The Series 9610 Carbon Dioxide Analyzer provides continuous, unattended measurement of either percent or trace levels of carbon dioxide in other gases. The product is ideally suited for both continuous or spot monitoring requirements. The focal point of the Series 9610 is its state-of-the-art sensor technology that features a next generation NDIR (non- dispersive infrared) measuring system. This carbon dioxide sensor incorporates closed-loop control for enhanced long-term calibration stability. The control signal is generated by means of an optical referencing element that monitors source intensity. This methodology, coupled with a novel source homogenizing gas sampling chamber, yields a system with greatly improved tolerance to changes in the infrared source outputs.