Fermi's Contributions
  • Fermi attempted to create **transuranic elements ** after Chadwick's discovery of the neutron by bombarding Uranium with neutrons.
  • However, instead of making larger elements like he wanted to, he instead got several smaller products.
(1)
\begin{align} U235 + n \rightarrow U236 \end{align}
(2)
\begin{align} U236 \rightarrow Kr92+Ba141 + 3n \end{align}
  • What he had observed, was in fact nuclear fission
  • It was then repeated by Hans and Stressman, who found the same results.
  • He also found that slow neutrons worked better.
  • By 1933, Fermi proposed that the process of Beta decay which changes the atomic number of atoms.

Fermi pronounced that protons may turn into neutrons and neutrons into protons but only through undergoing beta decay.

There were two types of decay:

Beta negative decay: (Electron released)

Neutron decays into a a proton, beta particle and anti-neutrino

Beta positive decay: (Positron released)

Proton decays into a neutron, beta particle and neutrino.

The announcement of Beta decay and the existence of a neutrino was quashed by the predictions that the neutrino would at best be hard if not impossible to detect as it had the following features:

neutral
almost massless or massless
extremely small