Patent GB-817033-A (GB)
Title: Improved method of and apparatus for treating materials with high energy electrons
Inventor: BLACK ROBERT MONRO
IPC: H01J37/32
Filed: 1955-11-14
Abstract: <PICT:0817033/III/1> A method of changing the chemical or physical properties of a body by causing molecular cross - linking in the material of the body comprises arranging the body in or passing it through a beam of electrons of an energy of 0.5 MEV. or higher (e.g. 2 MEV.) and allowing a part of the beam not impinging directly on the body to impinge on a metallic scattering surface or surfaces so arranged that high energy electrons scattered therefrom enter a part or parts of the body screened or partially screened from the direct beam whereby a more uniform irradiation of the body is obtained than would be obtained in the absence of the scattering surface or surfaces.  In the case of an electric cable the insulation thereof if to be affected by the irradiation.  The cables may be as described in Specification 766,802, 784,161 or 782,442.  The irradiation reaching the body may be partly scattered and partly direct.  The electron beam can be scanned over the body transversely to and/or along its longitudinal axis or, if the body is moving the beam may be scanned transversely and also longitudinally if desired.  The cable may be of non-uniform thickness along its length.  Cooling air or gas are directed on to those parts of the cable bombarded by the electron beam and on to the scattering plate, which need be only a few molecules thick. In general, the screen may prevent only part of the primary beam from striking the body and may itself emit X-rays which affect the body in the same way as the electrons.  The scattering surface is of lead or thorium and may be flat or curved, e.g. cylindrical, parabolic or spherical; if lead blocks are used they can also act as protective screens for the apparatus or alternatively as screens for stopping off part of the primary beam.  The body may have non-uniform thickness or opacity.  The cable insulator can be a high molecular weight thermoplastic linear polymer, e.g. polyethylene or a natural or synthetic elastomer.  The V-scattering surface of Fig. 1 can be used when the cable is rotated about its axis as well as being moved longitudinally, or when the cable passes two or more times past the electron beam with opposite sides of the cable successively exposed to the electron beam.  When the cable is rotated the beam can be scanned transversely as well as longitudinally.ALSO:<PICT:0817033/IV (a)/1> A method of changing the chemical or physical properties of a body by causing molecular crosslinking in the material of the body comprises arranging the body in or passing it through a beam of electrons of an energy of 0.5 MEV. or higher (e.g. 2 MEV.) and allowing a part of the beam not impinging directly on the body to impinge on a metallic scattering surface or surfaces so arranged that high energy electrons scattered therefrom enter a part or parts of the body screened or partially screened from the direct beam whereby a more uniform irradiation of the body is obtained than would be obtained in the absence of the scattering surface or surfaces.  In the case of an electric cable the insulation thereof is to be affected by the irradiation.  The cables may be as described in Specifications 766,802, 784,161 or 782,442, [Group III]. The irradiation reaching the body may be partly scattered and partly direct.  The electron beam can be scanned over the body transversely to and/or along its longitudinal axis, or, if the body is moving the beam may be scanned transversely and also longitudinally if desired. The cable may be of non-uniform thickness along its length.  Cooling air or gas are directed on to those parts of the cable bombarded by the electron beam and on to the scattering plate, which need be only a few molecules thick. In general, the screen may prevent only part of the primary beam from striking the body and may itself emit X-rays which affect the body in the same way as the electrons.  The scattering surface is of lead or thorium and may be flat or curved, e.g. cylindrical, parabolic or spherical; if lead blocks are used they can also act as protective screens for the apparatus or alternatively as screens for stopping off part of the primary beam. The body may have non-uniform thickness or opacity.  The cable insulator can be a high molecular weight thermoplastic linear polymer, e.g. polyethylene or a natural or synthetic elastomer.  The V scattering surface of Fig. 1 can be used when the cable is rotated about its axis as well as being moved longitudinally, or when the cable passes two or more times past the electron beam with opposite sides of the cable successively exposed to the electron beam.  When the cable is rotated the beam can be scanned transversely as well as longitudinally.