Fast-Neutron Activation of Long-Lived Isotopes in Enriched Ge

Abstract

We measured the production of \nuc{57}{Co}, \nuc{54}{Mn}, \nuc{68}{Ge}, \nuc{65}{Zn}, and \nuc{60}{Co} in a sample of Ge enriched in isotope 76 due to high-energy neutron interactions. These isotopes, especially \nuc{68}{Ge}, are critical in understanding background in Ge detectors used for double-beta decay experiments. They are produced by cosmogenic-neutron interactions in the detectors while they reside on the Earth's surface. These production rates were measured at neutron energies of a few hundred MeV. We compared the measured production to that predicted by cross-section calculations based on CEM03.02. The cross section calculations over-predict our measurements by approximately a factor of three depending on isotope. We then use the measured cosmic-ray neutron flux, our measurements, and the CEM03.02 cross sections to predict the cosmogenic production rate of these isotopes. The uncertainty in extrapolating the cross section model to higher energies dominates the total uncertainty in the cosmogenic production rate.

Revised after feedback and further work on extrapolating cross sections to higher energies in order to estimate cosmic production rates. Also a numerical error was found and fixed in the estimate of the Co-57 production rate

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Cited by in corpus (13)

• The Majorana Demonstrator Radioassay Program
• Recent Progress in Double Beta Decay
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• Cosmogenic production of tritium in dark matter detectors
• Cosmogenic activation of materials
• The Processing of Enriched Germanium for the MAJORANA DEMONSTRATOR and R&D for a Possible Future Ton-Scale Ge-76 Double-Beta Decay Experiment
• Cosmogenic Activation of Germanium Used for Tonne-Scale Rare Event Search Experiments
• Ge Detectors and $0\nu \beta \beta$: The Search for Double Beta Decay with Germanium Detectors: Past, Present and Future
• Cosmogenic-neutron activation of TeO2 and implications for neutrinoless double-beta decay experiments
• Cosmogenic activation in double beta decay experiments
• Study of cosmogenic activation above ground for the DarkSide-20k experiment
• Signatures of muonic activation in the Majorana Demonstrator
• Study of Radioactive Impurities in Neutron Transmutation Doped Germanium