Ionizing radiation detector adapted for use with tomography systems

An improved ionizing radiation detector functioning in a proportional chamber mode, for use with x-ray tomography systems, comprising an elongated curvilineal housing enclosing a chamber, a high-pressure gas of great atomic weight and substantially opaque to x-radiation in said chamber, anodes and cathodes mounted in said chamber enclosed in the gas, voltage supply means for supplying a positive voltage to said anodes and a negative voltage to said cathodes, said housing having a curvilineal side comprising a curvilineal window of a material substantially transparent to x-radiation for passing the x-radiation into the said chamber, said cathodes comprising a plurality of plate cathodes spaced at intervals along the elongated curvilinear axis of said housing at right angles thereto substantially parallel to the beam direction of radiation to be detected, each of said anodes comprising a frame and a plurality of metal wires extending parallel to the beam direction at spaced intervals within a substantially common plane on said frame for supporting said wires, each of said anodes being located midway between two adjacent cathodes thereby forming a voltage pulse after each absorbed x-ray quantum, said housing having a dimension parallel to the beam direction sufficient to allow at least 70 percent of the x-ray quanta to be absorbed in the gas, and means for separately detecting the voltage pulse on each anode wire.