Xcounter Ab

Juha Rantanen

Tom Francke

Christer Ullberg

The invention is related to a method for producing a collimator comprising an X-ray transparent substrate. The innovative method comprises the steps of: forming a slit in the substrate, wherein the slit has first and second side walls; filling the slit with an X-ray absorbing material so that the absorbing material extends from the first side wall to the second side wall; removing part of the X-ray absorbing material thereby forming a second slit that extends from the remaining absorbing material to the second side wall; filling the second slit with X-ray transparent material; removing part of the X-ray transparent material, thereby forming a third slit extending from the remaining transparent material to the second side wall; and finally filling the third slit with X-ray absorbing material. In accordance with the present invention a collimator can be produced having any desired aspect ratio.

Method for producing a collimator

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. To suppress the occurrence of sparks in the inter-electrode space an electrically conducting layer is formed on a second surface of the dielectric substrate of either one of the electrodes, and, during use, held at a selected electric potential held at a selected electric potential to thereby reduce the risk for occurrence of sparks between the cathode and anode arrangements.

Gaseous-based radiation detector

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&times;10 &OHgr;m.

Gaseous-based radiation detector and apparatus for radiography

A method and apparatus for radiography and also a detector for detecting incident radiation. In the method and the apparatus X-rays ( ) are emitted from an X-ray source ( ). The X-rays which have interfered with an object to be imaged are detected ( ) in a detector ( ). The detector ( ), 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. The detector detects electrical signals in at least two detector electrode modules, the electrical signals being induced by electron-ion avalanches, in at least one of a plurality of detector electrode elements arranged adjacent to each other, each along a direction essentially parallel to the incident radiation, and where the at least two independent detector electrode modules are arranged along a direction essentially parallel to the incident radiation.

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Solna, Sweden

Juha Rantanen