Determination of in situ detection efficiency for IM-NAA of non-standard geometrical samples

The k₀-based internal mono-standard (IM) method was first proposed for concentration analysis of samples of non-standard geometry in the 2000s. The method has demonstrated several advantages such as elimination of gamma-ray self-attenuation and geometrical effects. On the other hand, the accuracy of the method principally depends on the in situ relative detection efficiency, which requires to be obtained in each measurement. Therefore, the relative detection efficiency is always under consideration for improvement of the analysis results. The present paper describes a simple and automatic procedure for determination of the relative efficiency using one or more activation products emitting gamma rays over a considered range of the spectrum. The procedure can be applied for INAA and PGNAA analysis. (author)