INFICON STM-2XM 2-Channel Rate/Thickness Monitor - Manual (Page 28)

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STM-2XM Operating Manual
2.1.2 Ground Requirements
CAUTION
A ground post is provided on the rear panel. This point
should be connected to the common ground with a
grounding strap.
Use low impedance cables or straps to connect the chassis of all control
components to a common ground point on the vacuum chamber. The common
ground point must be connected to earth ground (see
section 2.1.3, Connection to
Earth Ground, on page 2-3 ).
Solid copper straps are recommended, where RF is present. Use a strap of the
shortest possible length, minimum width of 12.7 mm (0.5 in.), approximately
0.56 mm (0.22 in.) thick. This is particularly important in high-noise electron beam
(e-beam) systems. See
Figure 2-1 for the recommended grounding method.
NOTE: The oscillator is grounded to STM-2XM and crystal sensor through the
BNC cables.
The crystal sensor is typically grounded to the wall of the vacuum system. If the
sensor feedthrough is not properly grounded to earth through the vacuum system,
connect a copper strap between the feedthrough and the common ground point on
the vacuum system.
Figure 2-1 Recommended grounding
Substrate
Source
Sensor
Evaporator
Power Supply
2.4 m (8 ft.) Copper Ground Rods
7.62 cm (3 in.)
Wide Copper
Ground
Strap
12.7 mm (0.5 in.)
Wide Copper
Ground
Straps
Earth