A workshop was held at NPL in June 1995 in order to form a project consortium on improving the accuracy of ultraviolet radiation measurements in Europe. The workshop finally resulted in an agreed EC 4th framework program SMT4-CT98-2242 “Improving the Accuracy of Ultraviolet Radiation Measurement”. The project was formulated to address the requirement from the European ultraviolet measurement community for higher accuracy UV radiation scales, improved transfer standards for the dissemination of UV scales and for improved instrumentation and methods for the measurement of UV radiation. The project consortium consisted of five national metrology institutes (NPL, PTB, NMi-VSL, HUT, CNAM, BNM-INM and LNE) and two commercial industries (STUK and ASML).
The objectives of this project were:
1. to investigate detectors, filters, and other optical components for use in the ultraviolet with the objective of achieving UV irradiance measurements with an uncertainty between 0.1% and 1%.
2. to establish and compare ultraviolet spectral responsivity scales using new transfer standards, improving base UV scale uncertainties to between 0.1% and 0.3%.
3. to apply the developed knowledge and techniques to improve measurement of solar UV radiation.
4. to develop an enhanced intense UV irradiance meter with improved stability for a demanding industrial application capable of achieving an accuracy of 2%.
State of progress
Filter radiometers were constructed under work package one and were calibrated and verified by different NMI’s. Candidate transfer standard detectors were evaluated for sort term stability with the best photodiodes used to build trap detectors for spectral responsivity scale realization. Spectral responsivity scale realizations using three different methods were completed and also final stability checks and the investigation of discrepancies between derived scales have been completed. Many different optical components and detectors were evaluated for use in an intense UV irradiance meter. Performance of nearly all components tested was disappointing. The final testing and evaluation of the intense UV meter units has been completed. An improved calibrator has been built and tests indicate that it is functioning to the target specification. Succession of this EC Euromet project is found in Euromet program 437 on the improvement of UV transfer detectors (participating countries DE DK ES FI FR NL SE GB US HU). A workshop is to take place at NPL on June 12 - 14, 1995 where the participants will discuss the possibilities for submitting projects to the EU 4th Framework Programme. The main headings will be UV radiometry, Fibre optics, Lighting and Colorimetry.
Progress report submitted in May 2004.