Probing the shell valence structure underlying the B(E2: 0+->2+) for N,Z~40: preponderance of the p-n interaction over the sub-shell closures

The very simple product of the number of particles by the number of holes appearing in the expression of the reduced B(E2:0+->2+) transition probability of even-even nuclei obtained from the extension of the seniority scheme is used to analyze the experimental B(E2:0+->2+) values in the Cr up to Se isotopes. A new interpretation is given to the B(E2:0+->2+) measured in 68Ni and 70Zn. The B(E2:0+->2+) features of the even-even nuclei between Ni and Se with neutron number ranging from 28 up to 50 fit in with a global scenario involving p-n interaction. The evolution of the B(E2:0+->2+) curves presenting very large values is amazingly reproduced by very schematic binomial calculations.Comment: submitted to PRC the 14th May 2002, resubmitted to PRC the 24th June 200

Seniority scenario for the 68-72Zn and 66-68Ni B(E2)^ difference

The very simple product of the number of particles by the number of holes appearing in the expression of the reduced B(E2: 0+1 -> 2+1) (B(E2)^) transition probability of even-even nuclei obtained from the extension of the seniority scheme is used to analyze in a same time the experimental B(E2)^ values of 56-68 Ni and those of 62-72Zn. The evolution of these B(E2)^ values with neutron number fits in with a scenario involving p-n interaction

ETUDE DES NOYAUX D'IRIDIUM DEFICIENTS EN NEUTRONS PAR SPECTROSCOPIE LASER

GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Development of radioactive beams at ALTO: Part 1. Physicochemical comparison of different types of UCx_x targets using a multivariate statistical approach

International audienceThe optimization of the microstructure of the UCx target is a key point since many years in the field of ISOL method. The ultimate goal is to facilitate the release of the fission products, especially those with short half-lives. Fourteen UCx samples were synthetized from different uranium and carbon sources using three mixing protocols. All carburized samples were systematically characterized in terms of nature and proportion phases, grain and aggregate size, open and close porosity proportion and open pore size distribution. Our results were analysed using a multivariate statistical approach in order to remove any subjective bias. Strong correlations between the physicochemical characteristics of the samples as well as the impact of the synthesis process have been highlighted. In particular, using carbon nanotubes as carbon source combined with a new method of mixing is the key parameter to limit the sintering and to obtain samples with small grains and a high porosity well distributed over small pores. Moreover the microstructure obtained proved to be stable at high temperature

Influence of target thickness on the release of radioactive atoms

International audienceNowadays, intense exotic beams are needed in order to study nuclei with very short half-life. To increase the release efficiency of the fission products, all the target characteristics involved must be improved (e.g. chemical composition, dimensions, physicochemical properties such as grain size, porosity, density etc). In this article, we study the impact of the target thickness. Released fractions measured from graphite and uranium carbide pellets are presented as well as Monte-Carlo simulations of the Brownian motion

Charge radii and magnetic moments of odd-A 183-189Pb isotopes

Isotope shifts and hyperfine splitting parameters have been measured for the neutron-deficient odd-mass lead isotopes 183–189Pb. The measurement was performed at the ISOLDE (CERN) online mass separator using the in-source resonance ionization spectroscopy technique. The nuclear root mean square charge radii and the electromagnetic moments μ and Q_S have been deduced. They follow the smooth trend of the heavier isotopes and indicate the absence of deformation.status: publishe