FIBER-REINFORCED-SUPERCONDUCTORS WITH HIGH-ELASTIC MODULUS AND LOW THERMAL PRESTRAIN ON NB3SN LAYERS FOR HIGH-FIELD PULSED MAGNET

We have been developing a new type of Nb3Sn superconductor, a Fiber-Re inforced-Superconductor (FRS), to make an attempt at the application o f high-field pulsed superconducting magnets. FRSs have high elastic mo dulus fibers such as tungsten so that the strain on superconducting la yer caused by hoop stress can be reduced. Such high elastic modulus ma terials however, tend to have lower thermal expansion coefficient comp ared with Nb3Sn. The resultant tensile prestrain on Nb3Sn at liquid he lium temperature brings about the degradation of superconducting chara cteristics. In this paper, it is shown that the strain characteristics of FRS can be largely improved by adopting a tungsten alloy , keeping high elastic modulus of pure tungsten.