Direct measurement of the low energy resonances in ${}^{22}\mathrm{Ne}(\hat{\mathrm{I}}\pm ,{\hat{\mathrm{I}}}^3{)}^{26}\mathrm{Mg}$ reaction

Abstract

The ${}^{22}\mathrm{Ne}(\hat{\mathrm{I}}\pm ,{\hat{\mathrm{I}}}^3{)}^{26}\mathrm{Mg}$ is an important reaction in stellar helium burning environments as it competes directly with one of the main neutron sources for the s-process, the ${}^{22}\mathrm{Ne}(\hat{\mathrm{I}}\pm ,\mathrm{n}{)}^{25}\mathrm{Mg}$ reaction. The reaction rate of the ${}^{22}\mathrm{Ne}(\hat{\mathrm{I}}\pm ,{\hat{\mathrm{I}}}^3{)}^{26}\mathrm{Mg}$ is dominated by the low energy resonances at $E_{\hat{I}}{\pm }^{lab}$ = 650 and 830 keV respectively. The $E_{\hat{I}}{\pm }^{lab}$ = 830 keV resonance has been measured previously, but there are some uncertainties in the previous measurements. We confirmed the measurement of the $E_{\hat{I}}{\pm }^{lab}$ = 830 keV resonance using implanted ${}^{22}$Ne targets. We obtained a resonance strength of $\ddot{I}‰{\hat{I}}^3$ = 35 $\pm$ 4 $\hat{I}¼eV$, and provide a weighted average of the present and previous measurements of $\ddot{I}‰{\hat{I}}^3$ = 35 $\pm$ 2 $\hat{I}¼eV$ with reduced uncertainties compared to previous studies. We also attempted to measure the strength of the predicted resonance at $E_{\hat{I}}{\pm }^{lab}$ = 650 keV directly for the first time and found an upper limit of $\ddot{I}‰{\hat{I}}^3$ $<0.15$ $\hat{I}¼eV$ for the strength of this resonance. In addition, we also studied the $E_P^{lab}$= 851 keV resonance in ${}^{22}\mathrm{Ne}(\mathrm{p},{\hat{\mathrm{I}}}^3{)}^{23}\mathrm{Na}$, and obtained a resonance strength of $\ddot{I}‰{\hat{I}}^3$ = 9.2 $\pm$ 0.7 eV with significantly lower uncertainties compared to previous measurements.

10 pages, 6 figures