A. Banu

Spectroscopy of Nuclei Approaching the Proton Drip-line Using a Secondary-fragmentation Technique with the RISING Detector Array

An experiment utilizing a double fragmentation reaction was performed to study isobaric analogue states in A similar to 50 nuclei approaching the proton drip-line. gamma-ray spectroscopy will be used to identify excited states in the neutron-deficient nuclei produced in the second fragmentation reaction. Excited state level schemes will be obtained, through comparison with states in their well-known mirror partners, along with information on Coulomb effects through measurements of the Coulomb energy differences between isobaric analogue excited states. The validity of isospin symmetry for nuclei approaching the proton drip-line can also be investigated and the information gained will aid in testing and improving fp shell model calculations. The analysis of the collected data is at a preliminary stage and current status of this work is reported.

Neutron-deficient N≈126 nuclei produced in 238U fragmentation: Population of high-spin states

The population of metastable states produced in relativistic‐energy fragmentation of a 238U beam has been measured. For states with high angular momentum, I=17ℏ and I=21.5ℏ, a higher population than expected has been observed, with the discrepancy increasing with angular momentum. By considering two sources for the angular momentum, related to single‐particle and collective motions, a much improved description of the experimental results can be obtained. In addition, new results on the structure of 208Fr, 211Ra and 216Ac are reported.

Identification of heavy ion reaction channels with a new CAlorimeter TElescope within RISING

A newly developed CAlorimeter TElescope (CATE) is employed in the fast beam RISING γ-campaign with relativistic energies at the FRS at GSI. CATE consists of nine Si-CsI(Tl) detector telescopes for position and ΔE - E measurements. It registers the scattering angle and identifies the charge (Z) and the mass (A) of exotic heavy ions produced after secondary fragmentation or Coulomb excitation.

Relativistic coulomb excitation of neutron-rich 54,56,58Cr

The first excited 2+ states in neutron-rich 54,56,58Cr were populated by relativistic Coulomb excitation and B (E2, 2 1 + → 0+) values were determined for 56Cr and 58Cr. The B(E2) values show a minimum for 56Cr providing evidence for a subshell closure at N=32.

Identification and study of the very neutron deficient nuclide 111I: search for octupole correlations in the region of N≈Z≈56

High-spin states in the neutron-deficient nuclide “‘1 have been populated with the fusion reaction 58Ni + 58Ni at a beam energy of 210 MeV, in an experiment performed at the Tandem Accelerator of the Laboratori Nazionali di Legnaro. The gamma spectrometer GASP was used in time coincidence with the ISIS Si-ball and the CAMEL recoil mass spectrometer for the positive identification of the nuclide. Gamma transitions and structure details previously attributed to IllI by other authors are only partially confirmed. The obtained level scheme includes new rotational bands and a new low lying structure which suggests the presence of octupole correlations at predicted rotational frequency values.