Spectroscopic residue detection system and method

摘要

A spectroscopic detection system and method for quantitative measurements of non-volatile residues. A sample to be analyzed is spread out on the inside surface of a cup portion of a unique detector cup. The cup portion mates with a detector portion to create an enclosed reflecting volume. A small port in the detector portion permits entrance of light which diffusely reflects multiple times from the inside surface of the enclosed reflecting volume and which is partially absorbed by the sample depending on the spectral absorption characteristics of the sample. A light detector in the detector portion detects light after multiple reflections from the surfaces of the detector and cup portions and multiple passes through the sample on the surface of the cup portion. Light detected by the light detector is spectrally analyzed to determine the spectral characteristics of the sample. In a preferred embodiment of the present invention the light is infrared light, the diffusely reflecting volume is a sphere, the reflecting surface of the cup is a smooth hemispheric gold surface and the reflecting surface of the detector portion is a rough hemispheric gold surface. In this preferred embodiment light from a broad band infrared light source is directed through an interferometer system prior to entering the detector cup and signals from the light detector are Fourier analyzed along with mirror position data to determine absorption characteristics of the sample.