GB966746A - Improvements in or relating to apparatus for detecting radioactive particle emission - Google Patents

Abstract

966,746. Detecting radio-activity. PLESSEY CO. Ltd. June 21, 1961 [March 21, 1960], No. 9992/60. Heading G1A. The invention relates to apparatus for the detection of elementary particle emission from materials deposited or precipitated on to the surface of a moving member inside an enclosed, and possibly pressurised, vessel to obtain an indication of the radio-activity within the vessel. According to the invention the moving member, which may be a wire 4, is guided through a channel in a scintillation emitting phosphor 3 coupled to a light guide sealed into the wall of the vessel and having a flat surface 8a co-operating with a photo-sensitive device 8 and a curved surface acting as a reflector to reflect scintillations towards the flat surface. As shown the light guide 2 is semicylindrical over the central and greater part of its length and includes a channel in which is positioned the phosphor tube 3 surrounding the wire 4. The tube 3 is at the focus of the almost parabolic curved reflecting surface of the guide. The ends 2b, 2c, of the guide are circular in cross-section and one end (2c) is sealed directly into the wall of the vessel 1 by ring 5a whilst the other is sealed by ring 5b to a plug 6 sealed to the vessel by gas seal 7. The detector 8, which may be a photomultiplier, fits into a bore in the vessel and contacts the flat surface 8a of the light guide. It is not subject to internal pressure of the vessel and coolant may be circulated round it if required.