Speaker
Description
The $^{17}$O(p,$\gamma$)$^{18}$F reaction plays a key role in the hydrogen burning in CNO cycle. At temperatures of interest for the H-shell burning in AGB stars, the reaction rate is dominated by the $E_\mathrm{c.m.}=65\,\mathrm{keV}$ resonance.
The strength of this resonance is presently determined only through indirect techniques, with a literature value $\omega\gamma = (16 \pm 3)\,\mathrm{neV}$, leading to an expected counting rate of $0.3\,\mathrm{reactions}/\mathrm{C}$ for typical experimental quantities.
The LUNA collaboration has recently performed a new direct measurement of the $^{17}\mathrm{O}(p,\gamma){}^{18}\mathrm{F}$ cross section focused on the $65\,\mathrm{keV}$ resonance taking advantage of the ultra-low background of the deep underground Laboratori Nazionali del Gran Sasso (LNGS, Italy) and of a high stable intense proton beam ($ \left< I \right> = 200\,\mu\mathrm{A} $) provided by the LUNA400 accelerator. For this purpose, a high sensitivity and high efficiency setup based on a segmented $4\pi$ BGO detector was developed. All these experimental efforts allowed, for the first time ever, the evaluation of the $65\,\mathrm{keV}$ resonance strength by a direct technique. Moreover, also the $\Gamma_p$ width was calculated, confirming the results of the ${}^{17}\mathrm{O}(p,\alpha){}^{14}\mathrm{N}$ $65\,\mathrm{keV}$ resonance measured in a previous LUNA experiment.
In the talk, the results of the new LUNA measurement will be presented.
