PHYS 11 Lecture Notes - Lecture 7: Deuterium, Uranium-238, Thermonuclear Weapon
Document Summary
Occurs when an object is out in intense neutron radiation to mak. Sudden splitting of a large nucleus into unequal nuclei. Passing neutron is absorbed by a nucleus. Nucleus becomes unstable and fissions releasing extra neutrons. Joining of low mass nuclei to make a larger mass nucleus. 1 million electron volts (1 mev) is a unit of energy. When does a chain reaction happen n + 235u -> 2 fission fragment + 2n + energy. Critical mass = minimum mass to sustain a chain reaction. Number of neutrons on average per fission. Energy from 235u fission = energy from (30m mass of u) of tnt. One 235 u fission releases 30 million times energy. Has larger cross section for absorbing neutrons than 235u. N + 239pu -> 2 fission fragments + 3n + energy. Wide range of elements/isotopes made in the star. Natural isotopes are those with long half life. Short lived isotopes are made in acceleration and reactors.
