GB1385325A - Device for separating isotopes - Google Patents

Abstract

1385325 Isotope separators MAX-PLANCKGES ZUR FORDERUNG DER WISSENSCHAFTEN e V 26 July 1971 [25 July 1970] 35039/71 Heading H1D An isotope separator includes a vacuum separation chamber 10 surrounded by a coil 12 for producing within the chamber a magnetic field B parallel to the axis of the chamber, an electrode 14a in the chamber, the electrode having an active surface 18a transverse to the axis and capable, when heated, of ionizing, by contact ionization, isotopes to be separated and of emitting electrons, means (such as a cathode 20a) for heating the active surface, means 26 for supplying atoms of the isotopes to be separated to the active surface to enable ions of the isotopes and electrons to form a plasma, and respective extraction means 40, 42 for the heavy and light isotopes. In the embodiment shown the evaporator 26 contains material 34 from which the isotopes are evolved when the evaporator is heated, and is formed to direct a beam 32 of atoms at the surface 18a. A similar electrode 14b is provided at the end of the chamber 10 opposite electrode 14a. Materials from which the surface may be made for use in separating isotopes of uranium, alkali metals or alkaline earth metals are tungsten, rhenium, tantalum or carbon; alternatively ceramics which are electrically con. ductive at the operating temperature of the surface may be used and, e.g., comprise beryllium oxide and/or zirconium oxide and/or thorium oxide. The plasma formed is confined by the magnetic field B. An ion and electron density variation with distance from the axis 36 is maintained to produce a radial electric field Er which, with the magnetic field B, causes the plasma to rotate about axis 36. The density variation can be achieved by providing a radially varying temperature distribution on the surface 18a or by altering the composition of the material of the surface according to radial distance from axis 36. The rotational speed of the plasma can be increased by addition of lithium ions. In another embodiment (Fig. 2, not shown) in which the axis 36 is vertical, the evaporator (26) is a conductive boat positioned behind the electrode (14<1>) the latter having a perforate front plate (16<1>a) for passage therethrough of ions. Sides of the perforations form the active surface. In modifications (not shown) the active electrode surfaces may be unheated; only one electrode may be provided; a cylindrical electrode, in addition, can surround the plasma column to enhance the radial electric field; and the ionization electrode and evaporator can be combined in which case the combination comprises a hollow body which can be heated to evaporate its contents which are ionized by the wall of the body and escape from the body through openings.