Search

The delayed coincidence method with special reference to the in-beam experiments is considered as a means of identification and the lifetime measurements of isomeric states, as well as, the method of the investigation of radiations populating isomeric states. Isomers are detected and correlated with prompt events if they occur within a certain time of the prompt event. The 16O +208Pb reaction was investigated using the OSIRIS-II and the EAGLE arrays at HIL-UW. About eighty nuclei were identified as fission fragments among the reaction products. Several known isomeric transitions associated with reaction products in neutron-rich nuclei region were detected, as well as some new candidates were observed. [ABSTRACT FROM AUTHOR]

The beam pulse structure of the HIL cyclotron and thick target γ - γ co-incidence measurements in the in-beam and off-beam modes have been used to search for isomers in the A &asymph; 120 mass region using heavy-ion reactions. The half-life of the 2721 keV, (25/2+) level in 121Sb was determined in the off-beam mode to be 167 ± 19 µs. Two deexcitation sequences of this isomer are proposed. The isomeric state is considered to be of 3-quasiparticle nature π(d5/2)ν(h²11/2)10+. [ABSTRACT FROM AUTHOR]

Low-lying 0+ states, close in energy to the first excited 2+ state, have been observed in even--even molybdenum isotopes, indicating shape coexistence in these nuclei. Results of our previous Coulomb excitation measurements of 96Mo and 98Mo supported the shape coexistence scenario. A series of Coulomb excitation experiments to study the neighboring stable 100Mo isotope was performed on beams of the Warsaw Cyclotron. During the re- cent experiment with 100Mo target the new dedicated set-up for Coulomb excitation measurements was used at HIL. First results are presented. The performance of the new detection system opens promising possibilities for future Coulomb excitation experiments. [ABSTRACT FROM AUTHOR]

The lifetime of levels in 128Cs and 132La have been measured in-beam of the Warsaw University Cyclotron using DSA method. The absolute M1 and E2 transition probabilities have been deduced. Two cases have been found: 132La where the B(E2) values in yrast and partner bands differ up to 30 times and 128Cs - the B(E2) values in both bands differ only few times. It seems that bands in 128Cs are better candidates for chiral partner bands than the ones in 132La. [ABSTRACT FROM AUTHOR]

Coulomb excitation experiment of 100Mo has recently been performed using 40Ar beam from the Warsaw Cyclotron. Three lowest 2+ states, two 4+ and one 0+ excited states have been observed. It is a continuation of the systematic study of 96Mo and 98Mo nuclei having low lying 0+ excited state, with energy very close to the first 2+ state. [ABSTRACT FROM AUTHOR]

The properties of a gas-catcher/ion guide system, connected to a mass separator at the Heavy Ion Laboratory of Warsaw University, were investigated by using the α-decay recoil products 219Rn and 215Po, obtained from a 223Ra source. The “plasma effect” was studied by using a 14N beam with intensities ranging from 7 to 64 particle⋅nA, which correspond to power depositions between 1.6 ⋅ 1016 and 7.2 ⋅ 1017 eV/s for helium pressures of 75 and 380 hPa, respectively. [Copyright &y& Elsevier]