Effectiveness of Multi-Layered Radiation Shields Constructed from Polyethylene and Metal Hydrides Using HZETRN and OLTARIS for Space Applications

A major challenge for extended human spaceflights in deep space is the dangerous exposure to space radiation. These high-energy particles pose significant risks to astronaut health. To mitigate these risks, effective radiation shielding is essential. In previous studies, aluminium has been used as a multilayer shielding material in GCR (Galactic Cosmic Rays) space radiation environment with high dose equivalent. Because of aluminium's secondary particle production, the overall effective dose equivalent for astronauts behind an aluminium shield is higher than for more advanced shielding materials. To further reduce the dose equivalent, the shielding effectiveness of various metal hydrides in GCR free space environment is investigated using HZETRN2015 (High charge (Z) & Energy TRaNsport) and OLTARIS (On-Line Tool for the Assessment of Radiation In Space) in this work. Metal hydride materials are chosen because of their capacity to store hydrogen. Among these materials, lithium hydride has demonstrated superior effectiveness as a radiation shield. Given this, the potential of a multilayer shield composed of polyethylene and lithium hydride is also being explored considering the tensile strength certain varieties of polyethylene like UHMWPE (Ultra High Molecular Weight Poly-Ethylene) can provide. In multilayer shielding, different materials can target different types of radiation, providing more comprehensive protection. The results from HZETRN2015 and OLTARIS transport codes are compared and found in agreement.