The key objective of the proposed work is to develop a novel approach for reid (radiation exposure induced death) risk assessment using GEANT4, a radiation transport code developed at cern (european…

This is a Cooperative Agreement awarded by the National Aeronautics and Space Administration (NASA) to the University of Mississippi to develop a novel approach for Radiation Exposure Induced Death (REID) risk assessment using the GEANT4 radiation transport code. The key objectives of the project are to establish an expert GEANT4 user group to compare the results from GEANT4 with NASA's current HZETRAN code, and to extend the REID focus to include the health effects of radiation flux on astronaut DNA. This research is directly applicable to NASA's priorities in assessing and mitigating radiation health risks for deep space missions. The contract has a ceiling value of $741,121.11 and a period of performance through June 26, 2019. No set-aside designation is mentioned.

The key objective of the proposed work is to develop a novel approach for reid (radiation exposure induced death) risk assessment using GEANT4, a radiation transport code developed at cern (european organization for nuclear research). Methods/techniques: the proposed research involves two task that will accomplish the stated research objectives. The first task will establish an expert GEANT4 user group in collaboration with NASA msfc and compare the results from GEANT4 with results from hzetran (a 1-d deterministic transport code current used for reid calculations at NASA larc). We will study the effects of uncertainties in the quality factor, low let risk model and uncertainty in nuclear cross sections for galactic cosmic rays and solar particles. This first task will evaluate GEANT4's promise in reid calculations and apply the considerable capabilities of GEANT4 directly to current NASA needs in statistical evaluations related to mortality data. The second task of the project is to extend the reid focus to include the health effects of the radiation flux on the DNA of the astronauts. The GEANT4 community is actively involved in the development of databases related to radiation-induced DNA effects [1]. Although the physics related to the initial space radiation and the secondary particles IT generates typically involves high-energy interactions, low energy interactions are critical in when considering effects on biomolecules. Significance: this project is directly applicable to research priorities defined by the human exploration and operations mission directorate.as noted in NASA's human research program integrated research plan [2], radiation health effects and radiation protection for astronauts are among the most important issues encountered in deep space missions. The assessment of health risk can ultimately dictate the design and composition of the spacecraft. [3] NASA's current method utilizes hzetran, which has virtue in that IT is deterministic and computing time is much faster compared to monte carlo codes, but the compromise is that several assumptions, must be made including the "straight ahead approximation", which essentially makes the code 1-dimensional. Incorporation of GEANT4 into reid assessment will advance the state-of-the-art with its extremely effective monte carlo framework, 3-d modeling capability, radiation transport, and many atomic and nuclear databases. Finally, perhaps the most exciting outcome ofthe proposed research would be the bridging of the two tasks described above. Namely, success in both tasks will allow for evaluation of correlations between the reid calculations (GEANT4 or hzetran) and the DNA effects predicted by GEANT4 simulations. Connection between the macroscopic statistics and microscopic DNA impacts could yield fundamentally new insights into radiation-induced DNA damage.