[[35C Alignment Procedures]] ## Beam axis alignment ### Tilt - Use the sample holder without a specimen, or a wide area metal specimen, for this alignment - The first batch of steps are adjusting brightness and contrast so that the image is viewed at the baseline of the waveform monitor - Lens settings: ![[Screen Shot 2022-09-09 at 2.27.45 PM.jpg]] - The **upper two** beam alignment knobs are adjusted to increase the image brightness ### Shift + Lens axis alignment - The detector is switched to BEI (backscatter) to protect the secondary detector during this next step - The condenser lens is changed from 3 o'clock to fully clockwise - The filament image is viewed on screen (configured to be a 10mm circle) - The beam is centered with the alignment screws on the column - HV is changed from 25kV to 5kV - If axis is aligned, the circles at 5kV and 25 kV will be concentric (there's 30 seconds of overlap to see this) - If not concentric, center the circle and repeat - The **lower two beam alignment knobs** are used to center the circle image once the images stay concentric between kV ### Flowchart ![[JEOL 35C Operating Instructions#Axis Alignment]] ### Controls ![[35C beam alignment knobs function.jpg]] ![[35C beam alignment knobs.jpg|med]]