Feasibility of high-voltage systems for a very long drift in liquid argon TPCs

TL;DR

This paper reviews high-voltage system designs for liquid argon TPCs, demonstrating current capabilities up to 100 kV and evaluating the feasibility of 2 MV systems for very long drift lengths of around 20 meters.

Contribution

It compares different high-voltage approaches and assesses the potential for scaling to very long drift lengths in large-scale liquid argon TPCs.

Findings

Current systems achieve approx. 100 kV for 1.5 m drift

Two approaches: external power with resistive degraders and internal HV multiplier

Feasibility of 2 MV systems for 20 m drift is evaluated

Abstract

Designs of high-voltage (HV) systems for creating a drift electric field in liquid argon TPCs are reviewed. In ongoing experiments systems capable of approx. 100 kV are realised for a drift field of 0.5-1 kV/cm over a length of up to 1.5 m. Two of them having different approaches are presented: (1) the ICARUS-T600 detector having a system consisting of an external power supply, HV feedthroughs and resistive voltage degraders and (2) the ArDM-1t detector having a cryogenic Greinacher HV multiplier inside the liquid argon volume. For a giant scale liquid argon TPC, a system providing 2 MV may be required to attain a drift length of approx. 20 m. Feasibility of such a system is evaluated by extrapolating the existing designs.