Gatan Dry Pumping Station (655, 655‐0500) and 626 Cryoholder - Protocol
When the DPS os off:
- Remove one of the blanking plugs
- Open V1, V2
- Replace blanking plug.
- Close V1, V2
- Fill in log book
Pump Down:
- Inspect area and make sure all tubes are connected properly.
- Make sure all valves are closed
- Remove blanking plug.
- Insert cryoholder into specimen holder assembly and replace any plugs into open assemblies.
- Switch on Main power. Wait for right hand LEDs to turn from yellow to green. Open V2. The vacuum guage should drop quickly to ~10‐5 Torr.
- Open V1 and wait for vacuum to reach 5 x 10‐5 Torr. Depending on moisture it can take as long as 2 hours.
- Connect clear tubing to the dewar.
- Close V1.
- Open V3 and wait until vacuum reaches 5 x 10‐5 Torr.
- Open dewar evac needle and allow to pump overnight.
Bake Out:
Optionally, the cryo holder can be baked out overnight simultaneously. If the cryo holder has not been used for 1 week, baking is mandatory.
- Connect the cold stage control unit to dewar. (Model 900)
- Locate power switch(on back) and turn it on.
- Rotate or press the black knob 2 clicks.
- Start Smart Heater Control? Press black knob.
- Press button below "Yes" label.
- Note that the temperature is set to 89oC.
- Press button below "Yes" label.
- "Bake Out" overnight. Optionally it can be done for a minimum of 2 hours.
- Press the black knob ‐ to Discontinue current operation?
- Press button below "Yes" label.
- Wait until dewar reaches room temperature and Power Down
Shut Down:
- Close dewar valve(s).
- Close V3/V4 completely.
- Remove clear tubing from dewar and place on blanks located on rear of assembly.
- Remove holder and replace blanking plug.
- Open V1 and pump to 1 x 10‐5 Torr.
- Close V1 and V2.
- Log usage hours.
- Power down station.
Turning valves and dewar evac needles are fully open when 2 threads are visible.
Close valves: CW ‐ clockwise
Open valves: CCW