A superconducting transistor based on quasiparticle trapping

We propose a new superconducting electronic device which can provide either current or voltage amplification of low-level electrical signals at low te mperatures. The device, which we call the quatratran, is based on quasipart icle trapping from a superconductor into a normal metal, coupled with norma l-insulator-superconductor (NIS) tunnel junctions. Quasiparticles injected into the S electrode of a first junction are trapped in an N layer, produci ng excited charge carriers. This N layer is also used as the N electrode of a second NIS junction which produces an amplified signal. We explain the p rinciples of operation and describe the electronic characteristics. Results from test devices demonstrate the soundness of the principles. We also sug gest how quatratrans can be applied to the detection of particles and radia tion.