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: A tomographic apparatus for constructing a two-dimensional image of a cut (35) through an object comprises a source (3) for providing a planar beam of radiation so that the beam passes through said object, and thus defines said cut; a detector (9) positioned opposite said source and aligned therewith for detecting the radiation not absorbed or scattered by said object; an arrangement for causing relative movement, between said object and said source and detector combination about an axis of rotation (44) that is perpendicular to said cut through said object; a reconstruction device (39) coupled to said detector for performing a reconstruction process based upon non-absorbed and non-scattered radiation detected by said detector at a plurality of different relative positions between said object and said source and detector combination as reached by said movement causing arrangement, wherein said reconstruction device converts values of non-absorbed and non-scattered radiation into values of absorbed radiation i

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 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 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 for detection of ionizing radiation comprises a cathode; an anode; an ionizable gas arranged between these electrodes; a radiation entrance arranged such that ionizing radiation can enter and ionize the ionizable gas; and a readout arrangement. A voltage across the electrodes causes electrons created during ionization of the gas to drift towards the anode, where the readout arrangement detects them. To reduce the risk of occurrence of sparks, and/or to reduce the energy in occurring sparks, one of the cathode and anode has at least the surface layer facing the other electrode made of a material having a resistivity of at least 5×10−8 &OHgr;m.

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: 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.

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 method and apparatus for radiography, and a detector for detecting incident radiation. In the method and the apparatus, wherein X-rays (9) are emitted from an X-ray source (60), the X-rays are formed into a planar beam and are transmitted through an object to be imaged (62), and the X-rays transmitted through said object (62) are detected in a detector chamber (64). The detector chamber (64), which detects incident radiation, including electrode arrangements between which a voltage is applied for creating an electrical field, which may cause electron-ion avalanches of primary and secondary ionisation electrons released by incident radiation. The detector (64) is oriented, in relation to the incident radiation (9), so that the radiation preferably enters sideways between a first and a second essentially parallel plate, between which the electrical field is created.

Abstract: A method and apparatus for radiography, and especially for planar beam radiography, and also a detector for detecting incident radiation. In the method and the apparatus, wherein X-rays are emitted from an X-ray source, the X-rays are formed into a planar beam and are transmitted through an object to be imaged, and the X-rays transmitted through said object are detected in a detector. The detector, which detects incident radiation is a gaseous parallel plate 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. The detector is oriented, in relation to the incident radiation, so that the radiation enters sideways between a first and a second parallel plate, between which the electrical field is created.