SHORT-TIME NEUTRON-ACTIVATION GAMMA-RAY SPECTROSCOPY

Short-time instrumental neutron activation analysis, with high through put, sensitivity and accuracy without matrix interferences, can be ach ieved in spite of the initial high count rate from both short and long -lived nuclide activation, if the experimental conditions are optimize d by the combination of techniques. Thus the initial usually high coun ting rate can be faced by a loss-free counting system to avoid blockin g or distortion of the system. The rapid radioactive decay and the con sequent low counting statistics of short lived nuclides can be compens ated by source-detector distance variation during the counting period and by cyclic and cumulative activation. Matrix spectral interferences can be reduced by ion exchange before activation for selective elemen t preseparation and by neutron spectrum optimization such as epitherma l neutron activation for selective element peak enhancement.