Real time reflectometer

Abstract

Abstract A real time reflectometer with the particular utility of measuring fairly rapid (transient) changes in the specular reflectance of a sample which is continuously exposed to a perturbing environment containing a fixed radiation source, a fixed detector, a uniformly rotating sample wheel and a uniformly rotating optical wheel. The plane of rotation of the sample wheel and the optical wheel are normal to one another, and the gear drives of both wheels are interconnected and are driven by a single drive motor thereby insuring the alignment of the mirrors contained on the optical wheel with the sample present on the sample wheel. The radiation source generates light directed toward the uniformly rotating sample wheel, said sample wheel containing a test sample and an aperture. Light reflected off the test sample is also reflected from the optical wheel and directed toward the detector. The reflectance value of the reflected light is compared to that of a reference signal established by light passing through the aperture, reflected from the optical wheel and directed toward the detector. Except for the fact that the reference and the sample will have different reflectance values, the optics and the optical path length for the sample reflectance and the reference signals are identical.

Inventors

• 👤 James M. Zwiener

Bibliographic Details