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Page 25
Ion Pump Operation
The Terranova® 752A is capable of operating most, if not all, ion pumps through a wide range
of vacuum pressures. While small ion pumps can be started at relative high vacuum pressures,
larger ion pumps with higher current requirements must be started at lower vacuum pressures.
However, once the ion pump is started, the control unit is able to maintain normal operation for
all compatible units. See
for recommended starting pressures.
Before commencing ion pump operation, the user should verify the respective channel is set
to the proper output polarity. Diode ion pumps such as standard diode, Galaxy™ diode, and
differential (or noble) diode require positive polarity; triode ion pumps such as StarCell® and
Galaxy™ triode require negative polarity. See
"Changing the Output Polarity"
to modify the high
voltage output polarity.
Pumping Speed [L/s]
Pressure [Torr]
400 - 500
5 × 10
-5
220 - 270
1 × 10
-4
110 - 140
3 × 10
-4
60
5 × 10
-4
≤ 30
1 × 10
-3
To commence high voltage operation, the user should depress the corresponding
HIGH VOLTAGE
ON/OFF
button for more than 2 seconds. Otherwise, the Terranova® 752A will emit a BEEP and
the channel will remain on standby. The HIGH VOLTAGE ON/OFF LED will become illuminated
once high voltage operation commences. The HIGH VOLTAGE display will populate first, followed
by the CURRENT and PRESSURE displays. To terminate high voltage operation, the user should
press the corresponding
HIGH VOLTAGE ON/OFF
button.
To avoid erroneous transient values, CURRENT and PRESSURE
displays will not immediately output readings after high
voltage operation is commenced.
NOTE
Since 1976
StarCell® is a registered trademark of Agilent Technologies; Santa Clara, CA
Galaxy™ is a registered trademark of Duniway Stockroom Corporation; Fremont, CA
Table 6.
Recommended ion pump starting pressures
