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

Gopher Background Measurements

Sample Description

Notes 1

Notes 2

Live Time (days)

Run Numbers

Counting Dates
(if applicable)

Background 1

20.458

171213
171214
17121401

Dec 13, 2017

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Completely Empty Detector

171217
180104
18010401

Jan 5, 2018

(mBq)

1.56

0.25

2.35

3.81

0.89

0.54

1.86

0.28

4.55

1.49

<0.12

0.016

0.041

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

894.01

51.42

1.13

1.62

<0.11

2.73

0.50

5666.40

8743.00

Background 2

The two polyethylene bricks are used as sample holders

130.000

180108
180118
180123
180208

Jan 5, 2018

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Detector Chamber contains two 2x4x8 polyethylene bricks

180305
180306
180328
180409

May 25, 2018

(mBq)

4.38

0.19

7.98

1.91

0.94

0.22

1.14

0.10

5.52

0.69

0.100

0.051

0.092

0.024

This is the standard background to be subtracted from samples beginning on May 25, 2018

180420
180502
180504
180514

180524

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

876.52

45.60

0.62

0.78

0.028

0.033

3.33

0.23

8471.52

3457.00

Background 3

73.875

200324
200430

Mar 24, 2020

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Completely Empty Detector

Jun 10, 2020

(mBq)

4.09

0.21

5.89

2.34

0.25

0.12

1.51

0.14

5.28

0.85

0.061

0.065

0.126

0.033

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

836.47

44.29

<1.11

<0.032

3.60

0.31

3138.40

4375.00

Background 4

236.548

20070301

Jul 3, 2020

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Completely Empty Detector

Mar 5, 2021

(mBq)

5.73

0.45

5.52

1.34

0.23

0.07

5.48

0.35

3.35

0.42

0.046

0.033

0.101

0.018

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

800.48

41.24

0.71

0.45

<0.041

5.97

0.66

<3621.00

Background 5

This is the first background run with the Fast Discriminator set to Low Energy

34.528

21032203

Mar 22, 2021

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Completely Empty Detector

Apr 26, 2021

(mBq)

2.55

0.17

3.73

2.01

0.007

0.080

2.87

0.21

7.97

1.01

<0.078

0.188

0.040

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

300.22

16.49

<1.01

0.021

0.044

3.37

0.30

Background 6

36.021

210517
210524

May 17, 2021

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Background with large acrylic stand

Jun 25, 2021

(mBq)

2.57

0.17

9.77

2.11

0.17

0.08

2.79

0.20

5.93

0.86

<0.14

0.199

0.037

Acrylic Stand 1

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

286.76

15.79

<1.23

0.097

0.051

3.20

0.29

<6357.00

Background 7

141.978

210623
210803
210901
211008

Jun 23, 2022

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Background with small acrylic stand

Nov 13, 2022

(mBq)

1.92

0.09

3.74

1.02

0.15

0.04

2.96

0.12

7.79

0.61

0.059

0.021

0.157

0.019

Acrylic Stand 2

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

296.98

15.42

0.52

0.38

0.025

0.035

3.42

0.18

4900.70

2279.00

Background 8

130.895

211113
211217
220103
220218

Nov 13, 2021

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Background with small acrylic stand

Mar 25, 2022

(mBq)

2.41

0.10

3.10

1.08

0.12

0.04

3.01

0.13

7.77

0.63

0.061

0.039

0.106

0.019

Acrylic Stand 2

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

289.74

15.07

0.82

0.41

<0.032

3.54

0.19

<3248.00

In Progress and To Be Measured:

Sample Description

Notes 1

Notes 2

Live Time (days)

Run Numbers

Counting Dates
(if applicable)

Background 9

45.520

220901
221014
221109
230118

Sep 1, 2022

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Background with large acrylic stand

Jan 25, 2023

(mBq)

4.02

0.19

4.70

1.81

0.024

0.070

2.84

0.19

7.63

0.89

<0.11

0.166

0.281

Acrylic Stand 1

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

291.74

15.77

0.82

0.72

<0.094

3.64

0.28

<3780.00

Background 10

42.347

230502
230621

May 2, 2023

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Completely Empty Detector

May 31, 2023

(mBq)

2.50

0.16

4.37

1.91

0.286

0.075

2.87

0.20

8.64

1.02

0.05

0.07

0.052

0.035

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

277.34

15.13

<1.42

<0.035

3.58

0.30

8544.00

5299.00

Background 11

26.582

240226

Mar 15, 2024

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Background with large acrylic stand

Apr 11, 2024

(mBq)

2.63

0.20

6.06

2.46

<0.17

3.56

0.26

9.71

1.32

<0.13

0.071

0.045

Acrylic Stand 1

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq)

268.75

15.28

<1.19

0.082

0.066

3.43

0.35

6805.50

6785.00

Next Sample

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

(mBq/kg)

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq/kg)

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

(mBq/kg)

210Pb

7Be:

54Mn

228Ac:

210Po:

(mBq/kg)