Radiation experienced by astronauts determined with CR-39 dosimeters using a human phantom on ISS

Paper number

IAC-08.A1.4.3

Author

Dr. Dazhuang Zhou, United States

Coauthor

Dr. Denis O''Sullivan, Ireland

Coauthor

Ms. Edward Semones, United States

Coauthor

Dr. Neal Zapp, United States

Coauthor

Dr. Guenther Reitz, German Aerospace Center, Germany

Coauthor

Dr. Thomas Berger, German Aerospace Center (DLR), Germany

Coauthor

Dr. Eric Benton, United States

Year

2008

Abstract

Humans will soon return to the moon and travel to the planets near Earth. Space radiation hazards are a key concern for human spaceflight. Radiation in low Earth orbit (LEO) is mainly composed of Galactic Cosmic Rays (GCR), solar energetic particles, electrons and protons in the SAA (South Atlantic Anomaly) and albedo neutrons and protons scattered from the Earth’s atmosphere. Radiation in deep space is much stronger than that in LEO because there is no magnetosphere nearby to screen particle radiation and no big planet nearby to shadow the spacecraft.
     Research indicates that the impact of particle radiation on humans depends strongly on the particles’ linear energy transfer (LET) and is dominated by high LET radiation. High LET radiation is much more effective than low LET radiation in the induction of biological effects and the relative biological effectiveness (RBE) increases with LET. Therefore research on high LET radiation should be emphasized and conducted systematically so as to make radiation risk as low as reasonably achievable (ALARA) for astronauts.
     Owing to its many unique advantages, CR-39 plastic nuclear track detectors/dosimeters (PNTDs) are being widely used in radiation measurement and have proved to be the best personal passive dosimeters sensitive to high LET. LET spectra (differential and integral fluence, absorbed dose and dose equivalent) can be obtained using CR-39 dosimeters.
     The European Space Agency (ESA) MATROSHKA (MTR) facility, using a human phantom torso provided us with the best opportunities to measure radiation at the different locations corresponding to the astronaut’s organs. CR-39 detectors were placed at the different organ positions outside ISS (International Space Station) (MTR-1, 616 days) and inside ISS (MTR-2, 367 days). Data obtained as LET spectra for an astronaut’s organs will be useful for the future in high depth research on the radiobiological damage and risk to astronauts.
     This paper introduces the role of high LET radiation in radiobiology, the LET spectrum method for radiation measurement using CR-39 detectors, and presents the LET spectra and radiation quantities determined with CR-39 PNTDs for the Matroshka mission and compares the radiation levels outside and inside ISS for the same organ.

Abstract document

IAC-08.A1.4.3.pdf

Manuscript document

IAC-08.A1.4.3.pdf (🔒 authorized access only).

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