  LISA will use quadrant photoreceivers as front-end devices for the phasemeter
measuring the motion of drag-free test masses in both angular orientation and
separation. We have set up a laboratory testbed for the characterization of
photoreceivers. Some of the limiting noise sources have been identified and
their contribution has been either measured or derived from the measured data.
We have built a photoreceiver with a 0.5 mm diameter quadrant photodiode with
an equivalent input current noise of better than 1.8 pA/sqrt[Hz] below 20 MHz
and a 3dB bandwidth of 34 MHz.
