PAT Training Course Light Scattering

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PAT Training Course- Light Scattering

• Determine Particle Size, Shape and Denisty

I gratefully acknowledge Rich Becker of Lasentec
for use of these slides
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FBRM Focused Beam Reflectance Measurement

• FBRM provides a precise and sensitive measurement
  that allows the user to quantify, in process and
  in real time, the degree and rate of change to
• Particle dimension
• Particle population
• Particle shape
• FBRM data is typically implemented through a
  direct correlation to the product or process
  parameter of concern.

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FBRM in Early Stage Process Development
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FBRM in Late Stage Process Development
FBRM
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FBRM in Pilot and Manufacturing Environments
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The FBRM Measuring Zone
A. Side View of Probe Tip
C. Cutaway View of Probe Tip
B. Front View of Probe Tip
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FBRM Method of Measurement
The focused beam will cross the particle or
particle structure on a straight line between
any two points on the edge of the particle or
structure. The distance between these two
points is a chord length. Hundreds of
thousands of chords are typically measured and
counted per second, producing a robust Chord
Length Distribution.
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Unweighted vs. Weighted Distributions
Both graphs show the same data. Below, the
distributions are number-weighted. To the right,
the distributions are volume-weighted.
In this example, the weighted distribution
(similar to a volume Laser diffraction
measurement) does not detect small changes in the
concentration of fine material. The Unweighted
distribution is very sensitive to the amount of
fine material present.
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Typical FBRM Application Crystallization
Nucleation of two different polymorph forms
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Particle Size Data presentation drives
interpretation

• The four graphs at the right represent the same
  data set.
• The data presentation method, particle size by
  number, length, area, or volume determines the
  sensitivity to change in different regions of the
  of the particle population.
• Number distributions are typically more sensitive
  on the fine side, Volume distributions such as
  typically presented with laser diffraction are
  more sensitive on the course side.

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Particle Size What is important for a given
application?
One 100-µm particle (A) contains the same
quantity of material as one-thousand 10-µm
particles (B). But B has 10 times the surface
area