Analysis of intermediate-energy (γ,n) reactions in complex nuclei

An analysis of the available experimental data on (γ,n) reaction cross sections at intermadiate energies was made in order to obtain their dependence on the mass number A sub(t). The results were compared with those obtained by means of a Monte Carlo calculation based on photon-initiated intranuclear cascades. A relation has been established between the cross sections of elementary processes (pion photoproduction on single nucleon and Levinger's quasideuteron photodisintegration) and the (γ,n) probability. Cross section formulas have been obtained which give an A sub(t)-dependence of the type aA sub(t) sup(b), with b = 0.86 and 'a' approximately equal to the cross sections of the elementary processes γ+n → n+π0 and γ+p → n+π+. These formulas reproduce almost all known experimental cross sections within a factor of 2, which seems to be rather good accuracy in view of the large range covered by both cross sections values and target mass numbers