Correction factors for non-uniform large-area reference sources

Area of Science:

• Metrology and Instrumentation
• Radiation Detection and Measurement

Background:

• Calibration of surface contamination monitors relies on large-area reference sources.
• Deviations from ideal uniform intensity distribution in these sources introduce bias.
• Accurate calibration is crucial for reliable contamination assessment.

Purpose of the Study:

• To develop a method for estimating and correcting calibration bias.
• To address bias stemming from non-uniform surface source intensity distributions.
• To enhance the accuracy of surface contamination monitor calibrations.

Main Methods:

• Investigated uniformity measurements of large-area reference sources.
• Developed correction factors based on source uniformity distribution profiles.
• Simulated monitor calibration with real and ideally uniform source distributions.

Main Results:

• Correction factors were derived from counting rate estimates of different source distributions.
• The proposed method corrects for bias introduced by non-uniform sources.
• Validated against the NPL Good Practices Guide No.14 method.

Conclusions:

• The developed method effectively estimates and corrects calibration bias.
• Accurate calibration of surface contamination monitors is achievable with this approach.
• Improved accuracy in contamination monitoring is a key outcome.