Molecular tagging thermometry with adjustable temperature sensitivity

We report an extension to the technique of molecular tagging thermometry which allows for adjustable temperature sensitivity. The temperature dependence of laser-induced phosphorescence of the water-soluble phosphorescent triplex (1-BrNp MbCD ROH) is used to conduct temperature measurements in aqueous flows. It is shown that the temperature sensitivity of phosphorescence intensity can be adjusted by changing the time delay between the laser excitation pulse and the start of the phosphorescence emission acquisition. For example, for a phosphorescence integration period of 1 ms, the temperature sensitivity of the measured phosphorescence intensity varies in the range 8.15– 18.2% per C at 25 C as the time delay changes from 1 to7 ms. This temperature sensitivity is much higher than that of most fluorescent dyes used for temperature measurements (e.g. less than about 2% per C for Rhodamine B). The implementation and application of this new approach are demonstrated by conducting temperature measurements in the wake of a heated cylinder.