Feynman-α formula with dead time effect for a symmetric coupled-core system

The Feynman-α (variance-to-mean ratio) formula for a symmetric coupled-core system has been developed to analyse some kinetic parameters of coupled-core systems. Recently, this method has been applied to nuclear criticality safety studies, such as the determination of subcriticality or neutron interference effect between two fissile units. This method is based on neutron pulse counting so that it suffers a counting loss effect originating from a dead time due to the pulse-type neutron detector and counting circuit. To extend the method to more practical uses, the counting loss effect needs to be overcome. We have derived a new formula taking account of dead time effect, making the treatment proposed by Srinivasan our model, and have shown that kinetic parameters of coupled-core systems could be estimated by this new formula. (author)