Light Weight Radiation Hardened Enclosures for Electronic Components on board Missiles and Spacecraft

Nuclear radiation that penetrates the skin of an exothermic kill vehicle can damage sensitive electronic components on board. Radiation shields to protect these components must absorb the radiation (x-rays, neutrons, or gamma rays), absorb any cascade by-products, such as photoelectrons, and mitigate the effects of stress waves (shocks) generated by the absorption process. HY-Tech is proposing a multi-layer shield consisting of a high Z outer layer to absorb high energy x-rays (100-300 keV) and a porous B4C middle layer, which provides rigidity to the structure and moderates the neutron flux. The porous B4C layer absorbs photoelectrons emitted by the x-ray absorption in the outer layer and acts as an acoustic miss-match to mitigate shock wave propagation to the internal components. The Phase I effort will fabricate B4C samples with a high Z absorbing layer on one side. The transmission of 100-300 keV x-rays through this two-layered shield will be measured on a x-ray simulor. The neutron shielding and shock isolation properties will be calculated using analytical and numerical techniques.