The quatratran

We propose a new superconducting electronic device, which can provide ampli fication of low-level electrical signals at low temperatures. The device, w hich we call the quatratran, is based on quasiparticle trapping from a supe rconductor into a normal metal, coupled with normal-insulator-superconducto r (NIS) tunnel junctions. Quasiparticles injected into the S electrode of a first junction are trapped in an N layer, producing excited charge carrier s. This N layer is also used as the N electrode of a second NIS junction, w hich produces an amplified signal. We explain the principles of operation a nd describe the electronic characteristics. Results from test devices demon strate the soundness of the principles. We also suggest how quatratrans can be applied to the detection of particles and radiation. (C) 2000 Elsevier Science B.V. All rights reserved.