The idea of the atomic fountain was first proposed in the 1950s by Jerrold Zacharias. Zacharias attempted to implement an atomic fountain using a thermal beam of atoms, under the assumption that the atoms at the low-velocity end of the Maxwell–Boltzmann distribution would be of sufficiently low energy to execute a reasonably sized parabolic trajectory. However, the attempt was not successful because fast atoms in a thermal beam struck the low-velocity atoms and scattered them.