Isobaric analogue resonances in arsenic-75 (p,p) arsenic-75 and arsenic-75 (p,n) selenium-75 reactions
Paul, E. B.
Master of Arts
The reactions As(p,p)As and As(p,n)Se have been studied at bombarding energies from 3 to 5 MeV. Twelve resonances have been observed in both the (p,p} and (p,n) excitation curves and are identified as isobaric analogues of levels in the odd-odd nucleus As . In the (p,p) measurements, three solid state detectors fixed at laboratory angles of 1°, 12°, and 15° were used to detect the elastically scattered protons, while in the (p,n) measurements both a conventional long counter and a specially designed 4TT counter were used. There is strong evidence for a doublet at proton bombarding energies of 3.6 and 3.11 MeV and four pronounced resonance levels at 4.47, 4.58, 4.67, and 4.75 MeV. The doublet is identified as the ground state isobaric analogue resonance which corresponds to a Coulomb displacement energy of 1.2 MeV. The 1 values of the four states E = 4.47, 4.58, 4.67, and 4.75 MeV were determined and asymmetry in the (p,n) resonance peak was observed and analyzed for the states E^= 4.47 and 4.58 MeV.