Cryogenic front-end amplifier design for large SiPM arrays in the DUNE FD1-HD photon detection system

The photon detection system of the first far detector (FD1-HD) DUNE experiment will detect scintillation photons produced by particle interactions in a kiloton-scale liquid Argon time projection chamber. detectors choice are silicon photomultipliers (SiPM), 6$\times$6 mm$^2$ each, arranged groups 48, which present significantly low impedance to front-end electronics. This paper details design cryogenic amplifier with exceptionally white voltage noise 0.37 nV$\sqrt{Hz}$, based on silicon-germanium input transistor and BiCMOS fully differential operational amplifier. It yields excellent single photoelectron resolution even at overvoltage values. signal rise is below 100 ns, dynamic range about 2000 photoelectrons typical operating overvoltage. draws 0.7 mA from 3.3 V supply, for power consumption 2.4 mW per channel. Simplified models were developed predict photolectron shape ratio, good match measured performance.