Excitation functation for reactions 208 PB(p,n) 208 Bi and 208Pb(p,2n)207 Bi measured with the AFRODITE y-ray spectrometer

Abstract

Excitation functions for the population of 207Bi and 208Bi via the bombardment of a thin 208Pb (lmg/ cm2) target with a proton beam having energies of 11.6, 11.9, 13.2 and 14.8 MeV were measured. The corresponding nuclear reactions are 208Pb(p,n)208Bi and 208Pb(p,2n)207Bi. The y-y coincidence data associated with the above reactions were measured with the AFRODITE array consisting of 8 Clover detectors. The experiment was conducted at iThemba Laboratory for Accelerator Based Sciences (iThemba LABS). The analysis involved: the identification of y-ray transitions associated with the de-excitation of the residual 208Bi and 207Bi nuclei, y-y coincidence relationships and the y intensity measurements. Furthermore, the relationship between the proton incident energy and the intensity of the y-rays for 207Bi and 208Bi was established. The results show that the 208Pb(p,n)208Bi reaction is dominant at Ep = 11.9 MeV, and decreases as the proton energy is increased. The yield from the 208Pb(p,2n)207Bi reaction increases monotonically as the proton energy is increased to 14.8 MeV. The data suggest that the maximum yield for this reaction has not reached, and measurements at higher proton energies would be needed to complete the excitation function.