A new measurement of the¹⁷O(α,n)²⁰Ne cross section

The ¹⁷O(α,n) reaction recycles neutrons for the most efficient neutron absorber ¹⁶O(n,γ)¹⁷O during the core He-burning and shell C-burning phases of the weak s-process. A recent evaluation of previous measurements combined with statistical model calculations by P. Mohr point out a discrepancy in the experimental data. Thus, we have performed (α,nγ) and (α,n) cross section measurements at the 5U accelerator of the Notre Dame Nuclear Science Laboratory. We measured angular distributions of secondary gamma rays from E_α > 1.4 MeV using the HAGRiD (LaBr₃:Ce) array and neutrons from 0.8 < E_α < 1.5 MeV with an array of deuterated liquid scintillator detectors. The use of digital electronics allow for pulse shape discrimination in both detector arrays, and spectrum unfolding is used to obtain neutron energy information from the observed light output spectrum in the liquid scintillators. We will present new cross section results from the secondary gamma and neutron measurements.