Some Useful Information Concerning the results:
The Conversion factors for the primordial nuclides are given by: 1 Bq 238U/kg = 81 ppb U (81 x 10-9 gU/g) The 238U decay chain gammas used are: 226Ra: 186.1 keV
214Pb: 295.21 and 351.92 keV
214Bi: 609.31, 1120.29, 1764.49 and 2204.21 keV
The relationships are valid for any daughters in the 238U, 235U or 232Th chain only if the chain is in equilibrium. 1 Bq 232Th/kg = 246 ppb Th (246 x 10-9 gTh/g) The 232Th decay chain gammas used are: 212Pb: 238.63 and 300.09 keV
208Tl: 583.19 and 2614.53 keV,
228Ac: 911.21 keV
1 Bq 40K/kg = 32300 ppb K (32300 x 10-6 gK/g) The 40K decay chain gamma used is: 40K: 1460.83 keV
1 Bq 235U/kg = 1.76 ppm U (1.76 x 10-6 gU/g) The 235U decay chain gammas used are: 235U: 143.76, 163.33 and 205.31 keV

The measurements of the samples below take into account the background measurement shown in the Backgrouds Spreadsheet. If a measurement is below the background then the upper bound shown is the 90% confidence limit.
SENSEI Measurements:



























Sample Description Manufacturer Mass (g) Live Time (days) Counting Dates
(if applicable)






















SENSEI P01 SNOLAB 790.7 g 13.798 Dec 4, 2020 Results:
238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co
Comments
Clean Acid Etching Solution for Copper Mixture of Sulphuric Acid and UPW

Dec 18, 2020 (mBq/kg) <0.57

<14.50

<0.36

0.27 +- 0.60 1.91 +- 4.56 <0.24

<0.12







(ppm / ppb / ppt) <46.17 ppt

<1.17 ppb

<0.63 ppb

0.07 ppb +- 0.15 ppb 61.74 ppb +- 147.35 ppb












Results:
7Be:

54Mn




228Ac:















(mBq/kg) 0.96 +- 2.31 <0.25




0.18 +- 0.68
















(ppm / ppb / ppt)








0.04 ppb +- 0.17 ppb











SENSEI P02 SNOLAB 839.2 g 23.583 Dec 18, 2020 Results:
238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co
Comments
Used Copper Etching Solution Mixture of Sulphuric Acid and UPW (and some copper)

Jan 11, 2021 (mBq/kg) 1.35 +- 0.36 10.96 +- 12.28 <0.34

0.23 +- 0.45 23.06 +- 4.86 <0.26

<0.060







(ppm / ppb / ppt) 109.51 ppt +- 29.3 ppt 0.89 ppb +- 0.99 ppb <0.6 ppb

0.06 ppb +- 0.11 ppb 0.74 ppm +- 0.16 ppm












Results:
7Be:

54Mn




228Ac:















(mBq/kg) <2.70

<0.21




<0.59


















(ppm / ppb / ppt)








<0.15 ppb













In Progress and To Be Measured:



























Sample Description Manufacturer Mass (g) Live Time (days) Counting Dates
(if applicable)






















Next Sample



Results:
238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co
Comments




(mBq/kg)


























(ppm / ppb / ppt)



























Results:
7Be:

54Mn




228Ac:















(mBq/kg)




























(ppm / ppb / ppt)