A rotational band in82Zr

The neutron deficient nucleus⁸²Zr has been studied through the reaction⁵⁸Ni(²⁸Si, 2p 2n)⁸²Zr with a calculated cross section of 0.3% of the total fusion cross section atE(²⁸Si)=128 MeV. Gamma rays from excited states of⁸²Zr were measured and identified using the NORDBALL escape-suppression array at the Niels Bohr Institute. Reaction channel selection was performed by use of neutron and charged particle detector arrays in conjunction with the germanium detectors. A rotational band in⁸²Zr has been identified with spins up to 20 ? by analysis of reaction channel selectedγ-γ coincidence matrices. Band crossings were identified at frequencies 0.57 and 0.69 MeV.     

Low-lying four-quasiparticle state in82Rb

The g-factor of the 6⁺ 191.3 keV excited state with a half-life T_1/2=12.3(6) ns in⁸²Rb populated in the⁷⁹Br(⁴He,n) and⁸¹Rb(³He,2n) reactions has been measured by the TDPAD method. On the basis of the experimental g-factor g _exp =+0.670(8) the four-quasiparticle configuration [πg9/2?ν(g9/2) ₇ ^2/3 ]₆₊ involving an anomalous neutron coupling has been assigned to this state.     

Nuclear Spin-Lattice Relaxation of 82BrFe

The field dependence of the nuclear spin-lattice relaxation (SLR) of cold implanted ⁸²Br (T ≤ 25 mK) in α-Fe single crystals was investigated with nuclear magnetic resonance of oriented nuclei (NMR/ON) at low temperatures as experimental technique. The SLR at the lattice sites with the hyperfine fields found by earlier NMR/ON experiments was measured as a function of the applied external magnetic field B _ext parallel to the three principle axes [100], [110] and [111] of the iron single crystal. The data were evaluated with the full relaxation formalism in the single impurity limit and for comparison also with the often employed model of a single exponential function with an effective relaxation time T ₁′. With a phenomenological model the high field values of the relaxation rates r _{∞, [100]′} = 6.6(2) · 10⁻¹⁵ T²sK⁻¹, r _{∞, [110]} = 5.4(2) · 10⁻¹⁵ T²sK⁻¹ and r _{∞, [111]} = 5.2(1) · 10⁻¹⁵ T²sK⁻¹ were obtained.     

Low-lying four-quasiparticle state in 82Rb

The g-factor of the 6⁺ 191.3 keV excited state with a half-life T_1/2=12.3(6) ns in ⁸²Rb populated in the ⁷⁹Br(⁴He,n) and ⁸¹Rb(³He,2n) reactions has been measured by the TDPAD method. On the basis of the experimental g-factor g_exp=+0.670(8) the four-quasiparticle configuration \(\left[ {\pi g_{9/2} \otimes \nu \left( {g_{9/2} } \right)_{7/2}^3 } \right]_{6^ + }\) involving an anomalous neutron coupling has been assigned to this state.     

Renormalized proton- neutron QRPA and double beta decay of 82Se to excited states in 82Kr

We apply the self-consistent renormalized proton-neutron QRPA (RQRPA) method to calculate the two-neutrino double beta (2νββ) decay matrix elements associated with the ground-state and excited-state transitions of the ⁸²Se → ⁸²Kr decay. The RQRPA method is an extension of the pnQRPA method and promotes the Pauli exclusion principle violated by the pnQRPA ground state and yields more stable nuclear matrix elements with increasing strength of the proton-neutron interaction. In the present work the RQRPA wave functions are also used to evaluate 2νββ-decay rates to excited final states. The resulting theoretical half lives are compared with the new stringent experimental limits obtained by using a HPGe detector and external sources of enriched selenium.     

New exotic neutron-deficient nuclei nearN=82

Residual activities produced via³⁵Cl or³²S beams in thin¹¹²Sn and¹⁰⁶Cd targets have been studied by γ-ray and X-ray spectroscopy techniques behind a He-jet system. Mass identification of the products has been performed by coupling the He-jet to the medium current ion source of an isotope separator. Neutron-deficient nuclei with 137≦A≦144 have been identified. Decay schemes of several new isotopes as¹³⁸Eu (12s),¹⁴¹Gd (22s),¹⁴³Tb (12s and <17s),¹⁴⁴Dy (9s) and possibly¹⁴⁰Gd (11s) have been derived. New informations have also been provided for¹³⁷Sm (45s),¹³⁹Eu (24s) and¹⁴⁴Tb (5s). Data have been presented through systematics. The shapes of these nuclei and their trends versusN andZ have been analysed.     

Very proton rich nuclei withN≈82

Postaccelerated⁵⁸Ni and⁶⁰Ni beams from the Munich MP tandem have been used to study the compound reactions⁵⁸Ni→⁹³Nb,⁹²Mo,⁹⁴Mo and⁶⁰Ni→⁹²Mo. The final nuclei¹⁴⁸Er,¹⁵⁰Er and¹⁴⁷Ho have been investigated with in-beamγ-spectroscopic methods, such as excitation functions,γγ coincidences, bunched-beam and pulsed-beam techniques. Level schemes of¹⁴⁸Er,¹⁵⁰Er and¹⁴⁷Ho have been established with the following level energies, spins, parities and half-lives:¹⁴⁸Er: 646.6 keV 2⁺; 1,524.0(4⁺); 2,254.3(5^?); 2,526.9(6⁺); 2,537.3(7^?), 2,706.0(7^?, 8^?); 2,784.4(8⁺); 2,915.5(10⁺) 13±3 μs¹⁵⁰Er: 1,578.9 keV 2⁺; 1,786.4 3^?; 2,261.2(5^?); 2,634.1(7^?); 2,734.3(8⁺); 2,798.3(10⁺) 2.7±0.2 us; 4,001.9; 4,491.8; 4,886.0; 5,222.7¹⁴⁷Ho: 765.4; 1,737.2; 2,355; 2,656.6 The level scheme of¹⁵⁰Er has been discussed in the framework of the seniority scheme. Perfect agreement with the experiment has been found for the predictions of this scheme for the half-lives of 10⁺ states inN=82 isotones. This is the first nuclear region where the predictions of the seniority scheme have been observed without strong perturbation.     

High-spin levels in 63 145 Eu82

The level scheme of the N=82 nucleus ¹⁴⁵Eu has been extended to I=(55/2) and E_x=11.2 MeV in an experiment with the Tessa Compton-suppressed Ge detector array using the ¹²⁷I(²²Ne,4n) reaction. Most of the complicated and irregular level scheme of ¹⁴⁵Eu can be interpreted as proton multi-quasiparticle states in comparison to the ₆₄ ¹⁴⁶ Gd₈₂ core nucleus but also excitations across the neutron N=82 core have been observed.