INVERSE PROBLEMS FOR STOCHASTIC NEUTRONICS

Abstract

. Fissile matter detection and characterisation are crucial issues; especially in nuclear safety, safeguards, matter comptability, reactivity measurements. In this context, we want to identify a source of fissile matter knowing external measures such as instants of detection of neutrons during an interval of measure. Thus we observe the neutrons detection times emitted by the fissile matter and going through the detector, then we compute the moments of the empirical distribution of the number of neutrons detected during a time gate T. In order to identify the source we have to get the following parameters: the multiplication factor k of the system, the intensity of the source S , the fission efficiency ε F . Given the parameters of the source there are some models that allow us to predict the moments of counted number of neutrons during a time gate T. We consider a point model stating monokinetic neutrons are moving in an infinite, isotropic and homogeneous medium. The method makes it possible to compute the first moments of the count number distribution. Then, given the moments of counted number of neutrons during a time gate T we want to get the parameters of the fissile source. In order to achieve this goal, we will use the following method