GB1090745A - Flow counter for measurement of radioactive materials - Google Patents

Abstract

1,090,745. Ionization counters. FARBENFABRIKEN BAYER A.G. March 5, 1965 [March 7, 1964; Nov. 24, 1964], No. 9492/65. Heading H1D. [Also in Division G1] An external field is established in the vicinity of an open entrance 8 of a flow counter comprising a counting wire 3 maintained at a positive potential with respect to the wall of a chamber 2 to prevent positive ions from the chamber reaching a radio-active source 11 under investigation and to prevent externally produced secondary electrons from entering the chamber. The chamber 2 is formed in a metal block cathode 1 containing methane gas supply conduits 4, 5 and 6. The aperture 8 is a slot in a metal plate 7. The radio-active source 11 is supported by a conductive or non-conductive mounting material 9 on an electrode 10, and the external field is produced by applying a voltage U s between electrode 10 and cathode 1. In alternative arrangements the voltage is applied between two apertured conductive plates (14 and 15), Figs. 2 and 3 (not shown), separated by an insulating layer (16), or between two sets of inter-digitated wires (27 and 28), Figs. 4 and 5 (not shown), attached to bars (23 and 24) separated by insulating material (22) from an apertured conductive plate (20). The sensitivity of the counter can be varied by varying the external field or by switching it on and off, thus enabling the count rate of each component of a mixture of #-emitting isotopes, e.g. <SP>3</SP>H and <SP>14</SP>C, to be determined.