QUALITY OF HIGH COUNT RATE HIGH-RESOLUTION SHORT-TIME ACTIVATION-ANALYSIS

The fast transfer system was modified to enable a fixed counting geome try with high reproducibility using an endcap geometry. The optimal co unt rate for short time activation analysis by means of the loss free counting system was found to be within 100-140 kcts/s, if a high accur acy is needed (1%). The method of calculating the peak area after the dead time and pile up corrections was modified by changing the peak fi tting parameters gradually with increasing count rates. Epithermal act ivation by a (LiD)-Li-6 converter was found to be an ideal irradiation technique for short time activation analysis especially for heavy ele ments due to the lower contribution of Na-24 and Al-28 (up to 30 fold) .