Symmetry character of collective states in 104Pd populated in the EC-β+ decay of 104Ag

The states of ¹⁰⁴Pd, populated in the EC-β⁺ decay of the ground ( J ^π = 5⁺) and metastable ( J ^π = 2⁺) states of ¹⁰⁴Ag, have been investigated in the framework of the proton-neutron interacting boson model, extending a previous analysis to take into account the newly appeared experimental data. All positive-parity states up to an excitation energy of 3 MeV and spin in the range J = 1-6, fed by more than 0.3% in the decay of the parent nucleus, have been considered. As a result, strong evidence has been found for interpreting most of these states as states of collective nature having a quite pure full- or mixed-symmetry character and, in particular, for identifying the 1⁺ level at 2276 keV as the lowest 1⁺ mixed-symmetry state.     

Effective gyromagnetic ratios in odd Thallium isotopes

Effective gyromagnetic ratios in theM1 operator have been determined in odd Thallium isotopes. The analysis has been performed within the framework of the intermediate coupling model, taking into account penetration electron matrix elements in addition to static and dynamic magnetic dipole moments.     

Penetration effects in111Cd

Penetration effects in the conversion process of the 7/2⁺→5/2⁺, 171 keV and 5/2⁺→1/2⁺, 245 keV transitions in¹¹¹Cd have been investigated. The decay of¹¹¹In has been studied to deduce the relative intensity of theK-conversion lines I_K(171)/I_K(245) and the ratioI _K(245)/I _L+M... (245). The values obtained for the penetration parameters of the two transitions are 0≦λ(171)≦2.3 and ?0.4≦λ ₁(245)≦1.9.     

The 0 1 + →0+ electric monopole transition in112Cd

The low-lying levels of¹¹²Cd have been populated in the decay of¹¹²In (T _1/2=14 ^m ) produced through the¹¹²Cd (p, n)¹¹²In reaction atE _p=6.5–7 MeV. The intensity ratio of theE0 toE2K-conversion electrons from the 0 ₁ ⁺ level to the ground (0⁺) and to the first (2⁺) excited state in¹¹²Cd has been measured and the ratioX(E0/E2) =B(E0;0 ₁ ⁺ →0⁺)/B(E2;0 ₁ ⁺ →2⁺) has been determined. The result is compared with the predictions of current macroscopic models.     

Search for the lowest 2+ mixed-symmetry state in102Ru

TheK-conversion coefficients of some 2_i ⁺ 2_f ⁺ transitions in¹⁰²Ru have been measured and their electric monopole components have been deduced. The intensity of theE0 component in the 2₃ ⁺ 2₁ ⁺ transition supports a possible interpretation, based on gamma decay, of the 2₃ ⁺ level as the lowest mixed-symmetry state. Negative parity has been assigned to the level at 2261 keV.We would like to thank Mr. M. Ottanelli for his continuous, important technical support. One of the authors (D.C.) thanks the INFN for hospitality and financial support during this work.     

Penetration effects in the internal conversion process of the 204 keV transition in205Tl

Penetration effects have been detected in²⁰⁵Tl by measuring theK, L and (M+N+...) internal conversion coefficients of the 204 keV, 3/2⁺→l/2⁺ transition. From the resulting values α _K =0.29±0.04, α _L =0.132±0.006 and α _M+N+...=0.0397±0.0034 the penetration parameter and the mixing ratio have been deduced to be λ=13.1±2.7 andδ ²=1.40±0.46, respectively.