UV sensors are typically very sensitive to aging and solarization effects of the harsh environment in which they are used. Minimizing the long term effects of UVon a sensor/optics is extremely challenging, especially with on-line installed sensors used for continuous monitoring on a 24/7 basis. This paper describes a patented method of reducing the effects of aging and solarization to a minimal amount so a user can monitor and control a curing process with a robust, stable and consistent sensor. Thispaper reviews the impact of radiation (UV, Visible, IR) on the optical components (photodiodes, optical filters) in a sensor and presents the test data showing sensor performance over thousands of hours of operation with little or no deterioration.