A EUROBALL module at the S-DALINAC — Investigation of elementary and magnetic excitation modes

Abstract

Results from the first application of a EUROBALL Cluster module in (γ, γ′) experiments at the S-DALINAC are reported. The scissors mode was observed for the first time in a γ-soft nucleus, 196Pt. A combination of detailed spectroscopy of 165Ho and 169Tm with a fluctuation analysis technique demonstrates that the total scissors mode strength in odd-mass nuclei is comparable to that in the even neighbours, but fragmentation is so strong that large parts are below detection thresholds. The search for the spin M1 resonance in the heavy deformed nucleus 154Sm gives a hint on rather large cancellations of spin and orbital contributions. The fine structure of the E1 response in the semimagic 140Ce below particle threshold is fully resolved and successfully interpreted in the microscopic quasiparticle-phonon model.