Nuclear spectroscopy of low lying levels in 22Ne by the 13C(13C,αγ)22Ne reaction

States in 22Ne with excitation energies up to about 13 MeV were populated by the 13C(13C,α)22Ne heavy ion reaction at 20 MeV projectile energy in the lab system. Decay gamma rays were measured at 40, 50, 65, and 900 with a Ge(Li) detector (efficiency 19% compared to a 3'' x 3'' NaI(Tl) crystal) and particles were registered at 00 with a 200 μm Si surface barrier detector. An excitation function, obtained by monitoring five α-particle peaks corresponding to the states at 0.0, 1.275, 3.356, and 4.457 MeV and to the unresolved group of states around 6 MeV, showed no pronounced structure when the projectile lab energy was varied in .1 MeV steps from 15 to 21 MeV. The measured angular γ--α correlations in LF II geometry were fitted by theoretical expressions from Rose and Brink to extract spins and population parameters for the states at 5.144, 5.3365, 5.521, 5.914, and 6.116 MeV and multipole mixing ratios for their gamma decay. New information was gained for the 5.335 and the 5.914 MeV state, which are listed with spins of J = (1.2) and J/sup π/ = 2+ in the compilation by Endt and van der Leun. For the 5.335 MeV state J/sup π/ = 1+ was determined, independently of former results on branching ratios for the γ-decay of the 5.335/5.360 MeV doublet. For the 5.914 MeV state a spin of J/sup π/ = 3- is proposed and evidence for its classification as the second member of the K/sup π/ = 2- rotational band in 22Ne is presented. Lifetimes were extracted by DSAM techniques following calculations of Blaugrund and Lindhard, Scharff and Schiott. Good agreement with literature values was found. No lifetimes were known so far for the states at 5.335 and 6.116 MeV, which were determined as tau < 80 and tau < 50 fs respectively