Tecnai on-line help manual -- Alignments - UT Southwestern

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<strong>Tecnai</strong> on-line help Alignments 42<strong>Tecnai</strong> 12 Software version 2Method: Minimize the movement of the image. The microscope 'wobbles' the LAD diffraction shift whichshould cause no image shift.ProcedureThe alignment procedure consists of three steps:• A preparation step for setting up the image.• Two steps in which the X and Y pivot points are aligned.DescriptionThe alignment of the pivot points of the image deflection coils is essential to the proper functioning ofmany other alignments and calibrations: image shifts, diffraction shifts, detector alignments andmeasurement functions.The image coils pivot points (image shift and diffraction shift) alignment is reasonably insensitive to theoperating conditions and normally needs to be done only once. It is important that the image coils pivotpoints are aligned prior to aligning other parts of the microscope where the image coils are used,otherwise the latter alignments may have to be redone. Alignments where the image coils are used arethose where images or diffraction patterns are moved (image shift, diffraction shift/diffraction alignment).For images, see section 6.3.8.4 LM imagesPurpose: Aligning the LM-magnification image with the M image and all LM image magnifications witheach other.Importance: CONVENIENCE for finding the same image feature centered when crossing from M to LM(or vice versa) and within the LM range.Method: Focus the image (LM magnification) and center the recognizable image feature with MF-X,Y.ProcedureThe alignment procedure consists of three steps:• A preparation step in which an image feature is centered (with the specimen stage) in the lowest Mimagnification.• A step in which the whole LM range is aligned with the Mi magnification.• A step in which all LM magnifications are aligned relative to the highest LM magnification.Note: The magnification system (projector lenses) is normalized when the magnification is changed tomake the image position better reproducible.DescriptionThe alignment uses two different values:• One value determines the shift of the whole LM range relative to the lowermost Mi magnification (andis thus a shift of the whole LM range)• The other values determine the shifts between individual LM magnifications (defined as the shiftbetween a particular magnification and the highest LM magnification).8.5 Align LAD diffraction patternPurpose: Set the zero position for the LAD diffraction shift.Importance: CONVENIENCE for easy resetting of the diffraction shift to the screen center.Method: Center the diffraction pattern using Multifunction X,Y.Procedure
<strong>Tecnai</strong> on-line help Alignments 43<strong>Tecnai</strong> 12 Software version 2The alignment procedure consists of a single step.
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Tecnai on-line help manual -- Alignments - UT Southwestern

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