Q-Pix: a scalable readout system for kiloton-scale neutrino detectors

The Q-Pix readout system can provide 3D tracking readout for large-scale rare-event particle physics experiments, with the aim of opening up new windows of exploration into the properties of fundamental particles and their interactions. Q-Pix implements a per-pixel self-triggering cycle of charge integration with reset -- the output of an integrator is coupled to a comparator that triggers a reset of the integrator after a specified amount of accumulated charge. The time between resets encodes information about the signal current, thereby providing access to the physics signal of interest. By sitting idle until an event occurs, the system generates minimal data and consumes little power. Because of its scalability to the multi-kiloton regime, Q-Pix is a candidate readout for future DUNE far detector modules. In this talk, we describe the Q-Pix detection scheme, explain the enhanced physics sensitivity it provides, and present results from a lab-scale detector read out by a prototype Q-Pix system constructed from commercial off-the-shelf components. We also discuss the implementation of Q-Pix in a custom ASIC, and share initial measurements from the first batch of these ASIC chips at cryogenic temperatures.