[en] Researchers often feel that having to abide by safety rules could impair the quality of their work. However, being a researcher does not mean forgetting about safety, because the consequences of any breach of safety rules can be serious, as evidenced by a number of incidents in research facilities. All stages in the research process entail potential hazards that must be recognised and must be manageable. Safety is everyone's business, but researchers have to be made fully aware of this notion, in particular through appropriate training. Even if laboratory safety has improved significantly in recent years, progress is still needed to convince researchers that it can contribute to their success, rather than stand in their way. (authors)

[en] Decommissioning outlived industrial installations has been widely underestimated; and nuclear energy is no exception: 'We will solve the problem when the time comes'. As the year 2000 dawns, dismantlement is still a matter of general principles. For decades, no one seemed bothered about the absence of any strategy for answering questions such as 'What to do with shut-down nuclear plants?' or 'when and how to decommission them?' Naive faith in science and technical progress prevail, all the more so given the state's comforting presence in this key sector. At present, although industrialists are still dragging their feet because of the costs and lack of storage sites, safety authorities, having drawn the lessons from a few experiences, have acquired the conviction that operations must be completed as soon as possible. Otherwise, installations will be forgotten until they are so run down that demolishing them will be an even bigger problem. (authors)

[en] The Omega spectrometer has been utilised for experiments with relativistic heavy ion collisions. With the aid of the WA97 experiment (lead-lead at 167 GeV/c per nucleon) data were accumulated during three periods and almost 300 millions of triggers being recorded. To study the quark-gluon plasma (QGP) we have utilised the analysis of the strange particles and the following results were obtained for the ratios of the production rates: 0.54 ± 0.13 for Ωbar/Ω and 0.16 ± 0.1 for (Ω + Ωbar)/(Ξ + Ξ-bar). In order that the anti-strange/strange ratio be the presence signature of the quark-gluon plasma it must reach a value of the order of unity. The results of the West Hall and North Hall experiments gave hints in favor of QGP. However, these hints are not formally solid even for the lead beam at 160 GeV/nucleon. Work developed for the program of the data acquisition as well as for the particle track reconstruction are also mentioned

[en] Alpha knock out from light and medium nuclei up to ⁴⁰Ca was investigated. Preliminary values of the differential cross sections (dsigma/dΩ₁ dΩ₂ dE) are given for ⁶Li and ¹²C nuclei. The P/sub R/ recoil momentum distributions show a maximum at p/sub R/ = 0

[en] Knockout of α clusters from light and medium weight nuclei by 600 MeV protons has been investigated. The outgoing protons and α particles were detected in coincidence; their momenta were measured with two large magnetic spectrometers with proportional wire chambers. Experimental methods which were used to work with a high beam rate and an efficient proton rejection in the α arm are described. Separation energy spectra are given for ⁶Li, ⁷Li, ¹²C, ²⁴Mg, ²⁷AL, and ⁴⁰Ca nuclei. A peak is observed at an excitation energy equal to zero, except for the ²⁷Al target

[en] The HELLAZ experiment aims at obtaining the solar neutrino spectra as well as their angular correlation with the sun. The recoil electrons from the collision ν-e are detected in a time projection chamber (TPC) serving as target. The choice of helium as gas target lowers the electron energy threshold down to 100 keV i.e. to 200 keV for the neutrino energy. HELLAZ will be thus sensible to ν_pp, their flux being practically independent of the sun model, as well as to the ⁷Be neutrinos. To obtain a good energy resolution for neutrinos, namely a good separation between the pp neutrinos and the ⁷Be neutrinos a precise measurement of the emission angle of the recoil electron is necessary. In order to achieve this aim the TPC will be operated in the digital mode by individual measurement in the space of the each electron forming the recoil electron track and precise determination of the main axes of inertia ellipsoid of the cloud formed at the track beginning. The measuring error in the direction of recoil electron is thus low (∼ 35 mrad) leading to an uncertainty in the value of neutrino energy lower than 10%. Additionally, HELLAZ will be capable to identify the neutrino flavor from the angular distribution of the ν-e collision. The HELLAZ experiment will thus measure with high precision the pp neutrino spectrum which is thought to be determined by the sun luminosity and the current measurement of helioseismology. Thus, any deformation of this spectrum can be interpreted in physical terms. For instance, the HELLAZ precision will be high enough to measure the effect of the deformation due to the vacuum oscillations. A schedule of the 5 stages experiment is presented starting from HELLAZ 0 (0.5 l) to the final version of HELLAZ (2000 m³) which will measure the solar neutrinos at Gran Sasso. Two simulation programs where developed. The first, simulating the creation and the shift of ionisation electrons in a track, will serve as starting point in the analysis program, while, the second is dealing with subtraction of the radioactive background noise, specific to the HELLAZ experiment

[en] The cross section for the Ksub(L)⁰p elastic scattering has been measured for the first time. The incident momentum and momentum transfer ranges are 3<=p<=13 GeV/c. 0.1<=mod(t)<=1.3 GeV². The results are compared to those of other experiments related to ours by isotopic spin conservation, finding agreement with some and discrepancies with others. The differential cross sections have been parametrized in the form Aesup(bt). The coefficients show little or no dependence on energy, with A approximately= 9.8 mb/GeV^-2 and b approximately=4.7 GeV^-2. The effective linear trajectory has been determined and gives α₀=0.95+-0.15, α'=-0.35+-0.48 GeV^-2, in good agreement with dominance by pomeron exchange. (Auth.)

[en] Knockout of α-clusters from light and medium weight nuclei by 600 MeV protons has been investigated. The outgoing protons and α-particles were detected in coincidence; their momenta were measured with two large magnetic spectrometers with proportional wire chambers. Experimental methods used to work with a high beam rate and an efficient proton rejection in the α-arm are described. Separation energy spectra are given for ⁶Li, ⁷Li, ¹²C, ²⁴Mg, ²⁷Al and ⁴⁰Ca nuclei. A peak is observed at an excited energy equal to zero, except for the ²⁷Al target

[en] Alpha knock out from light and medium nuclei up to ⁴⁰Ca was investigated. Preliminary values of the differential cross sections are given for ⁶Li and ¹²C nuclei. The p(R) recoil momentum distributions show a maximum at p(R)=0

[en] Results on Λ polarization in the inclusive reaction K^-p->Λ+X at 12 and 16 GeV/c for 0.6< x<1.0, are presented. These results, obtained with the CERN Omega Spectrometer, show that the polarization is important at large x and increases with psub(t) over the covered range 0< psub(t)<1.2 GeV/c. The average polarization for 31 857 lambdas with x>0.6 is Psub(Λ)=0.35+-0.02, along the direction K^- x Λ. The polarization can be expressed as P(x,psub(t))=(0.66+-0.03)psub(t) independent of x in the range covered by the experiment. (orig.)