Strength measurement of the $E_{\alpha}^{lab}$ = 830 keV resonance in $^{22}\rm{Ne}(\alpha,n)^{25}\rm{Mg}$ reaction using a stilbene detector

TL;DR

This study remeasured the 830 keV resonance strength in the $^{22}$Ne$( ext{alpha},n)^{25}$Mg reaction, confirming its significant role in stellar neutron production and its comparable strength to the competing gamma reaction.

Contribution

The paper provides a new measurement of the 830 keV resonance strength, confirming its magnitude and impact on stellar nucleosynthesis models.

Findings

Resonance strength is approximately three times larger for the ($ ext{alpha},n$) reaction than for the ($ ext{alpha}, ext{gamma}$) reaction.

The measured resonance strength aligns with previous direct studies.

The results support the importance of this resonance in stellar neutron flux calculations.

Abstract

The interplay between the $^{22}$Ne$(\alpha,\gamma)^{26}$Mg and the competing $^{22}$Ne$(\alpha,n)^{25}$Mg reactions 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 $\alpha$-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 $\gamma$-ray strengths for this resonance are approximately equal. In this study, the $^{22}$Ne$(\alpha,n)^{25}$Mg 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 three larger for the $^{22}$Ne$(\alpha,n)^{25}$Mg reaction than for the $^{22}$Ne$(\alpha,\gamma)^{26}$Mg reaction.