Two proton high-spin excitations and dipole bands in192Hg

The¹⁹²Hg nucleus was populated in the¹⁶⁰Gd(³⁶S, 4n) reaction at a beam energy of E=159 MeV. Emittedγ-rays were detected with the EUROGAM array comprising 43 Compton-suppressed large volume Ge detectors. The level scheme of¹⁹²Hg has been extended up to an excitation energy of E=10.4 MeV and spin I=34 ?. Two new structures, made of competing ΔI=1 and ΔI=2 transitions have been observed and their connexions with the low-lying levels established. Their lowest levels are located at 6.304 MeV and 6.879 MeV excitation energy. The experimental results are compared with mean-field HF+BCS calculations. It is proposed that the new structures originate from deformation-aligned quasi-proton excitations π(i_13/2 * h_9/2)_K=11 andπ (h_9/2) _K=8 ² , coupled to rotation-aligned quasi-neutron ν(i_13/2)ⁿ and quasi-proton π(h_11/2)² excitations.     

High-spin states following multi-nucleon transfer

High-spin states in neutron-rich nuclei, populated following deep-inelastic multi-nucleon transfer, have been studied using the GAMMASPHERE array at the LBNL, USA. A ⁶⁴Ni beam at an energy ∼ 15% above the Coulomb barrier was incident upon a thick ²⁰⁸Pb target, leading to the population of more than 130 different nuclei. The strongest channels correspond to nuclei close to the projectile and target, although transfer of up to 50 nucleons has been observed. New high-spin states in neutron-rich ^60,62Fe and ^68,70,72Zn nuclei have been observed. Some limitations of this method of high-spin spectroscopy are discussed, including the apparent difficulty of populating odd-odd and odd-even isotopes via this type of reaction. The data have been searched for superdeformed (SD) states in the A = 190-200 region, but no evidence for their presence has been found. Received: 14 April 2000 / Accepted: 12 September 2000     

The search for Hyperdeformation in152Dy

Three experiments have been carried out to search for the existence of Hyperdeformed states (HD) in the nucleus¹⁵²Dy. These three experiments were designed to test different properties of the expected HD structures. As a result of these experiments no clear evidence for HD states in¹⁵²Dy has been observed.     

Dipole structures in 122Xe

High-spin levels in ¹²²Xe have been investigated by γ—γ coincidence measurements using the EUROGAMarray. The reaction ⁹⁶Zr(³⁰Si,4n)¹²²Xe at a beam energy of 135 MeV was used. New structures of competing dipole to quadrupole transitions have been observed. Experimental B(M1)/B(E2) ratios have been extracted and compared with theoretical estimates.