Measurements of radiation quality factor on Mars with the Mars Science Laboratory Radiation Assessment Detector

C Zeitlin; D M Hassler; B Ehresmann; S C R Rafkin; J Guo; R F Wimmer-Schweingruber; T Berger; D Matthiä

doi:10.1016/j.lssr.2019.07.010

Measurements of radiation quality factor on Mars with the Mars Science Laboratory Radiation Assessment Detector

Life Sci Space Res (Amst). 2019 Aug:22:89-97. doi: 10.1016/j.lssr.2019.07.010. Epub 2019 Jul 19.

Authors

C Zeitlin¹, D M Hassler², B Ehresmann², S C R Rafkin², J Guo³, R F Wimmer-Schweingruber⁴, T Berger⁵, D Matthiä⁵

Affiliations

¹ Leidos Innovations Corporation, Houston, TX, USA. Electronic address: cary.j.zeitlin@nasa.gov.
² Southwest Research Institute, Boulder, CO, USA.
³ Institute of Experimental and Applied Physics, Christian Albrechts University, Kiel, Germany; Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, China.
⁴ Institute of Experimental and Applied Physics, Christian Albrechts University, Kiel, Germany.
⁵ German Aerospace Center, Institute of Aerospace Medicine, Cologne, Germany.

PMID: 31421853
DOI: 10.1016/j.lssr.2019.07.010

Abstract

We report the first long-term measurements of the radiation quality factor of energetic charged particles on the surface of Mars. The Radiation Assessment Detector (RAD) aboard the Mars Science Laboratory rover, also known as Curiosity, has been operating on Mars since 2012. RAD contains thin silicon detectors that record the ionization energy loss of energetic charged particles. The particles are dominantly galactic cosmic rays (GCRs) and the products of their interactions in the Martian atmosphere, with occasional contributions from solar energetic particles (SEPs). The quality factor on the surface of Mars is influenced by two factors: variations in the shielding provided by the atmosphere, and changes in the spectrum of the incident energetic particle flux due to the 11-year solar cycle. The two cannot be easily disentangled using the data alone, but insights can be gained from calculations and Monte Carlo simulations.

Keywords: Energetic particle radiation; Galactic cosmic rays; Mars; Quality factor.

MeSH terms

Extraterrestrial Environment
Mars*
Monte Carlo Method
Radiation Monitoring / instrumentation*
Radiation Monitoring / methods