Solid-state fluorescence above 1000c: application to high temperature laser thermometry

Rare-earth doped phosphors are discussed here which exhibit intense fluorescence well above 1000C. This is a rare characteristic for solidstate materials. One immediate application for them is thermometry. For example surface temperatures of rotating components systems in hostile or restricted environments and systems in environments with very high temperature backgrounds are measurable with phosphor thermographic methods. The subject phosphors Y203:Eu LuPO4:Eu YPO4:Eu and LuPO4:Dy provide the capability to extend these methods to very high temperatures. The use of pulsed ultraviolet (UV) laser activation of these phosphors leads to numerous practical application possibilities. The phosphor characteristics plus various fluorescent decay times vs temperature are shown along with discussion of their high-temperature applications. The phosphor thermographic method Several papers in previous ICALEO meetings have described various aspects of the phosphor thermographic method. 13 Since 1982 the method has been used to perform temperature measurements under a variety of conditions. The major elements of the technology include the pulsed activation of a surface layer of phosphor usually by a UV laser and the recording of the characteristic decay of selected fluorescent emission bands. For applications above 1000C the methodology remains basically the same. The added difficulties arise from the need to find and calibrate phosphors that are temperature active in this range and the need to reject any effects from blackbody emissions or other background effects specific to hightemperature environments. L. I. A. Vol.