The LBF performs low background counting in two unique facilities-- a local surface site constructed with low activity serpentine concrete and an underground laboratory at the 4850L (~4300 m.w.e.) of the Sanford Underground Research Facility (SURF) in Lead, SD. Prior to 2014, the underground system was located in the Hyatt Power Plant (~600 m.w.e.) of the Oroville Dam in Oroville, CA.

Berkeley, CA 
Lead, SD
Depth  surface, ~10 m.w.e.4,850 ft, 4300 m.w.e. 
Vicinity  low activity concretelow activity bedrock 
 Muon Suppression3π active muon veto4300 m.w.e. overburden 
Radon suppression nitrogen purge nitrogen purge 
 HPGe115% n-type, 80% p-type 80% p-type 
 OtherNaI, BF3  

Samples are typically screened first at the surface laboratory at LBNL. Then, pending results and sensitivity requirements, the samples are then sent on to SURF for a more sensitive count. This prioritizes the time of the underground system for samples that actually require the enhanced sensitivity.

Counting Sensitivities

[for ~1kg samples] 
Berkeley Site

 SURF Site
[~1 week]
U series 0.5 ppb (6 mBq/kg)  50 ppt (0.6 mBq/kg)
 Th series2.0 ppb (8 mBq/kg)  200 ppt (0.8 mBq/kg)
K  1.0 ppm 100 ppb
 Co-60 0.04 pCi/kg (1.5 mBq/kg) 0.004 pCi/kg (0.15 mBq/kg)