Year
2014
Abstract
Neutron multiplicity measurements allow to estimate the mass of plutonium in a detector cavity for different applications. One future application is the verification of nuclear disarmament. Computer simulations are used to improve and test detector designs, to study a large range of use cases and, especially relevant for disarmament verification, possible ways to hamper or cheat specific systems. Based on the Monte Carlo particle transport framework Geant4, we developed an application to simulate multiplicity measurements of plutonium samples as an Open Source alternative to es- tablished codes. Although the main purpose of Geant4 has been detector simulations for high energy physics, it includes cross-sections and simulation capabilities for low-energy neutron reac- tions. However, to perform simulations of neutron multiplicity measurements additions have to be made. We implemented a special source definition and developed a routine to estimate the rate of neutrons produced by (a,n) reactions. We wrote a special library to derive the plutonium mass from the pulse train of neutron detection events by calculating the respective moments. Simulation outcomes show good accordance compared with measurements results obtained by other researchers and MCNPX simulations.