Phosphor thermometry at cryogenic temperatures

Abstract

The temperature dependence of the lifetimes of two phosphors, La2O2S:Eu and Mg4FGeO6:Mn, is presented from 300 to 11 and 140 to 8 K, respectively. Emission from the D35 state of La2O2S:Eu reveals a strong temperature dependence from 11 to about 130 K, where the signal becomes too weak to measure accurately. Emission from the F24 state of Mg4FGeO6:Mn changes throughout the temperature range measured. Both of these materials are used for higher temperature thermometry applications. This work illustrates their utility down to liquid helium temperatures.