Publications (3)3.64 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: The feasibility of a heating technique to induce quenches in superconductors using a single-mode diode laser coupled to an optical fiber was analyzed. It was found that the release of the optical energy onto the wire surface can induce a normal resistive zone, which either propagates or recovers. The diode was calibrated at room temperature by measuring its output optical power as a function of forward current. Hence, the optical energy was estimated by integrating the power over the pulse duration.
- [Show abstract] [Hide abstract] ABSTRACT: The stability of NbTi-based multifilamentary composite wires subjected to local heat disturbances of short durations is studied in pool boiling helium conditions. A new type of heater is being developed to characterize the superconducting to normal state transition. It relies on a single-mode Diode Laser with an optical fiber illuminating the wire surface. This first paper focuses mainly on the feasibility of this new heater technology and eventually discusses the difficulties related to it. A small overview of Diode Lasers and optical fibers revolving around our application is given. Then, we describe the experimental setup, and present some recorded voltage traces of transition and recovery processes. In addition, we present also some energy and Normal Zone Propagation Velocity data and we outline ameliorations that will be done to the system.
- [Show abstract] [Hide abstract] ABSTRACT: One possible application of Nb<sub>3</sub>Sn, whose superconducting properties far exceed those of NbTi, is the fabrication of short and powerful quadrupole magnets for the interaction regions of large particle accelerators. In some projects, as in the future linear collider TESLA, the quadrupole magnets are inside the detector solenoid and must operate in its background field. This situation gives singular Lorentz force distribution in the ends of the magnet. To learn about Nb<sub>3</sub>Sn technology, evaluate fabrication techniques and test the interaction with a solenoidal field, DAPNIA/SACM at CEA/Saclay has started the manufacturing of a 1-m-long, 56-mm-single-aperture quadrupole magnet model. The model relies on the same coil geometry as the LHC arc quadrupole magnets, but has no iron yoke. It will produce a nominal field gradient of 211 T/m at 11,870 A. The coils are wound from Rutherford-type cables insulated with glass fiber tape, before being heat-treated and vacuum-impregnated with epoxy resin. Laminated, collars, locked around the coil assembly by means of keys restrain the Lorentz forces. After a recall of the conceptual design, the paper will review the progress in the manufacturing and test of the main components as well as the design and delivery of the main tooling. The first coil should be wounded and reacted during the last quarter of the year 2003.