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.

COSINUS Measurements:

Sample Description

Manufacturer

Mass (g)

Live Time (days)

Run Numbers

Counting Dates
(if applicable)

COSINUS G01

Cleaned with NuClean Only

7682.4 g

17.743

250529

May 29, 2025

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Brass Plate

Jun 16, 2025

(mBq/kg)

<0.036

<6.15

0.03

0.24

1.19

0.21

<1.56

<0.095

0.276

0.056

(ppb or ppm)

<2.916 ppt

<0.498 ppb

0.05 ppb

0.43 ppb

0.29 ppb

0.05 ppb

<50.39 ppb

Results:

210Pb:

7Be:

54Mn

228Ac:

58Co

(mBq/kg)

<1828.00

1.20

1.03

0.20

0.07

0.54

0.29

1.18

0.13

(ppb or ppm)

<148.07 ppb

0.13 ppb

0.07 ppb

COSINUS G02

Ultrasonically cleaned with NuClean

15364.8 g

21.806

250616

Jun 16, 2025

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Brass Plate

Jul 8, 2025

(mBq/kg)

<0.028

<2.76

<0.14

1.27

0.16

0.56

0.58

<0.13

0.32

0.05

(ppb or ppm)

<2.27 ppt

<0.22 ppb

<0.25 ppb

0.31 ppb

0.04 ppb

18.04 ppb

18.87 ppb

Results:

210Pb:

7Be:

54Mn

228Ac:

58Co

(mBq/kg)

<4416.00

<0.77

0.18

0.05

0.20

0.24

0.88

0.10

(ppb or ppm)

<357.7 ppb

0.05 ppb

0.06 ppb

COSINUS G03

1116.8 g

11.944

250923
250926
250928

Sep 23, 2025

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Polyethylene Naphthalate

250930
251001
251002

Oct 8, 2025

(mBq/kg)

<0.16

<12.77

<0.48

7.25

0.95

114.90

11.19

<0.52

0.18

0.20

(ppb or ppm)

<12.96 ppt

<1.034 ppb

<0.84 ppb

1.78 ppb

0.23 ppb

3.71 ppm

0.36 ppm

Results:

210Pb:

7Be:

54Mn

228Ac:

(mBq/kg)

<62.82

10.02

<0.34

1.23

1.32

(ppb or ppm)

<5.09 ppb

0.3 ppb

0.32 ppb

COSINUS G04

Beaker made from silicon

10.9 g

18.556

25100702
251020
251021
25102101

Oct 17, 2025

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Silicon Beaker

Nov 5, 2025

(mBq/kg)

<3.73

<106.60

<5.86

113.10

18.36

231.73

108.60

<8.49

<4.87

(ppb or ppm)

<302.13 ppt

<8.63 ppb

<10.31 ppb

27.82 ppb

4.52 ppb

7484.88 ppb

3507.78 ppb

Results:

210Pb:

7Be:

54Mn

228Ac:

58Co

(mBq/kg)

<938.10

<98.08

4.47

5.08

50.25

27.47

(ppb or ppm)

<75.99 ppb

12.36 ppb

6.76 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)