An internal standard for Fast Neutron Activation Analysis spectra obtained by means of Plasma Focus devices

The behaviour of Pb activation peaks, which appear in an X-ray spectrum of Fast Neutron Activation Analysis (FNAA) performed by means of a Plasma Focus (PF) neutron source and an NaI scintillator counter, has been studied. The PF device generates neutron bursts of different intensities. To know the exact neutron flux illuminating a sample during PF discharges an external neutron counter is usually used. The nature and behaviour of the indicated peaks suggest that one could use one of them as an internal standard for neutron production measurement instead of an external counter. This technique allows more reliable and accurate determinations of the presence of various elements.