No abstract available

No abstract available

[en] This work presents an experimental study of fragmentation of helium by electron impact, in which absolute fully differential cross sections for single ionization, ionization-excitation and double ionization were determined. By applying a charged-particle imaging technique, the so-called 'reaction microscope', a large fraction of the final-state momentum space is covered, and the major limitations of previous experimental methods applied in this field could be overcome. Decisive modifications of the previous reaction microscope were undertaken, the most important one being the arrangement of the projectile beam parallel to the imaging-fields. For single ionization on helium an enhanced electron emission outside the projectile scattering plane is observed at both considered impact energies (102 eV and 1 keV), which is similar to the result found for ion-impact (M. Schulz et al., Nature (London) 422, 48 (2003)). The angle resolved cross sections obtained for double ionization at 105 eV impact energy reveal, that the process is dominated by the mutual repulsion of the three final-state continuum electrons. However, signatures of more complex dynamics are also observed. The data provide an ultimate benchmark for recently developed theories treating the dynamical three- and four-body Coulomb problem. (orig.)

[en] A chronological accounts of the most important points of French energy policy from 1945 to nowadays is given. Successively, the post-war period, the development of natural uranium-graphite-gas line period, the period of hesitation 1967-1970, the relinquishing graphite-gas line period and the choice between the lines, the choice of the PWR line, the successive output stages for PWR plants and, the situation in 1983 and the construction program for nuclear power plants are reviewed some key numbers of the technical and economical energy field are presented in tables

[en] The author presents EDF politics and all actions in matter of nuclear information of physicians, veterinaries, pharmacists (iodine problems), nurses by means of conferences, post-university training, special days, visits of nuclear plants and SCPRI, documentation delivery (books, booklets, journals), publication of articles in medical and veterinary journals, participation at Euromedecine Conference and inquiries near to physicians in Orne Champagne-Ardennes, Provence-Cote d'Azur, veterinaries and pharmacists in Isere. A balance of all actions is given

[en] The monitoring of fuel-cycle facilities provides a tool to confirm the compliant operation, for example with respect to emissions into the environment or to supervise non-proliferation commitments. Hereby, anomalous situations can be detected in a timely manner and responsive action can be initiated to prevent an escalation into an event of severe consequence to society. In order to verify non-nuclear weapon states' compliance with the non-proliferation treaty (NPT), international authorities such as the International Atomic Energy Agency (IAEA) conduct inspections at facilities dealing with fissile or fertile nuclear materials. One measure consists of collection of swipe samples through inspectors for later analysis of collected nuclear material traces in the laboratory. Highly sensitive mass spectrometric methods provide a means to detect traces from nuclear material handling activities that provide indication of undeclared use of the facility. There are, however, no relevant (certified) reference materials available that can be used as calibration or quality control standards. Therefore, an aerosol-generation based process was established at Forschungszentrum Juelich for the production of spherical, mono-disperse uranium oxide micro-particles with accurately characterized isotopic compositions and amounts of uranium in the pico-gram range. The synthesized particles are studied with respect to their suitability as (certified) reference material in ultra-trace analysis. Several options for preparation and stabilization of the particles are available, where preparation of particles in suspension offers the possibility to produces specific particle mixtures. In order to assess the stability of particles, dissolution behavior and isotope exchange effects of particles in liquid suspension is studied on the bulk of suspended particles and also via micro-analytical methods applied for single particle characterization. The insights gained within these studies will form the basis on the choice of the further route towards preparation of uranium particle reference standard and certification as a reference material. (authors)

[en] The Paluel center has two 1300-MW simulators, a 900-MW simulator and three function simulators (reactor control, chemical and volume control RCV, turbine generator GTA). A maintenance team of about 15 is required for this equipment. There are currently 30 instructors and ten others are being trained. During the extremely rapid growth of the French nuclear power park, the number of simulators was decided in accordance with initial training requirements, which entirely monopolized those facilities. Today, for the 900-MW simulators, and in a few years time for the 1300-MW simulators, refresher courses and newcomer courses will gradually give way to the development of new courses. Highly specialized, they will be available to plant unit personnel to further increase the competence of the operating teams. This is a vital aspect of nuclear power plant safety

[en] The influence of molecular vibrations on the reaction dynamics of H₂ on Si(001) as well as isotopic effects have been investigated by means of optical second-harmonic generation and molecular beam techniques. Enhanced dissociation of vibrationally excited H₂ on Si(001)2x1 has been found corresponding to a reduction of the mean adsorption barrier to 390 meV and 180 meV for ν=1 and ν=2, respectively. The adsorption dynamics of the isotopes H₂ and D₂ show only small differences in the accessible range of beam energies between 50 meV and 350 meV. They are traced back to different degrees of vibrational excitation and do not point to an important influence of quantum tunneling in crossing the adsorption barrier. The sticking probability of H₂ on the 7x7-reconstructed Si(111) surface was found to be activated both by H₂ kinetic energy and surface temperature in a qualitatively similar fashion as H₂/Si(001)2x1. Quantitatively, the overall sticking probabilities of H₂ on the Si(111) surface are about one order of magnitude lower than on Si(001), the influence of surface temperature is generally stronger

No abstract available

No abstract available