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At the XFLS chamber on the beamline:
- Unplug the power cable to the XFLS chamber turbo pump controller. (Note the time)
- Ensure the 4.5CF right angle isolation valve is CLOSED, fully CW.
- Isolate the XFLS chamber by closing both upstream and downstream manual gate valves.
- Close the manual valve on the turbo pump foreline vacuum hose.
In the FEH hallway outside XCS:
- Connect ionized air gun to a clean filtered compressed air supply or UHP nitrogen
- Verify LN Dewar has pressure 10psi and the valves are open to supply N2 to hutch systems.
In the XCS control room:
- Have the XCS AM, Controls PI, or Scientist, adjust the height of the lens to the lower limit.
- Open the XCS vacuum hutch 4 Screen and note the pressures at XCS-SB2-03 and 02
At the XFLS chamber on the beamline:
- Open the 5CF right-angle valve located above the XFLS chamber.
- Open the down-beam N2 valve at the turbo, ensure the PRV is venting.
- Once the turbo has been OFF for more than 30 minutes, slowly open the up-beam N2 valve.
- On the XCS vacuum screen, ensure XCS-SB2-02 and -03 pressures do not rise.
- Remove the viewport retaining screws so the doors are free to open when vented.
- The chamber is vented when the doors can open. Leave the N2 flowing.
- Via the viewport on back side, have a second person hold and support the lens cassette.
- Via the window port on the rollup door side, fully loosen the capture screw.
- Via the viewport on back side, have the second person carefully remove the lens cassette.
- Carefully take the lens cassette to the HEPA hood outside XCS in the FEH hallway.
- Loosely close both viewports to prevent atmospheric moisture from
In the FEH hallway outside XCS:
- Remove the lens hold-down springs and take a picture of current lens stacks, save as “BEFORE”.
- Loosen the screws on only one side of the side clamps for each lens stack. Ensure the opposite side screws are tight.
- Carefully remove the current lenses and place them in the appropriate storage tubes.
- One stack at a time, select the new lenses according to the recipe.
- If needed, blow off any particles from each lens and empty cassette with ionized air
- With cassette held and tilted upright, insert lenses in decreasing radii as viewed from left to right and ruffly centered in the tray with appropriate spacers on each end.
- Rotate lenses so that their radius inscription is visible and oriented the
- Snug the side clamp screws, ensure the lenses are secure.
- Ensure each lens is firmly seated and perfectly flush with each other.
- Place cassette under diffuser and take a picture clearly showing the R values, save as “AFTER”.
- Replace the hold-down springs.
- One stack at time and on only one side, loosen the side clamp screws.
- Lightly press on the springs to ensure each lens is firmly seated.
- Tighten the side clamp screws.
- Visually inspect the lenses to ensure they are fully seated and perfectly flush.
- Repeat the above hold down spring steps for each stack.
At the XFLS chamber on the beamline:
- Via the viewport on the back side, have a second person install the lens holder into the XFLS and carefully position it on the 3 kinematic mounts.
- Via the window port on the rollup door side torque down capture screw with driver in the kit.
- Close both N2 vent valves above the XFLS chamber.
- Close both XFLS viewport doors and lightly secure with retaining Do not over tighten, it may pull the hinge side open, and it will not pump down.
- Start pump down by slowly opening the turbo pump foreline vacuum
- After a few seconds, the scroll pump should quiet down, if not, firmly press on the center of both viewports to ensure they are seated and vacuum tight.
- After about 5 minutes, plug in the power cord to the turbo pump controller on the
- When XFLS gauge is < 1E-06 torr open upstream and downstream gate valves. (if a beamline gate valve trips, open it via the vacuum control screen)
- Close the 5CF angle valve on top of XFLS, fully CW.
- Leave the XFLS turbo ON with the 4.5CF right angle valve closed.
Out of the hutch:
- Ensure the beamline pressures and ion pumps are stable.
- Email the before and after lens pictures to the AM and attach to the ServiceNow ticket.
- Update Beryllium Lens Tracker on Google-Drive with the new lens
Note 6: If you haven not completed all steps then the lens change is incomplete. If the vacuum system is left in a non-standard configuration, you must inform the experimental POC and/or AM before leaving the hutch.