The assignment of the slow-neutron-produced activities of thallium and the dual disintegration of radium E

Abstract

Recoil experiments with a strong source of RaE (21 mC initial activity) electrolytically deposited on platinum show that an activity of half-value period 4·2 min. is obtained. This observation indicates that RaE undergoes dual disintegration with an α: β branching ratio of the order of 5 x 10 -7 . Rough absorption measurements favour the identification of the activity with the 4·2-min. activity produced in the ( n, γ ) and ( d, p ) reactions with thallium, and therefore require assignment of the latter to 206 TI, contrary to earlier suggestions. Consideration of the energies involved shows that the postulated α: β branching ratio has roughly the value which would be predicted on the basis of accepted regularities.