When the workload is light, we like to hone our skills by performing analysis on difficult samples (or at least that's the justification for this particular diversion). During the long winter of 1996-97, we took up the challenge of imaging snowflakes using our scanning electron microscope (SEM). Snow, being both nonconductive and liquid at room temperature, provides some challenges to the microscopist.

We have a JEOL 5800LV, which when operating in “Low Vacuum” mode, can image nonconductive samples without charging. This is achieved by allowing a relatively high pressure in the sample chamber. The air in the chamber ionizes in the beam and neutralizes the charge buildup on the sample.