EPJ Web of Conferences 260, 11017 (2022)
https://doi.org/10.1051/epjconf/202226011017

First direct limit on the 395 keV resonance of the ²²Ne(α, γ)²⁶Mg reaction

¹ Università degli studi di Milano and INFN Sezione di Milano
² https://luna.lngs.infn.it

^* e-mail: eliana.masha@unimi.it

Published online: 24 February 2022

Abstract

The ²²Ne(α, γ)²⁶Mg reaction (Q = 10614.74 keV) competes with the ²²Ne(α, n)²⁵Mg reaction (Q = −478.34 keV) which is the main source of neutrons for the s-process in low-mass Asymptotic Giant Branch and massive stars. The cross sections of these reactions are crucial to fix the cross over temperature at which (α, n) rate exceeds the (α, γ) one. Moreover, the uncertainty on the ²²Ne(α, γ)²⁶Mg reaction rate affects also the nucleosynthesis of isotopes between ²⁶Mg and ³¹P in intermediate-mass stars.

At lower temperatures (T < 300 MK) where the (α, γ) channel is dominant, the rate of the ²²Ne(α, γ)²⁶Mg reaction is influenced by several resonances. The present study focuses on the E_α = 395 keV resonance which so far have been studied only indirectly leading to a wide range of possible values for its resonance strength (10⁻¹⁵ −10⁻⁹ eV).

The experiment has been completed at LUNA using the intense alpha beam of the LUNA 400 kV accelerator and a windowless differential-pumped gas target combined with a high efficiency BGO detector. Experimental details and preliminary results will be shown.