Portable, DIY Radiography

[Matt] has a background in radiation, electronics, and physics, which means building a device to generate X-rays was only a matter of time. It’s something not everyone should attempt, and [Matt] discourages anyone from attempting anything like this, but if you’re looking for a project with a ‘because it’s there’ flair to it, building your own X-ray machine can be a fun and rewarding project.

Despite being scary and mysterious, X-rays are a rather old technology that date back to some of the first purposeful experiments in electronics. Most X-ray devices today are built around the same parts they were 100 years ago, namely, a Coolidge tube. Apply a high enough voltage to the Coolidge tube and electrons whizz from cathode to anode, and slam into a heavy metal target. This produces Bremsstrahlung radiation – breakingbraking X-rays – that can be directed to film or an X-ray intensifier screen that fluoresces in visible light when being struck by X-rays.

Aside from a cheap Coolidge tube, [Matt] constructed the rest of his X-ray generator with a voltage multiplier made out of sufficiently derated Chinese caps, a flyback transformer, and a transformer driver originally made for induction heating applications. The electronics were installed in a Tupperware container and insulated with mineral oil.

Being able to generate X-rays is one thing, viewing them is another matter entirely. For this, [Matt] is using an old X-ray intensifier screen from the 60s or 70s. This screen fluoresces blue, not the easiest color to photograph in low-light settings, but enough to capture images of the inside of tools sitting around his workbench. Following in the footsteps of [Roentgen], [Matt] also took an X-ray image of his hand. This is something he doesn’t recommend, and something he won’t do again, but it is a very cool example of what you can do with sufficient knowledge and respect for what can kill you.

31 thoughts on “Portable, DIY Radiography

  1. “Bremse” meaning “brake” in German, Bremsstrahlung is more like “braking radiation” than “breaking X-rays” — the rays don’t break anything (well, maybe your hand if you hold it in the beam too long); the electrons in the tube just decelerate when they hit the tungsten anode, producing X-rays in the process. I’m envious of his cheap Coolidge tube, it’s not the sort of thing you see floating around at affordable prices all too often.

  2. Perhaps an old CRT, shrinking it down, using one from an old camcorder, I’m not sure you’d get that far.
    If you can pull a half decent vacuum, you could always just use a roll of sellotape.
    Perhaps if you’re one of those who’ve had a go at making their own valves. A magnetron and some tungsten light bulb filaments might be the way to go.
    How hard can it be, one of those because I can moments. Theoretically it should be possible to make a nantenna in the xray range. I’d love to see xray leds :D

      1. It would be a pain to heat something by induction and have it conduct it’s heat into the tungsten due to the high melting point.
        Perhaps having it in an inert atmosphere and electrically heating it, taking advantage of the resistance and applying lots of current. A couple of microwave oven transformers might well do it.
        Although saying that a couple of magnetrons might be able to impart enough energy to melt it into one blob.

        If the xray tube was kept tiny it wouldn’t take much.

        1. Tungsten will melt no problem with inductive heating, it is the levitation part that will not work. So you need an exotic high temperature refractory ceramic crucible to contain it at its melting point of 3422 °C/​6192 °F, and that will not be cheap.

      2. On a tiny scale, you could burn out one filament on a two filament dip beam car headlight bulb and sustain a plasma arc. Directing it with a few neodymium magnets, so as not to destroy the other filament or crack the glass. That should cause the filament to bead up on one of the conductors and become the target. The second filament would become the heater. The gas pressure would be an issue but it might save a bit of time building it.

          1. i remember a book from either the ’70s the ’80s which had a bunch of dirt cheap DIY electronics projects, one being an X-ray machine. I don’t remember the full details but I do remember their source for stepping up the voltage was an auto-ignition coil and a rotary spark gap, with their improvised x-ray tube via a clear filament light bulb with the whole metal base and innards acting as the electron emitter with an application of tin foil on the outside at the crown as the anode.

  3. I’m helping out a friend at a scrapyard, he’s got about a dozen X-ray sources taken from airport X-ray scanners.

    It’s a metal box about the size of a briefcase, with an X-ray tube and embedded 175KV supply. The box is sealed, with pipe fittings for insulating oil.

    We’ve got about a dozen available for sale, I was just about to make a listing on my .io page and link to the garage sale section on Hackaday.io.

    Are these things that anyone would be interested in?

    (Contact me directly through the .io page from the link in my sig.)

    (Also note – you don’t have to drive the tubes at the full 175KV, and X-rays are safe to work with if you take some precautions and do some research, viz: http://web-docs.gsi.de/~stoe_exp/web_programs/x_ray_absorption/index.php)

      1. You have no idea.

        The scrapyard owner lets us strip machines and keep the stuff, and we do odd jobs around the site such as fixing the security cameras.

        From his point of view, all the machine stuff is “light iron”, which is virtually worthless to him.

        We’ve got about 10 totes of CNC parts: linear rails and bearings, linear actuators, pneumatic valves, power supplies, steppers… all sorts of stuff. I have a turbomolecular pump, three GPS boards, a mass flow controller, and three 15KW X-band microwave transmitters. That’s 10x the power of a consumer microwave oven.

        We *were* going to sell stuff on eBay, but the bottom’s dropped out of the surplus market. We literally can’t sell most items for more than $20 on eBay, and at that price it’s not worth our time to strip the machines to get the parts. (One exception: we did sell one high-price item.)

        Right now the plan is to use the kit to build stuff at the local hackerspace, and sell one or two big-ticket items as we find them.

        1. With microwave emitters like that, (providing you can create a generator capable of powering them) if ww3 does end up happening in our life time, that on a turret, would make for something reasonably formidable.

      1. The source I am mentioning below states he’s getting around 1000R/hour from a common vacuum tube – I wouldn’t call that “a small dose”, it’s lethal dose. Okay, I know, it’s measured very close to the tube, and it would be pretty impossible to get a full body dose of this magnitude from that tiny source, but still, be vewwy vewwy careful.

  4. I had a dental x-ray on the shelf for about a year, looking for a way to use it without photo paper or intensifier. the suddenly it struc me: I had also some A3 size EL-foil on the shelf. could you use that? It turns out you can: https://flic.kr/p/oHCTZY. I put a mirror behind the foil in 45 degrees so my camera would not be in the x-ray stream and took a long exposure as the light is dim. of course this was in a basement with the business end of the tube pointing down and me way back to stay clear of the rays.

    no. I did not x-ray myself..

  5. Actually, using relatively common vacuum tube as x-ray source is pretty easy, as long as you have the right type of vacuum tube. Rectifier diodes are easy and cheap (a few bucks each), and can generate really dangerous amount of soft x-rays. I have a pile of them, but never really had balls to try that out, I am more of the uranium type of guy (minerals) :).

  6. This is really stupid and dangerous. Not only could you be putting your health at risk but also your family and neighbors. Find another DIY project. It is also illegal.

    1. I’d also advise against it, but I think a tube like that isn’t likely to have enough power to actually affect neighbors though.
      Remember, a CRT tube like old TV’s and oscilloscopes also work on the same principle, but they designed the glass and phosphor layer so that it absorbs it all. So a wall should also pretty just stop any small tube’s radiation. And the output also spreads with distance of course.
      Nevertheless, I’d still avoid it and I agree that in general playing with radiation is tricky for others too and you should take that into account.

  7. Nice build, but someone should have told him about soft / hard x-rays.

    In case you want to do some “zap my hand with x-rays” kind of experiment, then wrap your x-ray source in aluminum foil. This will filter out the soft part and will leave the hard part. The soft x-rays do not do anything usefulm, they are mostly absorbed by your skin and only add to the radiation dose you have accumulated, while hard x-rays go through your body and are only somewhat absorbed by your body; that is what allows the x-ray films to develop and teh detectors to give a digital image.

  8. Must be pretty low filament current with the gator clip wires there. The tubes I deal with are drawing 10’s if not hundreds of amps of filament current. Looks like a pretty small tube though, and we don’t want our tubes emitting X-rays if we can help it.

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