MKS 943 Series, Инструкция по эксплуатации

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4 Installation
25
Series 943 Cold Cathode Vacuum Sensor
Instruction Manual - #100009887
4.2 Installing a Series 943 System Sensor
The Series 943 Controller must be turned OFF before connecting or disconnecting a sensor cable
from the sensor or Controller.
4.2.1 Locating a Cold Cathode Sensor
Locate a cold cathode sensor where it can measure process chamber or manifold pressure. Install it
away from pumps, vibration sources, and gas sources to give the most representative values.
Locate and orient a cold cathode sensor where contamination is least likely. If it is installed directly
above a diffusion pump, for example, oil vapor could contaminate the cathode, anode, or other
vacuum exposed parts, causing the calibration to shift.
If a low vacuum sensor, such as a Pirani sensor, is used to disable the cold cathode sensor remotely,
locate it closely to the cold cathode sensor.
4.2.2 Orienting a Cold Cathode Sensor
A cold cathode sensor can be installed in any operating position without affecting accuracy.
Installing it with the vacuum port facing down is best as this helps prevent contaminants falling into
it.
4.2.3 Managing Contamination in a Cold Cathode Sensor
If pressure readings appear to be erratic, the Sensor may be contaminated. Inspect it visually. If
contamination is visible (e.g., discoloration of the aluminum cathode), replace the internal
components with an Internal Rebuild Kit (see Section 6.7, Accessories).
Depending on the degree of contamination and application of the Sensor, the internal parts may be
cleaned - either ultrasonically, with mild abrasives, or chemically.
Operation at pressures above 10
-3
Torr for extended periods can increase the likelihood of
contamination.
4.2.4 Testing a Cold Cathode Sensor
HPSTM cold cathode sensors contain the anode and cathode (collector) electrodes. Test the sensor
with an ohmmeter. There should be no shorts between the electrodes or from the electrodes to the
tube body.
4.2.5 Connecting a Cold Cathode Sensor
Mount the sensor to a grounded vacuum system. Use a conductive, all-metal clamp to mount a
KF 25 or KF 40 flanged sensor body.
If the Series 423 Sensor has a CF flange, remove the magnet first to allow clearance for bolt
installation.
Notice
Install the gauge on the vacuum chamber where it is protected from
physical damage and high heat.
See Section 2.5, Over Pressure Conditions, for important safety information
before mounting the gauge.