STUDY OF NONEQUILIBRIUM SIGNALS IN SUPERCONDUCTING SINGLE-CRYSTAL NIOBIUM

We are developing a low temperature detector for dark matter based on single crystal superconducting Nb. This work requires a detailed knowl edge of the behaviour of phonons and quasiparticles in Nb which arise from particle interactions. We discuss the use of superconducting tunn el junctions (STJs) and series connected arrays of superconducting tun nel junctions (SASTJs) to detect the high energy phonon flux arising f rom laser and particle interactions. The signal shapes and their varia tion with temperature for Al-Ox-Al and Sn-Ox-Sn junctions are discusse d.