Proton inelastic scattering cross section measurements on O-16 and Si-28

A (p, p 'gamma) experiment was performed at the Tandem accelerator of IFIN-HH (Bucharest) with the purpose of measuring the proton inelastic cross-sections on O-16 and Si-28. The goal was to investigate to which extent the neutron cross-sections on these nuclei can be inferred from those obtained with charged particles (i.e., protons). In doing so, we are trying to exploit the isospin symmetry by taking under consideration that the chosen targets are N = Z nuclei and, consequently, two mirror nuclei are formed in the (p, p ') and (n, n ') reactions. The experimental setup consisted of two HPGe detectors with 100% relative efficiency placed at 110 degrees and 150 degrees relative to the direction of the incident proton beam. The incident protons, which had energies ranging from 6 up to 17 MeV, were scattered on a thick quartz (SiO2) target. A Faraday cup was used to integrate the beam current, thus allowing an absolute determination of the gamma production cross sections. We will briefly describe the data analysis procedure, the experimental particularities and difficulties and some preliminary results of the gamma production cross sections for the most intense transitions both in O-16 and Si-28.