Granville-Phillips Series 330, Instruction Manual, Page: 19 / 76

2 Installation
19
Series 330 Vacuum Gauge Controller
Instruction Manual - 330004 - Rev. 02
2.5 Ionization Gauge Types and Installation
The 330 VGC operates a Bayard-Alpert type or equivalent ionization gauge. It is ideally suited for a
nude ionization gauge such as the Granville-Phillips 274022 or 274023 which have an X-ray limit
in the low 10
-11
Torr range. Coated Iridium filament type gauges are recommended since at higher
pressures they provide longer operating life and greater burnout resistance.
When installing an ion gauge, note that if it is placed near the pump, the pressure in the gauge may
be considerably lower than in the rest of the system. If placed near a gas inlet or source of
contamination, the pressure in the gauge may be higher.
If an unshielded gauge is placed near an electron beam evaporation source or used in a sputtering
system, spurious electrons or ions may disturb the measurement. Screens or other shielding should
be placed between the gauge and the system if spurious charged particles or severe electromagnetic
interference is present. Consideration should also be given to electrostatic shielding of glass
tubulated gauges when measuring pressures near their x-ray limits.
Brooks Automation, Inc./Granville-Phillips offers 3 cable types for ion gauges. One has a standard
connector for the series 274 tubulated gauges; one has a standard connector for series 274 nude
gauges; and one has individual pin sockets for use with nonstandard pin configurations as well as
Granville-Phillips nude gauges.
Figure 2-3 shows typical gauge base configurations using the cables listed above and shown in
Figure 2-4, 2-5, and 2-6.
Figure 2-3 Standard Gauge Base Configuration
NOTE: To use the second filament of a dual
filament gauge, the cable connector at the
gauge is removed and rotated 180
o
, then
reinstalled.