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User Instructions for 2100F
- Assumed that the microscope has already been aligned and software set up for imaging
- Some familiarity assumed, as these instructions are not nearly enough for a first-time user
Controls needed
- F1 button -- lift screen
- Specimen movement trackball
- Focus knobs
- Brightness control
- Def/Stig in PLA adjust, in case beam gets out of line
- Z height to check eucentricity
- Mag 1 button to reset Defocus
- TEM/CCD toggle to change shuttering control to CCD
iMDS
Sequence of events
- Need to set up a "hysteresis cycle" of Search --> Focus --> MDS Photo --> Search ....
- In Search mode, lift screen and view display with Fastscan camera
- Find area of interest and center on Fastscan camera
- Go to Focus mode, and put specimen in focus (zero contrast, Thon rings maximized)
- Press Mag 1 to reset defocus to 0
- Adjust defocus to desired level
- Toggle TEM/CCD to CCD. Should see beam blank. Call for help if beam does not blank.
- Go to MDS Photo Mode
- In EM Menu 3 software, advance image number to a fresh image
- In EM Menu 3, press "Exposure". Should get a flash on Fast scan camera, and a new image should come up
- Optionally, lower screen for a few seconds to leave a good burn hole. Re-raise screen.
- Go back to Search mode. Change TEM/CCD toggle back to TEM to unblank beam
Taking a film image
- To take a film image, be sure that auto-exposure is unchecked
- Also be sure that CCD/TEM toggle is in TEM mode, otherwise you will get a blank film image
- After adjusting focus in Focus mode, lower screen
- Click Photo button in iMDS -- should hear film being inserted, screen raised, and exposure light should flash
- After film image taken, you are brought back to focus mode
- Optionally, can take a CCD image after a film image to verify that region is ok.
Problems
Eucentricity
- After you move very far (several grid squares), it is a good idea to check eucentricity, as sample may be bent
- In Search mode, center an object of interest
- In EM Menu 3 software, press Control TEM to open up a new window
- In Control TEM window, set X tilt angle to 15 degrees, and press execute
- If you are not eucentric, you will see image shift on the Fast scan camera window
- Adjust Z height until object of interest is re-centered (it will never be exactly recentered)
- Set tilt angle to 0, and execute tilt. Should see no (minimal) sample movement
- Close "control TEM" window
Cannot Trash.findDFdf Focus beam
- Focus beam may disappear if you have to adjust defocus a lot (indicating change in specimen height) or if you leave hysteresis cycle
- Bring it back as follows:
- lower screen to see beam
- Make sure PLA button is lit
- Move beam to center of screen using Def/Stig X and Y knobs (NOT beam shift knobs!)
- In EM Menu 3 software, click "Off-axis" button to move beam over Fast scan camera
Search and MDS Photo no longer aligned
- Search and Photo may go out of alignment, especially if you leave the hysteresis cycle
- Before realigning anything, cycle through Search --> Focus -- > MDS Photoset a few times
- In Search mode, go to a high-contrast and easy to Trash.findDFdf object, like a hunk of ice
- Go to Focus, then MDS photoset
- Lower screen
- Use specimen movement to center the object manually
- Go back to Search mode
- Be sure that PLA button is lit
- Use DEF/Stig X and Y to re-center object
Astigmatism in Focus mode
- Do not worry about astigmatism in focus mode. Because of beam shift and inaccuracy of centering beam over camera, you cannot rely on focus to set stigmatism
- If it is really bad, try re-centering Focus using PLA as described above
- At a 2 um radius, you often see the edge of the objective aperture in Focus mode
Use of SerialEM to montage Entire grid - In general, should not use SerialEM and iMDS at the same time unless you know what you are doing
- it is particularly important not to adjust magnification or iMDS mode if both programs are running
- SerialEM can be used for montaging while in iMDS as follows:
- Go to Standard Photoset mode (normally not used at all in cycle)
- Press Low Mag button and lower mag to 150X
- Center beam with beam shift, adjust brightness and spot size to 5
- Raise screen and put CCD/TEM toggle in CCD mode
- Quit EM Menu 3 if it is running
- Start SerialEM. Should hear a beep. If you get an error, quit and restart.
- Set up Record at binning 2, and 0.1 second exposure
- Take a test record image to be sure exposure is good
- Open a new Navigator window
- Choose to make a full grid montage. Change overlap to 15% and choose to ignore pieces to skip.
- Once things are set up, press "start" under Montage window. Takes 15-20 minutes to complete
- Once done, choose to make a new map.
- If map doesn't look good, try turning off or on "sloppy montage" option and see which is better. Double click map to reload
- Mark off good grid squares by using the "add points" function. Click the middle of the square to be sure you will hit it at higher mag
- Go to each point by highlighting it and picking "Go to xy" in SerialEM. When there, save stage position in JEOL stage menu.
- Optionally, save navigator file
- Quit SerialEM, go back to mag 1 mode
- Cycle through hysteresis cycle a few times. You will likely need to realign things.
- Restart EM Menu 3
- In Search mode, go to saved positions and search there
- Be sure that you are using alpha setting 3, as that is where SerialEM has been calibrated
- TEM/CCD toggle should be in CCD position
- If beam seems to go crazy in low-dose mode, check that alpha setting is 3 in all imaging modes
- Note the alpha setting is not copied when you copy one mode to another: you must manually adjust it then choose "continuous update of mag and beam"
- For montages, use at least binning 2
- Never try to use SerialEM and MDS/iMDS at the same time, except as described above
- Never use SerialEM with the standard tilt holder
- It is a good idea to do a dose calibration, or better, a flatfield, before starting your session
- If beam is moving around a lot when focusing, check that pivot points are OK (or call staff)
-- BillRice - 28 Sep 2007
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