Integration and performance of prototype nEXO charge-readout modules with built-in, cryogenic ASIC readout*

The nEXO experiment aims to discover neutrinoless double beta decay of xenon 136, with a lifetime sensitivity goal of greater than 10^28 years. Compared to using long cables to transmit signals outside of the detector, mounting amplification and digitization circuitry directly on detector submodules reduces noise and improves measurement fidelity. A cryogenic application specific integrated circuit (ASIC) called CRYO ASIC has been designed by SLAC and fabricated for direct readout of the nEXO ionization-charge detection modules. A prototype nEXO charge-readout module with attached ASIC has been operated in a liquid xenon time projection chamber; the challenges and performance of the prototype module with digitizing electronics will be discussed. Plans for the integration of a 2 x 2 array of 10 cm charge-readout modules will be presented.