Obtaining a history of the flux of cosmic rays using in situ cosmogenic 14C trapped in polar ice

Carbon-14 (14C) is produced in the atmosphere when neutrons from cosmic-ray air showers are captured by 14N nuclei. Atmospheric 14C becomes trapped in air bubbles in polar ice as compacted snow (firn) transforms into ice. 14C is also produced in situ in ice grains by penetrating cosmic-ray neutrons and muons. Recent ice core measurements indicate that in the 14CO phase, the 14C is dominated by the in situ cosmogenic component at most ice coring sites. Thus, it should be possible to use ice-bound 14CO to reconstruct the historical flux of cosmic rays at Earth, without the transport and deposition uncertainties associated with 10Be or the carbon cycle uncertainties affecting atmospheric 14CO2. The measurements will be sensitive to the cosmic-ray flux above the energy range most affected by solar modulation. We present estimates of the expected sensitivity of 14CO in ice cores to the historical flux of Galactic cosmic rays, based on recent studies of 14CO in polar ice. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0)

Keywords

Atmospheric circulation, Carbon 14, Cosmic ray flux, Cosmology, Ice, Earth core

Citation

BenZvi, S., Petrenko, V. V., Hmiel, B., Dyonisius, M., Smith, A. M., Yang, B., & Hua, Q. (2019). Obtaining a history of the flux of cosmic rays using in situ cosmogenic 14C trapped in polar ice. Paper presented at the 36th International Cosmic Ray Conference: ICRC2019, Madison, Wisconsin, U.S.A., July 24th - August 1st, 2019. In arXiv:1909.07994 [astro-ph.HE]. doi:10.48550/arXiv.1909.07994

URI

https://doi.org/10.48550/arXiv.1909.07994
https://apo.ansto.gov.au/dspace/handle/10238/13127

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