Strength measurement of the $E^{lab}_α = 830$ keV resonance in the 22 Ne (α,n) 25 Mg reaction using a stilbene detector
The interplay between the 22 Ne (α,γ) 26 Mg reaction and the competing 22 Ne (α,n) 25 Mg 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 22 Ne (α,n) 25 Mg resonance strength has been remeasured and found to be similar to the previous direct studies. Finally, this reinforces an 830 keV resonance strength that is approximately a factor of 3 larger for the 22 Ne (α,n) 25 Mg reaction than for the 22 Ne (α,γ) 26 Mg reaction.