First test of a high voltage feedthrough for liquid Argon TPCs connected to a 300 kV power supply

TL;DR

This paper reports the successful design, manufacturing, and testing of a high voltage feedthrough for liquid Argon TPCs, capable of handling up to 300 kV, addressing key challenges in cryogenic high voltage delivery.

Contribution

It introduces a novel high voltage feedthrough design that meets all operational and safety requirements for liquid Argon TPCs at unprecedented voltages.

Findings

Achieved stable operation at -300 kV for extended periods

Demonstrated compatibility with cryogenic conditions and purity requirements

Identified setup-specific instability unrelated to feedthrough design

Abstract

Voltages above a hundred kilo-volt will be required to generate the drift field of future very large liquid Argon Time Projection Chambers. The most delicate component is the feedthrough whose role is to safely deliver the very high voltage to the cathode through the thick insulating walls of the cryostat without compromising the purity of the argon inside. This requires a feedthrough that is typically meters long and carefully designed to be vacuum tight and have small heat input. Furthermore, all materials should be carefully chosen to allow operation in cryogenic conditions. In addition, electric fields in liquid argon should be kept below a threshold to reduce risks of discharges. The combination of all above requirements represents significant challenges from the design and manufacturing perspective. In this paper, we report on the successful operation of a feedthrough satisfying all the above requirements. The details of the feedthrough design and its manufacturing steps are provided. Very high voltages up to unprecedented voltages of -300 kV could be applied during long periods repeatedly. A source of instability was observed, which was specific to the setup configuration which was used for the test and not due to the feedthrough itself.