I. Nitu | Searcharxiv

arXiv2026

Design of a high voltage delivery system for noble liquid time projection chambers

Noble liquid time projection chambers (TPCs) are a leading technology in the detection of ionizing radiation, particularly in applications such as accelerator neutrino physics, dark matter detection, and neutrinoless double beta decay. This paper addresses the design considerations for implementing stable high voltage (HV) systems within large noble liquid TPCs, with a focus on the nEXO experiment. Utilizing insights from prior HV research and experimental investigations, we outline factors influencing HV stability and discuss design choices to improve stability and prevent electrical discharges. A novel HV delivery system concept is presented, tailored for the nEXO TPC, which incorporates these design considerations while also meeting the stringent radiopurity requirements of the nEXO neutrinoless double beta decay search. These design considerations and their specific implementation towards a HV delivery system offer guidance to future experiments applying high voltage in noble liquid environments.

physics.ins-det↗

arXiv2025

Characterization of CRYO ASIC for charge readout in the nEXO experiment

nEXO is a proposed next-generation experiment searching for the neutrinoless double beta decay of $^{136}$Xe using a tonne-scale liquid xenon (LXe) time projection chamber (TPC). To image the ionization signals from events in the liquid xenon, the detector will employ metallized fused-silica charge collection tiles instrumented with cryogenic application-specific integrated circuits (ASICs), referred to as CRYO ASIC, which are designed to operate directly in LXe to minimize input capacitance and pick-up noise. Here we present the performance of the CRYO ASIC mounted on an auxiliary printed circuit board and evaluated both in a cryogenic environmental chamber and in a dedicated LXe test stand. We demonstrate that the ASICs achieve the desired performance at liquid xenon temperatures, showing a gain stability better than 0.2% over 24-hour operation and reliable in-situ calibration using an on-chip pulser. In the LXe test stand, we show that boiling caused by the chip heat dissipation can be mitigated by operating the system above ~0.1 MPa. The in-LXe noise measured agrees with simulation, which indicates it the $150~e^-$ design requirement can be satisfied. These results establish CRYO ASIC as a viable low-noise in-LXe charge readout solution for nEXO.

physics.ins-det↗