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:

234Th: 63.29 and 92.59 keV
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: 277.371, 583.19, 860.557 and 2614.53 keV,

228Ac: 209.253, 338.320, 463,004, 911.21, 964.766 and 968.971 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 measurements from the background table.
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)

Run Numbers

Counting Dates
(if applicable)

238U from 226Ra

238U from 234Th

235U

232Th

228Ac

137Cs

210Pb

Comments

SENSEI CW01

TFA Lead
1” x 5/8” d

56.5 g

10.754

190926

Sep 26, 2019

(mBq/kg)

47.14

21.98

74.58

116.60

<6.94

19.95

25.22

42.26

75.16

<47.38

4238.90

999.80

Lead Cylinder

Fonderie de Gentilly

Efficiencies are corrected for self-absorption by the lead using ANGLE4

Oct 7, 2019

(ppb or ppm)

3.82 ppb

1.78 ppb

6.04 ppb

9.44 ppb

<12.21 ppb

4.91 ppb

6.2 ppb

10.4 ppb

18.49 ppb

343.35 ppb

80.98 ppb

In Progress and To Be Measured: