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Summarized manual for FLIM experiments
Figure 148:
3. Make sure that the maximum Peak Count Rate is below the values given in the table
below Table
Laser pulse frequency
(repetition rate)
40 MHz
20 MHz
10 MHz
5.0 MHz
2.5 MHz
Table 21:
The reason for limiting the detection count rate lies in the Pile-up effect that causes an
apparently shorter lifetime at high detection count rates.
For example, using a laser repetition frequency of 40 MHz and a detection count rate of 1
MHz leads to an error of below 1 % for the calculated lifetime. At a 3 MHz count rate, the
obtained lifetime will be 2 % too low. The error induced by the pile-up effect is proportional
to the ratio between the detection count rate and the laser repetition frequency. The
maximum measurement count rate is calculated from the maximum of the time trace
displayed on the tab of the same name (see Figure 148, left). The binning (resolution) should
be set to 1 ms. This allows you to see the changes of the count rate over time.
166
Online monitoring of the photon count rate in the SymPhoTime preview window. Left: Display
of the count rate over time. Right: FLIM image preview specifying the maximum count rate (red
rectangle).
21.
Upper count rate limit for different detectors, in [kcounts/s]
PMA photomultiplier or MPD
Upper count rate limit for FLIM detection with different detectors
APD (MPD)
1000
1000
500
250
125
PE AQR APD
PE APD (AQR)
700
700
500
250
125
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