Ktv. Grattan et al., Sapphire-ruby single-crystal fibre for application in high temperature optical fibre thermometers: studies at temperatures up to 1500 degrees C, MEAS SCI T, 12(7), 2001, pp. 981-986
In this work, a study of a fibre optic ruby crystal probe exposed to high t
emperatures has been carried out for the first time, and 'annealing' effect
s have been considered and reported upon. The work has enabled the device t
o be studied at temperatures up to 1500 degreesC to test its 'survivability
': the results show that a single-crystal probe is able to operate continuo
usly at temperatures up to 1400 degreesC, and can reliably cover a wide tem
perature measurement range from 0 degreesC to 1400 degreesC. Uncertainties
in the measurement of, at worst, approximately +/-7 degreesC result after m
any hundreds of hours of temperature cycling of the probe.