Instrumental and radiochemical proton activation analysis in biological samples and semiconductors

Charged particle activation analysis (CPAA) is based on the induction of nuclear reactions on the elements present in the matrix under investigation, followed by off-line determination of the radionuclides produced, by use of γ, X spectrometry or sometimes by α, β counting. CPAA is mostly based on the use of light charged particle beams (p, d, τ, α) accelerated in either a cyclotron or a linear accelerator, in an energy range from about 10 to 40 MeV/nucleon. As in the case of NAA both a purely instrumental version (ICPAA) and a radiochemical one (RCPAA) can be adopted. The latter, in general, permits to reach the best sensitivities by selective radiochemical separation (after the activation) of specific radionuclides from the gross interferents. The technique is almost an unique tool for the determination of light elements like B, C, N, O. The use of the technique for depth profiling of the elements in solid matrices is also investigated. Examples of the application of proton activation analysis to the determination of Pb in biological samples an As in silicon wafers are discussed. (author) 5 refs. 3 figs.; 2 tabs