Simple Steps for T12 Scope
(Last update 07/24/2013. Maofu Liao)
(1) Log in both EM computer and camera computer.
(2) Open FEI program on EM computer, and Gatan DM program on camera computer.
(3) If not on, click "High Tension" and then "Filament", wait for filament...
While waiting, make sure: cryo-box is in, OA is out, liquid nitrogen cylinder dewar is full.
(4) When "Filament" is ready, and column vacuum <~10, click to open column valve.
(5) Put down screen (L1). (See the light? Yes. Great! No. Don't panic!)
Make sure NOT in Diffraction mode ("Diffraction" button on the right-hand control pad).
(6) Camera spot size to 3.
(7) Magnification to the smallest SA (e.g. SA 2400X).
Now you should see the beam...
(1) Use "Intensity" knob to shrink beam, and "Beam shift" to center beam.
(2) Turn "Intensity" knob clockwise to enlarge beam, counter-clockwise to shrink beam.
(3) [Adjust only when necessary] Center C2 aperture, if the enlarged beam is very off-center.
(4) [Adjust only when necessary] If the beam is abnormally weak, "Gun tilt" to get the max brightness.
(All following alignment steps are on top of Gun Tilt, so do this before other steps.)
(5) Magnification to the level for data collection, as in Exposure mode of Low Dose.
Adjust "Intensity" to keep the beam visible while increasing magnification.
"Beam shift" to center beam if necessary.
(6) Camera spot size to 9, "Beam shift" to center beam.
(7) Camera spot size back to 3, "Gun shift" to center beam.
(8) Repeat the last two steps a couple times, until beam is centered at both spot sizes.
(9) Stop at spot size = 3, check C2 aperture centering again as above.
Start Low Dose:
*** If not using "Low Dose", skip all following steps and go to "Load Grid" ***
(1) Click and turn on "Low dose", "settings"-->"Load" the low dose setting file.
(2) "Options" to set Search/Focus/Exposure as R1/R2/R3 of right-hand control pad.
(3) Center beam in Exposure Mode using "beam shift".
Center beam in Search Mode (Diffraction Mode) using "Diffraction shift".
Center beam in Focus Mode using track ball on the left-hand control pad.
(3) Stop at Exposure Mode.
(1) Click and close Column Valve.
(2) Reset "Stage" --> "Holder" position.
(3) Take out sample holder, load grid, and insert back the sample holder.
(4) Wait for vacuum, click and open Column Valve.
*** If not using "Low Dose", directly collect images ***
(1) Search Mode : find a dot on grid, "Stage"-->"Wobbler", adjust "z height" to minimize the dot movement.
Focus Mode : press "Eccentric focus".
Exposure Mode: "Beam shift" to center beam, adjust "Beam tilt pivot point" ("Rotation center" and "Coma-free" for high resolution work);
"Beam shift" to center beam again, "Intensity" to spread the beam to ~2/3 screen
(If want to use OA, press "Diffraction", a focused beam appears in the center, put in OA, center OA,
and then press "Diffraction" to go back)
(2) Search Mode: go to the area of interest.
(3) Focus Mode: center beam using track ball, turn "Focus" knob to find the focus point.
(4) Blank beam (L3), reset focus value (L2), go to Exposure Mode (R3), raise screen (L1).
(5) Turn "Focus" knob to a focus value around -1.5 um.
(6) Unblank beam (L3), acquire image (usually 1s exposure) using Gatan DM program on camera computer.
(7) Blank beam (L3). Look at the collected image, and its FFT.
(8) Move to a new area and repeat the steps (2)-(7) to acquire another image.
(1) Reset "Stage" --> "Holder" position.
(2) Take out the sample holder, remove grid, and insert back the sample holder.
(3) Close DM program on camera computer. (This should also retract the camera.) Log off.
(4) Click and turn off "Filament".
If no one is going to use the scope, start "cryo cycle", remove OA, empty and put away liquid N2 dewar.
If someone will use the scope later, remove OA, refill liquid N2 dewar.
(5) Close the FEI program. Log off EM computer.