Activity standardization and nuclear decay data of 109Cd.

Area of Science:

• Nuclear Physics
• Metrology
• Radiochemistry

Background:

• Accurate activity determination is crucial for radionuclide metrology.
• Existing methods for (109)Cd activity often rely on pre-existing nuclear decay data.
• The International Reference System (SIR) requires precise activity measurements for international comparisons.

Purpose of the Study:

• To accurately determine the activity of a (109)Cd solution independently of nuclear decay data.
• To contribute to the SIR database with a high-quality (109)Cd activity measurement.
• To deduce accurate emission probabilities and internal conversion coefficients for the (109)Cd 88 keV transition.

Main Methods:

• Measurement of conversion electron emission rates using pressurized proportional counters and a liquid scintillation spectrometer.
• Measurement of photon emission rates using gamma-ray spectrometers.
• Combination of electron and photon emission rates to determine activity concentration.
• Calculation of emission probabilities and internal conversion coefficients from measured data.

Main Results:

• The activity of the (109)Cd solution was accurately determined.
• The results were successfully included in the SIR database.
• High-accuracy emission probabilities for the 88 keV transition were deduced: p(gamma)=0.03663(33).
• A total internal conversion coefficient of alpha(t)=26.30(25) was determined for the 88 keV transition.

Conclusions:

• It is possible to accurately determine radionuclide activity without relying on prior nuclear decay data.
• The study provides a new, accurate set of emission probabilities and internal conversion coefficients for (109)Cd.
• The methodology contributes to improved radionuclide metrology and data validation.