MUST’s Scholars Reveal the Cosmic Ray Flux and Energy Spectrum on the Lunar Surface in the World-renowned Academic Journal - Science Advances For the First Time
19/01/2022
19/01/2022
The research team of the State Key Laboratory of Lunar and Planetary Science of the Macau University of Science and Technology (MUST) obtained the cosmic ray flux and energy spectrum on the lunar surface for the first time in the world, based on the data of Chang'e-4 regarding lunar surface neutron and radiation dose detector. The research results were published in the world-renowned academic journal Science Advances on January 15, 2022, Beijing time, under the title of “First measurements of low-energy cosmic rays on the surface of the lunar farside from Chang’E-4 mission”. The first author of the paper is Dr. Luo Pengwei from the State Key Laboratory of Lunar and Planetary Sciences of MUST, and the corresponding author is Associate Professor Zhang Xiaoping.
Cosmic rays significantly affect the space environment. An in-depth understanding of the composition and energy spectrum of cosmic rays is helpful for researchers to better evaluate the radiation level in the space environment, which is of vital importance to human deep space exploration. The research team’s system measured the energy spectrum of the low-energy cosmic ray protons, α particles, CNO and heavy ion on the lunar surface during the solar minimum period of 2019/2020. The data show that the energy spectrum of low-energy cosmic rays obtained at the lunar surface is consistent with that obtained by the exploration satellite at the solar-terrestrial L1 point. The observations confirmed the dawn-dusk asymmetry of cosmic ray flux, indicating that the influence of the lunar environment in the landing area of Chang'e 4 including the magnetic anomaly area on cosmic ray flux can be ignored. The team also extracted the He isotopic ratio and identified a significant enhancement at ~12 MeV/nuc. There are significant differences between the energy spectrum of the measured cosmic ray proton and α particles and the predictions of the widely used CRÈME model, posing a challenge to the model of cosmic ray transport. The data of cosmic ray energy spectrum on the lunar surface obtained by the first in situ detection provide first-hand observational data for in-depth study of the interaction between cosmic rays and the lunar surface and radiation protection in future manned lunar missions.
Cosmic rays significantly affect the space environment. An in-depth understanding of the composition and energy spectrum of cosmic rays is helpful for researchers to better evaluate the radiation level in the space environment, which is of vital importance to human deep space exploration. The research team’s system measured the energy spectrum of the low-energy cosmic ray protons, α particles, CNO and heavy ion on the lunar surface during the solar minimum period of 2019/2020. The data show that the energy spectrum of low-energy cosmic rays obtained at the lunar surface is consistent with that obtained by the exploration satellite at the solar-terrestrial L1 point. The observations confirmed the dawn-dusk asymmetry of cosmic ray flux, indicating that the influence of the lunar environment in the landing area of Chang'e 4 including the magnetic anomaly area on cosmic ray flux can be ignored. The team also extracted the He isotopic ratio and identified a significant enhancement at ~12 MeV/nuc. There are significant differences between the energy spectrum of the measured cosmic ray proton and α particles and the predictions of the widely used CRÈME model, posing a challenge to the model of cosmic ray transport. The data of cosmic ray energy spectrum on the lunar surface obtained by the first in situ detection provide first-hand observational data for in-depth study of the interaction between cosmic rays and the lunar surface and radiation protection in future manned lunar missions.
Comparison of cosmic ray flux on the lunar surface with terrestrial satellite and CRÈME model
MUST’s State Key Laboratory of Lunar and Planetary Sciences has participated in the scientific data analysis of all tasks of China’s Chang’e Lunar Exploration Project and has continuously made new scientific achievements. At present, laboratory researchers are conducting an in-depth analysis of Chang'e-5 lunar samples and “Tianwen 1” Mars exploration data. In addition, researchers also actively engaged in the follow-up mission of the Chang'e Project and the development of scientific payloads in the “Tianwen-2” asteroid exploration mission, which provided strong scientific support for China’s Deep Space Exploration Program and facilitated the development of China’s lunar and planetary science.
Reprinted from MUST：https://www.science.org/doi/10.1126/sciadv.abk1760
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