Lessons on X-ray vision

Foolproof rules for any industrial CT scanner

Twelve rules. Three memes. No excuses.

Rule 1 Door shut. Always. Never bypass the interlock. Jammed interlock Door shut, lamp on iyenX
1Door shut. Always.
Rule 2 Warm up the X-ray tube. Cold tube, shaky X-rays. Cold start X-ray output X-ray output Warmed up iyenX
2Warm up the X-ray tube.
SKIPPING THE TUBE WARM-UP Expectation Reality 20 minutes saved! Arcing. Scan ruined. SAVED 20 MINUTES. LOST THE AFTERNOON. iyenX
Skipping the warm-up.
Rule 3 Set the tube's kV and mA. kV pushes through. mA brightens. Step 1: kV up until the thickest part shows through Darkest spot: not black Step 2: mA up until the brightest spot is just below full full Brightest spot: not white iyenX
3Set the tube's kV and mA.
Rule 4 Filter the beam. Dense metal? Copper or tin in front of the tube. Cu / Sn hard X-rays only steel part No filter: cupped Filtered: even iyenX
4Filter the beam.
Rule 5 Set the detector. Frame rate and integration time. Then calibrate. detector Frame rate 5 fps Integration 200 ms Longer integration = fewer frames per second. Too short: noisy Long enough: smooth iyenX
5Set the detector.
Rule 6 Calibrate the detector. Easy: one button press. Before every session. GO + = Beam off Beam on, empty Even images Skipped: faint stripes Calibrated: clean iyenX
6Calibrate the detector.
Rule 7 3D spins. 2D stays still. Pick the mode, then set the stage. 3D CT voxels Rotates: many angles 2D X-ray pixels Fixed: one angle iyenX
73D spins. 2D stays still.
Rule 8 Spin before you scan. One slow turn. No bumps. top view top view BONK Hits the tube gap Clear all round iyenX
8Spin before you scan.
Rule 9 Nothing may wobble. Fix it firmly: foam, tape or clamps. Just balanced Foam and tape iyenX
9Nothing may wobble.
Me: “It'll stay put.” The scan: FAMOUS LAST WORDS. iyenX
“It'll hold.”
Rule 10 Tilt the part just a little. Any part, not just flat ones: 10–20° off upright. Flat: streaks 15° Near upright, 10–20° off iyenX
10Tilt the part just a little.
Rule 11 Stay in the picture. The whole part, at every angle. Or extend the scan upwards or sideways. top view top view Red bits: incomplete image All inside the beam iyenX
11Stay in the picture.
Rule 12 3 voxels or it didn't happen. Smallest detail: at least 3 voxels wide. real pore in red Tiny pore: invisible 3 voxels 3 voxels wide: found iyenX
123 voxels or it didn't happen.
ME HUNTING A 1-VOXEL PORE “I see something. I think.” IT'S IN THERE. PROBABLY. 3 voxels or it didn't happen. iyenX
Squinting at one voxel.
Enjoy your nice X-ray data. Every rule followed. Every detail sharp. iyenX
Enjoy your nice X-ray data.