Measurement of the E_R=338 keV resonance strength for ²³Na(p,α)²⁰Ne

The absolute strength of the E_R=338 keV resonance for ²³Na(p,α)²⁰Ne has been determined. The experiment was carried out by measuring the number of resonant α particles, integrated over the yield curve, simultaneously with the number of Rutherford scattered protons. The method applied in the present work is independent of target stoichiometry, uniformity, stopping power, beam straggling, and current integration. For the resonance strength, we obtained a value of ωγ=(7.16±0.29)×10^-2 eV. Previous results are systematically higher, because the change of target stoichiometry under proton bombardment was not taken into account. With proper consideration, the present method can also be applied to other low-energy (p,α) resonances.