Validation of efficiency tracing and zero detection threshold techniques using liquid scintillation analyser TriCarb

Area of Science:

• Nuclear Chemistry
• Radiochemistry
• Analytical Chemistry

Background:

• Liquid scintillation analysis is a key technique for quantifying beta-emitting radionuclides.
• Quenching significantly impacts the accuracy of activity quantification in scintillation counting.
• Established methods for activity quantification require validation under varying quench conditions.

Purpose of the Study:

• To evaluate the effectiveness of unquenched carbon-14 (14C) and tritium (3H) as tracers for activity quantification.
• To investigate the influence of quench levels on the accuracy of these tracing techniques.
• To determine the applicable activity ranges for these methods in liquid scintillation analysis.

Main Methods:

• Utilized efficiency tracing with unquenched 14C and zero detection threshold with unquenched 3H.
• Employed a liquid scintillation analyzer for activity measurements.
• Studied the impact of varying quench levels on quantification accuracy.

Main Results:

• Both 14C and 3H tracing techniques showed good agreement with reference activity (≤4.6% discrepancy) at 166.67 Bq.
• A relative discrepancy of approximately 10% was observed under extreme quench conditions (quench value ~111).
• Quantification uncertainty was around 8% at 1.67 Bq, reducing to 1% for activity levels between 8.33 Bq and 100 Bq.

Conclusions:

• Unquenched 14C and 3H tracing are practical and simple methods for quantifying beta emitters via liquid scintillation analysis.
• These techniques are reliable within specific activity ranges and up to moderate quench levels.
• The study provides valuable data on the performance limits and accuracy of these tracers in radioactivity measurements.