Nuclear Photodisintegration

Study of the neutron flux generated at E-linac-driven neutron sources

“…Now we are to acquire the photoneutron distributions (1.12) associated with each photoabsorption reaction. A lot of experiments on the energy and angular distribution of the GR photoneutrons proves that γ rays mostly produce the statistical neutrons, though there exists a small, yet discernible, fraction χ(k) of nonstatistical, ®direct¯neutrons as well (see, for instance, [13]), which shows up to be substantial at high photoneutrons energies, ε 3 MeV. As is generally received for the reactions with E γ ∼ E GR [14], a nucleus remaining after direct neutron emission would never emit an additional neutron, yet the remainder of excitation energy is released as γ rays.…”

“…As is known, the statistical model fails to account completely for the observed photoneutrons energy and angular distribution [13]. The fraction χ(k) of the pre-equilibrium, resonant-direct neutrons increases with the photon-energy E γ growth, and one can infer from theˇndings of [17] that the linear relationship…”

“…4. As a dipole state is primarily excited by the γ-rays absorption, the angular distribution of pre-equilibrium, resonant-direct neutrons proves to be of the form 1 + C(ε) sin 2 (θ) [13]. From the data presented in [17], one can derive the plausible estimations: C(ε) = 0 at ε < e = 2.5 MeV, and…”

Quasi-Deuteron Model and the Internal Momentum Distribution of Nucleons inC12

“…cross section from hydrogen is by several orders of magnitude larger than the free deuteron photodissociation cross section. [10][11][12][13][14] In the light of the impulse approximation 15 and the available experimental data on photopion production cross section (see, for example, reference 13), we can assume that the highenergy photonucleon production process goes via the pion-production-reabsorption channel, as is well known in the case of the free deuteron photodissociation (see, for example, reference 14). If the reabsorption process were random, one would expect an isotropic distribution for the emitted nucleons.…”