The DALE40 Phototherapy Radiometer is designed for the accurate measurement of light radiation in the blue part of the spectrum from 400-480 nanometers. Phototherapy exposure in this range is used in the treatment of hyperbilirubinemia in newborn children. The DALE40 provides continuous measurement of irradiation by simply placing the detection probe under the phototherapy light (fluorescent lamps only). In addition to verifying output power, the DALE40 saves costs by eliminating premature replacement of lamps. Light measurement is according to the percent response given the wavelength characteristics curve. The detector probe, included with the unit, has a wide angle lens which matches the cosine receiving function of human skin.