LabAdviser/314/Microscopy 314-307/Technique/Holo/Off-axis ATEM: Difference between revisions
mNo edit summary |
|||
| Line 11: | Line 11: | ||
# Fill Liquid nitrogen in the dewar twice or thrice; once at the beginning of the session prior to inserting the TEM holder, once after 30 minutes into the session, and the once around half time of the full-day session. <br/><br/> | # Fill Liquid nitrogen in the dewar twice or thrice; once at the beginning of the session prior to inserting the TEM holder, once after 30 minutes into the session, and the once around half time of the full-day session. <br/><br/> | ||
# Switch on the power supply at the backside of the room | # Switch on the power supply at the backside of the room | ||
#:[[file:Off-axis-Holo_1.png|thumb| | #:[[file:Off-axis-Holo_1.png|thumb|left|200px|power supply biprism]] <br clear=all> <br/> | ||
# Switch on the control box (under the microscope PC screen) | # Switch on the control box (under the microscope PC screen) | ||
#:[[file:Off-axis-Holo_2.png|thumb| | #:[[file:Off-axis-Holo_2.png|thumb|left|200px|biprism controller]] <br clear=all> <br/> | ||
# Switch cables on SAD from red to grey <br/><br/> | # Switch cables on SAD from red to grey <br/><br/> | ||
# Load the appropriate TEM alignment, e.g. 120 keV TEM. This is done by going to Alignment tab → Alignment → Flapout → load the alignment file for the correct keV, e.g. Main_120kV. Select one particular alignment and the press Ctrl+A for selecting all and then move them from “Available” to “Selected” by clicking on the Apply button. <br/><br/> | # Load the appropriate TEM alignment, e.g. 120 keV TEM. This is done by going to Alignment tab → Alignment → Flapout → load the alignment file for the correct keV, e.g. Main_120kV. Select one particular alignment and the press Ctrl+A for selecting all and then move them from “Available” to “Selected” by clicking on the Apply button. <br/><br/> | ||
| Line 34: | Line 34: | ||
#: If the sample is slightly out of focus then don’t try to fix it. Also, if the FFT of the image shows signs of astigmatism, then don’t try to fix it. <br/><br/> | #: If the sample is slightly out of focus then don’t try to fix it. Also, if the FFT of the image shows signs of astigmatism, then don’t try to fix it. <br/><br/> | ||
# Set the biprism. Insert the SAD aperture (lever from right to left). Position of the biprism is SAD aperture #1. Find the biprism and center it. If you can’t see it, excite the biprism to ~100 V with the volume knob on the controls for the biprism. | # Set the biprism. Insert the SAD aperture (lever from right to left). Position of the biprism is SAD aperture #1. Find the biprism and center it. If you can’t see it, excite the biprism to ~100 V with the volume knob on the controls for the biprism. | ||
#:[[file:Off-axis-Holo_3.png|thumb| | #:[[file:Off-axis-Holo_3.png|thumb|left|200px|biprism controller close-up]] <br clear=all> <br/> | ||
#: Align the long axis of the biprism wire in such a way that it is parallel to the long axis of the feature of interest in case of nanowire in plan view OR align the long axis of the biprism wire along the edge of the lamella parallel to the grid, in case of dealing with specimens in the form of a lamella. For rotating the biprism wire, turn the black cylinder attached to the area where the controls for the SAD aperture exist in the microscope. Next, play with condenser stigmatism controls for getting the beam elliptical. When the beam is condensed it should be elliptical with the long axis of the ellipse perpendicular to the biprism wire. Upon turning the intensity knob clockwise, when the beam expands, the long axis of the ellipse should be parallel to the biprism wire. If what you see is opposite of this then you should try swapping the MFx and MFy values.<br/><br/> | #: Align the long axis of the biprism wire in such a way that it is parallel to the long axis of the feature of interest in case of nanowire in plan view OR align the long axis of the biprism wire along the edge of the lamella parallel to the grid, in case of dealing with specimens in the form of a lamella. For rotating the biprism wire, turn the black cylinder attached to the area where the controls for the SAD aperture exist in the microscope. Next, play with condenser stigmatism controls for getting the beam elliptical. When the beam is condensed it should be elliptical with the long axis of the ellipse perpendicular to the biprism wire. Upon turning the intensity knob clockwise, when the beam expands, the long axis of the ellipse should be parallel to the biprism wire. If what you see is opposite of this then you should try swapping the MFx and MFy values.<br/><br/> | ||
#:[[file:Off-axis-Holo_4.png|thumb|left|150px]] | #:[[file:Off-axis-Holo_4.png|thumb|left|150px]] | ||