Commissioning of a dual-phase xenon TPC at Nikhef

TL;DR

This paper reports the commissioning and initial calibration results of a dual-phase xenon TPC at Nikhef, demonstrating its capabilities for dark matter detection through measurements of light yield, electron lifetime, and energy resolution.

Contribution

The paper introduces the design, setup, and calibration techniques of a new dual-phase xenon TPC for dark matter research, including a novel PMT gain calibration method.

Findings

Average light yield of 5.6 photoelectrons/keV at 122 keV

Electron lifetime of 429 microseconds

Energy resolution of 5.8% at 511 keV

Abstract

A dual-phase xenon time-projection chamber was built at Nikhef in Amsterdam as a direct dark matter detection R&D facility. In this paper, the setup is presented and the first results from a calibration with a $^{22}$Na gamma-ray source are presented. The results show an average light yield of (5.6 $\pm$ 0.3) photoelectrons/keV (calculated to 122 keV and zero field) and an electron lifetime of (429 $\pm$ 26) $\mu$s. The best energy resolution $\sigma_E/E$ is (5.8 $\pm$ 0.2)% at an energy of 511 keV. This was achieved using a combination of the scintillation and the ionization signals. A photomultiplier tube gain calibration technique, based on the electroluminescence signals occurring from isolated electrons, is presented and its advantages and limitations are discussed.