A new method for the determination of very small Γγ partial widths

We present a new method for the measurement of very small Γγ partial width that is important for the synthesis of elements in astrophysics. The method is based on the simultaneous detection of scattered beam, residual nucleus and decay γ rays. This method is optimized for the use of the CHIMERA detector at LNS. Experimental details are described

A new method for the determination of very small Γ γ

We present a new method for the measurement of very small Γγ partial width that is important for the synthesis of elements in astrophysics. The method is based on the simultaneous detection of scattered beam, residual nucleus and decay γ rays. This method is optimized for the use of the CHIMERA detector at LNS. Experimental details are described

The mutable nature of particle-core excitations with spin in the one-valence-proton nucleus ¹³³Sb

The γ-ray decay of excited states of the one-valence-proton nucleus ¹³³Sb has been studied using cold-neutron induced fission of ²³⁵U and ²⁴¹Pu targets, during the EXILL campaign at the ILL reactor in Grenoble. By using a highly efficient HPGe array, coincidences between γ-rays prompt with the fission event and those delayed up to several tens of microseconds were investigated, allowing to observe, for the first time, high-spin excited states above the 16.6 μs isomer. Lifetimes analysis, performed by fast-timing techniques with LaBr₃(Ce) scintillators, revealed a difference of almost two orders of magnitude in B(M1) strength for transitions between positive-parity medium-spin yrast states. The data are interpreted by a newly developed microscopic model which takes into account couplings between core excitations (both collective and non-collective) of the doubly magic nucleus ¹³²Sn and the valence proton, using the Skyrme effective interaction in a consistent way. The results point to a fast change in the nature of particle-core excitations with increasing spin