Proximity Induced Josephson-Quasiparticle Process in a Single Electron   Transistor
  We have performed the first experiments in a superconductor - normal metal - superconductor single electron transistor in which there is an extra superconducting strip partially overlapping the normal metal island in good metal-to-metal contact. Superconducting proximity effect gives rise to current peaks at voltages below the quasiparticle threshold. We interpret these peaks in terms of the Josephson-quasiparticle process and discuss their connection with the proximity induced energy gap in the normal metal island. 
A. J. Manninen, R. S. Poikolainen, T. V. Ryynanen, and J. P. Pekola