A method for using neutron elastic scatter to create a variable energy neutron beam from a nearly monoenergetic neutron source

• We investigated neutron elastic scatter to reliably change the energy of neutrons.
• Idealized simulations showed distinct energy peaks at predicted lower values.
• Realistic simulations were less encouraging.
• The method requires accurate neutron timing information for proper discrimination.
• A discussion of scatter based uncertainty is included.

This work describes preliminary investigation into the design of a compact, portable, variable energy neutron source. The proposed method uses elastic neutron scatter at specific angles to reduce the energy of deuterium–deuterium or deuterium–tritium (D–T) neutrons. The research focuses on D–T Monte Carlo simulations, both in idealized and more realistic scenarios. Systematic uncertainty of the method is also analyzed. The research showed promise, but highlighted the need for discrimination of multiply-scattered neutrons, either through a pulsed generator or associated particle imaging.