[en] The ground-state band of the Z=102 isotope ²⁵⁴No has been identified up to spin 14, indicating that the nucleus is deformed. The deduced quadruple deformation, β = 0.27, is in agreement with theoretical predictions. These observations confirm that the shell-correction energy responsible for the stability of transfermium nuclei is partly derived from deformation. The survival of ²⁵⁴No up to spin 14 means that its fission barrier persists at least up to that spin

[en] The MINIBALL spectrometer utilizes successfully the huge variety of post-accelerated radioactive ion beams provided by REX-ISOLDE and since last year by HIE-ISOLDE at CERN. In-beam gamma-ray spectroscopy after Coulomb excitation or transfer reactions is performed with optimized setups of ancillary detectors for particle detection. The physics program is covering a wide range of shell model investigations from the light sd-shell nuclei up to the Ra region. Especially the enlarged availability of exotic heavy ion beams enables unique studies of collective properties up to the actinide region. First data taking with HIE-ISOLDE beams started very recently. The higher energies and intensities of the new post-accelerator provides a promising perspective for a new generation of MINIBALL experiments. An overview of the MINIBALL program with specific highlights from the REX-ISOLDE period will be given. Results from the first HIE-ISOLDE experiments, which will focus on Coulomb excitation measurements, will be presented. This document is composed of an abstract and the slides of the presentation. (author)

[en] In a series of experiments, ⁴⁸Ca induced cold fusion reactions on Pb targets were employed to populate states in ^253,254No isotopes. The ground-state band of ²⁵⁴No is identified up to spin 20⁺. The deduced quadrupole deformation is β = 0.27(2). Evidence for decays from a rotational band built on a 7/2[624] configuration was obtained in ²⁵³No. The initial angular momentum and excitation energy of ^253,254No residues, after neutron emission, was determined. States up to spin 22 ℎ and excitation energy of E^* = 8.5 MeV were observed. The data provide direct information on the fission barrier at high spins B_f≥ 5 MeV, and on the shell-correction energy Eshell ^exp_shell ≥ 4.1 MeV. (author)

No abstract available

[en] The vibrational first 2₁⁺ and 3₁^- states of the doubly-magic nucleus ¹³²Sn were excited via safe Coulomb excitation (CE) employing the recently commissioned HIE-ISOLDE accelerator at CERN in conjunction with the highly efficient MINIBALL array. The ¹³²Sn ions were accelerated to an energy of 5.5 MeV/nucleon and impinged on a ²⁰⁶Pb target. Dexciting γ rays from the first excited states of the target and the projectile nucleus were recorded in coincidence with scattered particles. The optimized beam energy, the high-energy resolution and good efficiency of the HPGe spectrometer provide a beneficial combination to master the challenging measurement characterized by small CE cross sections and excitation energies above 4 MeV. The reduced transition strengths were determined for 0_g.s.⁺ → 2₁⁺, 0_g.s.⁺ → 3₁^-, and 2₁⁺ → 3₁^- in ¹³²Sn. In the past first preliminary results for the B(E2;0_g.s.⁺ → 2₁⁺) value were obtained with an efficient BaF2 array at ORNL. The results on excited collective states in ¹³²Sn provide crucial information on cross shell configurations that are expected to be dominated by a strong proton contribution. State-of-the-art large-scale shell model calculations and new mean field predictions are compared to the results.

[en] Full text of publication follows. The MINIBALL spectrometer utilizes successfully the huge variety of post-accelerated radioactive ion beams provided by the new HIE-ISOLDE accelerator at CERN. In-beam gamma-ray spectroscopy after Coulomb excitation (CE) or transfer reactions is performed with optimized setups of ancillary detectors for particle detection. Especially the enlarged availability of exotic heavy ion beams and the higher beam energies of HIE-ISOLDE enable unique studies of collective properties up to the actinide region. Promising first results were obtained by employing a ¹³²Sn ion beam with an energy of 5.5 MeV/u. The vibrational first 2⁺ and 3^- states of the doubly magic nucleus ¹³²Sn were excited via safe Coulomb excitation after bombardment of a thin ²⁰⁶Pb target. The high beam energy, the high-energy resolution and good efficiency of the HPGe spectrometer provide a favourable combination to master the measurement characterized by small cross sections of the high lying states with excitation energies above 4 MeV. The results on excited collective states in ¹³²Sn provide crucial information on 2p-2h cross shell configurations that are expected to be dominated by a strong proton contribution. The experimental results are compared to large-scale shell model calculations and new mean field calculations. (author)

No abstract available

[en] Full Text: The specific enthalpy and the temperature of the titanium alpha-beta phase transformation were measured by a pulse-heating system, operating in the millisecond time regime. The measurement technique is based on self-heating of a tube-shaped specimen from room temperature to the beta phase of titanium in approximately 300 ms and measuring the current through the specimen, the voltage drop along a defined portion of the specimen, and the temperature of the specimen every 0.5 ms. From current, voltage drop and mass, the specific enthalpy as a function of temperature is calculated. The comparison between the measured phase transition temperature during heating and cooling of the specimen shows a difference of approximately 20 K. The temperature measured during the heating period is higher than the value obtained from the cooling cycle of the specimen. This is probably due to the high heating rate of approximately 4000 Kxs^-1. For the evaluation of the specific enthalpy of the alpha-beta transformation, the specific enthalpy versus temperature function of the beta phase of the heating period was extrapolated to the transition temperature obtained from the cooling cycle (1153 K). A total of 12 measurements on 3 tube-shaped specimens was made, a value of 89900 Jxkg^-1 was obtained for the specific enthalpy of the transformation. The reproducibility of the measured specific enthalpy at the begin and at the end of the transformation was 0.5 %, the reproducibility of the phase transformation enthalpy as difference was 3 %. The extended measurement uncertainty (at a confidence level of 95 %) is estimated to be 6 % for the specific enthalpy of the transformation and ±5 K for the transformation temperature. (author)

No abstract available

[en] Full Text: A transient interferometric technique to measure thermal expansion of pure metals and alloys during rapid heating is presented. The metallic specimen is resistively heated from room temperature to a high temperature close to melting within approximately 500 ms by the passage of an electrical high current pulse. The time dependent temperature of the specimen is measured by a fast pyrometer, the thermal expansion is obtained by a high-speed laser-interferometer. The device used is a modified polarized-beam Michelson-type interferometer with a phase quadrature detector that allows to distinct between expansion and contraction. Details of its principle, the construction, adjustment and operation are described. Furthermore, thermal expansion measurements performed an molybdenum and tungsten standard reference materials (SRM) are presented and compared with results obtained by other researchers. (author)