High voltage testing for the MAJORANA Demonstrator

TL;DR

This paper investigates high-voltage testing and micro-discharge effects in the MAJORANA Demonstrator's detector system, ensuring reliable operation at voltages up to 5 kV through optimized cable and feedthrough design.

Contribution

It presents a comprehensive study of high-voltage micro-discharge phenomena and develops optimized configurations for cables and feedthroughs in the MAJORANA detector system.

Findings

Micro-discharge effects can be mitigated with proper design.

Optimized cable and feedthrough configurations enable stable high-voltage operation.

All components tested meet the required voltage specifications.

Abstract

The MAJORANA Collaboration is constructing the MAJORANA Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in Ge-76. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the MAJORANA Demonstrator. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the MAJORANA Demonstrator was characterized and the micro-discharge effects during the MAJORANA Demonstrator commissioning phase were studied. A stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.