OL Series 426-S Low Level Radiance Standard

The OL Series 426-S Integrating Sphere Calibration Standard is designed for accurately calibrating very sensitive microphotometers, image intensifiers, telephotometers, and imaging spectroradiometers for photometric or spectroradiometric response at moderate to extremely low light levels. It serves as a highly accurate, large area, uniform, diffusely radiating source with a near normal luminance that can be varied over nearly six decades with essentially constant color temperature. The OL Series 426-S consists of an OL Series 426-S Optics Head and an OL 400-CS Controller. This enables remote location of either unit that facilitates alignment or positioning of the source with respect to the device to be calibrated. In order to achieve very low radiance levels that can be tracked accurately with a monitor detector, the instrument is based on a dual integrating sphere design. The arrangement of these spheres are in series, with the exit port of the first (primary) sphere producing a uniform beam into the entrance port of the exit (secondary) sphere