Cross sections from 5 to 35 MeV for the reactions natMg(3He,x)26Al, 27Al(3He,x)26Al,natCa(3He,x)41Ca,and natCa(3He,x)36Cl: Implications for early irradiation in the solar system |
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| Authors: | Gregory F HERZOG Marc W CAFFEE Thomas FAESTERMANN R HERTENBERGER Gunther KORSCHINEK Ingo LEYA Robert C REEDY J M SISTERSON |
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| Institution: | 1. Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854–8066, USA;2. Department of Physics, Purdue University, W. Lafayette, Indiana 47907, USA;3. Fakult?t für Physik, Technische Universit?t München, D‐85748 Garching, Germany;4. Fakult?t für Physik, Ludwig‐Maximilians‐Universit?t München, D‐85748 Garching, Germany;5. Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH 3012 Bern, Switzerland;6. Planetary Science Institute, 152 S. Monte Rey Dr., Los Alamos, New Mexico 87544, USA;7. Francis H. Burr Proton Therapy Center, Massachusetts General Hospital, 30 Fruit Street, Boston, Massachusetts 02114, USA |
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| Abstract: | Abstract– Cross sections were measured for the nuclear reactions natMg(3He,x)26Al, 27Al(3He,x)26Al, natCa(3He,x)41Ca, and natCa(3He,x)36Cl in the energy region from approximately 5–35 MeV. The rates of these reactions are important for studies of early solar system irradiation scenarios. The 26Al, 36Cl, and 41Ca were separated chemically, and the numbers of atoms produced in each reaction channel were measured using accelerator mass spectrometry (AMS). From these results, 26 cross sections were determined and compared with predictions of the TALYS code. Agreement is within 40% for most cross sections. Our measurements were used to model the production of 7Be, 10Be, 26Al, and 41Ca in the early solar system. For projectiles 1H, 3He, and 4He, we assumed energy spectra of the general form E?α. For a wide range of parameterizations, the modeled ratios of 7Be/Be and 10Be/Be on the one hand and of 26Al/27Al and 41Ca/Ca on the other are coupled because the excitation functions for the relevant nuclear reactions have similar shapes. Modeling of a closed system with the constraint that 10Be/9Be = 0.001 fails to reproduce simultaneously the range of 7Be/9Be, 26Al/27Al, and 41Ca/Ca ratios inferred for the early solar system from studies of meteorites. |
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