Monte Carlo simulations of new precision neutron time of flight detectors for the Z facility

The Z facility is currently undergoing the design and implementation of a new suite of three azimuthally separated precision neutron-time-of-flight (NTOF) detectors for measuring neutron spectra from the z=0 plane. Existing detector systems have not been optimized for high precision measurements in the radial or axial lines of sight (LOS). This new set of detectors aims to solve this problem as well as include several other improvements to enable higher quality neutron-time-of-flight measurements at the Z facility. To help inform this effort, a series of Monte Carlo simulations were conducted to investigate signal contributions from neutrons scattering in the facility. Additionally, simulations were performed to determine the impact of having multiple detectors in a single LOS. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.