GB1523395A - Charged particle irradiation apparatus - Google Patents

Abstract

1523395 Irradiation apparatus SUMITOMO ELECTRIC INDUSTRIES Ltd 29 June 1976 27112/76 Heading H5R In charged particle irradiation apparatus in which a beam of the particles is scanned in a plane through the angle #, to irradiate an object 14 of circular cross-section, e.g. a plastics coated cable drawn through the beam, a pair of magnetic field operating structures A and B are symmetrically disposed with respect to the centre line 16 of the scanning pattern, to ensure uniform irradiation of the object around its periphery, the structures producing oppositely directed D.C. magnetic fields normal to the scanning plane, and each structure having a non-uniform gap between its pole plates to produce a non-uniform magnetic field which is stronger near the centre line 16 than farther away, thereby producing the deflection pattern 16, 17, 18 shown in Fig. 1a. As shown, each structure includes a permanent magnet 19, and magnetic members 6, 7, and 20, and 10, 11, the members 10 and 11 being contoured at 15 to provide a space through which the cable 14 may be drawn. Reference is made to alternative arrangements in which the non-uniform gap is produced thus angling the members 6 and 7, or members 10 and 11 (Fig. 2, not shown), and to a structure in which the members 10 and 11 are connected by a further magnet (19<SP>1</SP>, Fig. 8, not shown) parallel to magnet 19. As described, the beam issues through a window 5. A plurality of pairs of magnetic structures may be disposed opposite a single particle transmissive window 5.