General Seminar

From different reasons proton-proton cross sections are of immense theoretical interest, and the explaining models need a test by measurements beyond the reach of ground-based accelerators. The seminar discusses the use of Extensive Air Shower observations as source of information of the total inelastic protonair cross section, illustrated by recent studies of the Pierre Auger Laboratory.

Istoricul brevetelor de inventie: Importanta brevetelor in dezvoltarea tehnologica a omenirii; Corelatii inventica-stiinta-tehnologie-inginerie Termeni: know-how, show-how, etc.; Top brevete de inventie, inventatori; Statistici - continente/companii/universitati Importanta brevetelor in dezvoltarea companiilor; Inregistrarea brevetelor de inventii in Romania si Uniunea Europeana, protectia asigurata, taxe, etc.

In parallel to the development, control, and realization of high frequency superconducting cavities by the mainstream accelerator community, smaller groups of physicists, mainly originating from the laser-plasma community, started in the 1980's to work on compact plasma accelerators. Ultra high-gradient acceleration techniques, using field amplitudes of 100 GV/m to TV/m, rely on space charge separation between electrons and ions in plasmas. Static electric fields are produced to accelerate ions, whereas "travelling" electric fields supported by electron plasma waves are used to accelerate lighter particles such as electrons or positrons. The continuing efforts of the research community devoted to this topic has led to a number of high quality radiation sources or particle beams obtained by focusing high-intensity laser pulses on a variety of target materials and densities. The LOA has played with other important laboratories in Europe, in Asia and in America a major role in the development of these innovative sources of particle and radiation, particularly in the electron acceleration improvement and in the control of beam parameters (energy, brightness, emittance).

Gamma-ray spectroscopy is the most prominent method of learning about the structure of the atomic nucleus and thus it is the most consistent part of the professional nuclear data evaluations, as the well-known ENSDF evaluations published by the US National Nuclear Data Center in Nuclear Data Sheets. On one side, precision is critical for a quantitative improvement of the nuclear data for science and technology, which we address by accurate measurements of conversion coefficients at TexasA&M Universitythat affects virtually all nuclear level schemes. At the other side we qualitatively question the significance of gamma-ray spectroscopy for drawing level schemes, based on new type of correlations we get out from data: what in fact is a level scheme, what in fact the nature of data is, and how they converge toward a new concept of level scheme and data.

A long history of research has shown that ceramic oxides and carbides are among the most promising matrices for the immobilization and/or transmutation of nuclear wastes, cladding materials for gas-cooled fission reactors and structural components for fusion reactors. For all these applications, there is an urgent need of data concerning the behavior of nuclear ceramics upon irradiation. Radiations produced in nuclear reactors or in storage forms may be simulated by external irradiations with various types of ions in a broad energy range. The two main slowing-down regimes (Sn and Se) were distinctly investigated: low-energy heavy ions account for the recoil nuclei arising from the alpha-decay of actinides (Sn); swift ions aim to reproduce the impact of fission fragments (Se). In this lecture, we present a few remarkable examples concerning ion-beam modifications of nuclear ceramics (zirconia, pyrochlores, silicon carbide...) with an emphasis on the mechanisms leading to damage creation and phase transformations. We report typical results obtained for ceramics irradiated with ions in a broad energy range (from KeV to GeV) in order to explore both nuclear collision and electronic excitation regimes. These results were recorded by combining ion-beam techniques (RBS, channeling, data analyzed with the McChasy Monte-Carlo code) with other advanced techniques which probe the sample at various spatial scales (XRD, TEM, Raman.