[en] We have developed a specific thermal conductivity measurement facility for solid materials at low temperature (LHe and LN2). At present, the Measurement of Thermal Conductivity of Insulators (MECTI) facility performs measurements on epoxy resin, as well as on bulk materials such as aluminum alloy and on insulators developed at Saclay. Thermal conductivity measurements on pre-impregnated fiber-glass epoxy composite are presented in the temperature range of 4.2 K to 14 K for different thicknesses in order to extract the thermal boundary resistance. We also present results obtained on four different bonding glues (Stycast 2850 FT, Poxycomet F, DP190, Eccobond 285) in the temperature range of 4.2 K to 10 K

[en] The Next European Dipole (NED) Consortium is working to develop the technology of high field, dipole magnets for a future luminosity upgrade of the LHC at CERN. The proposed magnet will be a large aperture (88 mm), high field (15 T) superconducting dipole using Nb₃Sn Rutherford cable and a wind-and-react manufacturing scheme. The magnet scale, forces and manufacturing route present real challenges for the conductor insulation technology. This paper reports on the insulation R and D programs carried out during the first phase of the NED project (2004 to 2007). In the R and D programs both conventional (glass fiber-polymeric matrix) and innovative (ceramic) insulation materials have been studied. A primary objective was to develop a working insulation specification for a dipole magnet at the NED scale. Specialized sample geometries and test methods (mechanical and electrical) have been developed to make comparison between different insulation materials and processing routes. In particular, the role of sizing on glass fiber insulation subjected to Nb₃Sn magnet processing parameters has been studied using thermo gravimetric analysis. (authors)

[en] Elementary particle study requires high resolution detectors (few tens microns and 10⁸ events/s.). Small detectors with these specifications are realized with scintillating plastic fibers and tested. The use of one dopant only in the scintillating core of the fiber limits the diaphoty

[en] Sixty kilometers of plastic scintillating fibers, 1 mm in diameter, have been manufactured using a preform/tube technology. The fibers consist of a polystyrene core surrounded by a polymethylmethacrylate cladding. The fabrication method is described and evaluated both qualitatively and quantitatively. A great effort has been made in order to measure the optical properties of the polymer at the different steps of the production. The global process efficiency is not more than 40% due to the yield of the polymerization process. Using a ternary blue scintillator, the mean light yield for a minimum ionizing particle, passing through a 1 mm diameter fiber at a distance of 1 m, is 5.4±0.6 photoelectrons. The mean attenuation length fitted between 0.5 and 2.0 m is 1.9±0.2 m. Some specific experiments that give independent measurements of core and interface losses are also reported. The principal cause of light loss is due to the lack of transparency of the polystyrene which leads to a spectral shift in fiber emission. This absorption already appears in the preform rods indicating that the purification and the polymerization process are of great importance. The attenuation length related to core losses is measured at the level of 3 m. The interface losses are about 10^-5-10^-4 per reflection leading to an equivalent attenuation length of 7 m

[en] At the present time, Nb3Sn is the best superconductor candidate for the realization of high field magnets (>10-11 teslas). However its implementation remains delicate because of the great brittleness of material after the heat treatment necessary to form the Nb3Sn compounds. The conventional insulation for Nb3Sn wind and react coils requires performing, after the heat treatment, a vacuum resin impregnation, which adds to the cost and raises failure risk. We propose a one-step innovating ceramic insulation deposited directly on the un-reacted conducting cable. The conducting cable is wound according to conventional techniques and, after the heat treatment necessary to the form the Nb3Sn, we obtain a coil having a mechanical cohesion, while maintaining a proper conductor positioning and a suitable electric insulation. We will have studied the electric properties of superconducting cable isolated at the room temperature and at 4.2 K

No abstract available

[en] The magnetic system of ITER is very challenging. Both the CS (Central Solenoid) coils and the TF (Toroidal Field) coils in ITER will use Nb₃Sn as superconducting material, very sensitive to applied strain and actually having a limited production. However 517 t will be required for ITER. PF and CC coils will use NbTi strands, but no conductors, carrying 45 kA and operating in pulse mode in a tokamak, have ever been produced. For Nb,Sn conductors, the tests of two model coils, the Central Solenoid Model Coil (CSMC) and the Toroidal Field Model Coil (TFMC) showed a reduced operating margin, compared to what was expected from strand measurements. This induced in 2003 a revision of the design of these conductors and a complementary R and D programme to qualify the modified design. Nevertheless, the first results show that more effort is still needed. For NbTi conductors for PF coils an important milestone will be the upcoming tests of a an ∼ 50 m long PF conductor. wound in a single layer solenoid and inserted in the CSMC bore. Although manufacturing techniques for TF and CS coils have been qualified by the construction of the model coils, nevertheless, several points require further development, like the metallic screen inside the insulation of the PF conductor, aiming at control of the dielectric quality of the insulation through the life of the machine, or the insulation system of the TF coils, for which it is necessary to demonstrate the feasibility of using radiation-resistant resins, such as cyanate-ester based systems. Contrary to the model coils, the CS, TF coils and PF coils will be wound into multiple pancakes, which implies the insertion of helium inlets at the innermost turn and a specific development, including as well mechanical qualification as hydraulic qualification. Dedicated developments are also carried out to demonstrate the manufacturing feasibility as well of the radial plates into which the TF conductor will be wound as of the pre-compression rings of the TF magnet and to qualify the PF tail design. (author)

[en] We have tested a calorimeter test beam module intended to simulate the endcap electromagnetic calorimeter of the solenoidal detector collaboration (SDC) experiment at the SSC. The test module is manufactured from scintillating tiles and is read out via 1 mm diameter wavelength shifting fibers with shower sampling at ∝ 1 radiation length intervals. The results of test beam calibration show that the calorimeter is linear to within 1% and has a resolution of (19.5 ± 0.1)%/√(E) + (0.47% ± 0.05)% for energies up to 200 GeV. Test beam data show that non-uniform, longitudinal radiation damage to the calorimeter (up to ∝50% light loss at shower maximum) can be corrected, and the original linearity of the calorimeter can be recovered with only a small degradation of resolution. A ''pre-shower detector'' improves the charged π rejection by a factor of 2-3 at an electron detection efficiency greater than 97.5 ± 0.3%. (orig.)