Ametek Dycor Dymaxion Mass Spectrometer, User Manual

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6-6 | Dycor Dymaxion Mass Spectrometer
Installing the new filament
1.
Install the new filament being careful not to bend or break the delicate
filament wires. Handle only the shorting tabs on the filament plate.
2. Tighten the set screws that hold the new filament in place.
3.
Replace the ion volume by setting it back on the head and secure it
with the set screw.
4.
Remove the shorting tabs on the filament by gently bending them
back and forth with needle nose pliers until the tabs break at the
notches at their bases. Be sure the filament coils are aligned with the
slots in the ion volume and source. If they are not aligned, a minor
adjustment can be made by gently bending the filament plate or by
raising the filament base rods in their barrel connectors.
Be sure the filament coils are aligned with the slots in the ion volume
and ionizer. Make sure the filament coils do not touch the base plate,
ionizer or ion volume in any manner other than at welds.
5.
Install a new copper gasket on the quadrupole feedthrough flange.
Be sure it remains centered on the flange as the head assembly is
installed into the vacuum system using the six bolts.
6.
Tighten the bolts using a cross pattern to ensure proper tightening
and a leak-tight connection. The maximum torque required is 110 in-lb
(9 ft-lb).
7. Check for electrical isolation between the feedthrough pins.
• The check should be performed on the pins on the atmosphere side
of the unit (Figure 6-1).
• The pins should be electrically isolated from each other and from
ground.
• There should be approximately one ohm continuous circuit between
the filament Pins 3 and 8. They should be isolated from ground.