CONFOCOR
3
ConfoCor 3
Processing
Carl Zeiss
02/2010 M60-1-0025
e
49
9.8.2
Data Handling
The
Data
Handling
panel allows you to specify
the way data will be recorded.
•
Click on the Data handling bar to open the
Data handling panel (Fig. 53). Click again to
close the panel.
All changed settings can be reset to the default
settings by pressing the
Default
button.
You have the following options:
(1) Correlation
The
Correlation
panel allows you to specify, how the raw data will be processed for correlation analysis.
•
Click on the
Correlation
register (see Fig. 53) to open the
Correlation
panel. Click any other register
to leave the panel.
Here you can set the initial binning time, the initial number of direct Tau channels and the maximum Tau
time used for the Multiple Time Algorithm. Adjust the numbers in the
Binning
(in µs),
Maximum
correlation time
(in s) and
Tau Channels
display boxes, respectively. You can either directly enter values
or use the arrows. Default values can be entered individually by pressing the
0.2
,
1000
and
8
buttons.
Please note that with the default settings, the algorithm works the fastest.
The algorithm for auto-correlation functions is as follows. In the first correlation step all events
within a certain correlation interval T are counted. The default T in the first correlation step (n=0)
equals 200 ns, which is 4x the maximum sampling rate of 50 ns, as limited by the dead time of the
APDs and the electronics. T will be changed by the entry in the
Binning
display window. This
corresponds to a clock speed of 20 MHz. Thus, for this correlation interval a maximum of 4 events
can be counted. These events / correlation intervals are shifted against themselves for a time
interval t. The first t equals the first T value, as a default 200 ns = 0.2 ms. t will be changed by the
entry in the
Binning
display window. T is linearly increased by step sizes of 200 ns (or the entered
value) for 8 times (direct tau) and than for another 8 times (multiple Tau), i.e. the maximum
correlation time in the first step is 16 x 0.2 ms =3.2 ms using the default settings. The direct and
shifted events / correlation intervals are multiplied interval for interval and the products are added
together and normalized. The normalization result is defined as: (result x received clocks)/(pulse
2
)
for auto-correlation or (result x received clocks)/(pulseA x pulseB) for cross-correlation. The received
clocks counted equal 4 x the number of correlation intervals, which are defined by the
measurement time. At the end the relevant data for the next correlation step are processed. Here,
the correlation interval is increased by a factor of 2. Hence, the correlation interval (T) in the n-th
correlation step is T= 0.2 ms x 2n for the default settings. The initial lag time for a certain
correlation step corresponds to the last lag time of the previous correlation step added to the
respective correlation interval. This value is then linearly increased 8 times. Therefore after step n,
the correlation or lag time (t) ultimately corresponds to t =16 x 0.20 + 8 x 0.2 x 2n ms. The
doubling of the correlation interval is performed on default 25 times. Thus the maximum is t = 16 x
0.2 + 8 x 0.2 x 225 ms.
Fig. 53
Data Handling panel