SNOLAB is drawing on expertise developed by the SNO collaboration for screening materials for new experiments.

Material Screening

DUSEL Town Meeting 2-4 November 2007

Ian Lawson SNOLAB

Ge Gamma Counter

Low Background Counting available for the experiments.

HPGe detector manufactured by Princeton Gamma-Tech, the crystal is 206 cm3 with an active mass of 1096 g.

Presently being used by SNO(+), EXO, PICASSO, DEAP/CLEAN.

Samples are usually counted for two weeks, longer for low activity samples.

Material Screening

DUSEL Town Meeting 2-4 November 2007

Ian Lawson SNOLAB

Ge Gamma Counter

Sensitivity is comparable to other Ge detectors worldwide.

1 L or 180 mL sample sizes, placed in Marinelli beakers.

Calibrated with mixed radionuclide standards and sources such as 152Eu, 60Co, and 137Cs.

Shielding is 5 cm OFHC copper and 20 cm lead, underground for more than 10 years.

Material Screening

No shielding

Shielding

DUSEL Town Meeting 2-4 November 2007

Ian Lawson SNOLAB

Material Screening

Radionuclide Sensitivity20 atoms/day10 atoms/day50 atoms/day

222Rn (U)220Rn (Th)219Rn (Ac)

ESC (Electrostatic Counter)

8 counters on site. Self contained samples

connected directly to the recirculating loop. Other samples placed in polypropylene cylinders with N2 or Ar gas recirculated through chamber.

Turnaround time 1 month (3 months notice recommended)

2 weeks/sample + 2 weeks for background.

DUSEL Town Meeting 2-4 November 2007

Ian Lawson SNOLAB

Radon Emanation Chambers

Used extensively for counting materials used in the SNO experiment.

sensitivity ~50 decays per day.

ICP-MS

Association with facility at NRC (National Research Council) ICP-MS facility in Ottawa.

Tuned to maximize sensitivity to U and Th at sub ppt levels. K limits to < 100 ppb.

Material Screening

DUSEL Town Meeting 2-4 November 2007Ian Lawson SNOLAB

Facility Usage and Future Prospects

Ge Gamma Counter

It is anticipated that this detector will be fully utilized for the next five years by the existing SNOLAB experiments as their construction proceeds.

Future possibility of adding 1 or 2 more detectors to expand counting capabilities.

ESC (Electrostatic Counters)

Currently not utilized at 100%, and should meet current needs.

No expansion anticipated.

Rn Emanation Chamber

Meets current needs, no expansion anticipated.

Material Screening

DUSEL Town Meeting 2-4 November 2007

Ian Lawson SNOLAB