| Abstract |
A nondestructive instrumental neutron activation analysis procedure permitted accurate and sensitive measurement of most elements with atomic numbers between 11 and 92. The sensitivity of the procedure was dependent on each element's intrinsic characteristics and the sample matrix. Arsenic was used both as an elemental single comparator and as a thermal neutron flux monitor. Comparison conditions were established for both long and short irradiations. Other elemental standards, or unknown samples, were irradiated with flux monitors. Gamma counts of the sample were compared with those of the standards, both having been adjusted to the standard conditions through the flux monitors. The procedure permitted wide latitude in irradiation time, decay time, multichannel analysis time, relative detector-to-sample geometry, and sample size. Analysis of standard reference materials showed that 16 out of 23 elements in Orchard Leaves, for which comparison data were available, agreed within 20%. In Coal 24 out of 30 elemental analyses, and in Coal Fly Ash 21 out of 29 elemental analyses, agreed within 20% of comparison data. Differences greater than 50% were found for antimony, zinc, and a few trace elements near their detection limits. |
