Eur. Phys. J. A (2010) 46: 165-185
https://doi.org/10.1140/epja/i2010-11053-6

Regular Article - Experimental Physics

Coexistence of “ + ²⁰⁸Pb ” cluster structures and single-particle excitations in ²¹²  ₈₄Po₁₂₈

¹ CSNSM, IN2P3/CNRS and Université Paris-Sud, F-91405, Orsay Campus, France
² INRNE, Bulgarian Academy of Science, 1784, Sofia, Bulgaria
³ Horia Hulubei National Institute of Physics and Nuclear Engineering, 407 Atomistilor, 077125, Bucharest, Romania
⁴ Academy of Romanian Scientists, 54 Splaiul Independentei, 050094, Bucharest, Romania
⁵ IPN, IN2P3/CNRS and Université Paris-Sud, F-91406, Orsay, France
⁶ LPMMC, CNRS and Université Joseph Fourier, F-38042, Grenoble Cedex 9, France

^* e-mail: astier@csnsm.in2p3.fr

Received: 10 September 2010
Accepted: 17 September 2010
Published online: 24 October 2010

Abstract

Excited states in ²¹²Po have been populated by transfer using the ²⁰⁸Pb(¹⁸O,¹⁴C) reaction at 85MeV beam energy and studied with the EUROBALL IV multi-detector array. The level scheme has been extended up to ∼ 3.2 MeV excitation energy from the triple- coincidence data. Spin and parity values of most of the observed states have been assigned from the angular distributions and - angular correlations. Several -lines with E _γ < 1 MeV have been found to be shifted by the Doppler effect, allowing for the measurements of the associated lifetimes by the DSAM method. The values, found in the range [0.1-0.6]ps, lead to very enhanced E1 transitions. All the emitting states, which have non-natural parity values, are discussed in terms of - ²⁰⁸Pb structure. They are in the same excitation-energy range as the states issued from shell-model configurations.