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 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: 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 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.
Type:
Grant
Filed:
December 7, 2000
Date of Patent:
May 14, 2002
Assignee:
XCounter AB
Inventors:
Tom Francke, Christer Ullberg, Juha Rantanen
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.
Type:
Grant
Filed:
November 19, 1999
Date of Patent:
May 7, 2002
Assignee:
Xcounter AB
Inventors:
Tom Francke, Vladimir Peskov, Christer Ullberg
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.