Target Chamber Vacuum Procedures for AYEball

Venting the Chamber

• Turn down Monitor bias voltage(s). The supply is in the rack with the germanium high voltage supplies.
• Disconnect the red banana plug from the 300 volt battery used for suppressing the faraday cup. It is sitting on the beamstand upstream of the chamber.
• Retract reset foil. Just pull skinny rod sticking out on beam left of chamber until it stops.
• At vacuum control panel closest to chamber:
  • Close valve in front of chamber
  • Close valve between chamber and FMA
  • Close valve above chamber turbo pump
  • Turn off Ion Gauge controller
  • Turn off Alarm
  • Switch turbo off
  • Close foreline valve
• Make sure nitrogen the vent line is connected to its source (near wall upstream of chamber mounted along beamline), the little valve is open, and the dial gauge reads some pressure (20-30 psi).
• While viewing the Edwards vacuum gauge controller, begin to open the needle valve mounted below the chamber. It is the little knob facing beam right, NOT the big valve facing beam left.
• Proceed at a venting speed appropriate for what is in the chamber. If you are not sure, get assistance.
• When the LED readout says 7.6E2, close the vent valve. Note that while closing, it begins to turn freely at some point. It is closed at this point. Do NOT keep turning and jam it closed. This can damage the valve.
• To remove and change targets consult that section.
• If the chamber is to be open for a while, re-open the vent valve to keep nitrogen flowing through the chamber. Just remember to close the vent valve before replacing the target ladder so you do not overpressurize the chamber.

Changing Targets

• Unplug LEMO connector from the target ladder.
• Move the ladder to the most retracted position for ease of removal.
• Loosen the 4 socket head screws with the special tool.
• Carefully extract the ladder. The faraday cup is a tight squeeze.
• Do not turn it upside down or you will have four screws on the floor.
• Put the ladder on the little stand on the table and take care of business.
• While the ladder is out, insert a small mirror in the chamber opening and shine a light to check on the reset foil.
• Before re-inserting the ladder, make sure the green wires are tucked out of the way so they do not get crushed or caught by the o-ring.
• Carry the ladder over to the chamber with the 4 screws already in their holes.
• Insert carefully. Do not bump. The faraday cup will be a tight squeeze.
• Tighten the screws a little at a time with the special tool. For the final tightening, do it without battery assistance.

Pumping out the Chamber

• By now you should have already closed the vent valve and replaced all flanges.
• The reset foil should be in the retracted position.
• The target ladder should be in the faraday cup position.
• Turn on the little mechanical pump sitting on the beam-left side of the FMA. It is the one connected to the bottom of the chamber by a clear hose.
• Turn on the backing pump for the beamline turbo (if it is not on). The controls are on the panel. Switch the backing valve to open and the turbo to off so it does not start yet.
• Begin to open the large-knobbed roughing valve below the chamber. It does not respond immediately. The first sign of pumping is when the pump begins to gurgle. Keep an eye on the dial gauge (on beamline upstream of chamber near turbo) and/or the pirani gauge under the chamber (Edwards LED readout). Proceed at a rate appropriate to what is in the chamber.
• At 500 microns on the chamber bargraph readout (on panel):
  • Close the hand valve below the chamber.
  • Turn the key to bypass on the vacuum control panel.
  • Open the valve above the turbo.
  • Turn the turbo switch to on.
• When the turbo has come up to speed (LED turns green) switch the turbo and the backing valves to protected.
• After the bargraph readout reaches zero, turn on the ion gauge controller.
• At ~1e-4 torr, open the valve upstream of the chamber from the beamline vacuum control panel by pushing the button (check that the valve upstream of that is still closed).
• At 1e-5 torr in the chamber:
  • Degas the ionization gauge for a minute or so
  • Turn the key on the target vacuum control panel to interlocked.
  • Turn on the alarm.
• Open the upstream beamline valve.
• Plug in the red banana plug to the battery.
• Turn the monitor voltage back on.
• Insert the reset foil.
• Choose appropriate target or faraday cup on Mac.