Development of in situ real-time sensor for molecular contamination

Organic contamination is a major problem in the space industry, particularly for satellite optical devices. Although the standards governing this problem are extremely strict, there is no efficient method to measure the in situ, real-time deposition of organic contaminants. An original method based on thickness measurement is reported and tested in this paper. The use of microwave transduction allows to estimate the thickness of paraffin oil and silicone oil deposits from a few nanometers to several hundred nanometers in a low-pressure (mbar) environment. A linear response of the microwave sensor as a function of contaminant layer thickness is thus evidenced for both silicone and paraffin oils, paving the way for the integration of this method as an on-board contamination detection device.