Malvern Instruments Spraytec, User Manual

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.
Automatic – selecting this option enables an automatic algorithm designed
to automate the selection of the first detector when beam steering is known
to be a problem. The algorithm sets the first detector to the detector num-
ber at the scattering minimum between the beam steer signal and the parti-
cle scattering signal. The Beam Steering section above has more details.
.
No Extinction Analysis (if available) – when measuring very fine mate-
rials, the Spraytec software can use the amount of light extinguished by the
sample as a data point in order to improve the sub-micron resolution. This
option can only be used if the measurement path length is correctly set in
the Spray Profile options (Chapter 10). By default this option is disabled.
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N o t e
. Excluding detectors from the analysis limits the dynamic range of the
analysis. Do not exclude detectors unless it is known that an issue such
as beam steering or vignetting has affected the results.
Scattering threshold
The Scattering Threshold defines the number of scattering units that must be
reported on a single detector before the response from that detector is included in
the analysis. The threshold is set to 1 by default. In applications where a
significant amount of optical noise is observed users can increase the threshold.
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N o t e
. Increasing the detector threshold impacts the accuracy of the reported
size distribution. In particular, it may affect the reported distribution
width, as the small signals associated with particles at the limits of the
spray size distribution may be excluded from the analysis.
C H A P T E R 6
S p r a y t e c
P a g e 6 . 2 4
M A N 0 3 6 8