Deducing ¹⁵⁵Gd(n,xn) cross sections using the surrogate method.

Neutron induced cross sections for unstable nuclei are essential to constrain models in Nuclear Astrophysics and also in applications such as reactor design/safety and Stockpile Stewardship. The surrogate method is an indirect technique that uses a charged particle reaction to populate the same Compound Nucleus as the neutron induced reaction and the cross section is subsequently deduced. The technique has been successfully applied for σ(n,f) and more recently σ(n,γ) but for (n,n') and (n,2n) cross sections, the surrogate method is unproven. An experiment was performed with the newly commissioned NeutronSTARS array comprising a silicon telescope (STARS) and high-efficiency, large volume liquid scintillator detector (Neutron Ball). The ¹⁵⁶Gd(α,α'xn) reaction with 54MeV α's was used as a surrogate for ¹⁵⁵Gd(n,xn) in order to deduce the (n,n') and (n,2) exit channel cross sections across a large equivalent neutron energy range. Results will be discussed.