The Surface Effect of Sodium Iodide Scintillators

The response of NaI(Tl) crystals to $\alpha$-particles originating outside of the crystal was compared to that of $\alpha$-particles originating within the crystal in order to determine any possible surface effects of the crystal. It was found that any such effect, if present, is too small in magnitude to explain the nonlinearity of response of NaI(Tl) crystals to $\alpha$-particles of energy less than 8 Mev.