid implementation, and conventional single-amplifier detector electronics can be used.

Abstract: The application of gas-detection principles on both dual-energy detection, such as for chest radiography and mammorgraphy, and quantitative autoradiography enhances dramatically the image quality of the digital dual-energy detector with great implications in general-purpose digital radiography, computer assisted tomography (CT), microtomography and x-ray microscopy, and offers notable advantages over film autoradiography with a higher sensitivity, much lower exposure times, as well as imaging access at the cellular level. A gas microstrip detector receives incident radiation through a subject to generate an image. The detector includes a substrate having on a first surface a plurality of alternating anodes and cathodes, a detector cathode spaced apart from and opposing the substrate, and a zone for dispensing a gaseous medium between the substrate and the detector cathode and for receiving incident radiation imparted through the subject.

Abstract: A parallax-free X-ray imager in which a parallel X-ray beam is directed to a crystal for illuminating an entrance window is formed in a vessel filled with an ionizing gas in which primary electrons are generated. A spherical conversion volume chamber is formed by the entrance window and a first and a second parallel electrodes are adapted to generate electrical equipotential surfaces of spherical shape allowing the primary electrons to drift along corresponding radial field lines. A third electrode parallel with the second electrode is provided so as to form a gas electron multiplier structure consisting of a matrix of electric field condensing areas which are adapted to operate as an amplifier of the primary electrons through an avalanche phenomenon. A signal readout electrode is provided to allow a bi-dimensional readout in the absence of parallax readout phenomenon.