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Measurement of ultraviolet radiation is a common issue in many fields of applications. The easy way to approach to ultraviolet measurement is by using broad band probes. Their use should be straightforward, but their calibration is not always simple to be applied in small industrial, test and research laboratories. The paper presents the two main approaches to the calibration of ultraviolet probes, with their related limitation on their use and difficulties in the extension of the calibration to the cases considering radiating source different from the one used in the calibration. Starting from the approach applied at metrological laboratories, an attempt to overcome this problem is presented which takes advantage of the information commonly provided by manufacturer on data sheets of probes and sources, i.e. data easily achievable by all laboratories

Two methods for the measurement of the luminous flux are presented: the first is based on an integrating sphere and a luminous flux standard lamp, the second utilizes an accurate goniometer and an accurate illuminance meter. A comparison between the two methods is carried on for two different light sources: an LED and a halogen source, presenting different luminous fluxes. The measuring procedure and an evaluation of the measurement uncertainties are described for both the methods. The comparison shows a good agreement between the two measuring processes: both of them allow the identification of the luminous fluxes with relative uncertainties of about 1.5%, covering the differences between the luminous flux values. The comparison is considered a valid possibility of verifying the calibration constancy of the laboratory luminous flux and illuminance standards

An accurate goniometer was constructed, being a part of a system that is designed for the measurement of reflecting properties of surfaces. It can be used to orient a surface of the sample under test arbitrarily with respect to the observing direction and the direction of the shooting light beam. The high performance (revolution angle uncertainty equal to 0.1deg), which is required as a specification for the construction, is checked. Particular attention has been given to analyzing the orthogonality among the revolution axes of each goniometer component and their convergence in the goniometer center. The linearity error of each revolution motion has been measured by using a differential method, which proves to be effective in highlighting the small linearity deviation and verifying the uncertainty declared by the manufacturer

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