Enhancing Shielding Efficiency against Galactic Cosmic Radiation: Secondary Neutron Optimization

GCR (Galactic Cosmic Rays) are highly energetic ionizing radiations originating from sources beyond our solar system. During long-duration missions to outer space such as the Moon or Mars, the health hazards posed by these cosmic rays become a pressing concern for astronauts. Consequently, prioritizing the protection of both the spacecraft and its crew becomes of the highest importance, and the materials most frequently used for shielding are aluminum (Al) and polyethylene (PE). The objective of this study is to simulate the effectiveness of shielding against GCR, particularly focusing on secondary neutrons, using a combination of aluminum and polyethylene materials. Monte Carlo simulation (PHITS code) was used in the simulation. The effectiveness shielding of Al and PE is compared. The flux spectra of secondary emitted from the back of the slab shielding was computed. It shows that secondary neutron is produced mainly by GCR-protons and when multi-layer of PE materials is employed, secondary neutron flux has been reduced (about 10%). This reduction is of paramount significance since neutrons are a crucial component of the radiation emanating from GCR. In summary, the utilization of multi-layer polyethylene materials was demonstrated as an efficient approach to enhance the shielding effectiveness against GCR radiation.