  We present a resistance bridge which uses a SQUID to measure the shot noise
in low impedance samples. The experimental requirements are high DC bias
currents (typically 10mA) together with high AC sensitivity (pA/VHz). This
system is used to investigate the shot noise in
Superconductor/Normal/Superconductor junctions where Andreev reflection
enhanced shot noise is expected. Because our setup has an intrinsic noise much
smaller than the thermal noise of the resistance bridge at 4.2K, reliable
results can be obtained on impedances out of the range of classical measurement
schemes.
