Nuclide Mixtures NG1 to NG6

Seven different mixtures of radionuclides for calibrating high resolution gamma-ray spectrometers are offered. The radionuclides are recommended by NIST (USA) and PTB (Germany) and cover the energy range 46-1836keV. The solutions are calibrated in our DAkkS accredited measurement laboratory and are traceable to national standards world-wide, including the USA, France, Germany and the UK.

To ensure the highest accuracy and consistency possible, each radionuclide in the mixture is individually assayed. The mixed solutions are prepared by gravimetric dispensing and then checked by high resolution gamma-ray spectrometry. For high sensitivity, gamma-ray emitting impurities are determined by high resolution gamma-ray spectroscopy of each individual radionuclide in the mixture. Some radionuclides are also checked by radiochemical analysis. The final mixture is then checked for cross-contamination.

In addition to the principal gamma rays shown on the certificate of calibration, several low intensity photopeaks may be observed in the spectrum. The most significant are shown in the table below.

Energy [keV] Origin
1325 Escape peak from 1836keV peak of Y-88
814 Double escape peak from 1836keV peak of Y-88
511 Annihilation radiation from positron decay of Y-88 (may not be resolved from the 514keV peak from Sr-85)
225 From decay of Sn-113
136 From decay of Co-57
80-90 X-rays from decay of Hg-203
2506 Sum peak from the decay of Co-60 (1173+1333keV)
2734 From decay of Y-88
161, 223 From decay of Ba-133
437 Sum peak from Ba-133 (356+81keV)

The seven mixtures can be used for the energy ranges shown below.

NG1 – Energy Range: 80keV – 1836keV

Standard Activity Aliquot: 44kBq

Nuclides and approx. activities:

Ba-133 2 kBq Mn-54 4 kBq
Ce-139 2 kBq Sr-85 10 kBq
Co-57 2 kBq Y-88 10 kBq
Cs-137 4 kBq Zn-65 10 kBq

Reference Dates: 1st January, 1st April, 1st July, 1st October

Notes: The half lives of the component radio-nuclides are relatively long (shortest is 65 days, Sr-85). At close source-detector distances, summation effects become important.

NG2 – Energy Range: 88keV – 1836keV

Standard Activity Aliquot: 37kBq

Nuclides and approx. activities:

Cd-109 15,6 kBq Hg-203 2,2 kBq
Ce-139 0,8 kBq Sn-113 2,8 kBq
Co-57 0,6 kBq Sr-85 3,6 kBq
Co-60 3 kBq Y-88 5,8 kBq
Cs-137 2,6 kBq

Reference Dates: 1st March, 1st June, 1st September, 1st December

Notes: The shortest half life is 47 days (Hg-203). The Hg should be precipitated as a sulphide if the solution is dried, to avoid loss of the radioactivity. Summation effects are less important than for NG1.

NG3 – Energy Range: 60keV – 1836keV

Standard Activity Aliquot: 40kBq

Nuclides and approx. activities:

Am-241 3,4 kBq Cs-137 2,6 kBq
Cd-109 15,4 kBq Hg-203 2,2 kBq
Ce-139 0,8 kBq Sn-113 2,7 kBq
Co-57 0,6 kBq Sr-85 3,6 kBq
Co-60 3 kBq Y-88 5,7 kBq

Reference Dates: 1st March, 1st June, 1st September, 1st December

Notes: As NG2, but extends the calibration down to 60keV.

NG4 – Energy Range: 46keV – 136keV

Standard Activity Aliquot: 46kBq

Nuclides and approx. activities:

Am-241 4 kBq Co-57 2 kBq
Cd-109 20 kBq Pb-210 20 kBq

Reference Dates: 1st January, 1st July

Notes: Intended for low energy calibration only (46-136keV).

NG5 – Energy Range: 88keV – 1836keV

Standard Activity Aliquot: 69kBq

Nuclides and approx. activities:

Cd-109 17,1 kBq Cs-137 2,8 kBq
Ce-139 0,8 kBq Sn-113 3 kBq
Co-57 0,6 kBq Sr-85 4 kBq
Co-60 3,4 kBq Y-88 6,6 kBq
Cr-51 30,7 kBq

Reference Dates: 1st March, 1st June, 1st September, 1st December

Notes: The shortest half life is 28 days (Cr-51).Preparation of solid standards is easier than for NG2 and NG3, as the Cr-51 replaces the Hg-203.

NG6 – Energy Range: 60keV – 1836keV

Standard Activity Aliquot: 72kBq

Nuclides and approx. activities:

Am-241 3,4 kBq Cr-51 30,4 kBq
Cd-109 17 kBq Cs-137 2,8 kBq
Ce-139 0,8 kBq Sn-113 3 kBq
Co-57 0,6 kBq Sr-85 4 kBq
Co-60 3,4 kBq Y-88 6,6 kBq

Reference Dates: 1st March, 1st June, 1st September, 1st December

Notes: As NG5, but extends the calibration down to 60keV.

NG7 – Energy Range: 60keV – 1836keV

Standard Activity Aliquot: 49kBq

Nuclides and approx. activities:

Am-241 3,4 kBq Hg-203 2,2 kBq
Cd-109 15,5 kBq Mn-54 2,8 kBq
Ce-139 0,8 kBq Sn-113 2,7 kBq
Co-57 0,6 kBq Sr-85 3,6 kBq
Co-60 3 kBq Y-88 5,8 kBq
Cs-137 2,6 kBq Zn-65 6 kBq

Reference Dates: 1st March, 1st June, 1st September, 1st December

Notes: As NG3, but with Mn-54 and Zn-65 for high accuracy calibration.

 

7500 and 7600 Nuclide Mixtures

The nine-nuclide gamma standard, routinely used to establish efficiency curves for gamma spectrometers, covers an energy range from 88 keV to 1836 keV. As options, Am-241 and/ or Pb-210 can be added to extend the calibration curve down to 60 keV and 46 keV respectively.

Two nine-nuclide gamma standards are offered:
– Series 7500 contains Te-123m and Cr-51 for those customers who require a non-mercury containing standard.
– Series 7600 contains Hg-203 and Ce-139.

Please note that Hg-203 may leach out from polyethylene containers and may contaminate the entire container. Proper handling techniques must be observed. The component nuclides of each series have been chosen to minimize peak interference, and the activity ratios have been selected to yield similar count rates in all major peaks on typical coaxial germanium detectors. These mixed nuclide sources are calibrated, traceable to NIST or with DAkkS certificate. They are prepared gravimetrically from calibrated solutions and then confirmed using a high purity germanium detector to ensure the highest possible quality.

 

7500ML – Energy Range: 88keV – 1836keV

Standard Activity Aliquot: 37kBq

Nuclides and approx. activities:

Cd-109 10,6 kBq Sn-113 1,92 kBq
Co-57 0,406 kBq Sr-85 2,44 kBq
Co-60 2,07 kBq Te-123m 0,518 kBq
Cr-51 13,2 kBq Y-88 4,03 kBq
Cs-137 1,78 kBq

Reference Dates: 1st February, 1st April, 1st June, 1st August, 1st October, 1st December

7501ML – Energy Range: 60keV – 1836keV

Standard Activity Aliquot: 38,1kBq

Nuclides and approx. activities:

Am-241 1,11 kBq Cs-137 1,78 kBq
Cd-109 10,6 kBq Sn-113 1,92 kBq
Co-57 0,406 kBq Sr-85 2,44 kBq
Co-60 2,07 kBq Te-123m 0,518 kBq
Cr-51 13,2 kBq Y-88 4,03 kBq

Reference Dates: 1st February, 1st April, 1st June, 1st August, 1st October, 1st December

7502ML – Energy Range: 46keV – 1836keV

Standard Activity Aliquot: 48,1kBq

Nuclides and approx. activities:

Cd-109 10,6 kBq Pb-210 11,1 kBq
Co-57 0,406 kBq Sn-113 1,92 kBq
Co-60 2,07 kBq Sr-85 2,44 kBq
Cr-51 13,2 kBq Te-123m 0,518 kBq
Cs-137 1,78 kBq Y-88 4,03 kBq

Reference Dates: 1st February, 1st April, 1st June, 1st August, 1st October, 1st December

7503ML – Energy Range: 46keV – 1836keV

Standard Activity Aliquot: 49,2kBq

Nuclides and approx. activities:

Am-241 1,11 kBq Pb-210 11,1 kBq
Cd-109 10,6 kBq Sn-113 1,92 kBq
Co-57 0,406 kBq Sr-85 2,44 kBq
Co-60 2,07 kBq Te-123m 0,518 kBq
Cr-51 13,2 kBq Y-88 4,03 kBq
Cs-137 1,78 kBq

Reference Dates: 1st February, 1st April, 1st June, 1st August, 1st October, 1st December

7601ML – Energy Range: 60keV – 1836keV

Standard Activity Aliquot: 38,1kBq

Nuclides and approx. activities:

Am-241 1,11 kBq Cs-137 2,59 kBq
Cd-109 15,5 kBq Hg-203 2,22 kBq
Ce-139 0,74 kBq Sn-113 2,81 kBq
Co-57 0,592 kBq Sr-85 3,55 kBq
Co-60 3,03 kBq Y-88 5,92 kBq

Reference Dates: 1st February, 1st April, 1st June, 1st August, 1st October, 1st December

7602ML – Energy Range: 46keV – 1836keV

Standard Activity Aliquot: 48,1kBq

Nuclides and approx. activities:

Cd-109 15,5 kBq Hg-203 2,22 kBq
Ce-139 0,74 kBq Pb-210 11,1 kBq
Co-57 0,592 kBq Sn-113 2,81 kBq
Co-60 3,03 kBq Sr-85 3,55 kBq
Cs-137 2,59 kBq Y-88 5,92 kBq

Reference Dates: 1st February, 1st April, 1st June, 1st August, 1st October, 1st December

7603ML – Energy Range: 46keV – 1836keV

Standard Activity Aliquot: 49,2kBq

Nuclides and approx. activities:

Am-241 1,11 kBq Hg-203 2,22 kBq
Cd-109 15,5 kBq Pb-210 11,1 kBq
Ce-139 0,74 kBq Sn-113 2,81 kBq
Co-57 0,592 kBq Sr-85 3,55 kBq
Co-60 3,03 kBq Y-88 5,92 kBq
Cs-137 2,59 kBq

Reference Dates: 1st February, 1st April, 1st June, 1st August, 1st October, 1st December