Thermal Therapy - RF/Microwave Interaction with Biological Tissues - page 190

PFA

Plastic fiber

Temperature sensing element (fluorescent material)

Optical part of the fluorescent fiber in optical thermometer

Operation
and
control

Photodetector

Red filter

Temperature sensing element
(fluorescent material)

Blue LED

Mirror which penetrates the blue with a red reflection
FIGURE 4.38 Construction of optical fiber thermometer.

LED

waveform

T 1 < T 1 °C

T 1

After grow
integral
luminance

T 2

Fluorescence

and after grow
waveform

m convolution

n

2 1 1 2 3

summing
up

Signal sampling

FIGURE 4.39

Principle of measurement.

is calculated as a result of comparing the mean value of the each afterglow
integral luminance with the known data (reference temperature) by
repeated sampling. The characteristic of the afterglow integral luminance is
shown in Figure 4.39. Specifications of the present sensor are given in
Table 4.3.