Every time we check in on [Project326], he’s doing something different with X-rays. This week, he has a passive X-ray imager. On paper, it looks great. No special tube is required and no high voltage needed. Actually, no voltage is needed at all. Of course, there’s no free lunch. What it does take is a long time to produce an image.While working on the “easy peasy X-ray machine,” dental X-ray film worked well for imaging with a weak X-ray source. He found that the film would also detect exposure to americium 241. So technically, not an X-ray in the strictest sense, but a radioactive image that uses gamma rays to expose the film. But to normal people, a picture of the inside of something is an X-ray even when it isn’t.What was odd was that he tried three different sources with different materials, and only the Americium made an impression on the film. However, of the three samples, the Americium was the weakest. However, some measurements show that the spectrum of the gamma ray emission for each material is quite different. Clearly, the film was sensitive to a narrow range of gamma rays.Compared to the previous makeshift X-ray tube, which was weak, the radioactive material emitted just a fraction of that tube’s output. He estimates that the americium, which you can rescue from smoke detectors or repair parts for them, emits less than 1% compared to the tube. He uses twelve of them, however, so the total output should be around 10%.The image of an IC is impressive. But it also took two days of exposure. Not sure if this would be practical, but if you need imaging after the apocalypse, salvaged smoke detectors and dental film might be what you need.The upper part of the machine, made from machined copper, looks impressive. It does, however, require some maintenance. We might have been tempted to put some sort of sealant over the copper. The story of how it came to exist isn’t your usual sponsorship story, either.You might have better luck with the previous X-ray machine. Or bite the bullet, get a real X-ray tube, generate about 70 kV, and make a real one.