No abstract available

[en] In this paper we give the specifications of the Opera loop used to qualify PWR fuel elements and operating in similar conditions that those of a PWR

No abstract available

No abstract available

No abstract available

[en] A magnet of three tons has been built to obtain zero-dispersion, horizontal and vertical (triple) focusing of particles emitted with Δp/p <= 3.5% in a solid angle of 10^-2 sr. The profile of the pole-pieces was designed by pursuing the minimization of a quantity defined in such a way as to represent the 'astigmatism' of the focusing. The early test-runs made with the magnet allowed to detect and to eliminate a contamination of the alpha-particle beam employed (at a level of the order of 10^-7) by ions of carbon, nitrogen and oxygen, having the same momentum/charge ratio as the particles of the beam. (orig.)

[en] An experiment on the ¹⁴N(α,γ)¹⁸F reaction leading to the parity- and isospin-forbidden 0⁺ level at 6.138 MeV is reported. A ¹⁴N gas target was exposed to a pulsed singly charged α-particle beam from the CN accelerator of the Laboratori Nazionali di Legnaro, and γ-rays emitted in coincidence with the beam were measured with a 90 cm³ Ge(Li) detector. A similar run with the same target as well as an activation experiment were carried out on the nearby parity-allowed resonance at 6.241 MeV, in order to test the electronic gain and the efficiency in the parity-violating experiment. The energy spectrum from the Ge(Li) shows no peak due to the decay of the 6.138 MeV state and allows to set an upper limit of 2.10^-3 eV for the parity-violating width of this resonance. (author)

[en] The quasi-elastic cross-sections sigmasub(el)sup(tot) and dsigma/dq² for the reactions (1) νn→μp and (2)antineutrinop→μsup(+)n have been measured by using the data of the ν Gargamelle collaboration. 687 ν events, candidates for reaction 1), and 476 antineutrino events, candidates for the reactions 2), have been used for the analysis. Because the ν and antineutrino interactions are on nuclei, suitable corrections for nuclear effects have been taken into account. In the framework of the ''usual'' V-A theory, by assuming for the axial form factor the dipolar form Fsub(A)(q²)=1.231/(1+q²/Msub(A)sup(2)), our data have been fitted to the differential cross-sections dsigma/dq² integrated over the ν and antineutrino energy spectra and to the total cross-section sigmasub(el)sup(tot) as a function of the ν, antineutrino energy to determine the best value for the parameter Msub(A)

[en] An experiment is reported on the parity-violating reaction d(α,γ)⁶Li, leading to the Jsup(P)=0⁺, I=1, Esub(kappa)=3.562 MeV state, which, being a ΔI=1 transition, could be strongly enhanced by the presence of neutral currents in hadronic weak interactions in nuclei. The experiment has been carried out by exposing a deuterium target to a beam of α-particles reaching the resonant energy in the region in the middle of the tube containing the gas. Gamma-rays from this region are detected by a 90 cm³Ge(Li) counter connected to a 4096 channel analyser through an amplifying and analysing chain. The various sources of the background of spurious counting in the Ge(Li) and the procedure adopted to reduce their effect are discussed. No evidence has been found for a nonzero parity-violating width of the 3.562 MeV state of ⁶Li and can set an upper limit for this width of 8.10^-4eV, which is an order of magnitude or more lower than that obtained in the previous experiments on this reaction

[en] Ageing effects on aerogel due to irradiation and absorption of humidity have been investigated. Aerogel tiles have been exposed to γ radiation from a ⁶⁰Co source and to proton and neutron high intensity beams. The transmittance has been monitored in the wavelength range between 200 and 800 nm, determining the clarity factor C as a function of the increasing dose of irradiation. The index of refraction n was also measured