K. Hashimoto et al., Reduction of delayed-neutron contribution to variance-to-mean ratio by application of difference filter technique, J NUC SCI T, 36(7), 1999, pp. 555-559
The difference-filtering correlation analysis was applied to time-sequence
neutron count data measured in a slightly subcritical assembly, where the F
eynman-a analysis suffered from large contribution of delayed neutron to th
e variance-to-mean ratio of counts. The prompt-neutron decay constant infer
red from the present filtering analysis agreed very closely with that by pu
lsed neutron experiment, and no dependence on the gate-time range specified
could be observed. The Ist-order filtering was sufficient for the reductio
n of the delayed-neutron contribution. While the conventional method requir
es a choice of analysis formula appropriate to a gate-time range, the prese
nt method is applicable to a wide variety of gate-time ranges.