Abstract: An electron filtering layer placed on a photocathode of a UV light detector allows to selectively filter out electrons generated from a photoconversion of long wavelengths. The filter may be tuned by selecting the material and the thickness of the electron filtering layer. By means of the filtering layer, background noise due to visible parts of the spectrum may be efficiently suppressed. Applications of the invention include a solar-blind flame and/or smoke detector.

Abstract: A radiation detector for imaging a sheet-shaped beam (11) of ionizing radiation comprises an electron multiplication chamber (12) filled with a medium for electron multiplication; and a solid multichannel structure (14) arranged in the path of the sheet-shaped beam within the chamber, wherein the structure liberates electrons (16a) in response to being exposed to the radiation. An electron detecting means (17d) is provided for detecting the electrons spatially resolved to thereby image the sheet-shaped beam. The structure (14) is of a scintillating material, so that said the structure emits scintillating light in response to being exposed to the radiation; and detecting means (19–20) are provided for detecting scintillating light (18) emitted from the structure.

Abstract: The invention is related to a detector assembly for detecting vapours, smoke and flames, comprising a detector unit 1 having a UV sensitive photocathode 3, an anode 5, a voltage supply unit 9 connected to the UV sensitive photocathode 3 and to the anode 5 to create an electric field such that photoelectrons emitted from the UV sensitive photocathode 3, when struck by UV light, are forced to move towards the anode 5, and a readout arrangement for detecting charges induced by electrons moving towards the anode 5 thereby generating a signal related to the intensity of detected UV light. The detector assembly further comprises an artificial source 21 for emitting radiation having wavelengths within a wavelength interval, the source 21 being oriented such that UV light from the source 21 can strike the UV sensitive photocathode 3. The wavelength interval coincides with a transmission band of air, and with an absorption band of vapours containing molecules of a complex structure.

Abstract: A radiation detector for imaging a sheet-shaped beam (11) of ionizing radiation comprises an electron multiplication chamber (12) filled with a medium for electron multiplication; and a solid multichannel structure (14) arranged in the path of the sheet-shaped beam within the chamber, wherein the structure liberates electrons (16a) in response to being exposed to the radiation. An electron detecting means (17d) is provided for detecting the electrons spatially resolved to thereby image the sheet-shaped beam. The structure (14) is of a scintillating material, so that said the structure emits scintillating light in response to being exposed to the radiation; and detecting means (19-20) are provided for detecting scintillating light (18) emitted from the structure.

Abstract: The invention relates to a multi-layered radiation converter, a radiation detector comprising such a converter as well as a radiation-based imaging system using such a detector. Each converter layer (32) in the radiation converter is adapted for interaction with incident radiation to cause the emission of electrons into drift holes defined in the converter layer. The drift holes of one converter layer (32-1) are staggered with respect to the drift holes of another converter layer (32-2). By mutually shifting the converter layers such that the drift holes of two different layers are no longer well-aligned, but rather staggered with respect to each other, the effective conversion area will be increased, and the probability of incoming radiation passing through the stack without interaction with the converter layers will be significantly reduced.

Abstract: A radiation detector including a chamber capable of being filled with an ionizable and scintillating substance, and a radiation entrance arranged such that radiation can enter said chamber partly for ionizing said ionizable and scintillating substance, partly for being converted into light therein, is disclosed. The detector further includes a light detector for detection of said light, and an electron avalanche detector for avalanche amplification and detection of electrons released as a result of the ionization. Further, there are provided means for correlating detected light and detected electrons, which are derivable from a single radiation photon; and means for producing a signal from the correlated detected light and detected electrons. The detector is particularly suitable for positron emission tomography (PET).

Abstract: The present invention relates to an apparatus for detection of radiation comprising a photocathode layer adapted to release photoelectrons in dependence on incident radiation; a radiation entrance arranged such that a beam of radiation can be entered into the apparatus through said radiation entrance and can impinge on said photocathode layer at grazing incidence; an electron avalanche amplifier adapted to avalanche amplify photoelectrons released from said photocathode layer; and a readout arrangement adapted to detect avalanche amplified electrons from said amplifier. The invention further relates to a corresponding method for detection of ionizing radiation and to an arrangement for use in planar beam radiography comprising the detector apparatus.

Abstract: The present invention relates to a flame detector for detection of the presence of a flame or spark in front of the detector comprising a UV sensitive photocathode (12; 21) and an anode (14; 22), respectively, wherein the UV sensitive photocathode is oriented such that UV light from a flame present in front of the detector can strike the photocathode; a voltage supply unit (18; 23) connected to the UV sensitive photocathode and to the anode to force photoelectrons emitted from the UV sensitive photocathode when struck by UV light from a flame present in front of the detector to move towards the anode; and a readout arrangement (15-17; 24) adapted to detect charges induced by electrons moving towards the anode to thereby detect the presence of a flame in front of the detector. The flame detector can be combined with an alarm unit (33) to form an automatic alarm (31).

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: An apparatus and method for detecting ionizing radiation are presented. The apparatus includes a scintillator adapted to convert incident ionizing radiation into light; a photocathode adapted to release photoelectrons in dependence on the light; an electron avalanche amplifier adapted to avalanche amplify the photoelectrons; and a readout arrangement adapted to detect the avalanche amplified electrons. The electron avalanche amplifier in one implementation is a gaseous avalanche amplifier including an array of amplification regions. A protective layer is provided to prevent the avalanche gas from coming into contact with the photocathode.

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: The present invention relates to an apparatus (11) for conversion of visible light to UV light, and includes an entrance window (17) transparent to visible light; a photocathode (23) adapted to release photoelectrons in dependence on being irradiated by visible light; an electrode arrangement (27, 29) connectable to a voltage supply; a scintillator (21, 35) adapted to emit UV light in dependence on being struck by electrons; and an exit window (19) transparent to UV light. Visible light is, during conversion, entered through the entrance window and irradiates the photocathode. Photoelectrons released from the photocathode is, by means of an electrical field created by the electrode arrangement, drifted towards the scintillator, where they are converted into scintillating light, which is output through the exit window. The converter is advantageously arranged in front of a gaseous based two-dimensional UV light detector for detection of visible light.

Abstract: The present invention relates to a flame detector for detection of the presence of a flame or spark in front of the detector comprising a UV sensitive photocathode (12; 21) and an anode (14; 22), respectively, wherein the UV sensitive photocathode is oriented such that UV light from a flame present in front of the detector can strike the photocathode; a voltage supply unit (18; 23) connected to the UV sensitive photocathode and to the anode to force photoelectrons emitted from the UV sensitive photocathode when struck by UV light from a flame present in front of the detector to move towards the anode; and a readout arrangement (15-17; 24) adapted to detect charges induced by electrons moving towards the anode to thereby detect the presence of a flame in front of the detector. The flame detector can be combined with an alarm unit (33) to form an automatic alarm (31).

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 radiation detector including a chamber capable of being filled with an ionizable and scintillating substance, and a radiation entrance arranged such that radiation can enter said chamber partly for ionizing said ionizable and scintillating substance, partly for being converted into light therein, is disclosed. The detector further includes a light detector for detection of said light, and an electron avalanche detector for avalanche amplification and detection of electrons released as a result of the ionization. Further, there are provided means for correlating detected light and detected electrons, which are derivable from a single radiation photon; and means for producing a signal from the correlated detected light and detected electrons. The detector is particularly suitable for positron emission tomography (PET).

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 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: A detector for detection of ionizing radiation, an apparatus for use in planar beam radiography, comprising such a detector, and a method for detecting ionizing radiation.

Abstract: A detector unit for two-dimensional detection of incoming radiation from an X-ray source, primarily for use in X-ray radiography. The unit includes a solid material structure (2) having a plurality of passages (6) extending therein and comprising surface portions (7) comprising a conversion medium. The surface portions of the passages are inclined, so that the incoming radiation impinges at an acute angle onto the surface portions. In this way, the efficiency of the detector and the positional resolution are improved.