Front-end Electronics for Single Photon Detection with Large Arrays of SiPMs in Liquid Argon

Operation of large arrays of silicon photomultipliers (SiPM) in tanks of noble liquids requires low noise, low power front-end amplifiers able to operate reliably in a cryogenic environment. A design based on discrete components is presented, which achieves a white voltage noise of 0.37 nV/√Hz at 2.4 mW/channel, or 0.25 nV/√Hz at 4.6 mW/channel. Combined with an optimal series/parallel combination of SiPMs at the input, it demonstrates excellent single photon sensitivity up to 96 6x6 mm ² SiPMs (total area 34.6 cm ² ). The measured results are in a good match with calculated values, predicting the possibility to achieve a clear separation of photoelectron peaks up to a total SiPM area of 200 cm ² . The long term reliability of the design was assessed, with emphasis on aging due to hot-carrier effects.