A dosimeter for ionizing radiation is of oblong shape. It comprises a gas-filled measuring chamber surrounded by a casing. The casing is formed of two oblong frames (7,8) of insulating material that are substantially similar in shape. The two frames are mounted on each other in a gas-tight manner. The anode wires (13) are situated in the plane of separation between the frames and are secured by the frames in contact with each other. At least one of the frames is provided with a cathode (14,15) over its whole length and parallel to the plane in which the anode wires are situated. Along the edge of the cathode extends a guard electrode which surrounds the cathode with a certain gap. The dosimeter is made of materials that are transparant to the ionizing radiation. It can be used particularly in slit radiography equipment in which the slitwidth can be controlled locally and independently along the length of the slit.

An apparatus for slit radiography comprising an X-ray source by means of which a body being irradiated can be scanned through a slit diaphragm by a substantially planar, fan-shaped X-ray beam, the scanning X-ray beam passed through the body impinging upon an X-ray detector. The apparatus comprises controllable attenuation elements coacting with the slit diaphragm, each element being adapted to influence a sector of the scanning X-ray beam under the control of signals generated by a radiation detector device. The radiation detector device is disposed between the body being irradiated and the X-ray detector. The radiation detector device comprises at least one radiation detector extending at any moment into the scanning X-ray beam passed through the body and moving in synchronism with the scanning movement of the X-ray beam. The radiation detector device is divided into sections corresponding with the sectors of the scanning X-ray beam influenceable by the attenuation elements, while, in operation, each section of the radiation detector device generates a signal usable for controlling the attenuation elements.

An apparatus for slit radiography comprising discrete controllable attenuation elements coacting with a slit diaphragm, each attenuation element being affixed to damping means.

An optical wedge (115) compensates for a vertically drifting laser beam (45A, 45B, 45C) in response to ambient temperature fluctuations. A slit sensor (75) is formed onto a surface (155) of the wedge to separate a single light pulse (100d) from a plurality of light pulses (100a...e). A reflective filter layer (140) is applied to a side opposite the slit sensor (75) so an incident laser beam (45A, 45B, 45C) is attenuated thereby precluding damage to the slit sensor (75). The reflective filter coating (140) further filters out unwanted light energy. The wedge (115) is shaped so as to maintain a position of a focal point (60A, 60B, 60C) of a laser beam (45A, 45B, 45C) on the slit sensor (75) and to prevent reflected light (80) from damaging a laser source (40).

An optical wedge (115) compensates for a vertically drifting laser beam (45A, 45B, 45C) in response to ambient temperature fluctuations. A slit sensor (75) is formed onto a surface (155) of the wedge to separate a single light pulse (100d) from a plurality of light pulses (100a...e). A reflective filter layer (140) is applied to a side opposite the slit sensor (75) so an incident laser beam (45A, 45B, 45C) is attenuated thereby precluding damage to the slit sensor (75). The reflective filter coating (140) further filters out unwanted light energy. The wedge (115) is shaped so as to maintain a position of a focal point (60A, 60B, 60C) of a laser beam (45A, 45B, 45C) on the slit sensor (75) and to prevent reflected light (80) from damaging a laser source (40).

Die Erfindung betrifft eine Schlitzblende (50, 70, 90), insbesondere für eine bildgebende Einrichtung (100), welche geeignet ist, von einer Strahlungsquelle (102) ausgehende, insbesondere hoch-energetische, Strahlung (104) zu begrenzen und entlang einer optischen Achse (x) nach dem Lochkameraprinzip auf einen Abbildungsbereich (106) zu richten, wobei die Schlitzblende (50, 70, 90) ein erstes Absorptionselement (52, 72) umfasst, welches eine erste nicht-ebene Außenfläche (54) aufweist, von der zumindest ein Teilbereich auf einer Regelfläche liegt, deren gaußsche Krümmung in dem Teilbereich nirgends verschwindet, wobei die Schlitzblende (50, 70, 90) ein zweites Absorptionselement (56, 76) umfasst, welches eine zweite nicht-ebene Außenfläche (58) aufweist, deren Oberflächenkontur zumindest teilweise komplementär zu der nicht-ebenen Außenfläche (54) des ersten Absorptionselements (52, 72) geformt ist, und wobei die beiden Absorptionselemente (52, 72; 56, 76) derart positioniert oder positionierbar sind, dass zwischen den beiden nicht-ebenen Außenflächen (54, 58) ein Spalt (60, 80, 92) vorhanden ist. Der Abstand in einer Richtung (y) senkrecht zu der optischen Achse (x) zwischen den Erzeugenden der Regelfläche verringert sich zum Abbildungsbereich (106) hin. Die Erfindung betrifft ferner eine Vorrichtung und ein Verfahren zur Herstellung einer Schlitzblende, wobei eine erste Rotationsbewegung, eine zweite Rotationsbewegung und eine Translationsbewegung miteinander gekoppelt sind.