A short history of nuclear activation analysis.

The major developments in the field of nuclear activation analysis, from 1936 to 1989, are discussed. The developments are grouped into five consecutive time periods. The impact of various scientists on the development of the field in the first 35 years is also discussed.

Instrumental neutron activation analysis of biological samples.

The elemental compositions of 18 biological reference materials have been processed, for 14 stepped combinations of irradiation/decay/counting times, by the INAA Advance Prediction Computer Program. The 18 materials studied include 11 plant materials, 5 animal materials, and 2 other biological materials. Of these 18 materials, 14 are NBS Standard Reference Materials and four are IAEA reference materials. Overall, the results show that a mean of 52% of the input elements can be determined to a relative standard deviation of +/- 10% or better by reactor flux (thermal plus epithermal) INAA.

Mercury concentrations in museum specimens of tuna and swordfish.

The mercury levels of museum specimens of seven tuna caught 62 to 93 years ago and a swordfish caught 25 years ago have been determined by instrumental neutron activation analysis. These levels are in the same range as those found in specimens caught recently.

Ge(Li) gamma-ray spectrometry as a pilot for NaI(Tl) gamma-ray spectrometry.

Lithium-drifted germanium semiconductor detectors give much better resolution than do thallium-activated sodium iodide detectors, but much lower sensitivity. They can often advantageously be used in conjunction with NaI(Tl) detectors, to show whether corrections must be applied for activities other than the one to be measured and to provide the necessary information for calculation of the corrections.