Proximity-induced Josephson-quasiparticle process in a single-electron transistor

We have performed experiments in a superconductor-normal-metal-superconduct or single-electron transistor in which then is an extra superconducting str ip partially overlapping the normal-metal island in good metal-to-metal con tact. The superconducting proximity effect gives rise to current peaks at v oltages below the quasiparticle threshold. We interpret these peaks in term s of the Josephson-quasiparticle process and discuss their connection with the proximity-induced energy gap in the normal-metal island.