Technical Results from the Surface Run of the LUX Dark Matter Experiment

TL;DR

The LUX experiment's three-month surface run demonstrated excellent detector performance, validating its readiness for underground dark matter searches with promising sensitivity projections for WIMP detection.

Contribution

This paper reports the first surface commissioning results of the LUX detector, including performance validation and updated sensitivity estimates for dark matter detection.

Findings

Achieved 8.4 photoelectrons per keV for 662 keV electron recoils

Validated detector's light collection, energy, and position resolution

Provided updated sensitivity projections for WIMP-nucleon scattering

Abstract

We present the results of the three-month above-ground commissioning run of the Large Underground Xenon (LUX) experiment at the Sanford Underground Research Facility located in Lead, South Dakota, USA. LUX is a 370 kg liquid xenon detector that will search for cold dark matter in the form of Weakly Interacting Massive Particles (WIMPs). The commissioning run, conducted with the detector immersed in a water tank, validated the integration of the various sub-systems in preparation of the underground deployment. Using the data collected, we report excellent light collection properties, achieving 8.4 photoelectrons per keV for 662 keV electron recoils without an applied electric field, measured in the center of the WIMP target. We also find good energy and position resolution in relatively high-energy interactions from a variety of internal and external sources. Finally, we have used the commissioning data to tune the optical properties of our simulation and report updated sensitivity projections for spin-independent WIMP-nucleon scattering.