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

Sample Description

Manufacturer

Mass (g)

Live Time (days)

Counting Dates
(if applicable)

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Background 1

61.794

Nov 16, 2005 – Dec 15, 2005

(mBq)

1.31

+/-

0.21

0.10

0.30

1.47

+/-

0.19

21.30

+/-

2.40

1.90

+/-

0.20

0.45

+/-

0.07

Empty Marinelli Beaker

Jan 20, 2006 – Mar 22, 2006

Background 2

4.244

Aug 25, 2006

(mBq)

2.69

+/-

1.04

0.75

12.07

2.60

+/-

1.05

30.20

+/-

9.20

1.50

+/-

0.70

0.21

+/-

0.26

Empty Marinelli Beaker

Sep 6, 2006

Background 3

14.727

Oct 12, 2007

(mBq)

1.36

+/-

0.44

0.787

0.591

1.47

+/-

0.48

18.40

+/-

4.00

2.70

+/-

0.40

0.30

+/-

0.14

Completely Empty Detector

Oct 30, 2007

Background 4

20.784

Dec 21, 2010

(mBq)

1.173

0.293

0.103

0.400

1.129

0.346

15.20

3.10

1.900

0.300

0.240

0.089

7Be Signal:

Completely Empty Detector

Jan 11, 2010

1.70 mBq

1.60 mBq

Background 5

23.191

Dec 20, 2013

(mBq)

0.770

0.289

16.920

14.470

0.444

1.092

0.266

17.44

3.14

1.811

0.321

0.287

0.126

Completely Empty Detector

Jan 13, 2014

Background 6

25.895

Dec 18, 2014

(mBq)

0.841

0.246

0.727

6.631

0.064

0.365

1.546

0.263

18.40

3.16

1.879

0.289

0.151

0.093

Completely Empty Detector

Jan 13, 2015

Background 7

32.638

Dec 2, 2016

(mBq)

0.595

0.203

<4.36

0.043

0.310

1.035

0.204

16.30

2.67

0.918

0.205

0.050

0.067

Completely Empty Detector

Jan 4, 2017

Additional Backgrounds:

210Po:

7Be:

54Mn:

19.39 Bq

10.09 Bq

1.189 mBq

1.231 mBq

<0.027 mBq

Background 8

24.333

Aug 1, 2018

(mBq)

0.88

0.25

4.71

6.27

<0.42

1.43

0.27

15.48

2.94

1.20

0.26

<0.013

Completely Empty Detector

Aug 28, 2018

Additional Backgrounds:

210Po:

7Be:

54Mn:

(mBq)

8212.22

10159.02

<1.01

0.12

Background 9

55.359

Mar 24, 2020

(mBq)

1.76

0.20

<8.79

0.21

0.13

2.35

0.22

25.01

2.62

1.49

0.20

0.083

0.058

Completely Empty Detector

May 19, 2020

Additional Backgrounds:

210Po:

7Be:

54Mn:

(mBq)

4206.90

7877.00

0.55

1.04

0.067

0.074

Background 10

N/A

19.715

May 17, 2021

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Completely Empty Detector

May 27, 2021

(mBq/kg)

0.62

0.27

18.52

9.55

<0.20

1.50

0.39

14.61

3.19

1.18

0.29

<0.15

Run: 210517
210524

Jul 29, 2021

Run: 210729
210805

Aug 9, 2021

Results:

7Be:

54Mn

210Po:

228Ac:

(mBq/kg)

<4.37

<0.22

1968.80

10600.00

1.96

0.55

Background 11

N/A

13.833

Jan 28, 2022

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Completely Empty Detector

Run: 220128

Feb 11, 2022

(mBq/kg)

0.74

0.35

<15.50

0.35

0.23

1.39

0.47

16.01

3.82

2.11

0.42

0.15

0.14

Results:

7Be:

54Mn

210Po:

228Ac:

(mBq/kg)

4.21

2.29

<0.13

<27690.00

<0.49

Background 13

N/A

29.789

Sep 16, 2023

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Completely Empty Detector

Oct 18, 2023

(mBq/kg)

0.78

0.22

<12.76

<0.25

1.81

0.34

17.10

2.82

1.49

0.25

0.091

0.073

Run: 230916
23091801
230927
230929
23092901
230930
23093001
231001
231003
231008
231012
231014

Results:

7Be:

54Mn

210Po:

228Ac:

(mBq/kg)

<1.58

0.083

0.089

<21260.00

0.20

0.35

Combined Background

Combined Backgrounds of Runs 1, 3, 4, 5, 6, 7 and 8

203.361

(mBq)

1.035

0.107

<0.221

0.124

0.159

1.325

0.103

17.90

1.42

1.673

0.132

0.260

0.041

Displayed on Webpage

Additional Backgrounds:

210Po:

7Be:

54Mn:

9.91 Bq

3.88 Bq

0.872 mBq

0.580 mBq

0.060 mBq

0.043 mBq

If a measurement is below the background then the upper bound shown is the 90% confidence limit.

In Progress and To Be Measured:

Sample Description

Manufacturer

Mass (g)

Live Time (days)

Counting Dates
(if applicable)

Background 14

N/A

63.297

Jun 3, 2024

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Completely Empty Detector

Run: 240603
240613
240707
240710

Aug 9, 2024

(mBq/kg)

0.86

0.16

0.64

4.52

0.11

1.77

0.23

16.74

1.99

1.26

0.17

.0.3247

0.047

Results:

7Be:

54Mn

210Po:

228Ac:

(mBq/kg)

<0.97

0.013

0.067

5519.00

6978.00

1.17

0.28

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

(mBq/kg)

Results:

7Be:

54Mn

210Po:

228Ac:

(mBq/kg)