Trace analysis with protons [i.e. proton] and heavy ion activation

Abstract

The capabilities of 12 MeV proton activation were compared with those of reactor neutron and 35 MeV photon activation. A series of biological specimens (plant and animal tissues) were chosen for this study limited to nondestructive assays. Based on y-ray spectrometry, As, Ca, Cu, Fe, Mo, Pt, Sr, Ti, Zn and Zr at levels ranging from 2 to 20,900 ppm were detected following proton activation of 1 hour. Al, Br, Ca, Cl, Cu. Mg, Mn, Rb and V. ranging from 0.4 to 20,900 ppm, were measured by neutron activation (1 min. irradiation). As, Ba, Br, Cr, Co, Fe, Hg, La, Na, Rb, Sb and Zn, .ranging from 0.2 to 2400 ppm, were determined following a 14 hour neutron irradiation. Photon activation data was obtained by computer simulation of y-ray spectra, based on published radioisotope production yields. Assuming a 4 hour irradiation, As, Ba, Br, Ca, Cl, Fe, I, Mg, Mn, Na, Pb, Rb, Sb, Sr could be detected at concentration levels ranging from 3 to 20,900 ppm. Although covering different elements, the three techniques are comparable in their scope, i.e. detection limits that can be achieved and number of elements that can be detected simultaneously. In terms of determining known essential elements, detection limits below the average concentrations of such elements in the human body were obtained for Co, Fe, Zn with neutron activation, for Cu, Fe, Zn with proton activation and for Fe, I, Zn with photon activation..