EURAMET PRK KEY COMPARISON K6 SPECTRAL REGULAR TRANSMITTANCE

In October 1999 thirty-eight Member States of the Metre Convention and representatives of two international organisations signed the Mutual Recognition Arrangement (MRA)1. Now the list of signatories of the Mutual Recognition Arrangement has 45 Members States, 20 Associates of the CGPM and 2 international organisations. A particular aspect of the MRA is the organisation of international comparisons of measurements, to be known as key comparisons. They are introduced, organised and processed according to guidelines which ensure the equivalence of values assigned to transfer standards by different National Metrological Institutes (NMIs). The aim of this first key comparison in this field was restricted to check only the accuracy of the radiometric scale of the reference spectrophotometers of National Metrological Institutes. ∗ The comparison will be a star type comparison with the samples provided by the pilot laboratory and sent out to all the participants at the same time. ∗ The filters will be coloured glass filters plates 50 x 50 mm2. ∗ The nominal transmittance will be approximately 92%, 56%, 10%, 1% and 0.1%. ∗ The wavelengths of measurement should be 380, 400, 500, 600, 700, 800, 900 and 1000 nm.