  The performance of hybrid superconducting electronic coolers is usually
limited by the accumulation of hot quasi-particles in the superconducting
leads. This issue is all the more stringent in large-scale and high-power
devices, as required by applications. Introducing a metallic drain connected to
the superconducting electrodes via a fine-tuned tunnel barrier, we efficiently
remove quasi-particles and obtain electronic cooling from 300 mK down to 130 mK
with a 400 pW cooling power. A simple thermal model accounts for the
experimental observations.
