GB746269A - Improvements in or relating to radiation detectors - Google Patents

Abstract

746,269. Geiger counters. TEXACO DEVELOPMENT CORPORATION. May 8,1952, No. 20396/55. Divided out of 746,172. Class 39 (1). In a plate-type radiation detector as described in Specification 612,899 comprising a plurality of cathode plates 22 and an anode wire 24 extending through aligned apertures 25 in the cathode plates, travel of the ion sheath along the anode wire is limited by means of conducting plates 23 mounted between groups of cathode plates. The plates 23 are of the order of two to three times the thickness of the cathode plates and are of slightly less diameter. The anode wire 24 is maintained at the operating potential E<SP>1</SP> of the counter and extends through aligned apertures 26 in the plates 23, these apertures being of less diameter than the apertures 25 in the cathode plates. A bus-bar 27 connected to the plates 23 and passing through apertures in the cathode plates maintains the plates 23 at a potential E<SP>2</SP> such that the field strength in the apertures 26 is insufficient to sustain ionization along the anode wire and will thus block the travel of the ion sheath. The period during which the detector is insensitive is thus reduced so that high counting rates are possible. The counter is filled with gas at a low pressure, for example a mixture of argon and alcohol at a pressure of 5-20 inches of mercury. The invention is applicable to detectors of the plural anode type as described in the parent Specification.