UCSD Baker Home Page
Introduction Lab Members Courses Images Publications Computer Programs Procedures Access Scope Facilities

  • Click on open/close to expand/contract the menu item or on the link to go directly to the page.

Use of the Gatan Dry Pumping Station PDF

Dry Pumping Station
Dry Pumping Station (Click on image for larger view)
Controller
Smartset Controller (Click on image for larger view)
The dry pumping station is primarily used for four purposes in the lab:
  1. It is a safe place to store the Gatan cold holders when they are not being used. The proper way to store the holders is to leave them in the station under vacuum.
  2. It is used to regenerate the zeolite desiccant in the cryoholder dewars. This is necessary so that the vacuum in the holders can be maintained which is important for holding a constant temperature when doing cryomicroscopy.
  3. It is used to warm up the cold holders and to pump off the frost buildup that occurs when the holder is removed from the microscope vacuum.
  4. It is used to pump out and regenerate the multi-specimen holder of the Polara.
Turning on the Dry Pumping Station
  1. Place the holder into the specimen holder chamber. If you plan on running the zeolite cycle also hook up one of the Tygon evacuation tubes from the pumping station to the port underneath the vacuum valve of the holder.
  2. Make sure that all valves on the station (V1, V2, and V3) and on the holder are closed.
  3. Turn on the power switch and wait until the LED on the right turns from yellow to green. The Penning gauge meter should quickly read 10-5 Torr.
Running the Zeolite Cycle to Regenerate a Holder

Note: Gatan recommends running the zeolite cycle about once every week. It does little good to evacuate a holder without also running the zeolite cycle at the same time. Standard procedure in this lab is to run the cycle overnight if it has not recently been done. Otherwise a short zeolite cycle of two hours will also help.
  1. Make sure that the station is running, down to proper vacuum, and that the holder is properly connected. Check to see if the Tygon evacuation tubing from the pumping station is connected to the port underneath the vacuum valve of the holder.
  2. Turn on the SmartSet controller and allow it to go through its startup procedure (Caution: The controller hooked up to the microscope is set for 220 voltage but the one next to the pumping station is set for 110. These two controllers cannot be interchanged).
  3. Plug the control cord into the holder.
  4. The zeolite cycle should not be run if the holder is colder than room temperature. That means you should not run the zeolite cycle immediately after a cryo session. The temperature in the room is also sometimes cool enough that the controller gives a temperature error message. If this happens run the warmup cycle (below) for a few minutes until the temperature in the holder is above 20o C. Then hit a button to cancel that cycle and continue.
  5. Turn the knob until you get to the Start Zeolite Cycle option. Push the knob to select the option.
  6. If you plan on running the cycle for the default two hour period hit the button labeled [Yes]. If you want a longer cycle period push the knob. An asterisk will appear in front of the two hour default time on the display. Turn the knob till the desired time and hit [Yes].
  7. If the LED light on the dry pumping station is green open the butterfly valve V2.
  8. Open butterfly valve V1.
  9. Open the dewar evacuation valve, V3. When it is fully open you will feel it a slight "catch" as you continue to turn the valve. You cannot over loosen this valve. The pumping station will then evacuate the line to the holder and the LED light may momentarily turn to yellow. Wait until the light changes back to green.
  10. Open the valve on the holder.
  11. When the cycle is complete close the valves in the opposite order that you opened them: the valve on the holder, then V3, V1, and finally V2.
  12. Turn off the dry pumping station and the SmartSet controller.
Warming up a Holder

This procedure is usually done immediately after removing the holder from the microscope. It can also be done while the holder is in the microscope. If the cryo sample is infectious warming up the sample in the microscope can work to decontaminate the holder. (Caution: The SmartSet controller hooked up to the microscope is set for 220 voltage but the one next to the pumping station is set for 110. These two controllers cannot be interchanged).
  1. Make sure that the pumping station is running, down to proper vacuum, and that the holder is properly connected.
  2. Turn on the SmartSet controller and allow it to go through its startup procedure.
  3. Plug the control cord into the holder.
  4. Turn the knob until you get to the Start Warm-up Cycle option. Push the knob to select the option.
  5. Hit the button labeled [Yes].
  6. If the LED light on the dry pumping station is green open the butterfly valve V2.
  7. Open butterfly valve V1.
  8. When the cycle is complete close the valves in the opposite order that you opened them: V1 and then V2.
  9. Turn off the dry pumping station and the SmartSet controller. Allowing the pumping station to run after the warmup is complete just necessitates more frequent maintenance.
Baker Home Page Contact Site Map Search Baker Site Baker Group Calendar