The 22Ne,26Mg is the competitor of the22Ne,25Mg in AGB stars, which, in turn, is an efficient source of neutrons for s-processes in medium masses AGB stars. There is a significant uncertainty in the22Ne,26Mg thermonuclear reaction rate. This has been clearly remarked the ChETEC COST Action (CA16117) considering the (22Ne,26Mg among the nuclear reactions with major impact on stellar nucleosynthesis. A narrow resonance at an energy E = 395 keV has been claimed in the22Ne,26Mg reaction and it has been studied only with indirect methods leading to a range of possible values for its strength from10-9 to 10-15 eV. At LUNA (Laboratory for Underground Nuclear Astrophysics) this resonance can be studied directly, thanks to a high efficiency setup, composed by a 4 -BGO detector and a windowless gas target filled with neon gas enriched in the22Ne, isotope to 99.99%. This setup has been already used in a previous experiment for the study of the22Ne,23Na reaction, and in April-June 2018 a new measurement campaign will be performed. Thanks to its position inside the Laboratory of Gran Sasso, LUNA already benefits from a reduced background and in particular a factor one thousand for the neutron component. Still this remains the most important source of background in the region of interest for the22Ne,26Mg. Therefore a new borated polyethylene shielding will be employed to reduce the neutron contamination due to the environmental background by an additional order of magnitude.
Study of the E = 395 keV Resonance of the22Ne(α, γ)26Mg Reaction at LUNA
Caciolli A.;
2019
Abstract
The 22Ne,26Mg is the competitor of the22Ne,25Mg in AGB stars, which, in turn, is an efficient source of neutrons for s-processes in medium masses AGB stars. There is a significant uncertainty in the22Ne,26Mg thermonuclear reaction rate. This has been clearly remarked the ChETEC COST Action (CA16117) considering the (22Ne,26Mg among the nuclear reactions with major impact on stellar nucleosynthesis. A narrow resonance at an energy E = 395 keV has been claimed in the22Ne,26Mg reaction and it has been studied only with indirect methods leading to a range of possible values for its strength from10-9 to 10-15 eV. At LUNA (Laboratory for Underground Nuclear Astrophysics) this resonance can be studied directly, thanks to a high efficiency setup, composed by a 4 -BGO detector and a windowless gas target filled with neon gas enriched in the22Ne, isotope to 99.99%. This setup has been already used in a previous experiment for the study of the22Ne,23Na reaction, and in April-June 2018 a new measurement campaign will be performed. Thanks to its position inside the Laboratory of Gran Sasso, LUNA already benefits from a reduced background and in particular a factor one thousand for the neutron component. Still this remains the most important source of background in the region of interest for the22Ne,26Mg. Therefore a new borated polyethylene shielding will be employed to reduce the neutron contamination due to the environmental background by an additional order of magnitude.
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