Beckman Coulter Multisizer 4, User Manual

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PN A51387A
B
4-14
Selecting Analysis Settings: SOM and SOP
Using a Standard Operating Method (SOM)
Click
(
Defaults
)
to set current and gain, and sizing threshold, automatically, based on the aperture
size.
In the SOM Wizard, click
(
Next
)
to proceed to the next step.
Using the Current & Gain Tab in the Edit the SOM Window
The Edit the SOM / Current & Gain tab differs from the SOM Wizard / Threshold, Current and Gain
window. Unlike the Wizard, the Edit the SOM / Current & Gain tab allows you to interact with the
Table 4.5 Threshold, Current and Gain (Step 5): Entries or Selections
In the field... Enter or select...
Sizing Threshold The size above which particles are counted (or the lower limit of a size
distribution). If the size entry is high or low, a warning message is displayed
as follows:
“Low” message is displayed for sizes less than 1.9% of aperture diameter
“Too Low” message is displayed for sizes less than 1.5% of aperture
diameter
“High” message is displayed for sizes greater than 20% of aperture
diameter
“Too High” message is displayed for sizes greater than 50% of aperture
diameter
NOTE
This setting cannot be changed during or after an analysis.
Aperture Current
The current that will pass through the aperture. Click
(
Defaults
)
to set the
current and gain automatically for the aperture size you are using. If the
aperture current entry is high or low, a warning message is displayed as
follows:
“Low” message is displayed for sizes less than 100
µ
A
“Too Low” message is displayed for sizes less than 10
µ
A
“High” message is displayed for sizes greater than 800
µ
A when measuring
cells
“High” message is displayed for sizes greater than 3200
µ
A
“Too High” message is displayed for sizes greater than 6000
µ
A
If you are using a small aperture, current set too high can damage the
aperture. For information on small aperture settings, see
Using Small
Aperture Tubes (20 µm and 30 µm) , page 3-4 .
Preamp Gain
The amplification factor. Click
(
Defaults
)
to set the current and gain
automatically for the aperture size you are using.
Extended Size Range Controls what happens if particles larger than 60% of the aperture diameter
are detected. You can specify the large particle count either as an absolute
number, as a percentage of the total count, or turn off this feature.