ABSTRACT
The origin and development of activation analysis has largely resulted from overlapping interests in nuclear physics and radiochemistry. Classical activation analysis, focusing upon elemental composition, or more correctly upon isotopic composition, is essentially a comparative technique in which the substance under investigation and a standard sample of known composition are identically irradiated by a fixed quantity of radiation. Modern activation analysis methods include not only chemical isolation, but also various physico-chemical methods such as, for instance, ion exchange chromotography, extraction, reduction melting in inert gases and sorption. The photoactivation method is based on the production of photonuclear reactions, usually through irradiation of samples by the bremsstrahlung from electron accelerators. The major development of neutron activation analysis (NAA) came with the availability of nuclear research reactors in the mid 1950s. The applications of NAA in the field of crime investigation involved the detection and measurement of one particular toxic element, arsenic, in specimens of hair from the human head.
