Determination of prompt neutron decay constant by time-domain fluctuation analyses of detector current signals
Artikel i vetenskaplig tidskrift, 2018

The conventional time-domain reactor noise techniques analyse the number of neutron detector pulse signals, so that they sometimes encounter serious difficulties owing to the count-loss effect due to the dead time of detector systems. To avoid all the difficulties coming from the count-loss effect, a novel time-domain technique was recently proposed (Pál and Pázsit, 2015). This technique analyses the auto-covariance function of continuous current signals arising from ionization chambers such as the fission chamber, so that it is inherently insensitive to the count-loss effect. In the present study, a different time-domain technique that analyses the integral values of current signals is proposed. With regard to these two techniques, the experimental conditions under which they successfully measure the subcriticality through determination of the prompt neutron decay constant are clarified.

Neutron detector current

Reactor noise

Auto-covariance function technique


Time-domain analysis

Prompt neutron decay constant

Count-loss effect

Variance-to-mean function technique


Yasunori Kitamura

Kyoto University

Imre Pazsit

Chalmers, Fysik, Subatomär fysik och plasmafysik

Tsuyoshi Misawa

Kyoto University

Annals of Nuclear Energy

0306-4549 (ISSN)

Vol. 120 691-706


Acceleratorfysik och instrumentering

Atom- och molekylfysik och optik