GTS meeting 10 31 16

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  • Gun high voltage chamber is under vacuum
    • The electrode was checked by S&A in their lab, while Bubba was tightening the 10" top CF flange. The center of the spherical electrode is about 1.5 mm high, we left it at that.
    • The gun chamber is now under vacuum, after Phil and Bubba made all vacuum piping connections to the bake pump, replaced the 40 l/s ion pump with a smaller 25 l/s ion pump so that the connector could fit with Riad's magnet in nominal position. Phil also added a right angle valve to the Kr line, and the extractor gauge is mounted on a 1" double side flange to prevent the filament from protruding in the gun chamber (this is bad for high voltage conditioning).
    • the bellows spool piece was completed, Bubba and Phil installed it and now Riad's coil magnet is trapped between the gun and the valve. The chamber was evacuated and preliminary leak checks shows both gate valves are leak tight.
    • We have installed the AR-cated viewports, they can only sustain bakes to 200C, so we will do a long 190C bake instead.
    • Shukui measured the transmission ,Laser: 532nm/ p-polarized
      • viewport #1: 99.47% at both normal angle and 45deg
      • viewport #2: 99.21% at normal angle and 99.74 at 45deg
    • Bubba and Phil found an issue with the concept of the sliding solenoid coil. For baking configuration, the solenoid coil does not go towards the beam line far enough, the actual beam line 80/20 prevents it to go any further. The 80/20 beam line holds the mount for the first beam line focusing solenoid, and to hold this solenoid at the specified distance (22") from the cathode, the 80/20 beam line has to be at such position that prevents the solenoid coil move further downstream, leaving little room for the oven.

Once more, Bubba and Phil devised a solution. The added a 'sliding shelf' allowing the 80/20 beam line to be placed far enough from the gun to slide the solenoid coil far enough for the bake, and when the focusing solenoid needs to be placed into its specified location, the 'sliding shelf' is moved towards the gun, with the focusing solenoid mounted on it. Clever! This is something we all should have recognized from the design, my asking the designers to generate a model with the two solenoid magnets in the bake and in the nominal configurations.

    • GTS gun under vacuum with magnet.jpg

    • GTS gun under vacuum with magnet side view.jpg

  • Refurbished cathode prep chamber is under vacuum!
    • Mamun and Yan have completed the cathode prep chamber refurbishing assembly!.
    • The improved chamber has Mamun's idea for top heater puck holder which allows biasing the puck and changing the working distance to effusion sources at will, an additional Cs effusion source, more robust mask with long travel for keeping up with adjustable puck working distance, TC mounted on bellows.
    • All the sources, mask, heaters, storage and fork manipulators of the GTS deposition system have been aligned. All the screws were tightened. After couple of times of dry N2 purging, the deposition chamber is under vacuum with turbo pump.

    • Refurbished cathode prep chamber back view.jpg

    • Refurbished cathode prep chamber iso view.jpg
  • The long manipulator has been aligned for a very smooth puck insertion and retraction
    • The puck is fully engaged when the distance from the face of the 4-1/2" CF manipulator flange is 115 mm. When the schneedle ears are out of alignment with the puck's slots, that is when one is rotating the manipulator to engage the ears, the distance from the manipulator magnet to the face of the 4-1/2" CF manipulator flange is 125 mm.
    • Puck fully engaged at 115mm from manipualtor flange.jpg
    • SS wafer engaged inside ball electrode.jpg
    • SS wafer out.jpg