Primary activity standardization of ⁹⁹Tc by three different absolute methods

Area of Science:

• Nuclear physics
• Radiochemistry
• Metrology

Background:

• Accurate activity concentration determination is crucial for nuclear applications and safety.
• Traditional methods like 4πβ-γ coincidence counting have limitations.
• The triple-to double-coincidence ratio (TDCR) method offers a promising alternative for absolute activity measurements.

Purpose of the Study:

• To absolutely determine the activity concentration of a (99)Tc solution.
• To compare the TDCR method with established 4πβ-γ coincidence and anticoincidence counting techniques.
• To assess the consistency and accuracy of different measurement systems for (99)Tc.

Main Methods:

• Absolute activity determination of (99)Tc using liquid scintillation counting with the TDCR method.
• Comparison with results from 4πβ(LS)-γ(NaI) live-timed anticoincidence counting.
• Comparison with results from classical 4πβ(PC)-γ(NaI) coincidence counting, using (60)Co for efficiency tracing.

Main Results:

• The TDCR method provided an absolute activity concentration for (99)Tc.
• Anticoincidence and coincidence counting results were higher than TDCR by 0.18% and 0.66%, respectively.
• All measurement results were consistent within their experimental uncertainties, validating the TDCR method.

Conclusions:

• The TDCR method is a reliable technique for the absolute determination of (99)Tc activity concentration.
• The findings support the use of TDCR as an accurate and consistent alternative to traditional coincidence counting methods.
• This research contributes to improved metrology in radioactivity measurements.