Robust temperature control in the measurement of high temperature vapor pressures

The problem of measuring the vapor pressure of high temperature materials likely to be used in a space environment is considered. The purpose of this experiment is to determine whether these materials are suitable for use as protective coatings for optical components and photovoltaic materials in a space environment. An ultra high vacuum (UHV) chamber is used to measure the vapor pressure of the candidate materials at elevated temperatures up to 2000 K and background vacuum pressures down to 10^-8 Pa. Because the temperature of the sample must be constant during the experiments, an automated temperature control system is designed and constructed. In this paper, the results of the data and the temperature control system are discussed