The DarkSide Multiton Detector for the Direct Dark Matter Search

Table 1

A summary of the expected nuclear and electron recoil backgrounds depositing 55–240  in an 18-ton-year exposure of DarkSide-G2. We assume ³⁹Ar at our recently measured limit [25]. For PMTs, we use the expected background in the R11065-G2s based on measurements reported by Hamamatsu and our ongoing R&D. For the cryostat, we use detailed measurements of the steel used for the DarkSide-50 cryostat. After cuts include fiducial, energy, and multihit cuts.

Detector element	Electron recoil BG after PSD and cuts	Radiogenic neutron BG after cuts
^39Ar (<6.5 mBq/kg)	<0.1	—
R11065-G2 PMTs	<0.01	0.05
Cryostat and insulation	<0.01	0.05
Total	<0.1	0.1