Speaker
Description
Accurate modeling of neutron induced capture γ-production is essential for reactor and shielding calculations, understanding γ-heating in critical systems, and non-proliferation applications. To determine the accuracy of nuclear data evaluations and simulation tools used to transport capture γ-cascades, the 16-segment γ-multiplicity NaI(Tl) detector at the Rensselaer Polytechnic Institute (RPI) Gaerttner Linear Accelerator Center (LINAC) has been upgraded to measure capture γ-ray spectra and multiplicity as a function of energy. Several samples including Fe, Mn, Co, Ta, and $^{235,238}$U have been measured using the time-of-flight (TOF) method for incident neutrons in the low-energy region from 0.01 – 100 eV. A new method has been developed to model the event-by-event capture γ-cascade energy deposition in the detector array using DICEBOX and a modified version of MCNP-6.2. The method has been validated using $^{22}$Na and $^{60}$Co coincidence sources and the well-studied thermal $^{56}$Fe(n,γ) capture γ-ray intensities. Additional measured samples will be used for further validation and analysis. The new modeling capabilities coupled with measured γ-ray spectra can be used to test transport codes and nuclear data evaluations of capture γ-rays used to simulate experimental results.
