Breakup of carbon 12

For the ¹²C (n, n'2$\alpha$) ⁴He reaction the first step is inelastic scattering, with the residual either at a discrete excitation level or treated as an average of a continuum. In the case of discrete excitation we are given angular distributions and the excitation level, and we use (11) based on discrete two-body kinematics to calculate the average energy of the secondary neutron. For the continuum we are given energy distributions, and we use the integral (16) to calculate the average secondary neutron energy.

The remaining energy is split equally between the three alphas. The endep code writes a file of pairs

(E_yi, 2$$\langle$$E_yo$$\rangle$$)

for two of the alphas ( $\tt yo$ = 6), and it writes a file of pairs

(E_yi,$$\langle$$E_yo$$\rangle$$)

for the residual alpha ( $\tt yo$ = 16).

Note that ENDL also contains energy distributions for both types of alphas. The code therefore checks for consistency of the average energies.