Doctor of Philosophy (PhD)


Physics and Astronomy

Document Type



Purpose: To develop a physiologically scaled cosmic ray generator that will accurately replicate the relative dose distribution of astronauts in Low Earth Orbit in ground-based radiobiology studies on mice subject.

Methods: A database of absorbed dose to the critical structures in a mouse computational model was developed and used in conjunction with a genetic algorithm to develop the theoretical design of a cosmic ray generator that replicates the relative absorbed dose distribution seen in astronauts in Low Earth Orbit. The design was then fabricated using 3D printing techniques to application on a heavy-ion accelerator. Measurements of the resulting spectrum were compared to the simulation results, analyzing the expected energy deposition and the charged particle distribution.

Results: Using genetic algorithms and 3D Monte Carlo software, a theoretical design was developed that improved the average and max percent deviation of absorbed dose from 5.62% to 5.2% and 17.66% to 10.95%, respectively. The cosmic ray generator was fabricated completely in house and can be assembled with relative ease on a heavy ion accelerator. Comparison of the measured data versus predicted show good agreement from Z=8 to Z=21, but large deviations for high- and low-Z ions, including the primary ion peak.

Conclusions: This work shows the feasibility of developing a cosmic-ray generator for animal-specific radiobiology experiments with decent agreement in simulation and measured results. This work highlights some significant gaps in knowledge for available cross section data, which is necessary for further progress of space radiation research.



Committee Chair

Chancellor, Jeffery

Available for download on Tuesday, May 13, 2031