Dc. Glasgow et al., METHODS FOR PREPARING COMPARATIVE STANDARDS AND FIELD SAMPLES FOR NEUTRON-ACTIVATION ANALYSIS OF SOIL, Journal of radioanalytical and nuclear chemistry, 192(2), 1995, pp. 361-370
One of the more difficult problems associated with comparative neutron
activation analysis (CNAA) is the preparation of standards which are
tailor-made to the desired irradiation and counting conditions. Freque
ntly, there simply is not a suitable standard available commercially,
or the resulting gamma spectrum is convoluted with interferences. In a
recent soil analysis project, the need arose for standards which cont
ained about 35 elements. In response, a computer spreadsheet was devel
oped to calculate the appropriate amount of each element so that the r
esulting gamma spectrum is relatively free of interferences. Incorpora
ted in the program are options for calculating all of the irradiation
and counting parameters including activity produced, necessary flux/bo
mbardment time, counting time, and appropriate source-to-detector dist
ance. The result is multi-element standards for CNAA which have optima
l concentrations. The program retains ease of use without sacrificing
capability. In addition to optimized standard production, a novel soil
homogenization technique was developed which is a low cost, highly ef
ficient alternative to commercially available homogenization systems.
Comparative neutron activation analysis for large scale projects has b
een made easier through these advancements. This paper contains detail
s of the design and function of the NAA spreadsheet and innovative sam
ple handling techniques.