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

PICO Measurements:

Sample Description

Manufacturer

Mass (g)

Live Time (days)

Run Numbers

Counting Dates
(if applicable)

PICO G01

51.483 g

7.458

240305

Mar 5, 2024

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

PICO Kapton Heater Material

Mar 15, 2024

(mBq/kg)

<9.24

<131.20

<3.77

45.30

8.85

377.53

71.26

<5.92

<7.33

(ppb or ppm)

<0.75 ppb

<10.63 ppb

<6.64 ppb

11.14 ppb

2.18 ppb

12.19 ppm

2.3 ppm

Results:

210Pb:

7Be:

54Mn

228Ac:

(mBq/kg)

<313.20

46.15

41.92

<2.52

12.45

12.88

(ppb or ppm)

<25.37 ppb

3.06 ppb

3.17 ppb

PICO G02

2314.5 g

9.854

240920

Sep 20, 2024

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Stainless Steel Plates

Sep 30, 2024

(mBq/kg)

<0.17

<29.96

<0.31

3.38

0.67

5.05

2.94

<0.45

4.85

0.41

(ppb or ppm)

<13.77 ppt

<2.43 ppb

<0.55 ppb

0.83 ppb

0.16 ppb

163.23 ppb

95.09 ppb

Results:

210Pb:

7Be:

54Mn

228Ac:

57Co

58Co:

(mBq/kg)

<1058.00

<2.14

3.04

0.43

0.95

0.92

1.15

1.42

0.41

0.22

(ppb or ppm)

<85.7 ppb

0.23 ppb

PICO G03

1233.7 g

5.271

241002

Oct 2, 2024

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Welded Stainless Steel Plates

Oct 9, 2024

(mBq/kg)

<0.99

<22.93

<1.01

5.48

1.15

11.87

4.95

0.47

6.23

0.67

(ppb or ppm)

<0.08 ppb

<1.86 ppb

<1.78 ppb

1.35 ppb

0.28 ppb

0.38 ppm

0.16 ppm

Results:

210Pb:

7Be:

54Mn

228Ac:

57Co

58Co:

(mBq/kg)

<803.40

<4.73

3.73

0.67

0.94

1.48

<3.14

0.31

0.39

(ppb or ppm)

<65.08 ppb

0.23 ppb

0.36 ppb

PICO G04

364.8 g

14.302

241009
241011

Oct 9, 2024

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Stainless Steel Rod

Oct 24, 2024

(mBq/kg)

<0.80

34.58

32.85

<0.69

18.64

1.63

12.92

6.08

<0.55

1.05

0.35

(ppb or ppm)

<64.8 ppt

2.8 ppb

2.66 ppb

<1.21 ppb

4.59 ppb

0.4 ppb

417.22 ppb

196.51 ppb

Results:

210Pb:

7Be:

54Mn

228Ac:

57Co

58Co:

(mBq/kg)

<926.80

<9.13

1.82

0.52

10.40

2.00

<3.85

<0.30

(ppb or ppm)

<75.07 ppb

2.56 ppb

0.49 ppb

PICO G05

304.7 g

13.763

241024
241030

Oct 24, 2024

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Stainless Steel Plate

Nov 7, 2024

(mBq/kg)

<0.48

<26.74

<1.57

7.40

1.30

14.45

6.76

<0.55

4.62

0.59

(ppb or ppm)

<38.88 ppt

<2.17 ppb

<2.76 ppb

1.82 ppb

0.32 ppb

466.8 ppb

218.28 ppb

Results:

210Pb:

7Be:

54Mn

228Ac:

57Co

58Co:

(mBq/kg)

<881.20

<9.00

2.15

0.54

1.09

1.79

1.95

2.06

0.40

0.39

(ppb or ppm)

<71.38 ppb

0.27 ppb

0.44 ppb

In Progress and To Be Measured:

Sample Description

Manufacturer

Mass (g)

Live Time (days)

Run Numbers

Counting Dates
(if applicable)

Next Sample

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

(mBq/kg)

(ppb or ppm)

Results:

210Pb:

7Be:

54Mn:

228Ac:

210Po:

(mBq)

(ppb or ppm)