GB712009A - Improvements in gamma ray apparatus - Google Patents

Abstract

712,009. Gamma-ray apparatus. STEIN, S. Nov. 28, 1952 [June 27, 1952; June 27 1952; July 8, 1952] Nos. 16192/52, 16193/52, and 17122/52. Class 98(1) Gamma-ray apparatus of the kind including a container for the source composed of lead or other shielding metal and means operable from a remote point for moving the source from a safe position in which the source is totally enclosed within the container walls to a position in which the source occupies an exposed position for operative use, is characterized by a tubular conduit or other guideway associated with the container along which tubular conduit the source can be guided to a remote examination point and means operable from a point remote from the container for moving the source out of the container and along the conduit and after the examination has been completed for returning the source to its safe position within the container. As shown, a lead container 1 is trunnioned in arms 6 upstanding from a base 7 and is movable about a horizontal axis by a handle 8. A cylindrical plug 9 is rotatable iri a bore in the container, and has two bores containing radioactive γ-ray sources which can be brought separately into register with a bore 13 through which rays may emerge. The plug is fast with a boss 16 which can be turned by a handle 17, and which has cams 18, 18a operating plungers 19, 19a bearing indicators 20, 20a which are moved above the surface of the casing when either of the sources is opposite bore 13. As shown, the bore 11 in plug 9, containing a radioactive source 2, is in register with bore 13, and rays emerging from bore 13 are used e.g. for radiography of an object just in front of the container. It may be necessary to move the source out of the container to a required position. For this purpose a flexible conduit 21 and the flexible sheath 24 of a flexible cable 23 are screwed to the container. Cable 23 is considerably longer than sheath 24, and is moved through the sheath by gearing in a casing connected to the other end of sheath 24 at a point remote. from the container. Source 2 is carried by a holder 34 connected to a stem 37 by a series of interconnected lead discs 31 and springs 32 forming a flexible but ray-proof connector. The stem is engaged by a spring-urged plate 38 pivoted to the container, which prevents the source from being drawn backwards out of the container but permits stem 37 to be pushed forward by cable 23, which has a claw connector 28 gripping the stem 37. By this means an operator at a safe distance may move the source 2 out of the container along the conduit 21 to the required position. In a modification, two or more conduits 21 may be used, so that two or more sources may be moved out of the container at once. Cable 23 may be reversed to push out a source which may later be picked up by connector 28. Exposures made. using two or more sources may be used e.g. for locating defects in material.