Instructions for Use
Operating Notes
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Miniature and 2 l/s VacIon Pumps User Manual / 87-400-044-01 (F)
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Operating Notes
VacIon pumps operate as a multiple-cell Penning discharge. A
potential of about 3 kV is applied to the anode cell; the cathodes are
at ground potential. Electrons are constrained from going directly to
the anode by the presence of an axial magnetic field of about 1200
gauss. A self-shielding insulator isolates the anode from ground
potential. When the VacIon pump is operating properly (with magnet
installed), the current drawn is proportional to pressure (see the
following figure).
Figure 1
Pressure versus current curve
After the system is rough-pumped to below 10
-2
Torr, the pump can
be started by simply switching on the VacIon pump control unit. A
current draw on the control unit will indicate that the pump dis-
charge has started.
NOTE
Always wait at least 30 seconds after turning off the high voltage switch before
disconnecting the power supply leads. This should allow the power supply
output capacitor to discharge adequately.
