A Method for Simulating Real-Time Neutron Populations, Materials and Geometries Using the GEANT4 Monte Carlo Toolkit
36th Annual CNS-CNA Student Conference - 2012 June 12

Presented at:
36th Annual CNS-CNA Student Conference
2012 June 12
Saskatoon, Canada
Session Title:
CNS/CNA Student Conference 2012

Liam Russell (McMaster University )
Guy Jonkmans (AECL Chalk River )
Adriaan Buijs (McMaster University )


GEANT4 is an expandable Monte Carlo particle physics toolkit that simulates particles moving through matter spatially and temporally. This allows a population of particles, such as neutrons, to be tracked in a multiplying medium as the population and the medium evolve. Such simulations can be used to investigate problems such as criticality calculations, heating and feedback, and rod removal. However, to track a population for a period on the order of seconds, the neutron population must be artificially stabilized so that it remains relatively constant. We present a stabilization method where the simulation is divided into short intervals (in time) and the population is renormalized at the end of each interval by duplicating or deleting some of the surviving neutrons. The evolution of the population over an interval is tracked using a multiplication constant that is equal to change in the population. Any changes to the material or geometric properties of the simulation are made at the end of the intervals since these may not change while the particles are being tracked. This method has been successfully employed to simple sphere U235 to prove a stable population is possible and that the evolution of the population may be used to calculate the criticality of the sphere.

Individual Conference-Paper Copies (Electronic Where Available):

  • For CNS members, the first 5 copies per calendar year are free, and additional copies are $10 each.
  • For non-members, the price is $25 for the first Conference-paper copy in a request, and $10 each for additional copies of papers in the same conference and in the same request.
  • Contact the CNS office to order reprints.