USING THE INTERNAL STANDARD METHOD TO IMPROVE THE RELIABILITY OF THE LUMINESCENCE DETERMINATION OF NEPTUNIUM IN A CAF2-BASED CRYSTAL PHOSPHOR

It is shown that, in the analysis of neptunium by its luminescence in the visible spectral region using a CaF2-based crystal phosphor, measu ring the ratio between the luminescence intensities of neptunium and a n internal standard allows the reliability of the analytical signal to be substantially improved and the effect of quenching impurities to b e reduced in comparison with those attained by measuring the absolute luminescence intensity. A special-purpose analyzer has been designed i n which automatically changeable interference filters are employed to separate analytical bands in the emission spectra of neptunium and ura nium used as the internal standard. A procedure for determining neptun ium in plutonium with the use of the new analyzer is described.