Measurement of proton induced γ-ray emission cross sections on Al from 2.5 to 4.1 MeV

Differential cross section for proton induced γ-ray emission from the reaction 27Al(p,p′γ)27Al (Eγ = 844 and 1014 keV) were measured for proton energies from 2.5 to 4.1 MeV, at 90° and 45°, using a 29 μg/cm2 Al target evaporated on a self-supporting thin Ag film. The γ-rays were detected by two HPGe detectors with nominal 50% and 25% relative efficiency, respectively for the detector placed at 90° and at 45°. Absolute γ-ray differential cross sections were obtained with a method not dependent on the absolute values of the collected beam charge; the overall uncertainty was estimated to be better than 8%, at both angles and at all the beam energies.