(a) Obtain the de Broglie wavelength of a neutron of kinetic energy 150 eV. As you have seen in Exercise 11.31, an electron beam of this energy is suitable for crystal diffraction experiments. Would a neutron beam of the same energy be equally suitable? Explain. (mn = 1.675 x 10-27 kg)
(b) Obtain the de Broglie wavelength associated with thermal neutrons at room temperature (27 C). Hence explain why a fast neutron beam needs to be thermalized with the environment it can be used for neutron diffraction experiments.