Compute the final energy from the final wavelength.
The result is
\[E_f = \frac{h^2}{2 m_n \lambda_f^2}\]
Where \(m_n\) is the neutron mass and \(h\) the Planck constant.
- Parameters:
final_wavelength (Variable) – Final neutron wavelength \(\lambda_f\).
- Returns:
Variable – Final energy \(E_f\).
Has unit meV.
