QUANTIFICATION OF SOME SOURCES OF VARIATION IN NEUTRON-ACTIVATION ANALYSIS

Mutually independent statistical methods were developed to determine the contribution of: (i) peak area determination; (ii) counting geometry; and (iii) neutron flux to the total variation of peak areas obtained from pipetted standards in neutron activation analysis. (i) Was estimated making use of the fact that pulser peak areas do not vary according to Poisson statistics, (ii) was measured by counting standards on different detectors and analyzing the variation in peak area ratios and (iii) was obtained from trends in the peak areas related to the position of the standards in the irradiation container, using polynomial fitting.