MKS HPS 903 Series, Руководство по эксплуатации и обслуживанию

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20
Cold Cathode Ionization Vacuum Sensor
Do not damage the leaf spring while cleaning the Sensor.
Each of the above cleaning methods should be followed with multiple rinses
of deionized water.
Dry all internal components and the sensor body in a clean oven. The two
ceramic spacers , are slightly porous and will require longer drying time
to drive off the absorbed water.
Assembly
Wear gloves and assemble with clean tools.
Check the anode . It should be straight and centered with the
sensor body for proper operation. Roll the sensor body on a flat surface
and look for any radial run out motion.
1) Install the ground shield using tweezers. Make sure that, at the groove
of its larger diameter, the ground shield interlocks with the locating collar .
2) Slide the small ceramic spacer over the small end of the ground shield
. Check that the leaf spring will contact the base of the cathode
as shown to the right. If not, remove the small ceramic spacer and the ground
shield, and gently bend the leaf spring towards the anode and then replace
the
ground shield and ceramic spacer.
3) Slide the cathode , the grid washer , and the large ceramic spacer
into place. The grid washer has a concave shape. Refer to the figure to see
its installation orientation.
4) Insert the small end of the compression spring into the sensor body .
Using your thumbs, push the larger end of the spring into the sensor body
until it is contained within the tube. Using the smooth-jaw, needle-nose pliers,
work the
compression spring down into the sensor body until it is fully seated
in the formed groove.
5) Inspect the ground shield and the grid washer to verify they are
centered with respect to the anode . If adjustment is needed, gently
reposition the grid washer/cathode assembly, taking care not to scratch the
grid washer.
HPS
TM
suggests you measure the resistance between the ion
current feed through pin and the grid washer to verify that
the leaf spring is in contact with the cathode . The
measurement should indicate a short circuit between them.
There should be an open circuit between the ion current
feed through pin and both the high voltage feed through pin
and sensor body .
The (IMT) is ready for installation. If it is not immediately installed,
cover the flange with clean, vacuum-grade aluminum foil and cap it
with a flange protector.
Leaf spring in
contact with
cathode
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