Effects of Crystal Growth Environment on Defect Concentrations in Anthracene Crystals

An efficient yet inexpensive crystal growing furnace has been constructed. With this furnace crystals have been grown with helium, argon, nitrogen or xenon as the inert gas heat exchanger. The nature of this inert gas affects the concentration of defects within the bulk of the crystal. Thus, though several crystal parameters are invariant under these conditions, this is not always the case, particularly at low temperatures. A low pressure of helium is found to have the least effect upon these crystal parameters.