49Cr: Towards full spectroscopy up to 4 MeV

The nucleus 49Cr has been studied analysing gamma-gamma coincidences in the reaction 46Ti(alpha,n)49Cr at the bombarding energy of 12 MeV. The level scheme has been greatly extended at low excitation energy and several new lifetimes have been determined by means of the Doppler Shift Attenuation Method. Shell model calculations in the full pf configuration space reproduce well negative-parity levels. Satisfactory agreement is obtained for positive parity levels by extending the configuration space to include a nucleon-hole either in the 1d3/2 or in the 2s1/2 orbitals. A nearly one-to-one correspondence is found between experimental and theoretical levels up to an excitation energy of 4 MeV. Experimental data and shell model calculations are interpreted in terms of the Nilsson diagram and the particle-rotor model, showing the strongly coupled nature of the bands in this prolate nucleus. Nine values of K(pi) are proposed for the levels observed in this experiment. As a by-result it is shown that the values of the experimental magnetic moments in 1f7/2 nuclei are well reproduced without quenching the nucleon g-factors.Comment: 13 pages, 8 figure

E2 Transition Probabilities in 114Te: a Conundrum

Lifetimes in {sup 114}Te were determined using the recoil distance Doppler-shift technique with a plunger device coupled to five HP Ge detectors enhanced by one Euroball Cluster detector. The experiment was carried out at the Cologne FN Tandem facility using the {sup 93}Nb({sup 24}Mg,p2n) reaction at 90 MeV. The differential decay curve method in coincidence mode was employed to derive lifetimes for seven excited states, while the lifetime of an isomeric state was obtained in singles mode. The resulting E2 transition probabilities are shown to be very anomalous in comparison with the vibrational energy spacings of the ground state band

Recoil-gated plunger lifetime measurements in 188Pb

Electromagnetic transition probabilities were measured using the recoil distance Doppler-shift technique and the 40Ca(152Sm,4n) 188Pb reaction at a beam energy of 805 MeV to investigate shape coexistence in 188Pb. For the first time, a plunger was combined with Gammasphere and the Argonne Fragment Mass Analyzer. It was possible to measure the lifetimes of two states in the prolate band of 188Pb and, thus, provide for the first time evidence for the collectivity of this band. A three-level mixing calculation revealed that the first 2+ state is predominantly of prolate character

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

Question of dynamic chirality in nuclei: The case of ^134 Pr

Tonev, D.; Angelis, G. de; Brant, Slobodan; Frauendorf, S.; Petkov, P.; Dewald, A.; Dönau, F.; Balabanski, D. L.; Zhong, Q.; Pejovic, P.; Bazzacco, D.; Bednarczyk, P.; Camera, F.; Curien, D.; Vedova, F. Della; Fitzler, A.; Gadea, A.; Bianco, G. Lo; Lenzi, S.; Lunardi, S.; Marginean, N.; Moller, O.; Napoli, D. R.; Orlandi, R.; Sahin, E.; Saltarelli, A.; Dobon, J. Valiente; Zell, K. O.; Zhang, Jing-ye; Zhang, Y. H

Lifetime study of particle-hole excitations in the semimagic nucleus 93Tc

14 págs.; 10 figs.; 2 tabs.; PACS number(s): 21.10.Tg, 21.60.Cs, 23.20.Js, 27.60.1jThe recoil-distance Doppler-shift technique was employed for determining lifetimes of high-spin states in the semimagic nucleus 93Tc. The nuclei were populated using the reaction 64Zn(35Cl, α2p) at a beam energy of 135 MeV, and the γ radiation from their decay was detected in the GASP spectrometer. A total of 26 reduced transition probabilities and limits for 19 further transitions were extracted and compared to large-scale shell model calculations, considering different configuration spaces and residual interactions. The information deduced about transition strengths turned out to be essential for the correct assignment of the calculated to the experimental excited states. ©2003 The American Physical SocietyThis work has been supported by the European Commission through the Contract No. HPRI-1999- CT-00083 and the Deutsches Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie (BMBF). A. Jungclaus acknowledges financial support from the Deutsche Forschungsgemeinschaft (DFG) within the Heisenberg program.Peer Reviewe

Measurement of lifetimes in 46^{46}V with the EUROBALL γ\gamma-ray spectrometer

In V-46 picosecond lifetimes were determined using the recoil distance Doppler-shift technique with the Cologne plunger device coupled to the EUROBALL IV spectrometer. The experiment was carried out using the Mg-24(Si-28, alpha pn) reaction at 110 MeV at the Strasbourg VIVITRON accelerator. Subsequently the differential decay curve method in coincidence mode was employed to derive lifetimes for four excited states in the K-pi=0(-) band. The resulting transition probabilities give a comparison of isospin allowed and forbidden E1 transitions, which clarifies the decay properties of the 2(-),T=0 state. Furthermore the B(E2) values within the K-pi=0(-) band are discussed