FIG. 1.

The SA used in the heating experiments. The custom-made SA built at the University of California at San Diego was designed specifically for the Lindberg Blue tube furnace and consists of a quartz tube (2.5 by 31 cm) and a Pyrex glass cold finger (1.6 by 15.5 cm), which are sealed together under a vacuum with a clamp and an O-ring. The total cost of the SA was approximately $400. Several vacuum sublimator designs are also available commercially and can be purchased online from Safety Emporium.