A setup for simultaneous many-angle measurements of elastic backscattering cross sections

A scattering chamber is described, which was constructed and installed at the KN3000 Van de Graaff accelerator in Florence, for a systematic study of proton and alpha elastic backscattering cross sections on light nuclei, as a function of both bombarding energy and scattering angle. Sixteen silicon detectors, which can be cooled down to LN2 temperature, have been mounted at backward angles from 95° to 170°. Test measurements show that an overall accuracy of the order of 1–2% is attainable for the cross section values. These measurements also point out that special care should be devoted to the determination of the effective target thickness under beam bombardment.