Radon backgrounds in the DEAP-1 liquid-argon-based Dark Matter detector

Understand

The DEAP-1 \SI{7}{kg} single phase liquid argon scintillation detector was operated underground at SNOLAB in order to test the techniques and measure the backgrounds inherent to single phase detection, in support of the \mbox{DEAP-3600} Dark Matter detector.

• Backgrounds in DEAP are controlled through material selection, construction techniques, pulse shape discrimination and event reconstruction.
• This report details the analysis of background events observed in three iterations of the DEAP-1 detector, and the measures taken to reduce them.
• The $^{222}$Rn decay rate in the liquid argon was measured to be between 16 and \SI{26}{\micro\becquerel\per\kilogram}.