GEOMETRICALLY-METASTABLE SUPERCONDUCTING STRIP DETECTORS

Geometrical metastability, observed in superconducting type I tin flat strips, has already been proposed as a principle for particle detecti on. In this paper, we first show that the geometrical metastability is not specific to superconductors that undergo a first order transition in magnetic field. Geometry dependant irreversible flux penetration i s also observed in type II niobium strips, submitted to a continuously increasing perpendicular magnetic field. Secondly, the rupture of the geometrical metastability can also be achieved by thermal nucleation. First results on irradiation experiments show that the energy deposit ion of an incoming beta-particle induces the penetration of multiquant um flux tubes into a superconducting tin strip.