Inelastic Scattering

For inelastic scattering, the currently supported final states are (nA \(\rightarrow\)) n\(\gamma\)s (discrete and continuum), np, nd, nt, n³He, n\(\alpha\), nd2\(\alpha\), nt2\(\alpha\), n2p, n2\(\alpha\), np\(\alpha\), n3\(\alpha\), 2n, 2np, 2nd, 2n\(\alpha\), 2n2\(\alpha\), nX, 3n, 3np, 3n\(\alpha\), 4n, p, pd, p\(\alpha\), 2p d, d\(\alpha\), d2\(\alpha\), dt, t, t2\(\alpha\), ³He, \(\alpha\), 2\(\alpha\), and 3\(\alpha\).

The photon distributions are again described as in the case of radiative capture.

The possibility to describe the angular and energy distributions of the final state particles as in the case of fission is maintained, except that normally only the arbitrary tabulation of secondary energies is applicable.

In addition, we support the possibility to describe the energy angular correlations explicitly, in analogy with the ENDF/B-VI data formats. In this case, the production cross-section for reaction product n can be written as

\[\sigma_n(E, E', \cos(\theta))~=~\sigma(E)Y_n(E)p(E, E', \cos(\theta)).\]

Here \(Y_n(E)\) is the product multiplicity, \(\sigma(E)\) is the inelastic cross-section, and \(p(E, E', \cos(\theta))\) is the distribution probability. Azimuthal symmetry is assumed.

The representations for the distribution probability supported are isotropic emission, discrete two-body kinematics, N-body phase-space distribution, continuum energy-angle distributions, and continuum angle-energy distributions in the laboratory system.

The description of isotropic emission and discrete two-body kinematics is possible without further information. In the case of N-body phase-space distribution, tabulated values for the number of particles being treated by the law, and the total mass of these particles are used. For the continuum energy-angle distributions, several options for representing the angular dependence are available. Apart from the already introduced methods of expansion in terms of legendre polynomials, and tabulation (here in both the incoming neutron energy, and the secondary energy), the Kalbach-Mann systematic is available. In the case of the continuum angle-energy distributions in the laboratory system, only the tabulated form in incoming neutron energy, product energy, and product angle is implemented.

First comparisons for product yields, energy and angular distributions have been performed for a set of incoming neutron energies, but full test coverage is still to be achieved. In all cases currently investigated, the agreement between evaluated data and Monte Carlo is very good.