[en] Triple differential cross sections in momentum p, polar angle θ, and azimuthal angle φ with respect to the reaction plane, have been measured at the Saturne synchrotron in Saclay for collisions between neon and lead nuclei

[en] This work is part of a systematic investigation of Ne-nucleus collisions undertaken with the 4 π detector Diogene. Only data obtained with Ne at 400 and 800 MeV/A on Pb nuclei are presented. Experimental data are also compared with the resuts of an intranuclear cascade calculation which takes, into account nuclear binding, Pauli blocking and isospin

[en] The characteristics of a spectrometer to study neutral meson decaying into two gamma rays and η meson production in nuclei are described. An energy resolution is better than 2 MeV at T_π⁰=100 MeV and efficiency is greater than 50% for gamma of energy lower than 400 MeV. The spectrometer consists of two-identical gamma ray detectors. The spectrometer has been installed and tested at SATURNE for studying at different energies the reactions (p,pdπ⁺); (p,d,³Heη) (pd,³Heπ⁰) and in future for measuring the n+p→d+η reaction, detecting both the deuteron and η meson. 7 refs.; 6 figs

[en] Short communication. 4 refs

[en] A possible way to estimate the reaction plane of the ion-ion collision is to measure the sideward deflection of the spectator neutrons. In the ALICE experiment this kind of measurement can be performed by means of the two neutron zero degree calorimeters (ZN), which are located at opposite sides with respect to the beam intersection point (IP). In fact the ZN calorimeters, thanks to their segmentation in four towers, are position sensitive devices. Concerning their localizing capability, a spatial resolution of ∼3 mm has been measured for a 100 GeV/c hadron beam. This performance will be used to reconstruct, event by event, the centroid coordinate of the spectator neutron spot on the ZN front-face, which is sensitive to the directed flow ('bounce off') of spectator neutrons. The measurement of the centroid will therefore allow to reconstruct the 1st-order event plane azimuth. A simulation is performed in order to estimate the dependence of the event plane resolution on the magnitude of the directed flow v₁ of the spectator neutrons and on the neutron multiplicity (event centrality). In particular, it will be shown that the event plane resolution is not dominated by the smearing on the centroid measurement, but by the smearing due to the transverse lead beam divergence at the IP. Finally a possible tool to select events with small lead beam divergence at IP is discussed, using the information coming from both the ZN calorimeters. (author)

[en] The main results concerning dilepton production in ultrarelativistic heavy-ion collisions at CERN SPS are reported. The e⁺ e^- and μ⁺μ^- measurements are briefly reviewed as well as their theoretical interpretations

[en] In this communication we will discuss the production of η meson by proton interaction in nuclei at energies below 1.26 GeV, the free nucleon-nucleon threshold. The experimental values have been obtained at SATURNE with the spectrometer PINOT. Data will be compared with the theoretical predictions. Finally an outlook on the future measurements at SATURNE will be presented. (orig.)

[en] The reaction p¹²C→nX has been studied, at several proton kinetic energies ranging from 800 MeV to 1500 MeV, at the proton synchrotron Saturne at Saclay. The measured doubly differential cross-sections are presented and discussed in the framework of a simple theoretical model. The model fails in describing the deepest subthreshold data while the above-threshold data are fairly well reproduced. (orig.)

[en] The PINOT collaboration has carried out an experimental study on η production in proton-nucleon and proton-nucleus interactions at SATURNE synchrotron. Results on differential and total cross sections for the pp → ppη reaction in the proton energy region from threshold to 1.5 GeV allow to test the proposed theoretical models, which emphasize the role played by N*(1535). A parallel study of pd → ηX reaction, at the same incident proton energies, has shown that η production in the pn channel is strongly enhanced with respect to the pp one. Finally η production has been studied on several nuclei with A ranging from 6 to 197 and at various incident proton energies, both below and above the pp → ppη threshold. A-dependence and T_p-dependence of η production cross sections have been measured. The comparison with the prediction of the theoretical models allows to obtain information on reaction mechanisms and on the role of η reabsorption in the nuclear medium. (authors). 15 refs., 3 figs

[en] The possibility to detect thermal neutrons with single gap resistive plate chambers (RPCs) has been investigated. The development of the detector has been performed in the frame of the detection and imaging of antipersonnel land-mine by neutron back-scattering (DIAMINE) European Project for humanitarian de-mining. The RPCs are simple devices widely used in many particles physics experiments as trigger detectors because of their fast response and good spatial resolution. The RPC detects the charged particles generated by neutrons via the (n,α) reaction on boron. A ¹⁰B₄C thin coating on the inner surface of one RPC electrode is used as thermal neutron converter. A simulation study has been performed to optimize the converter thickness and the RPC working parameters. Tests on converter samples have been performed with a thermalized ²⁵²Cf source in order to evaluate the conversion efficiency. A first detector prototype has been realized and tested with cosmic rays and thermal neutrons. Results of simulation and experimental measurements of conversion efficiency, together with the description of the RPC prototype, are presented