Local trap spectroscopy in superconducting tunnel junctions

We show that thermal activation of quasiparticles from local traps is responsible for the temperature variation of responsivity observed for some superconducting tunneling junction photon detectors. With this model, the depth of the local traps in two different proximized Ta structures was found to be the same, 0.20 +/-0.02 meV. (C) 2001 American Institute of Physics.