MKS HPS I-MAG 423 Series, Operation And Maintenance Manual, Page: 16 / 26

10
10 Cold Cathode Ionization Vacuum Sensor
Installing and Using the Series
423 I-MAG
®
Sensor
Locating and Orienting the Sensor
Locate the I-MAG ® Sensor where it can measure process chamber or
manifold pressure. Install it away from pumps, other vibration sources, and
gas sources to give the most representative values. The magnetic field of
the Sensor should also be kept away from ion or electron beam sources.
Locate and orient the I-MAG ® 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 components,
causing the calibration to shift.
The I-MAG ® Sensor can be installed with the body set in any direction.
Operating position does not affect accuracy. Installing it with the vacuum
port facing down is optimal as this helps prevent contaminants falling into it.
Operation at pressures above 10 -3 Torr for extended periods will
increase the likelihood of contamination.
Connecting the Sensor
Mount the Sensor to a grounded vacuum system.
If the I-MAG
®
Sensor has a CF flange, remove the magnet first to allow
clearance for bolt installation. When replacing the magnet, note that it is
keyed to the sensor body to protect the feed through pins from damage. The
pins should be straight and centered.
Use an all-metal clamp to mount a KF 25 or KF 40 flanged sensor body.
Connect the cable to the Sensor and to your controller before turning on
your system. Tighten the thumb screw on top of the cable to make sure it is
securely in place and for strain relief.
Starting the Sensor
The I-MAG
®
Sensor starts quickly in the rough to medium vacuum ranges.
In the UHV pressure range, starting may be delayed by several minutes.
Use a HPS
TM
IgniTorr™ Cold Cathode Starting Device to help significantly
reduce starting time (see Accessories, p. 16).