BSA Flow Software Installation and User's Guide - CSI

4.10.5 Data rate requirements
Below are some recommendations. For a detailed description, please consult
the Reference guide chapter.
Mean and RMS velocity
4.10.6 Stop criterion possibilities
If you are looking for average quantities such as mean and RMS velocity,
the data rate is not critical, but you should acquire sufficient samples for
reliable statistics. This usually means 1000 - 2000 samples per position, but
depends on the flow characteristics.
To avoid statistical bias, you can use the Controlled Dead Time mode, with
the Dead Time interval set to at least 2 times the integral time scale of the
flow. Alternatively, you can use burst mode and select Transit Time
Weighting in the Moments object.
Time series, spectrum and correlation functions
For this type of results where the dynamics of fluctuations is investigated,
the data rate should obviously be high. If you expect a dominant frequency
in a spectrum, the data rate should ideally be around 2 π times the highest
frequency you are looking for since the spectrum will fall off at a frequency
of mean data rate/2 π. If you cannot achieve such data rate, the optical
system must be optimised in terms of laser power, receiving optics aperture,
and use of forward scatter if possible. Changing from backscatter to forward
scatter typically increases the data rate by at least an order of magnitude.
BSA Flow software includes several stop criteria to stop the acquisition:
• Sample numbers to stop when the acquired sample numbers is reached
(see group properties in chapter 5).
• Acquisition time to stop when the acquisition time is reached (see
group properties in chapter 5).
• Statistical stop criteria to stop the acquisition on the confidence (see
using confidence limits as stop criteria for data acquisition in chapter 5).
• Cyclic phenomena stop criteria to stop the acquisition either on a
number on particles per phase bin or on the cycle numbers (see
Properties of the Cyclic Phenomena Object in chapter 6.
Note Please note that multiple stop criteria can be made inside the same project:
sample number, elapsed time, etc. The acquisition will stop based on the
criterion met first.
4.11 How to add new data to a project
In BSA Application, add the new positions to the position co-ordinates list,
either by typing into the list, or by adding a new region, and using the Mesh
Generator to define the new positions.
Click the Run button. Click Run in the Data Overwrite Warning window. In
the Ready to Acquire… window, select Positions, and specify the indices of
the new positions:
4-62 BSA Flow Software: The user interface