DSA lifetime measurements of high spin states

We have performed DSA lifetime measurements for the series of isotopes 154,155,156Dy at the Argonne-Notre Dame γ-ray facility. Doppler broadened γ-ray lineshapes could be extracted for (near) yrast states with spins as high as 44ℎ. The lineshapes were analysed by simulating (Monte Carlo) the slowing down process of the recoiling Dy isotopes emerging from the reaction 122,124Sn (36S,xn) into 208Pb material and adjusting the lifetimes of the involved excited states in a least square minimalisation. We have studied the transitional Dy isotopes with neutron numbers N=88-90, first results will be presented for the 156Dy isotope. It appears that the measurement of lifetimes could be extended into a regime of spins where collective structures and terminating single particle configurations coexist in the vicinity of the yrast line. 13 refs., 7 figs. (author)