Strength measurement of the 𝐸lab 𝛼=830 keV resonance in the 22Ne⁢(𝛼,𝑛)⁢25Mg reaction using a stilbene detector

The interplay between the 22Ne⁢(𝛼,𝛾)⁢26Mg reaction and the competing 22Ne⁢(𝛼,𝑛)⁢25Mg reaction determines the efficiency of the latter as a neutron source at the temperatures of stellar helium burning. In both cases, the rates are dominated by the 𝛼-cluster resonance at 830 keV. This resonance plays a particularly important role in determining the strength of the neutron flux for both the weak and main 𝑠 process as well as the 𝑛 process. Recent experimental studies based on transfer reactions suggest that the neutron and 𝛾-ray strengths for this resonance are approximately equal. In this study, the 22Ne⁢(𝛼,𝑛)⁢25Mg resonance strength has been remeasured and found to be similar to the previous direct studies. This reinforces an 830 keV resonance strength that is approximately a factor of 3 larger for the 22Ne⁢(𝛼,𝑛)⁢25Mg reaction than for the 22Ne⁢(𝛼,𝛾)⁢26Mg reaction.