Gamma-ray and neutron attenuation of carbon fiber/epoxy composites with carbon nanotubes and boron nitride nanoparticles for passive shielding applications in space

Composite materials have made far-reaching changes in the space industry since they have been adopted into the structural and thermal control subsystems of space vehicles because of their several multi-functions, including being lightweight as well as having advanced mechanical and thermal properties. The use of composites as space radiation shielding materials is also one of the most crucial applications because space radiation is a major impediment for current and future deep-space missions. Investigation of carbon fiber composites with a diverse array of element and nanoparticle reinforcements has revealed their potential as an alternative to conventional radiation shielding materials in space. This study focused on the alleviation of gamma-ray and neutron radiation by carbon fiber/epoxy composites incorporated with various weight ratios of carbon nanotube (CNT) and boron nitride (BN) nanoparticles. A narrow beam geometry setup was used for gamma radiation tests with a Cs-137 gamma-ray source, while neutron radiation experiments were conducted in a neutron howitzer with a ²³⁹Pu-Be neutron source. Six groups of specimens, namely, pure carbon fiber/epoxy, 0.5 wt% CNT, 0.5 wt% BN, 0.5 wt% CNT + 0.5 wt% BN, 1 wt% CNT + 1 wt% BN, and 2 wt% BN, were examined against these two types of radiation. Results have indicated that the 2 wt% BN specimen showed the best attenuation properties against both gamma-ray and neutron radiation among all tested specimens; furthermore, it was almost three times more effective against neutron radiation than against gamma-ray radiation. Highlights: Varying weight ratios of CNT and BN nanoparticles used for radiation shielding. A Cs-137 gamma-ray source used in narrow beam geometry. Neutron radiation studies were conducted in a ²³⁹Pu-Be neutron howitzer. The 2 wt% BN sample showed the best attenuation against gamma-ray and neutron radiation. It resulted in an HVL of 6.86 cm for gamma-ray radiation and 2.13 cm for neutron radiation.