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

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