Characterization of large area APDs for the EXO-200 detector

Understand

EXO-200 uses 468 large area avalanche photodiodes (LAAPDs) for detection of scintillation light in an ultra-low-background liquid xenon (LXe) detector.

• We describe initial measurements of dark noise, gain and response to xenon scintillation light of LAAPDs at temperatures from room temperature to 169K - the temperature of liquid xenon.
• We also describe the individual characterization of more than 800 LAAPDs for selective installation in the EXO-200 detector.