Neutron Diffraction:

• Neutron was discovered in 1932 & their (de-Broglie) wave properties were proven in 1936.

Energy: E = (p²)/(2m_n)

Momentum: p = (h / λ)

λ = Wavelength , m_n = 1. 67 × 10^-27 kg

• Wavelengths needed for crystal diffraction are of the order of

λ ~ 1Å

• So this gives neutron energies of

E ~ 0.08 eV

This is of the same order of magnitude as the thermal energy at room temperature, k_BT ~ 0.025 eV. Hence, these are typically called as thermal neutrons.