ASTM E824-10, in its present form, has been found to be incorrectly interpreted, as well as short-circuited in its application to the calibration of UV-A and UV-B radiometers. For example, in 18.104.22.168, it is suggested that the calibration of UV-A and UV-B radiometers be, as one approach, against a standard of spectral irradiance, i.e., a standard lamp. While the language in paragraph 22.214.171.124 suggests that filter correction factors be used per Angstrom & Drummonds article in Applied Optics, circa July 1962, it is almost an afterthought and I have never found a laboratory that uses this correction factor. Even more important is the fact that if filter factor corrections are used, the UV radiometer of interest can only be used to measure lamps based on the same technology, i.e., standard lamps. Furthermore, while paragraphs 5.6 and 6.1.1 admonish the reader to ensure that the spectral response of both the reference and test radiometer must be as nearly identical as possible, it has been found that several testing laboratories have calibrated a UV-B radiometer from one manufacturer using UV-B radiometers from another manufacturer. The Labs argument was that these radiometers were essentially identical. However, they did not know the spectral response functions of either unit and hence propagated significant spectral mismatch errors.
Keywordscalibration; field radiometers; Calibration--nuclear analysis instrumentation; Field radiometers; Pyranometer equipment/method; Solar energy;