The WArP Experiment: A Double-Phase Argon Detector for Dark Matter Searches
Figure 7
Primary signals collected with the WArP 100 l detector in 2011: (a) primary energy spectrum in units of phe. The low energy region is dominated by the -spectrum, then at higher energies signals from other radioactive contaminants are present. The -peaks of and are visible at 6-7 × phe; (b) ( versus sf/) scatter plot, showing the separation between slow events, induced by radiation, and fast ones, mostly due to -decays.
