The 818-RAD Irradiance and Dosage Sensor replaces traditional radiometeric sensors which are calibrated to specific wavelength or bands such as UVA, UVB, UVC, or Photopic. It is deal to measure the radiant flux per unit area for a large area uniform light source. It offers calibration over a broad spectral range, which the user can access by entering any wavelength in the calibration range. 818-RAD is a general purpose circular geometry photodiode with an 8mm aperture and a cosine corrected diffuser. Its spectral range is 200 - 850 nm and its irradiance measuring range is 100 nW/cm² - 250 mW/cm². The sensor has a 1.5 meter length cable for connecting to a power meter. It has a 1/4-20 tapped hole for post or plate mounting. The product includes a 2.25 inch long 1/2 inch diameter post with a 1/4-20 tapped hole on both ends.