A surface temperature measurement technique for rotating samples is propose
d. It is based on the concept of fluorescence thermometry. The fluorescent
and phosphorescent phenomena have been applied in thermometry for ambient a
nd high-temperature measurement but not the cryogenic domain, which is expl
ored using thermocouple- or platinum resistor-based thermometers. However,
thermal behavior of Yb2+ ions in fluoride matrices seems to be interesting
for thermometry in the range 20-120 K. We present here a remote sensing met
hod which uses fluorescence behavior of Yb2+ ion-doped fluoride crystals. T
he fluorescence decay time of such crystals is related to its temperature.
Since we developed a specific sol-gel process (OrMoSils) to make strongly a
dherent fluorescent layers, we applied the fluorescence thermometry method
for rotating object surface temperature measurement. The main application i
s the monitoring of surface temperature of the ball bearing or turbopump ax
is in liquid propulsion rocket engines. Our method is presented and discuss
ed, and we give some experimental results. An accurate calibration of the d
ecay time of CaF2:Yb2+ versus temperature is also given. (C) 1999 American
Institute of Physics. [S0034-6748(99)04107-6].