Anode-Coupled Readout for Light Collection in Liquid Argon TPCs

TL;DR

This paper introduces an innovative anode-coupled readout method for light detection in large liquid argon TPCs, reducing costs and complexity while maintaining high timing resolution.

Contribution

It proposes a capacitive coupling technique that integrates light signal readout with charge collection, simplifying system design and improving reliability.

Findings

Demonstrated sensitivity of wire planes to photon signals

Simulated timing resolution of ~30 ns for single photoelectrons

Showed reduction in cabling and cryostat feed-throughs

Abstract

This paper will discuss a new method of signal read-out from photon detectors in ultra-large, underground liquid argon time projection chambers. In this design, the signal from the light collection system is coupled via capacitive plates to the TPC wire-planes. This signal is then read out using the same cabling and electronics as the charge information. This greatly benefits light collection: it eliminates the need for an independent readout, substantially reducing cost; It reduces the number of cables in the vapor region of the TPC that can produce impurities; And it cuts down on the number of feed-throughs in the cryostat wall that can cause heat-leaks and potential points of failure. We present experimental results that demonstrate the sensitivity of a LArTPC wire plane to photon detector signals. We also simulate the effect of a 1 $\mu$s shaping time and a 2 MHz sampling rate on these signals in the presence of noise, and find that a single photoelectron timing resolution of $\sim$30 ns can be achieved.