Removal of disturbances in carbon determination by activation analysis for lowering the detection limit

A sensitive method of carbon determination in silicon by activation with deuterons and³He particles followed by chemical separation of the measured nuclides¹³N and¹¹C has been developed. Aside from the etch removal after irradiation, it is essential for a low detection limit to avoid too much thermal exposure of the target surface during the irradiation process, or else microflaw formation and diffusion on the surface have to be anticipated. The ion current must have an optimal rather than a maximum value.