Measurement of proton induced γ-ray emission cross sections on Na from 1.0 to 4.1 MeV

Differential cross sections for proton induced γ-ray emission from the reactions 23Na(p,p′γ)23Na (Eγ=441 and 1636keV) and 23Na(p,α′γ)20Ne (Eγ=1634keV) were measured for proton energies from 1.0 to 4.1MeV in five different ion beam laboratories. Backscattered protons were collected simultaneously for normalization purposes, avoiding the measurement of the absolute values of the collected beam charge. The overall uncertainty was estimated to be around 7–8% for the cross section of the 441keV γ-ray line from the 23Na(p,pγ1-0)23Na reaction, and of 8–12% for the cross section of the 1634–1636keV γ-ray lines from the 23Na(p,αγ1-0)20Ne and 23Na(p,pγ2-1)23Na reactions. To check the possible anisotropy of the emitted 441keV γ-ray, angular distribution measurements were performed at 1292, 1468, 1931, 2083 and 2851keV proton energy, where sharp and well separated resonances occur in the excitation function; moreover, in the energy range from 2.5 to 4.1MeV proton energy, differential cross sections at 0°, 45° and 90° were measured as well.