Radon Emanation Result of : DEAP Camera.

Date: 2022/05/31


The DEAP camera sample was received for radon emanation counting with the low background Radon board system on surface at SNOLAB. The request for the Rn emanation counting was received in May 2022.

1. Sample Handling

Clean unused gloves were used to handle the sample. Sample was wiped with UPW. No further cleaning was needed and the sample was deemed ready for counting. The sample was placed in the emanation chamber. The chamber and the sample was flushed and rinsed with N2 couple of times. The chamber and sample was then pumped down to desired level (3.3E-2 mnbar). The chamber was then isolated to start the radon emanation process.

2. Summary of Emanation Counting Results

The sample run for the above-mentioned sample was extracted on May 31, 2022 and counting started on the same day. The sample was emanated for 4.73 days.

For precision measurements, two counting runs are necessary per sample: a Blank (BLK) run with no sample in the chamber and a Sample (SPL) run itself, in which the entire set-up is counted again. The net emanation rate (atoms/d) of the sample is obtained by subtracting the BLK rate from the SPL rate. Typically one would perform the Blank runs each time prior to the the sample run. But the frequency of Blanks is often reduced due to consistent Blank rates of our system. The total efficiency of the Rn board system used for the calculation was: (199.23 +/- 4.46)%. Systematics studies are in progress for the newly built system.

In this report, only the 222Rn emanation rate is presented. It is left to the experiment to determine how to interpret and scale these results based on their radiopurity target.

Sample Run Type Counting Time (d) Emanation Time (d) 222Rn (atoms/d)
DEAP Camera Sample 16.16 4.73 78.01 +/- 4.51
Blank 24.71 23.99 5.13 +/- 2.03
Net Counts 72.88 +/- 4.94




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