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Abstract:: A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm−1. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

Protons, deuterons, tritons,a-particles and Li have been studied in coincidence with evaporation residues produced at low impact parameter for the40Ar(1100 MeV)+13C reaction. Experimental characteristics of the light particle — heavy residue correlations, and among them an effect of left-right asymmetry, are analyzed and discussed in some detail on the basis of Monte Carlo simulations. This reaction appears to be governed by an incomplete fusion process. Due to transverse emission of preequilibrium particles, the compound nuclei associated with light-particle-evaporation-residue coincidence events recoil at a non-zero degree lab. angle with some dispersion around this direction. When these effects are introduced into statistical decay calculations, it is then possible to reproduce various experimental results and to understand features like the asymmetry effect. Discrimination of light particles of preequilibrium and of evaporative origin appears possible.

In an attempt to separate preequilibrium and thermalised emissions of light particles in low impact parameter heavy-ion collisions, the40Ar+24Mg reaction has been studied at 27.5 MeV/nucleon. Exclusive measurements have permitted us to examine, in some detail, heavy fragments and charged particles (p, d, t,a-particle). The fragments recognized as evaporation residues have been selected and, due to inverse kinematic conditions, the related preequilibrium and statistical emissions of light particles resulting from incomplete fusion reaction appear to be distinguishable to a fair extent. This separation is fully supported by Monte Carlo calculations. Some experimental characteristics of the light particles have been examined and compared to the predictions of dynamical calculations. These calculations, associating a preequilibrium (interpreted as prompt emitted particles) model with a statistical-decay model, follow the evolution of the collision from the point of contact between the projectile and the target to the final evaporation-residue formation on an event by event basis. The predictions of these calculations have been compared to experimental data and satisfactory agreement is achieved for fragment-mass distribution, proton-energy spectra, and proton-angular distribution.

Abstract: The possibility of using high-energy ion beams for analytical purposes is explored. The most promising field is the identification of medium-weight elements by detection of K X-rays following alpha-particle and proton bombardment, where a sensitivity well bellow 1 ppm was predicted. In the case of heavy elements, interferences are possible because of competition of nuclear reactions. In the case of rare earths, the method is interference free, quantities of 0.1 mg/cm2 can be determined.

Angular distributions were measured for the elastic scattering of16O and20Ne from70, 72, 74Ge at 4.75 MeV/amu. All the data could be described satisfactorily by a four-parameter optical model using a same parameter set except for the imaginary strength which was stronger for20Ne than for16O. The isotopic shift of the quarter-point was in good agreement with the predictions given by the semi-classical method due to Brink and Rowley. Barrier heights and critical angular momenta were deduced.

Multiparticle Electroproduction Modular Upgradable Spectrometer (MEMUS) is a large acceptance detector intended to run on the ELFE machine at a luminosity of 1036cm−2s−1per nucleon with a hydrogen target. The detector is designed to study reactions with multiparticle final states. We present a brief description of the overall detector design and of the ongoing research program on the determination of the adequate characteristics of the different detector components.