Steps to Removing the MeVVA from the EBIT:
*Preparatory
note: Always use non-powder gloves when handling exposed vacuum
parts. Make sure to put aluminum foil on your working surface. Clean
exposed openings with alcohol and then cover them with foil. Always
use "clean" tools when working with vacuum parts.
1) Make sure high voltage is off as well as the 200V
anode power supply located in the screen room.
2) Vent the system with dry nitrogen.
3) Close the separation valve to isolate the MeVVA
from the EBIT.
4) Disconnect the 4 high voltage connections using tweezers.
5) Turn off ion pump control #3 , remove the ion pump with a screwdriver, and wait
20 minutes or until pressure goes up to ~10^-4.
6) Turn off the mechanical pump and allow 30 minutes
for the turbines to wind down.
7) Unscrew the needle valve to bring the MeVVA chamber
up to air pressure.
8) Remove the six screws on the base of the MeVVA.
Be careful when unscrewing because the MeVVA stand is spring
loaded.
9) Put a piece of aluminum foil over the opening that is
exposed to the EBIT.
10) Get
another person to help bring the MeVVA down the stairs. Don't be
afraid to ask!
Steps to Replacing the MeVVA sample:
1) Remove the bolts that secure MeVVA to the carrier.
2) Pull
up the MeVVA holder and use clean tweezers to disconnect the 4 wires
connected inside.
3) Place foil over the exposed opening on the
carrier.
4) Loosen the bolt that clamps the cathode down.
5)
Pull out cathode/trigger assembly.
6) Slide off the
cathode-anode insulator and loosen the grub screw on the cathode
that holds the trigger in place.
7) Pull out the trigger assembly
and loosen the grub screws on the trigger head. Separate the
trigger, trigger head, and trigger insulator. |
