Stabilization of sample temperature in a surface-science vacuum chamber to 0.03 K and quartz-crystal microbalance frequency to 0.06 Hz over 0.5 h.

Improvements have been made to a high-stability quartz-crystal microbalance for use in a typical surface-science, ultrahigh vacuum chamber, with a frequency stability of one part in 10(8) (0.06 Hz) over 0.5 h. This gives a resolution equivalent to 2% of an atomic monolayer of oxygen over 0.5 h. The quartz-crystal microbalance (QCM) crystal can be rotated to different surface-analysis positions in the chamber. These characteristics open up the combination of surface and bulk adsorption studies on the same sample without transferring the sample to another chamber. To accomplish this, it was necessary to stabilize the sample temperature to ±0.03 K over several hours. The oscillator performance is illustrated by the uptake of oxygen by a gold-plated QCM crystal.