Design and testing of optimal personal protective equipment for high energy radiation on earth and beyond

Abstract

This study incorporates an experimental and an associated modeling investigation of human protective shielding methodologies for two extreme environments: first responders or military personnel in the case of nuclear or radiological incidents (360 Gamma); second a deep space mission (AstroRad). Both solutions utilize selective shielding of organs, tissues, and stem cell niches which are relatively more radiosensitive to either deterministic or stochastic effects depending on the application to derive the greatest biological benefit per unit mass shielding. This is accomplished by allocating the shielding over the surface of the body in a variable thickness architecture which is inversely related to the radio-density of the intervening tissues between the shielding and the organ, tissue, or stem cell niche being targeted for protection. This structural design of shielding placed adjacent to the area of the body being protected and being of a variable thickness which augments the self-shielding of the body at each point on the surface provides the function of optimized use of shielding material to reduce the absorbed doses to the organs, tissues, or stem cell niches targeted for protection. The experimental studies utilized the best available facilities to provide a dose realistic environment and the best available phantoms for dose absorption. MCNP6 and HZETRN were used for the modeling. In the case of the 360 Gamma, the shielding concept experiments matched well with the model. In the case of the AstroRad, experiments verifying the simulations are planned for the near future. The work demonstrated significant reduction in absorbed dose to the organs and tissues targeted for protection in both cases. This study involves human protective shielding in two distinct environments: First, human protection for military personnel or first responders to a nuclear or radiological incident; Second for astronauts on a deep space mission. The two human protection environments will be discussed separately, thereby dividing this dissertation into 2 distinct but related parts beginning with the 360 Gamma study and results followed by the AstroRad study and results because even though there are some commonalities, the environments and needs for protection differ.