Browsing by Author "Abdela, Awel"

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    Neutrons and Production of Neutrons of Various Energy
    (Addis Ababa University, 2013-06) Abdela, Awel
    Neutrons are normally bound into an atomic nucleus, and do not exist free for long in nature. The unbound neutron has a half-life of just under 15 minutes. The release of neutrons from the nucleus requires exceeding the binding energy of the neutron, which is typically 7-9 MeV for most isotopes. Neutron sources generate free neutrons by a variety of nuclear reactions, including nuclear ssion and nuclear fusion. Whatever the source of neutrons, they are released with energies of several MeV. Neutrons are found bounded inside a nucleus of an atom, almost all elements in pe- riodic table contains at least one neutron bounded inside their nucleus except ordinary hydrogen atom which contains only one proton inside its nucleus. Free neutrons do not occur naturally, so they have to be created arti cially. If one needs neutrons of di erent energy for any purpose he should extract neutrons from the nucleus of certain element by imparting energy to it.The minimum energy needed by a nucleus to emit one neutron is nearly equal to the binding energy of a neutron, approximately around 7Mev. As neutral particles with an average lifetime of 15 minutes they cannot be stored or accelerated like charged particles. Therefore neutrons have to be created with energies higher or equal of the intended treatment energy