The ratio of γ counting efficiencies has predominant importance in trace element analysis carried out by prompt- and delayed-γ neutron activation based on k0 standardization. Although the effect of correlation between counting efficiencies is well-known and methods have been developed and adopted in prompt-γ neutron activation analysis to correctly evaluate the uncertainty, proposals and applications in delayed-γ neutron activation analysis are still missing. To fill the gap, we developed a new method based on the use of reference γ-sources to determine the detection efficiency ratio and its uncertainty by taking full account correlations. A measurement model to some extent different from the classical k0 formulation widely used in delayed-γ neutron activation analysis is required. A detection system was characterized to test the suitability of the method in a double-counting position setup, where the standard is placed far from and the sample is placed close to the detector end-cap. The present paper is a significant expansion over a relevant abstract presented at the “Mathematical and Statistical Methods for Metrology” Workshop, Torino, Italy, 30-31 May 2019 (pages 27-28 in http://www.msmm2019.polito.it/programme).
A method to deal with correlations affecting γ counting efficiencies in analytical chemistry measurements performed by k 0-NAA
Oddone, M
2020-01-01
Abstract
The ratio of γ counting efficiencies has predominant importance in trace element analysis carried out by prompt- and delayed-γ neutron activation based on k0 standardization. Although the effect of correlation between counting efficiencies is well-known and methods have been developed and adopted in prompt-γ neutron activation analysis to correctly evaluate the uncertainty, proposals and applications in delayed-γ neutron activation analysis are still missing. To fill the gap, we developed a new method based on the use of reference γ-sources to determine the detection efficiency ratio and its uncertainty by taking full account correlations. A measurement model to some extent different from the classical k0 formulation widely used in delayed-γ neutron activation analysis is required. A detection system was characterized to test the suitability of the method in a double-counting position setup, where the standard is placed far from and the sample is placed close to the detector end-cap. The present paper is a significant expansion over a relevant abstract presented at the “Mathematical and Statistical Methods for Metrology” Workshop, Torino, Italy, 30-31 May 2019 (pages 27-28 in http://www.msmm2019.polito.it/programme).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
