A system for the determination of silicon in the human lung using neutrons from a 2MV Van de Graaff generator

Neutron activation analysis, using inelastic scattering, provides a quantitative, non-invasive technique of studying silica burdens and is potentially useful as a screening procedure for occupationally exposed workers. In this method, silicon is measured using the fast neutron inelastic scattering reaction 28Si(n,n'γ)28Si which emits 1779 keV γ-rays. A 2MV Van de Graaff generator was developed to produce a pulsed beam of 5.2 MeV neutrons. The incident neutron energy was chosen to maximise the silicon γ-ray count rate, while keeping the signal from the competing reaction 31P(n,α)28Al negligible. (author) 2 refs.; 4 figs