Proton hole states excited by monoenergetic gamma quanta

Abstract

Abstract.Earlier work has shown how information about the giant dipole resonance and proton hole states can be inferred from high resolution photoproton spectra obtained in irradiation with the 17.62 MeV gamma quanta produced by the ~Li(p, 7)SBe-reaction. To exploit this method the high energy photoproton spectra from 45Sc, 51V, 59Co, 5SNi, 63Cu and natural nickel have been measured with 60-120 keV resolution. The absolute cross sections for transitions to levels in the daughter nucleus have been determined. The results are compared with a simple model assuming a semidirect reaction proceeding via a dipole doorway state. Good correlation is found between the cross sections and the spectroscopic factors measured in proton pick-up reactions. Comparison with the total photoproton cross section for 5SNi indicates, however, that the majority of protons are emitted at lower energies from more complicated states.

Some (?, 1p � n) reactions in118Sn at intermediate energies

“…However, the equality of the isomeric ratios calculated by Hummel with a knock-out model and with a compound nucleus model for 24 MeV bremsstrahlung makes it difficult to draw any conclusion about the reaction mechanism. The best way to test different reaction theories in this low energy region is probably high resolution measurements of the energy and angular distributions of particles emitted, since these quantities are more sensitive to the reaction model proposed than the isomeric cross section ratio [24].…”