In a Nuclear reactor a neutron of high speed(typically 10^7 m/s) must be slowed to 10^3 m/s so that it can havea high probability of interacting with isotope of Uranium (AtomicNumber:92 , atomic mass:235) and causing it to fission. Show that aneutron can lose most of it's kinetic energy in an elasticcollision with a light nuclei like deuterium or carbon which has amass of only a few times the neutron mass. the material making upthe light nuclei, usually heavy water (D2O) or graphite is called amoderator
Note ( Deuterium has mass 2m and carbon has mass 12mwhere m= mass of neutron)
