BSA Flow Software Installation and User's Guide - CSI

Figure 5-75: FiberPDA phase plot.
A typical phase plot for a FiberPDA is shown in Figure 5-75. The displayed
phases are measured phase differences which are corrected by the phase
offset determined during phase calibration. The diagonal continuous line
represents the theoretical relationship between the two phase differences for
perfectly spherical particles. To account for a finite accuracy of the system, a
certain deviation from the ideal line has to be tolerated. Therefore, a
tolerance band, indicated by the two dashed lines, is defined. The width of
this tolerance band can be set by the user by changing the value of the
parameter Spherical validation band in the PDA Receiver menu.
Every single measurement is displayed in the phase plot as a colored dot.
Validated samples (samples inside the tolerance band) are displayed as blue
dots. Rejected samples (samples outside the tolerance band) are indicated by
red dots on Figure 5-75.
With optimized optical alignment and correct parameter settings, a cloud of
dots will build up centered around the continuous line and mostly within the
tolerance band. Poor alignment or e.g. wrong setting of the fringe direction
will be indicated in the phase plot by a more or less significant deviation of
the data points from the theoretical line.
The phase plot also provides some information about the sphericity of the
measured particles. Whereas the FiberPDA has only a rather limited ability
to detect non-sphericities, the DualPDA is significantly more sensitive to
distinguish deformed droplets. This is due to the different detector
arrangements.
For the FiberPDA, ClassicPDA the maximum phase difference between
detectors U1 and U3 is set to a default value of 260 degrees. This is due to
signal visibility reasons. For the DualPDA the maximum phase of the planar
PDA (V1-V2) is set to a default value of 260 degrees.
Figure 5-76: example of phase plot with a wrong fringe direction settings.
The Phase plot properties are diplaid in the properties windows and include
Data properties, Scale properties and Display properties:
BSA Flow Software: Project explorer objects 5-83