An advanced method of activity determination of large area beta emitting sources

• Efficiency tracing transmission method of beta activity determination.
• Efficiency determined by means of a parameter independent of initial absorption conditions.
• Parameter is derived from two counting results obtained with using a test foil.
• Particularly useful for calibration and measurement of radionuclide standard sources.

The presented advanced method of activity determination of large area beta emitting sources is based on a version of efficiency tracing method using a test foil placed between the source and a conventional large area detector. It is shown that the total efficiency of the measuring system may depend on a dimensionless parameter derived from the difference in count rates caused by inserting the test foil while other disturbing effects are mostly reduced or compensated.