BSA Flow Software Installation and User's Guide - CSI

Beam spacing The spacing between the beams in the selected beam system, before the
beam expander. This figure is multiplied by the expander ratio to find the
resulting beam spacing at the exit of the beam expander or entry to the front
lens. Used for calculation of the fringe spacing in and dimensions of the
measurement volume.
Frequency shift: The specified frequency is the Bragg cell frequency. This value can positive
or negative according to frequency shift direction. The normal value is
positive. In this case, a positive flow velocity will produce a photo-multiplier
signal frequency higher than the shift frequency.
Negative is used if the optical system is set up to reduce the signal frequency
by an amount corresponding to the shift frequency. It is typically the case if
the velocities are so high that they would produce out-of-range signal
frequencies for the processor, if a positive frequency shift was chosen.
5.5 Optical Calibrated LDA System properties
Dantec Dynamics delivers calibration data on a CD-ROM for certain optical
systems.
The calibration data are automatically installed when inserting the CD-ROM,
if Auto-run is enabled.
The calibration data includes the calibration date, the calibrated fringe
spacing, and nominal values for the optical parameters (wavelength, focal
length, beam spacing, beam diameter). The relevant parameters are
transferred to the Device Configuration, so that the software uses these when
new projects are created.
To see the parameters, start the device Configuration :
Select Optical Calibrated LDA System:
5-28 BSA Flow Software: Project explorer objects