Study on Gamma Emission Mechanism in Exciton Model—A Unified Compound Pre-Equilibrium Model(1)

Abstract

To study the descriptions of nuclear pre-equilibrium and equilibrium processes, a unified compound and pre-equilibrium model including not only particles but also -ray emissions is developed. The -ray emission mechanism is studied first. The calculated -ray emission cross-section and spectrum of fast neutron bombarding are in good agreement with experimental data.

Low-Energy Exciton-Model Limit for the Gamma Emission

“…Therefore, the difference made in this aspect in Ref. [3] between our approach and the giant resonance model is not sufficiently justified (Of course, there is a significant difference between the Lynn model' 22 ' and that of us' 11 ', but not in the form of the giant resonance, which enters both of them). The third model investigated in Ref.…”

“…In this respect, the approach of Ref. [3] is not fully consistent, because the authors use different mechanisms for the particle and the 7 emission from the second nucleus (that after the emission of the neutron).…”

“…The third model investigated in Ref. [3] is the Weisskopf compound nucleus model (see, e.g., Ref. [23]), which is clearly the most simple one, and probably it is fully sufficient at the energies considered.…”

“…However, the coefficient in the emission rate should vary as A 2 / 3 , and cannot therefore change by more than a factor of 2 between 184 W and 208 Pb, as one could fioid in Table 1 of Ref. [3].…”

“…However, several attempts at much lower energies can be traced in the literature. Calculations go as down as to 3 MeV incident neutron energy' 3 ' or 5 MeV incident proton energy' 4 ', and some very rough considerations are even much lower' 5 '. A special interest in this region is the possibility of suitable description of the 7 emission at low excitation energies, as emphasized also in a recent paper within this journal' 3 '.…”