Neutron-Gamma Correlation Analysis Using the Fission Sphere (FS-3)

We have designed and assembled a new organic scintillator detector array used for the analysis of the properties of the radiation emitted following nuclear fission. The goal of the array is to measure correlated fluctuations in the event-by-event neutron-gamma emission multiplicities and test the validity of theoretical fission models. To ensure an unbiased experiment, the system possesses spherical geometrical coverage of the source, and its energy acceptance covers most of the neutron-gamma spectra from fission. In the experimental results presented here, we show that the system has excellent neutron-gamma discrimination and can be used to quantify neutron-gamma emission correlations. The particle discrimination is achieved through a combination of pulse-shape analysis and time of flight analysis. We have observed energy regions of positively and negatively correlated neutron-gamma emission. The magnitude of these correlations varies from ~ -5% to +3%. To improve the accuracy of our data analysis and the interpretation of the experimental data, we are designing and trainng a simple neural network for the rejection of cross-talk and room-return events.