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

<strong>Tecnai</strong> on-line help Alignments 82<strong>Tecnai</strong> 12 Software version 2Notes:• The lowermost EFTEM-LM magnifications may not be usable. Simply skip the alignment for thesemagnifications.• Because of the difficulty of aligning the microscope for EFTEM (image/diffraction shift and cross-overcorrection are often quite critical, otherwise there is no image or diffraction pattern visible on theImaging Filter), the EFTEM alignment procedure contains two parts, one a pre-alignment, where allalignments are done with the screen down, the other the final alignment where all is aligned on theFilter itself. Once the microscope has been aligned properly, the pre-alignment should not benecessary anymore and the final alignment can be used for fine-tuning.• In case the cross-over correction is strongly misaligned, it is possible to switch to the cross-overcorrection adjustment and back by pressing the R2 button.15.5 LM-EFTEM Image-shift alignmentPurpose: Aligning all EFTEM-LM images with each other and with the LM images of the normal mode.Importance: CONVENIENCE so that the image remains centered when the magnification is changed.Method: Center a recognizable image with the specimen stage. Lower the magnification one step,center the image with the Multifunction X,Y knobs. Repeat for all magnifications.ProcedureThe alignment procedure consists of four steps :• A preparation step in which an image feature is centered (with the specimen stage) in the highest LMmagnification for the normal mode.• A step in which the same feature is centered with the MF-X,Y for the highest EFTEM-LMmagnification.• A step in which all EFTEM-LM magnifications are aligned relative to the highest EFTEM-LMmagnification.• A step in which the cross-over correction is set for each EFTEM-LM magnification.Notes:• The lowermost EFTEM-LM magnifications may not be usable. Simply skip the alignment for thesemagnifications.• Because of the difficulty of aligning the microscope for EFTEM (image/diffraction shift and cross-overcorrection are often quite critical, otherwise there is no image or diffraction pattern visible on theImaging Filter), the EFTEM alignment procedure contains two parts, one a pre-alignment, where allalignments are done with the screen down, the other the final alignment where all is aligned on theFilter itself. Once the microscope has been aligned properly, the pre-alignment should not benecessary anymore and the final alignment can be used for fine-tuning.• In case the cross-over correction is strongly misaligned, it is possible to switch to the cross-overcorrection adjustment and back by pressing the R2 button.