TECHNICAL INFORMATION
DESCRIPTION OF THE VACION PUMP
The Varian VacIon
Plus
20 pumps are ion pumps
and are available in three types:
•
StarCell
•
Noble Diode
•
Diode
They operate in the pressure range from 10
-2
to
below 10
-11
Torr (mbar). Virtually all gases and va-
pors can be pumped successfully with the ion
pump. The pumping speed will vary depending on
the system pressure, the gas type, and the applied
operating voltage. The latter can be optimized us-
ing Varian controllers to achieve the lowest possi-
ble operating pressure.
The VacIon
Plus
StarCell pumps allow starting
from as high as 5x10
-2
Torr (6.6x10
-2
mbar), be-
cause ions are prevented from bombarding the
system and pump walls at starting pressures, and
have high speed for inert gases. The VacIon
Plus
Diode and Noble Diode pumps require a lower
starting pressure (i.e. 10
-3
Torr (mbar)). The Diode
contains more titanium than triode pumps, and
thus has a higher hydrogen capacity and longer
life.
The tantalum in the Noble Diode pump enhances
the noble gas pumping capacity, although it
somewhat reduces the high getterable gas pump-
ing speed that the standard diode pump provides.
The VacIon
Plus
StarCell is the latest version of
this pump. Its patented design makes this ion
pump the only one that can handle a high amount
of Noble Gases (equal or better than Noble Diode)
and Hydrogen (comparable to the Diode).
A positive polarity, high voltage supply is required
to operate Diode and Noble Diode pumps. A nega-
tive polarity high voltage supply is required to op-
erate StarCell pump since 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).
Fig. 1 shows the VacIon
Plus
20 pump, Fig. 2
shows the main assemblies of the pump.
Fig. 1 - VacIon Plus 20 pump
Fig. 2 - Pump main assemblies
TECHNICAL SPECIFICATION
The following table details the main technical
specifications of the VacIon
Plus
20 pumps.
MODEL
SPECIFICATION
STARCELL
NOBLE
DIODE
DIODE
Nominal pumping
speed for Nitrogen
(*) (l/s)
20 22
27
Operating life at
1x10
-6
mbar (hours)
80,000 50,000
50,000
Operating voltage
(max)
-7000 Vdc
+/- 10%
+7000 Vdc
+/- 10%
Max starting current
150 mA
Max baking current
10 mA
Protect current
20 mA
Maximum starting
pressure (mbar)
≤
5x10
-2
≤
1x10
-3
Ultimate pressure
Below 10
-11
Inlet flange
2 3/4” CFF (NW 35) AISI 304 ESR SST
Internal volume (li-
tres)
0.9
Maximum baking
temperature (°C)
350
Temperature limits
(°C): Pump
Magnet (ferrite)
Flange
400
350
500
Material: Body
AISI 304 SST
Cathode Titanium
Titanium/
Tantalum
Titanium
Anode
AISI 304 SST
Magnet
Ferrite or Sm-Co
Weight, lbs (kg)
with ferrite magnet
with Sm-Co magnet
7 (11)
5 (8)
(*) Tested according to ISO/DIS 3556-1-1992
Figures 3 to 10 show the pumping speed vs pres-
sure 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.
9
87-900-106-01(B)
