ON A REPORTED ISOMERIC STATE IN Mn54

Abstract

An attempt was made to detect the 2 minute isomeric state in Mn54 reported by Caldwell and Stoddart. Irradiation of pure Mn55 with various energy bremsstrahlung of 12 to 24 Mev. failed to disclose any (γ, n) reactions leading to this state. Iron targets irradiated by 13.5 Mev. neutrons failed to disclose any positron activity of 2 minute half-life resulting from an (n, p) reaction to this state. In view of these experiments we conclude that the existence of the reported isomeric state in Mn54 should not be accepted without reservation.