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

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

(mBq/kg)

(ppb or ppm)

Results:

210Pb:

7Be:

54Mn

228Ac:

(mBq/kg)

(ppb or ppm)

COSINUS G02

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

(mBq/kg)

(ppb or ppm)

Results:

210Pb:

7Be:

54Mn

228Ac:

(mBq/kg)

(ppb or ppm)

In Progress and To Be Measured:

Sample Description

Manufacturer

Mass (g)

Live Time (days)

Run Numbers

Counting Dates
(if applicable)

COSINUS G01

Cleaned with NuClean Only

7682.4 g

13.826

250529

May 29, 2025

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Brass Plate

(mBq/kg)

<0.0072

<0.34

0.02

0.22

0.04

<0.38

0.02

0.059

0.012

Efficiency Simulation Correction Not Included

(ppb or ppm)

<0.001 ppb

<0.028 ppb

0.04 ppb

0.05 ppb

0.01 ppb

<12.27 ppb

Expect a large correction

Results:

210Pb:

7Be:

54Mn

228Ac:

(mBq/kg)

<1.55

0.37

0.20

0.04

0.02

0.09

0.06

(ppb or ppm)

<0.13 ppb

0.02 ppb

COSINUS G02

Ultrasonically cleaned with NuClean

15364.8 g

Results:

238U from 226Ra

238U from 234Th

235U

232Th

40K

137Cs

60Co

Comments

Brass Plate

(mBq/kg)

Efficiency Simulation Correction Not Included

(ppb or ppm)

Expect a large correction

Results:

210Pb:

7Be:

54Mn

228Ac:

(mBq/kg)

(ppb or ppm)

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)