Characterizing a Neutron Energy Spectrum Using a Forward Edge Neutron Time-Of-Flight Spectroscopy Technique

A Fermi-style thermal neutron disc chopper was designed, constructed, and calibrated in conjunction with a boron-loaded organic scintillator for use in creating a forward edge neutron time-of-flight spectroscopy technique. The forward edge neutron time-of-flight spectroscopy technique inferred the characteristics of a neutron energy spectrum. The system analyzed the spectrum of a moderated and unmoderated PuBe source with the aid of a MATLAB code. Through the use of pulse shape analysis techniques and energy spectroscopy the thermal neutron capture event was identified and isolated. Data analysis provided positive feedback in the disc chopper's ability to partially attenuate higher energy neutrons in the PuBe spectrum. The analyzed data from the MATLAB code indicates the forward edge neutron spectroscopy technique works; however, in terms of an application useful for passive interrogation the system's low efficiency and cumbersome size prove too prohibitive.