Zeiss LSM 880 Operating Manual page 231

LSM 880
together and normalized. The normalization result is defined as: (result x received clocks)/(pulse
for auto-correlation or (result x received clocks)/(pulseA x pulseB) for cross-correlation. The received
clocks counted equal 4x 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.
(2) Count rate
The Count rate panel allows you to specify the
binning time used for the count rate trace.
• Click on the Count rate tab to open the Count
rate panel (Fig. 292). Click any other tab to
leave the panel.
You can either check the Automatic check-box, in
which case dynamic binning will be applied, or you
can de-activate the check box and enter a number
of a constant binning time (in ms) in the Binning
display window. You can either type in values or
use the arrows. Units are displayed at the right of
the display box. The default value of 1 ms can be
selected by pressing the 1 button.
If Automatic count rate binning is applied, the system averages three data points and rebinds
then data in dependence of the measurement time. The diagram will have a mean with
fluctuations above and below the mean. In constant binning, data points are not averaged. This will
result in a baseline with fluctuations above.
In (automatic) dynamic binning the count race trace will be adjusted to the measurement length.
The count rate trace represents the averaged binned count rate versus measurement time, in other
words photons / second therefore intensity. The bin window in dynamic binning now depends on
the measurement time, whereby the bin window doubles, if 500 values are exceeded. In the first
step, the binning time is 3.2 ms. For the next steps, the binning time (t
The measurement time (t
x 500 x 2n. In automatic binning mode, the Binning display window and the 1 default button will
not be accessible.
10/2014 V_01
CHAPTER 1 - SYSTEM OPERATION
Left Tool Area and Hardware Control Tools
), at which the binning time doubles is calculated according to t
d
000000-2071-464
Fig. 292 Correlator tool - Count rate active
) becomes t
r
ZEISS
2
)
= 3.2ms x 2n.
r
= 3.2 ms
d
225