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DESCRIPTION OF THE VACION PUMP
The Varian VacIon Plus 25 pumps are ion pumps
and are available in three types:
• Triode
• Noble Diode
• Diode
They operate in the pressure range from 10
-11
below 10
Torr (mbar).
The VacIon Plus Triode pumps allow fast starts
-2
from as high as 1x10
cause ions are prevented from bombarding the
system and pump walls during glow discharge in
the starting pressure range, and have higher
speed for inert gases. The VacIon Plus Diode and
Noble Diode pumps require a lower starting pres-
-3
sure (i.e. 10
Torr (mbar)). The Diode contains
more titanium than triode pumps, and thus has a
higher hydrogen capacity and longer life.
A positive polarity high voltage supply is required
to operate Diode and Noble Diode pumps.
A negative polarity high voltage supply is required
to operate Triode pumps. The anode is grounded
and the cathode is held at negative potential.
The pump can operate in any position and can be
supported on the mounting flange. The inlet Con-
Flat flange is a 2 3/4" (NW 35 CF).
The following figure shows the VacIon Plus 25
pump.
VacIon Plus 25 pump
-2
-2
Torr (1.3x10
mbar), be-
TECHNICAL SPECIFICATION
The following table details the main technical
specifications of the VacIon Plus 25 pumps.
MODEL
SPECIFICATION
to
Nominal pumping
speed for Nitrogen
(*) (l/s)
Operating life at
-6
1x10
mbar (hours)
Operating voltage
(max)
Maximum starting
pressure (mbar)
Ultimate pressure
Inlet flange
Internal volume (li-
tres)
Maximum baking
temperature (°C)
Temperature limits
(°C):
Pump
Magnet (ferrite)
Flange
Material:
Body
Cathode
Anode
Magnet
Weight, lbs (kg)
(*) Tested according to ISO/DIS 3536/I
The following figures show the pumping speed vs
pressure diagrams for saturated and unsaturated
pumps and the pressure vs current diagrams for
the same pump. The diagrams are for pumps con-
trolled by means of a Dual controller.
The steps on the diagrams are characteristic of the
Dual step operation: steps occur whenever the
current reaches a value at which the Dual control-
ler high voltage output changes to optimize pump
speed.
The pumping speed of a newly regenerated (i.e.
baked) sputter ion pump decreases during opera-
tion until it reaches a stabilized level known as
"saturation" (nominal pumping speed). To saturate
the VacIon Plus 25 pump, it normally requires an
amount of gas equal to 0.8 Torr-litres. Conse-
quently, pumps can operate for extended periods
of time at low pressures in the non-saturated state,
if they are properly conditioned.
9
TECHNICAL INFORMATION
NOBLE
TRIODE
DIODE
20
22
35,000
50,000
-5000 Vdc
+5000 Vdc
+/- 10%
+/- 10%
-2
-3
≤1x10
≤1x10
-11
Below 10
2 3/4" CFF (NW 35) AISI 304 ln SST
01.4
350
400
350
500
AISI 304 SST
Titanium
Titanium/
Titanium
Tantalum
AISI 304 SST
Ferrite
Net: 21 (9.5)
Shipping: 27 (12)
NOTE
87-900-063-01(C)
DIODE
24
50,000
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