Atmospheric Gamma-Ray Transport from a Radioactive Cloud to a Low Earth Orbit Satellite using MCNP

摘要

Modeling the gamma-ray transport from a radioactive cloud to a satellite in orbit requires variance reduction techniques for MCNP to achieve low uncertainty in a reasonable amount of computer time. Using point detector tallies can compute a gamma flux at a satellite location in under 1 minute of computer time. To estimate the detector response at the satellite using MCNP's pulse-height tally, weight-windowing techniques are far less computationally efficient than using DXTRAN spheres. The spectrum obtained by the pulse-height tally using a DXTRAN sphere has a valid physical detector response compared to non-variance reduction pulse-height tallies at closer distances. In conclusion, using DXTRAN spheres is the better method in MCNP for converging the gamma-ray flux from a cloud to a satellite detector.