No abstract

The nucljde 105 has been produced jn the Cf(' N, 4') reaction and its docay properties investigated. The a-decay branch of 1.52~0.13-sec ' 105 has been measured to be (90.4~0.6)% with spontaneous-fission decay the remainder [(9. 6+0.6)%]. Measured a-particle energies and intensities (% per decay) are 9.041+ 0.014 MeV (48 + 5), 9.074~0.014 MeV (25 + 3), and 9.120 + 0.017 MeV (17 + 3). Characteristic Lseries x rays of element 103 were observed in coincidence with these a-particle groups, thus providing elemental identification. The ' Lr aMecay daughter was observed in a direct time-correlated genetic linkage, thus providing the mass number assignment. The absence of characteristic Lor K-series x rays of element 104 in time coincidence with, but preceding, spontaneous-fission-decay events, has allowed an upper limit of 2.5% to be placed on the electron-capture decay branch of ' 105 to the elusive nuclide 0.1-sec '~104. If 104 is a spontaneous-fission emitter with a half-life & 100 p.sec, as some predictions would indicate, then the electron-capture decay branch of ' 105 is &0.2%. RADIOACTIVITY 105 [from Cf( N, 4s) reactionj; measured &f/2 EẼ