1. AQT90 FLEX Service Training
Optical Unit
21/04/2019
RADIOMETER A/S
RADIOMETER PRESENTATION

2. 21/04/2019
RADIOMETER PRESENTATION
Photometer
Photodiode measures actual excitation energy, used for correction of measured counts

3. Measurement Cycle MEASUREMENT CYCLE
21/04/2019
RADIOMETER PRESENTATION
Measurement Cycle
MEASUREMENT CYCLE
UV light pulse is focused onto the sample
Europium is excited
Europium relaxes and emits red light
Red emission is focused onto the detector through a narrow band pass filter
Typically cycles per measurement
MEASUREMENT CHARACTERISTICS
Lowest light about 1 fW
Lowest count ~
Dynamic range
Precision is limited by the number of photons counted
CRITICAL ISSUES
Sensitivity
Background phosphorescence
Dark counts

4. 21/04/2019
RADIOMETER PRESENTATION
Measuring

5. 21/04/2019
RADIOMETER PRESENTATION
Measuring - Reference
During this measurement the photo count is high (> ) requiring fewer cycles (=1000) to obtain a precise result.
After excitation the europium emits light with a decreasing intensity as shown. The time constant for the decay, Tau, must be in the range [800 ; 1200] for measurements on the reference cup

6. 21/04/2019
RADIOMETER PRESENTATION
Measuring - Dark
During this measurement the photo count is very low (<20) requiring a large number of cycles (=3000) to obtain a precise result.
The flashlight is off (low integrator value).
The output is constant (except for noise).
Since there is no decay, Tau should in principle be indefinite, which it is here (“NaN” means “Not a Number”). However, the low number of counts and the noise decreases the accuracy of the calculation, so almost any number could appear here.

7. Optical Unit RADIOMETER PRESENTATION
End of session
Optical Unit
21/04/2019
RADIOMETER A/S
RADIOMETER PRESENTATION