Laser-induced fluorescence of phosphors for remote cryogenic thermometryRemote cryogenic temperature measurements can be made by inducing fluorescence in phosphors with temperature-dependent emissions and measuring the emission lifetimes. The thermographic phosphor technique can be used for making precision, noncontact, cryogenic-temperature measurements in electrically hostile environments, such as high dc electric or magnetic fields. The National Aeronautics and Space Administration is interested in using these thermographic phosphors for mapping hot spots on cryogenic tank walls. Europium-doped lanthanum oxysulfide (La2O2S:Eu) and magnesium fluorogermanate doped with manganese (Mg4FGeO6:Mn) are suitable for low-temperature surface thermometry. Several emission lines, excited by a 337-nm ultraviolet laser, provide fluorescence lifetimes having logarithmic dependence with temperature from 4 to above 125 K. A calibration curve for both La2O2S:Eu and Mg4FGeO6:Mn is presented, as well as emission spectra taken at room temperature and 11 K.
Document ID
19920042186
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Beshears, D. L. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Capps, G. J. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Cates, M. R. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Simmons, C. M. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Schwenterly, S. W. (Oak Ridge National Laboratory TN, United States)