Speaker
Description
Accurate modeling of neutron induced capture γ-ray production is essential for many applications such as understanding γ-ray heating in critical systems, shielding calculations, nuclear medicine, particle physics experiments and active neutron interrogation. To determine the accuracy of nuclear data evaluations and simulation tools used to transport thermal neutron capture γ-ray cascades, the 16-segment NaI(Tl) detector array at the Rensselaer Polytechnic Institute (RPI) Gaerttner Linear Accelerator (LINAC) Center has been upgraded. The updated system is capable of measuring neutron capture γ-ray spectra and multiplicity as a function of incident neutron energy by using the time-of-flight (TOF) method and detecting prompt γ rays emitted via capture reactions. A new simulation method has also been developed to model the event-by-event capture γ-ray cascade energy deposition in the detector array using DICEBOX and a modified version of MCNP-6.2 (mod-MCNP-6.2/DICEBOX). The updated modeling capabilities have been tested using the well-studied thermal $^{56}$Fe(n,γ) γ-ray intensities. Validation of the system has been extended with $^{55}$Mn and $^{59}$Co thermal neutron capture measurements. The experimental capture γ-ray spectra results agree with mod-MCNP-6.2/DICEBOX calculations using evaluated nuclear data from the ENSDF and RIPL-3 databases.
