We Have X-Rays

A project log for X-Ray CT scanners get new life

Two small GE Explore Locus SPs find a new home, and they happen to be mine.

ahron-wayneAhron Wayne 08/06/2023 at 01:320 Comments

Watch as much as you want, but a few minutes into a 13-minute conditioning process, we got x-rays. And a much higher voltage than I was planning to reach for a while. 88 kV! 20 or so microamps! That's more than a watt! 

Also, I put my handy dandy graphical radiation detector inside the machine directly in the path of the beam. First I did 40 kv, but not microamps, and was surprised to see 600 counts per minute. 

This is about 10 times background --- the same level as if you place it on an old thorium gas mantle. 

Then I tried it with 10 (9) microamps of current. In other words, we are at slightly less than half a watt of power, about 1% of which is actually x-rays. 

Now THOSE are x-rays. You definitely don't want to be putting anything in your body directly in the path of this beam. It is not an incredibly huge total amount of x-rays compared to medical imaging. But it is very concentrated for something directly in the path of the beam. 

Just a wild theory, but I wonder if the x-ray counts when no current switched could be used as a proxy for how rarefied the tube is --- in other words, is this leakage current through gunk and stuff in the tube? Or alternatively, is this the cathode filament staying at a "maintenance" temperature --- just not hot enough to emit significant electrons, but it still does a little bit? 

Anyway, woo hoo. Capture card comes this week, while I will be in oklahoma. Next weekend... Gosh willing, we might be able to take some images.