Alpha- decay studies of Rf, No and Fm

Heberger, F. P.*; Hofmann, S.*; Ackermann, D.*; Antalic, S.*; Kindler, B.*; Kojouharov, I.*; Kuusiniemi, P.*; Leino, M.*; Lommel, B.*; Mann, R.*; Nishio, Katsuhisa   ; Popeko, A. G.*; Sulignano, B.*; Saro, S.*; Streicher, B.*; Venhart, M.*; Yeremin, A. V.*

Decay properties of Rf, No and Fm were investigated by measuring the and decays. The experiment was carried out by using the linear accelerator UNILAC and velocity filter SHIP at GSI. The evaporation residues were separated by the SHIP and implanted into a silicon detector located at the focal plane. The decays were detected by the silicon detector itself and the rays were detected by Ge detectors. These isotopes were produced by the reaction Pb(Ti, 2n)Rf and the decay daughters from Rf, or by the reaction Pb(Ca, 3n)No and the decay daughter of No. It was found that (1) the 1.0 s isomeric state in No is located in the level of 106 keV. (2) The new isomeric state with 2 s was found in No, which was directly populated in the reaction Pb(Ca,3n)No. The state is located at the level larger than 1700 keV and decays by accompanying two rays. These two -ray energies agreed with the lines which was followed by the decay of Rf.