Rotational Bands in 171Lu

Abstract

A variety of experiments has been performed in order to establish and identify the states in the rare earth deformed nucleus 171Lu. Proton particle states have been studied using (3He,d) and (α,t) stripping reactions. The reaction products were analyzed with an "Enge" split-pole magnetic spectrograph. The expected components of the following intrinsic proton states have been identified: 7/2+[404] (ground state), 1/2−[541], 1/2+[411], 5/2+[402], and 9/2−[514]. In addition, tentative assignments are made for rotational states based on the 3/2−[532], 1/2−[530], and 1/2+[660] orbitals, and for states which are mixtures of β and γ vibrations and particle states. The cross-section ratios of the two stripping reactions were used as an indication of l value and spectroscopic factors were extracted using DWBA calculations. Gamma radiation and conversion electrons following the reaction 169Tm(α,2n)171Lu have been studied, using high resolution Ge(Li) detectors in singles and coincidence mode, and an on-line, double-focussing, electron spectrometer. Coincidence probabilities have been calculated and have been used to determine the intensities of unresolved gamma transitions. Excitation functions of gamma rays following the 168Er(7Li,.xn) reaction were used to check isotopic assignments. The ratio of the relative intensities of gamma transitions following the 7Li and 4He induced reactions was found to be a good indicator of the spin of the deexciting level. A level scheme is proposed which includes a number of K-forbidden inter-band transitions.