neutron howitzer
英[ˈnu:ˌtrɔn ˈhauitsə]美[ˈnuˌtrɑn ˈhaʊɪtsɚ]
The name neutron howitzer was given to a neutron source that was developed after it was discovered in the 1930s that alpha radiation that strikes the beryllium nucleus would release neutrons. The high speed of the alpha is sufficient to overcome the relatively low Coulomb barrier of the beryllium nucleus,the repulsive force due to the positive charge of the nucleus, which contains only four protons, allowing for fusion of the two particles, releasing energetic neutrons.