A possible improvement of the determination of 133Ba activity and detection efficiency by the sum-peak method, by inclusion of the previously neglected transitions

In the treatment of 133Ba decay by the method of coincidence summing, the transitions to the first two excited states of 133Cs were ignored in former works. By applying the most accurate values for these transitions available in literature, we include them into the count rate equations and obtain solutions for the corresponding system. As a result of this more accurate forming of count rate equations, some terms, which contain previously ignored transition probabilities, turn out to be more significant than the conventionally included terms. We show that their inclusion in the system of count rate equations leads to fine improvements in the determinations of detection efficiencies and the activity of the 133Ba source.