Standardisation of luminescence life-time decay measurement for thermal mapping

"Sensor Coating Systems Ltd (SCS) has developed an innovative temperature measurement technology for harsh industrial applications. The technology is based on the luminescence properties of a special material that has been also developed by SCS. This material is applied as a paint or a coating on the surface of the parts to be measured and it is called Thermal History Paint (THP) or Thermal History Coating (THC) respectively. The coated components are then used in standard operation conditions where they exposed to high temperatures. By measuring the luminescence properties of the components and performing a sophisticated calibration method, the past maximum temperature of the component can be calculated.

The principle behind the temperature measurement is that when the THP or THC material is exposed to high temperatures, its structural properties are permanently changed. These structural changes are correlated with the lifetime decay (LTD) of the luminescent signal that is emitted by the material when it is illuminated by an excitation source of appropriate wavelength. The LTD signal is then measured using a custom-made readout system developed by SCS before it is calibrated against temperature. The readout device consists of collimation optics, a photodetector, a data acquisition system and in-house developed software that is used to record and analyse the recorded signals. A number of these readout devices have been built using the same modular approach, but it has been found that identical devices are sometimes produce different results.

Recent efforts have been focused on fully homogenise all the measurement devices and make steps towards the standardisation of the SCS technology. The objective of this project is to review the existing SCS measuring and signal processing system and develop a standard calibration device that could be used to homogenise all measurement devices. We are also aiming to identify and fully characterise measurement parameters in a quantitative way in order to improve the robustness and reduce the uncertainty of the measurement. Working closely with a leading measurement organisation with highly trained stuff and cutting-edge facilities such as NPL, will be greatly beneficial for SCS, as it will be introduced to the best measurement standards and practices. This project will be a great opportunity for SCS to fine-tune its measurement and analysis approach and further develop their technology towards a fully certified and commercial product."