DOC-0128 Rev F
© 2017 DROPLET MEASUREMENT TECHNOLOGIES
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8.1.2
SS% Calibration Procedure
The CCN temperature is tested with gradients of 3, 4, 6, and 8. The 50% activation point (Figure 24)
for that size of ammonium sulfate is converted from the Köhler curve to a SS%. A linear regression
between the measured SS and the temperature gradient is run on the data and that becomes the
SS% calibration curve for the CCN instrument (Figure 25). The curve is very linear down to 0.1%.
Running SS% below 0.1% will require special calibration and interpretation. (Below 0.1% SS growth
kinetics become very important and can influence the data.)
Calibration parameters:
•
Sample Flow Rate:
45 Vccm
•
Sheath Flow Rate:
450 Vccm
•
Sheath:Sample Flow Ratio:
10:1
Figure 24: Activation Curve Used in SS% Calibration
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Dry Particle Diameter (nm)
3-Degree Activation Curve (500 Vccm, 840 mb)
