Slowing Down of Neutrons in Zirconium Hydride

A method based on a power series expansion of the neutron spectrum in time is used to solve the space-independent Boltzmann equation. The coefficients are obtained from a relatively simple recursion formula well suited for numerical calculations. Assuming the atoms of a hydrogenous moderator free when the neutron energy is large, this formula is further simplified. Adopting the Einstein oscillator model and transforming the recursion formula into a matrix equation, the time-dependent energy spectrum of neutrons in zirconium hydride has been calculated with a small computer.