Cross section for non-Rutherford backscattering of α on Be

Be is an important element in fusion and fission reactor technology and in X-ray optical components. Non-Rutherford backscattering is desirable when the stoichiometry and depth profile of Be and other heavy elements have to be measured simultaneously. Cross sections for θ_lab=165° of He-ion backscattering on ⁹Be in the 0.88-5.3 MeV energy range were measured. Self-supported films of 15 μg/cm ² Be were used as targets. The measured resonance at 5.05 MeV shows a cross section 47 times as large as the Rutherford cross section. The relative cross sections are presented in graphic and tabular forms with a typical ±2.7% uncertainty.