Production, L x-ray identification, and decay of the nuclide 260105

The nuclide ²⁶⁰105 has been produced in the ²⁴⁹Cf(¹⁵N,4n) reaction and its decay properties investigated. The α-decay branch of 1.52 +/- 0.13-sec ²⁶⁰105 has been measured to be (90.4+/-0.6)% with spontaneous-fission decay the remainder [(9.6+/-0.6)%]. Measured α-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 L series x rays of element 103 were observed in coincidence with these α-particle groups, thus providing elemental identification. The ²⁵⁶Lr α-decay daughter was observed in a direct time-correlated genetic linkage, thus providing the mass number assignment. The absence of characteristic L- or 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 ²⁶⁰105 to the elusive nuclide 0.1-sec ²⁶⁰104. If ²⁶⁰104 is a spontaneous-fission emitter with a half-life <= 100 μsec, as some predictions would indicate, then the electron-capture decay branch of ²⁶⁰105 is μ0.2%. RADIOACTIVITY ²⁶⁰105 [from ²⁴⁹Cf(¹⁵N,4n) reaction]; measured t₁₂, E_α, I_α, E_SF, E_SF, I_EC, E_X, L_X, E_γ, I_γ α-X coin. and SF-X coin. α-α time correlation; deduced ²⁵⁶Lr levels, J, K, π α hindrance, SF hindrance, atomic number mass number. Enriched target.