High-voltage electrode development for xenon-based direct Dark Matter detectors

The XENONnT detector is the current-generation experiment of the XENON Dark Matter project dedicated to direct dark matter search. It aims at reaching sensitivity for spin-independent WIMP-nucleon cross-sections down to 1.4 × 10−48 cm2 for a 50 GeV/c2 mass WIMP at 90% C.L. with 20 t×yr exposure [1].

XENONnT has been successfully running since more than two years [2]. One of the central elements of two-phase xenon TPCs are the electrodes. With ever larger TPCs, these electrodes and their operation become a technological challenge. Therefore, a set of backup electrodes has been developed. The work encompasses different tasks, including redesigning and testing the mechanical structure of the electrodes and performing electric field and optical simulation. As the realization and manufacturing process progressed, we did extensive optical inspections and high-voltage and mechanical stability tests. Here I present our results, the assembly of these electrodes, and the lessons learned from the project towards future-generation detectors such as DARWIN.

This work is supported in part through the Helmholtz Initiative and Networking Fund (grant agreement no. ... mehrW2/W3-118) and through BMBF (ErUM-Pro grant agreement no. 05A23VK3). Support by the graduate school KSETA at KIT is gratefully acknowledged.

[1] JCAP 11 (2020) 031, [2] PRL 131 (2023) 041003.