Bombarding atoms with electron gun?
Well, I think, in principle, depending on the energy of electrons, different events can happen, but in the classical experiment electrons will diffract from the spacing within crystal lattice of gold in the foil.

P.S. The experiment is actually very well known in the history of science due to the following reason (quoted from here).


  It is interesting to recall that G.P. Thompson, who shared the 1937
  Nobel Prize with Davisson for these experiments which proved that
  electrons are waves, is the son of J.J. Thompson who received the
  Nobel Prize in 1906 for proving that cathode rays were actually
  particles - electrons! And the amazing thing is that they were both
  right.