[en] The today's situation of the experiment towards a fusion reactor seems to imply that in the near future a superconducting magnet system has to be used. A reliable and effective cooling system is one of the fundamental steps towards the reliability of the whole magnet system. This paper deals with the advantages of cooling systems based on forced circulation of liquid helium in hollow conductors. Available experimental data on forced flow of supercritical, subcooled and boiling helium are discussed. The analysis shows that, for the large superconducting magnets of a fusion reactor, forced circulation of two-phase helium seems to be very attractive. In view of the scatter of data, we are designing an experimental set up to study heat transfer, stabilization and hydrodynamic features in forced flow cooling

[en] This paper, after a short introduction to superconductivity and to multifilamentary superconducting composites is aiming to review the state of the art and the future perspective of some of the applications of the superconducting materials. The main interest is focussed to large scale applications like, for istance, magnets for accelerators or fusion reactors, superconducting system for NMR thomography, etc. A short paragraph is dedicated to applications for high sensitivity instrumentation. The paper is then concluded by some considerations about the potentialities of the newly discovered high critical temperature materials

[en] In the framework of the international collaboration among SIN-Villigen (CH), ECN-Patten (NL) and CNEN-Frascati (I) aiming at the realization of the SULTAN (SUpraLeitender TestANlage) test facility the CNEN contribution is concerned with the realization of the outer part of the solenoid, i.e., the section which will provide the 6T field in the useful region, the remaining 2T being supplied by the coaxial ECN insert. A description of the 6T superconducting solenoid is presented. The main features are: (1) pancake structure wound by a Nb-Ti multifilamentary hollow cable; and (2) cooling by forced flow of slightly subcooled liquid helium. Details of the design, winding technique and structure, the hydraulic circuitry as well as the status report of the construction are discussed. 10 refs

[en] The response of a stainless steel/liquid argon sampling calorimeter has been studied with electrons from 20 to 40 GeV. Best conditions for the efficiency in ionization charge collection were found. An E-₁/₂ dependence of the relative energy resolution on the incident electron energy was found, which well interprets the experimental results. 4 refs

No abstract available

[en] In the ITER research program framework a full size cable in conduit NbTi short length conductor has been manufactured. The conductor is composed of two straight parallel legs with a copper joint between them at one extremity. The legs are based on different strands, Ni plated the first, CuNi internal barrier the second. The system is fully instrumented; in particular several voltage taps and thermometers measure the conductor behaviour and allow following the superconducting/normal transition. Full sets of experimental runs have been performed at the SULTAN facility obtaining a complete conductor characterisation. In this paper experimental data about the V-I characteristic as a function of the more relevant physical parameters have been investigated

[en] Experimental results about the superconducting properties of a nineteen filament Nb₃Al wire are reported. This wire has been fabricated by extending a technique previously developed for the construction of a single core wire. An analysis of the heat treatment conditions which give rise to good superconducting properties is presented. A critical current density (at 4.2⁰K and 64 kG) of the order of 1 to 1.5 x 10⁵ A/cm² has been obtained while the critical temperature, although lower than the bulk value, reaches 15.7⁰K. Preliminary results concerning pinning forces are given. Bending effects and small coil results are also given

[en] The results of some experiments on the vacuum reaction between butylcellosolve and sodium, contained in small diameter capillaries, are reported. The effects on the cleaning rate of the temperature, amount of solvent, diameter and position of the capillaries are analyzed. The facility, used for the cleaning of small components of complex geometry, is described. (author)

[en] As a first approach, a wire with a single Nb₃Al filament has been manufactured to study the rapid heating and quenching parameters. A reel-to-reel continuous rapid quenching apparatus has been designed and fabricated which will be able to produce some hundred meters of wire. The heating temperature is monitored by an infra-red two colours detector. Structural characterization of Nb₃Al wires has been investigated by means of X-ray diffraction. Due to the absence of stabilizing Cu, superconducting transport properties were estimated by Bean formula as a function of a background magnetic field up to 10 T, while hysteresis losses were measured by vibrating sample magnetometer facility

[en] Problems related to the fabrication of high J/sub c/ Nb₃Al multifilamentary superconductors by Jelly roll technology are discussed. In particular, a new method called IMF (intrinsically multifilamentary), which should allow the achievement of J/sub c/ 1500 A/mm² at 11.T, 4.2 K, on a multifilamentary structure, is presented