AUTHOR=Li Sufen , Li Kaile , Zhang Quanhu , Cai Xingfu 

TITLE=Study on the Fast Neutron Multiplicity Measurement of Uranium Material

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.835495

DOI=10.3389/fenrg.2022.835495

ISSN=2296-598X

ABSTRACT=As a non-destructive testing and analysis technology, the neutron multiplicity measurement method plays an important role in the field of arms control verification. Great progress has been achieved in the fast neutron multiplicity measurement of plutonium, while there are few studies have been conducted on the fast neutron multiplicity measurement of uranium. In this paper, a set of fast neutron multiplicity measurement device based on BC501A liquid scintillation detector was built, and two small-mass and low-density uranium samples was studied. It is found that the change of the total neutron counting rate is irregular, and the coincidence counting rate will increase linearly with the mass. It may be due to the energy loss caused by the scatter of Am-Li source neutron with sample, resulting in part of the neutron energy below the detector threshold. A simulation detection system is built by Geant4 software to verify the reliability of the conclusion. On this basis, four kinds of packaging materials such as steel, copper, aluminum and graphite were studied, and the measurement result of different materials were compared and analyzed. The thickness of the material was studied and the functional relationship curve was fitted. In this paper, the fast neutron multiplicity measurement of small-mass and low-density uranium samples was carried out and verified by simulation detection system. The influence of different packaging material on the multiplicity measurement was analyzed, which is of great significance for the development of the fast neutron multiplicity measurement technology.