Design and Demonstration of Digital Readout Chain in NνDEx Experiment

$\text{N}\nu $
DEx is an experiment proposed to search for the neutrinoless double-beta decay of 82Se using a high-pressure gaseous time projection chamber (TPC). In Phase-I of the experiment, the
$\text{N}\nu $
DEx-100 detector is filled with about 100 kg SeF6. The readout and data acquisition (DAQ) systems are crucial components of the experiment. The 2-D pixelated readout plane, consisting of approximately 15 000 sensors for charge measurement, is placed at one end-cap of the chamber. The electrode and charge-sensitive preamplifier in each sensor collect drifted ions and amplify the signal, with the analog output transmitted to a digital ASIC, where an internal analog-to-digital converter (ADC) continuously digitizes the pulse. All digital ASICs on the plane form two routing networks, utilizing four pairs of bidirectional I/Os in each chip. The digitized waveform data from all chips is transmitted toward one edge of the plane via these two networks. Data aggregation modules (DAMs) at the edge aggregate slow parallel data links to fast serial data links, which are then connected to the DAQ system in the back-end. This article aims to introduce the design and testing of the demonstrator system for the full digital readout chain, including a digital chips array, a DAM and the back-end DAQ system.