[en] All the existing observations which did resolve low energy deuterons and He³'s appear to form a self-consistent set with a hysteresis type of variation over the solar cycle of the ratio PHI(d)/PHI(He⁴*), where PHI(He⁴*) is the He⁴ flux corrected for the ''anomalous'' low energy component. This hysteresis can be understood if one accepts an interplanetary deceleration which is weak during the rising phase, and strong during the recovery phase of the solar cycle, and a continued increase of the escape length from the galaxy below a few GeV/n

[en] The detailed pattern of elemental abundances in the Galactic Cosmic Rays is well determined at energies of a few GeV per nucleon. After correction for propagation effects the inferred source composition shows significant deviations from the standard pattern of Galactic elemental abundances. These deviations, surprisingly overabundances of the heavy elements relative to Hydrogen, are clearly a significant clue to the origin of the cosmic rays, but one which has proven very difficult to interpret. We have recently shown that the 'standard' model for the origin of the bulk of the Galactic cosmic rays, namely acceleration by the diffusive shock acceleration process at the strong shocks associated with supernova remnants, can quantitatively explain all features of the source composition if the acceleration occurs from a dusty interstellar medium. This success must be regarded as one of the stronger pieces of evidence in favour of the standard model

[en] Developing a tens of picosecond sensor which will survive the radiation environment of the future high physics experiments is a challenge. For position detection, sensors in the HV-CMOS 150 nm process technology have proven to be inherently rad-hard thanks to the full depletion of several hundred microns of the substrate. A first iteration of a timing sensor in this technology, named CACTUS, has been tested with encouraging results but with a time resolution far from the 60 ps expected from the simulations due to unforeseen capacitance. A new prototype called MiniCACTUS has been designed and submitted to fabrication in order to address this issue. It includes integrated front-end electronics with discrimination for each pixel, a programmable slow-control, internal DACs and bias circuits. The baseline pixel pitches are 1 mm² and 0.5 mm² with additional test structures sizing 50 µm x 50 µm and 50 µm x 150 µm. The prototypes received from the foundry have been thinned to 100 µm and 200 µm and were post processed for backside polarization. The 200 µm samples have shown a breakdown voltage higher than 300 V, a S/N better than 50 with cosmic rays, and a timing resolution around 80 ps, limited by the resolution of our timing reference system. A test-beam campaign is foreseen at CERN this year in order to assess precisely the timing resolution of the sensor. All these results will be presented at the conference.

[en] NOMAD is a short baseline neutrino oscillation experiment searching for ν_μ→ν_τ oscillations in the CERN SPS wide band neutrino beam. The experiment has been collecting data since July 1995 and the data taking will continue until at least the end of 1997. A preliminary analysis based on the 1995 data sample allows NOMAD to set a 90% confidence limits on sin²(2θ_μτ)<4. x 10^-3 for ν_μ→ν_τ oscillations at large Δm². (orig.)

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[en] The authors describe the clues to the origin of the cosmic ray nuclei that can be derived from their composition, and especially from their heavy element composition (Z>=3). In the cosmic ray source composition, the pattern of heavy element abundances is reminiscent of that of galactic matter. As to their isotopic composition however, our knowledge of the source is still quite limited. The authors discuss how the observed isotopic anomalies can be interpreted by nucleosynthetic processes. (Auth.)

[en] The observed deficit of the solar neutrino flux is now well established. This puzzling problem of today's particle physics could be resolved soon. The most likely explanation would be the vacuum neutrino oscillation phenomenon, indirectly proving the non-zero mass of these fleeting particles. Following the proposition of Raghavan of using ¹⁷⁶Yb as a target for low-energy solar neutrino spectroscopy, an intense R and D work has started a few years ago to define a suitable scintillator incorporating a large amount of ytterbium. Recently, the observation of UV scintillation in mixed yttrium/ytterbium aluminium garnets opened the field of investigation to a new class of scintillating crystals with interesting luminescence properties, very attractive not only for neutrino physics but also for radiation detection, in general. Their luminescence properties present some peculiarities that make them interesting by themselves

[en] This paper is concerned with the volume-averaged mathematical description of heat transfer through packed pebble beds, with special application to pebbled bed modular nuclear reactors. Although much work has been done on constructing such mathematical equations, very little is available for systems which are in a state of local-thermal-non-equilibrium. The latter is the case when the solid and fluid are at different temperatures on a volume averaged level, which is prevalent the in the work under consideration. This paper details the fundamental derivation of the implicated governing equations viz. fluid and solid energy conservation. This is followed by order of magnitude estimates for the case of helium flow through a bed of randomly packed graphite spheres in order to identify the dominant heat diffusive type heat transfer modes. Conclusive deductions are made from the study. (author)