A prototype for the AMS-RICH experiment

The AMS spectrometer will be installed on the International Space Station in 2005. Among other improvements over the first version of the instrument, a ring imaging Cherenkov detector (RICH) will be added and should open a new window for cosmic-ray physics, allowing isotope separation up to A = 25 between 1 and 10 GeV/c and element identification up to Z = 25 between threshold and 1 TeV/c/nucleon. It should also contribute to the high level of redundancy required for AMS and reject efficiency albedo particles. A second generation prototype has been operated for a few months : the architecture and the first results are presented.Comment: Proceedings of the 3rd International Conference on "New developments in photodetection" (Beaune - France

La compressibilité nucléaire et ses déterminations expérimentales

École thématiqu

Atmospheric neutrino flux around Super-Kamiokande

The simulated atmospheric neutrino flux around Super-Kamiokande detector is tabulated in this report. The corresponding fitting is also given

Parameterization of the antiproton inclusive production cross section on nuclei

A new parameterization of the antiproton inclusive production cross section in proton-proton and proton-nucleus collisions is proposed. A sample of consistent pA->pbar X$ experimental data sets measured on 1<A<208 nuclei, from 12 GeV up to 400 GeV incident energy, have been used to constrain the parameters. A broader energy domain is covered for the pp->pbar X reaction with a simplified functional form used in the fits. The agreement obtained with the data is good. The results are discussed.Comment: 10 pages, 11 figures, 7 tables, submitted to Phys. Rev.

Cerenkov angle and charge reconstruction with the RICH detector of the AMS experiment

The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cerenkov (RICH) detector, for measurements of particle electric charge and velocity. In this note, two possible methods for reconstructing the Cerenkov angle and the electric charge with the RICH, are discussed. A Likelihood method for the Cerenkov angle reconstruction was applied leading to a velocity determination for protons with a resolution of around 0.1%. The existence of a large fraction of background photons which can vary from event to event, implied a charge reconstruction method based on an overall efficiency estimation on an event-by-event basis.Comment: Proceedings submitted to RICH 2002 (Pylos-Greece

Fermi and Gamow-Teller Strength in Charge Exchange with Radioactive Beams

At forward angles, and bombarding energies E > 200 MeV, the (p,n) and (n,p) reactions are thought to be directly proportional to the Gamow-Teller transition strengths in the nuclei. Assuming that this relationship also holds for charge exchange induced by high-energy heavy ions, it would be very useful in studies with radioactive beams. Contrary to this expectation, we show that the determination of Gamow-Teller and Fermi matrix elements from heavy-ion charge-exchange at forward angles is very inaccurate.Comment: 9 pages, RevTeX, 4 PostScript figures available upon reques

Coulomb breakup effects on the optical potentials of weakly bound nuclei

The optical potential of halo and weakly bound nuclei has a long range part due to the coupling to breakup that damps the elastic scattering angular distributions. In order to describe correctly the breakup channel in the case of scattering on a heavy target, core recoil effects have to be taken into account. We show here that core recoil and nuclear breakup of the valence nucleon can be consistently taken into account. A microscopic absorptive potential is obtained within a semiclassical approach and its characteristics can be understood in terms of the properties of the halo wave function and of the reaction mechanism. Results for the case of medium to high energy reactions are presented.Comment: 25 latex pages, 4 tables, 6 figures. Submitted to Nucl. Phys.