DOSIS - Radiation Dose Mapping Onboard Columbus

Although astronaut exposure to cosmic radiation may be reduced by careful mission design and constructive measures, it still seems to be the most essential constraint for long-term human missions of exploration. The radiation environment in space is characterized by a high degree of complexity and dynamics. When the incident radiation penetrates the spacecraft structure, it undergoes a number of nuclear interactions, by which a complex secondary radiation field of charged and uncharged particles arises.

The constituents obviously produce distinct biological damage, which – compared to radiation on ground – leads to large uncertainties in the projection of cancer and other health risks, and obscures evaluation of the effectiveness of possible countermeasures. Accurate risk evaluation depends on the degree of knowledge of the physical characteristics of the radiation field inside the space vehicle.

Fully autonomous radiation sensors are also implemented in the EXPOSE exobiology experiment on the extravehicular European Technology Exposure Facility (EuTEF). Application of a broad variety of instrumentation, e.g., alternating layers of thermoluminescence (TL) and plastic nuclear track detectors, allows for covering the entire charge and energy spectrum and cross-calibrating the measurements.

The Institute of Atomic and Subatomic Physics of the Vienna University of Technology contributes one fifth of the employed TL dosimeters. The energy absorbed from ionizing radiation is stored at controlled lattice defects or impurities in alkali halide crystals and re-emitted as luminescence light upon heating in the laboratory. The light intensity is a measure of absorbed dose and radiation quality.

The gained know-how will support the improvement of particle transport algorithms and constitute essential information to the refinement of radiation protection standards for human spaceflight. The developed prototype area dosimeter could later be implemented into Columbus operational dosimetry and would hence indirectly lead to an improvement of the economic impact.

Coordinator

Vienna University of Technology, Institute of Atomic and Subatomic Physics - Ass.Prof. Michael Hajek

Partners

• German Aerospace Center
• Christian-Albrechts-Universität zu Kiel
• Dublin Institute for Advanced Studies
• Health Protection Agency, UK
• Polish Academy of Sciences, Institute of Nuclear Physics
• Università degli Studi di Roma La Sapienza
• Lawrence Berkeley National Laboratory, USA
• Hungarian Academy of Sciences, Atomic Energy Research Institute
• NASA Johnson Space Center
• Oklahoma State University, USA
• Physikalisch-Technische Bundesanstalt, D
• Russian Academy of Sciences, Institute for Biomedical Problems
• Japan Aerospace Exploration Agency
• National Institute of Radiological Sciences, JP

Vienna University of Technology - Institute of Atomic and Subatomic Physics
Ass.Prof. Michael Hajek
Stadionallee 2
A-1020 Vienna
Tel.: +43 (1) 58801 - 14193
E-mail: mhajek@ati.ac.at
Web: www.ati.ac.at