Beckman Coulter Multisizer 4, User Manual

Page: 84 / 238

PN A51387A
B
3-30
Installing and Calibrating an Aperture Tube
The Change Aperture Tube Wizard
requires a higher current setting. If you are using a more concentrated electrolyte solution,
the software will select a lower current setting.
A low current with high gain will increase the noise level. A current set too high could
saturate the amplifier, damage the aperture orifice, distort your results, or damage cells.
The Auto-Set feature selects the optimum conditions based on the aperture size and
electrolyte solution.
NOTE
A blocked aperture or air in the aperture tube will raise resistance and cause an error message
to display. Click
(
Cancel
)
to close the wizard, then, in the Instrument Toolbar, click
(
Unblock
)
to clear the aperture orifice, or click
(
Flush
)
to flush particles out of the system before
proceeding.
When the system finishes the unblocking process, re-open the wizard by selecting
Run >
Calibrate Aperture Tube Wizard
and clicking
(
Next
)
until Set Current and Gain is selected. Click
the
(
Current & Gain
)
button, then click
(
Auto-Set
)
.
4. In the expanded Current and Gain Settings window, select Particles or Cells. If you select Cells,
enter the Maximum Cell Volume.
CAUTION
Selecting Particles when you are analyzing Cells can cause cell damage due to a
higher current setting.
5. To return to system default settings, click
(
Defaults
)
.
6. Click
(
OK
)
to return to the Change Aperture Tube Wizard.
7. The Wizard automatically highlights the next step, Measure noise level (page 3-30 ).
Step 9: Measure Noise Level
When the system sets current and gain (page 3-28 ), the software selects an electrical current setting
based on the size of the aperture tube and the concentration of the electrolyte solution. If you are
using a small aperture tube or a concentrated electrolyte solution, the software will select a low
current/high gain setting.
For information on reducing noise levels when using small apertures, see Reducing Environmental
Factors That Create Noise , page 3-5 .
For information on current and gain settings appropriate for small apertures, see Using Appropriate
Current and Gain Settings , page 3-9 .
To measure the noise level:
1. In the Change Aperture Tube Wizard, click
(
Next
)
until you reach the step Measure noise level
if it is not already highlighted.
2. To the right of the Measure noise level step, click
(
Measure Noise
)
.
3. The Status Panel displays MEASURING NOISE LEVEL.