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Operating the Polara CryoWorkstation

Polara Workstation
The directions given here will only be about operating the workstation. Tutorials on loading samples and using the multispecimen holder will be added in the future or are found elsewhere on this site.

  1. Fill the dewar of the cryopump with liquid nitrogen. This will take at least four liters before the pump is cool.
  2. Make sure all valves (VC and V1 through V4) are closed.
  3. If you are going to be transferring samples into the microscope turn on the Polara's turbopump.
  4. Turn on the mechanical pump and open V3 (Roughing). This will rough out all of the lines.
  5. Fill the workstation with nitrogen. When bubbling has subsided load your samples into the cartridges. Watch to make sure the level of nitrogen remains over the cartridges during the rest of the procedure.
  6. Go to the "Helium" tab of the "Vaccum" page on the Polara and hit "Vent Airlock". Follow the directions to remove the multispecimen holder (MSH) from the scope and then attach it to the cryo-workstation.
  7. Open V2 (Airlock). This will allow the mechanical pump to evacuate the area between VC and VA. If the MSH is correctly attached you will hear the tone of the mechanical pump change as it evacuates the area and then quiet down. This should take only a few seconds.
  8. Close V3 and open V4 (Vent). This bleeds cold, dry nitrogen into the area between VC and VA.
  9. Hold in the VA release button and open VA. VA release
  10. Open VC.
  11. Hold in the silver release button on the MSH and insert the holder into the workstation.
  12. Insert your cartridges into the MSH.
  13. Close V4.
  14. Retract the MSH.
  15. Close VC.
  16. Open V3. When the mechanical pump quiets down (approximately 10 sec.) then proceed.
  17. Close V3.
  18. Open V1 (High Vacuum). The needle on the Pirani gauge should get close to 10-2 millibar.
  19. Close VA.
  20. Close V1.
  21. Open V4 and remove the MSH.
  22. Attach the MSH to the microscope, go to the "Helium" tab of the "Vaccum" page and Hit "Pump Airlock" and follow the directions on the tab .
  23. If the above procedures were adequately performed the temperature in the MSH should not rise above 106 degrees Kelvin while the MSH is being pumped.
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Produced by the Timothy S. Baker Cryoelectron Microscopy Laboratory
Main Address: Department of Chemistry and Biochemistry MC-0378,
University of California, San Diego,
9500 Gilman Dr., La Jolla, CA 92093-0378
© 2006-2008 Timothy S. Baker. Material may not be used or reproduced in any way without permission.
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Date Modified: December 4, 2007