Transition probabilities in 134Pr : A test for chirality in nuclear systems

Excited states in 134Pr were populated in fusion-evaporation reaction 119Sn(19F, 4n)134Pr.Within a dynamical context the presence of intrinsic chirality can be supported

Is the 4.742 MeV state in 88^{88}Sr the 1−^- two-phonon state?

A nuclear resonance fluorescence experiment on $^{88}$Sr has been performed with bremsstrahlung of 6.7 MeV endpoint energy. The $\gamma$-ray linear polarisation has been measured with a EUROBALL CLUSTER detector used as a Compton polarimeter. The results indicate positive parity for the $J=$1 state at 4.742 MeV in $^{88}$Sr, in contrast to the previous interpretation as a 1$^-$ two-phonon $(2^{+}_{1} \otimes 3^{-}_{1})$ state and in conflict with the predictions of the quasiparticle-phonon model. On the basis of such calculations the 1$^{+}$ state at 3.486 MeV may be considered as the 1$^{+}_{1}$ one-phonon state and the very strong 1$^{+}_{1} \rightarrow$ 0$^{+}_{1}$ deexcitation as proton spin-flip 2p$_{1/2}$ $\rightarrow$ 2p$_{3/2}$ transition

Lifetimes Measurements for 134Nd and Neighboring Nuclei with the Coincidence-Plunger Technique

The Lifetimes of 12 excited states in Nd-134 were measured with a high precision by means of the GASP spectrometer applying the coincidence recoil-distance Doppler-shift method. The Pd-110(Si-28,xnyp) reaction was used at a beam energy of 125 MeV. The data were analyzed with the differential decay curve method and the derived lifetimes were used for a sensitive test of various nuclear models. The transition quadrupole moments (Q(t)) in the ground state band agree nicely with the predictions of both the rotor model and the O(6) symmetry of the interacting boson approximation up to the 4(g)(+) state of Nd-134. The Q(t) values for the 8(g)(+), 10(S1)(+), and 12(S1)(+) states, however, give evidence for a strong change of the nuclear deformation. The lifetimes of 12 low lying yrast states in the Ce-130,Ce-131,Ce-132, Pr-133,Pr-134, and Nd-135 nuclei have been also determined

Lifetime measurements with the Euroball spectrometer

Lifetimes of low-lying members of a DeltaI = 1 band in Ph-196 and of the superdeformed (SD) band in Nd-135 have been measured with the EUROBALL spectrometer and with the Cologne plunger apparatus at Legnaro. The (DY)-D-164(S-36,4n)Pb-196 and the Pd-110(Si-30,5n)Nd-135 reactions were used to populate the states of interest at beam energies of E-36 S=168 MeV and E-30 Si=148 MeV, respectively. The experimental data were analyzed with the differential decay-curve method (DDCM). Measured B(M1) values are consistent with the picture of the shears mechanism which has been used to describe the DeltaI = 1 bands in Pb-196. It was found that in Nd-135 the decay out of the SD band is caused by accidental level mixing

Test of the critical point symmetry X(5) in the mass A = 180 region

Based on the energy spectra and relative transition probabilities 176,178,180Os turned out to be very promising candidates for testing the features of the critical point symmetry X(5). In order to also test absolute transition probabilities predicted in the framework of the X(5) symmetry lifetime measurements were performed at the Cologne FN tandem accelerator. The lifetimes of the first 2+ states in 176,178,180Os were measured using electronic timing and in the case of 178Os with the recoil distance Doppler shift (RDDS) technique using an 16O-induced fusion evaporation reaction. In addition, a coincidence RDDS measurement was performed at the Laboratori Nazionali di Legnaro with the GASP spectrometer using the 154Sm(29Si,5n)178Os reaction. The deduced transition quadrupole moments agree well with the X(5) predictions, thus further supporting an X(5) structure for 178Os. The experimental data for 178Os are compared to calculations in the framework of the interaction boson model (IBM) and of the general collective model (GCM)