34
K. Hashimoto
Fig. 2.16 Cross-power
spectral density measured
previously at a subcritical
KUCA system driven by a
pulsed DT neutron source
(Ref. [21])
(a) Pulse repetition frequency 20 Hz
(b) Pulse repetition frequency 500 Hz
in Fig. 2.15. The non-Poisson character of the spallation source must enhance the
amplitude of the correlated component over a precision limit of the FFT analyzer.
2.2.3.2 Prompt Neutron Decay Constant
Figure 2.17 shows a least-squares fit of Eq. (2.49) to the correlated noise component
of the cross-power spectral density measured at pattern F. In this fitting, 33 deltafunction-like peaks were masked. No systematical deviation of the fitted curve from
the data can be seen. Figure 2.18 shows a least-squares fit of Eqs. (2.47) and (2.48)