No abstract available

No abstract available

[en] ²¹Mg with PW interaction is used to show that the observed β⁺ -decay strength is only a small fraction of the total and that a proper understanding of the strength distribution can come from SU(4) symmetry considerations and statistical spectroscopy methods. (orig.)

[en] Beta-delayed proton emission has proven to be a useful tool for understanding nuclei far from stability. Most of the beta decay strength is concentrated at and below the isobaric analog state (IAS) of the parent nucleus (precursor) ground state. Identification of beta strength to states above the IAS is important not only because it provides additional tests of nuclear models of beta decay, but also because proton emission from such beta daughter nuclei frequently constitutes an important component of the background in searches for more exotic nuclei. Therefore the authors have re-measured the beta-delayed proton spectra of four T/sub z/ = -3/2 nuclei: ²¹Mg, ²⁵Si, ²⁹S, and ⁴¹Ti. Fourteen previously unreported proton groups were observed and beta decay branching ratios were derived for each

No abstract available

[en] Recent experimental studies on ²⁰Na and ²¹Mg and the implication to the onset of the rapid-proton process in stellar sites are discussed. A plan of the nuclear reaction studies with using radioactive nuclear beams is also presented. (author)

[en] We present recent results of collinear laser spectroscopy measurements on ²¹Mg performed at ISOLDE (CERN). The radioactive Mg ions were produced by 1.4 GeV protons impinging on a SiC target and subsequent selective resonant ionization of the reaction products by a laser ion source. The extracted and mass-separated beam is superimposed with an ultra violet cw laser beam in collinear geometry and optical pumping is performed in a weak magnetic guiding field. If the laser is at resonance with the ionic transition, nuclear spin polarization is created by optical pumping of the hyperfine structure Zeeman levels. After implantation into a suitable crystal an asymmetry in the spatial distribution of the positrons from the β⁺ decay can be observed. Detecting this β-asymmetry while Doppler-tuning the laser wavelength yields the hyperfine structure. High-resolution β-NMR measurements were also performed and the nuclear g-factor was determined. After combining the results of β-asymmetry and β-NMR, also the nuclear spin of ²¹Mg could be extracted. The results are compared to nuclear shell-model predictions, and an outlook to further experiments is given

[en] This document presents the activities of the CENBG for the 1999 and 2000 years. The activities are arranged into 7 topics: 1) astro-particles, 2) high spins and big deformations, 3) fundamental interactions, 4) exotic nuclei, 5) the down end of the nuclear fuel cycle and ADS (accelerator driven system), 6) theoretical physics and 7) at the interface between physics and biology. Among a lot of achievements relevant to INIS we can note: -) the investigation of 2 new modes of decay: the bound internal conversion and the Pauli forbidden bound internal conversion, -) the progress made on the Nemo-3 experiment whose purpose is the possibility of detecting the neutrinoless double beta decay from the kinematics specificities of the 2 electrons released, -) the first observation of the doubly-magic nucleus Ni⁴⁸, -) the beta delayed proton and gamma -ray spectroscopy of Mg²¹ and Si²⁵ nuclei, -) the identification of the fundamental state of Li¹⁰, -) the measurement of the masses of nuclei close to N = Z line in the region A = 80, -) the measurement of the beta decay of Ga⁶² (T = 116 ms), and concerning ADS technology: -) the neutron capture cross-section of Th²³² has been measured in the energy range from 60 keV to 2 MeV, -) the determination of neutron induced fission cross-section of Pa²³³ in the fast neutron energy range from 0.5 to 10 MeV, and -) the measurement of isotopic distributions for all residual elements from Ti to Pb produced in the reaction 1 A.GeV Pb²⁰⁸ on proton. (A.C.)

[en] The spectroscopic study of the decay modes of ²¹Mg, ²⁵Si and ²⁶P gives the opportunity to test the predictions of theoretical models when applied to the description of the properties of very unstable nuclei. Some shell model calculations and the charge independence hypothesis of nuclear forces are compared to experimental results. Finally, the observation of the rare phenomenon of the two-proton emission is the first step toward the research and study of the ²He radioactivity. (author)

[en] The aim of this study was to evaluate the adsorption capacity of a novel activated carbon coated with chitosan for the removal of Cr (VI) and Cd (II) ions from single and bi-solute dilute aqueous solutions. In addition, the adsorption abilities of activated carbon (AC), chitosan (CH) and chitosan / activated carbon composite (CHAC) were compared. The adsorption studies were performed in a batch system, and the effects of various operating parameters such as solution p H, particle size and the dose of adsorbent were considered for the removal of Cr (VI) and Cd (II) via the Taguchi method. The equilibrium experimental data were well fitted to the Langmuir isotherm for single and bi-solute solutions. The adsorption capacities of the AC and CH adsorbents were improved by means of the synthesized CHAC composite. As expected, the competitive adsorption of metal ions on the CHAC surface led to a reduction in the adsorption capacity from 90.9 mg/g to 41.94 mg/g for Cr (VI) ions and 52.63 mg/g to 30.21 mg/g for Cd (II) ions, respectively. The adsorption potential of CHAC for Cr (VI) was greater than Cd (II) for the different metal solution–adsorbent systems. The kinetic studies indicated that the adsorption process was best described by pseudo-second-order kinetics for single and bi-solute solutions.