GB847604A - Ion sources - Google Patents

Abstract

847,604. Ion sources. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Feb. 15, 1946 [Oct. 9, 1944], No. 4900/46. Class 39(1). In an arc type uranium ion source the amount of uranium to be ionized while supported on tungsten is limited to prevent appreciable conversion of the tungsten into an alloy melting at the arc temperature. The amount of molten uranium is less than can be retained by surface tension against gravity on the under-surface of the support. In Figs. 2 and 3, the arc is formed between a hot cathode filament 31 and a tightly coiled wire or rod anode 30. The uranium is supplied as a thin layer 34, 35 on the anode and the arc is struck in a magnetic field set up between pole-pieces 36, 37. In Fig. 5, the anode 38 is a platform of rods placed side by side and a cathode filament 41 is disposed on each side of the platform. A wire or ribbon 44 of uranium is advanced continuously or in steps through a duct 43. The anode may be a single rod and a ring or partial ring cathode may encircle the anode. In Fig. 11, the arc is struck between cathode filaments 61 and a rod anode 57 which may be advanced to bring a fresh portion into position. The uranium 72 is supplied through a feed tube 69. The structure includes a massive pole-piece 60. All supports in each of these embodiments may be liquid cooled. Several structures may be placed side by side to provide a gang type source. Reference is made to the use of the ion source in an highfrequency mass separator in which the ions are successively accelerated and retarded through a series of grid electrodes and subsequently deflected. Reference is also made to a Nier-type mass spectrometer. Specification 841,821 is referred to.