دانلود رایگان مقاله فعال سازی پیدایش اولیه مواد مورد استفاده در آزمایش جستجو رویداد نادر

ABSTRACT

We evaluate the cosmogenic production rates in some materials that are commonly used as targets and shielding/supporting components for detecting rare events. The results from Geant4 simulations and the calculations of ACTIVIA are compared with the available experimental data. We demonstrate that the production rates from the Geant4-based simulations agree with the available data reasonably well. As a result, we report that the cosmogenic production of several isotopes in various materials can generate potential backgrounds for direct detection of dark matter and neutrinoless double-beta decay.

5. Conclusion

The cosmogenic activations of several key components of the next generation rare event search experiments at sea level have been simulated using the GEANT4 and ACTIVIA packages. Fast neutrons, thermal neutrons and muons at the Earth surface are considered individually. The total production rates of several isotopes are compared with other calculations [12,15,20] as well as the available experimental data from LUX [18] and Baudis et al. [19].Significant differences are found in the results between Geant4 and ACTIVIA packages. We attribute these differences to the different input neutron energy spectra and the cross-section libraries used in the two packages. We emphasize the key requirement of using the accurate neutron energy spectrum and cross-sections for particular nuclear reactions. We have found that Geant4 can predict the production rates of different radioactive isotopes by cosmogenic activation pretty well.