An internal standard for Fast Neutron Activation Analysis spectra obtainedby 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 Focu s (PF) neutron source and an NaI scintillator counter, has been studied. Th e PF device generates neutron bursts of different intensities. To know the exact neutron flux illuminating a sample during PF discharges an external n eutron counter is usually used. The nature and behaviour of the indicated p eaks suggest that one could use one of them as an internal standard for neu tron production measurement instead of an external counter. This technique allows more reliable and accurate determinations of the presence of various elements.