Effect of Neutral Bremsstrahlung on the Operation of Two-Phase Argon Detectors.

Two-phase noble liquid detectors are widely used in experiments for dark matter search. Ionization signals caused by particle scattering in a noble-gas liquid are commonly recorded using the effect of proportional electroluminescence in the gas phase. In addition to the standard electroluminescence mechanism based on vacuum ultraviolet emission of noble gas excimers, the mechanism of electron bremsstrahlung on neutral atoms with a continuous spectrum from ultraviolet to near infrared range was recently revealed. In this paper, we demonstrate the effect of bremsstrahlung on characteristics of a DarkSide-50 two-phase argon detector. In particular, the sag of the electroluminescent gap grid and the contribution of the fast component to the proportional electroluminescence signal will be estimated. [ABSTRACT FROM AUTHOR]