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I previously worked on Virtual Reality and other hardware at Valve.  I currently work at Google[x].

Prior to starting at Valve, I built computer peripherals such as keyboards, mice, and joysticks that were designed to be used inside MRI machines.  My company, Mag Design and Engineering, sold these devices directly to researchers at academic institutions who used them to publish scientific papers in peer-reviewed journals.

After work, I spend time on many different types of projects that usually involve circuit design, machining, material selection, and general fabrication/hacking.  My favorite place to be is my home workshop.

ben dot krasnow at gmail

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Sunday, January 20, 2013

Random X-ray photos

24 comments:

  1. Okay Ben, this has to be one of the coolest things ever! Not many people have this capability in their garage! This is a different technique than your backscatter images isn't it? Can't wait for your next video.

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  2. Jaw dropping! Any thought to DIY X-ray fluorescent spectrometry? Imagine the power to see inside stuff AND know exactly what materials it's made of...

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  3. Thanks! These images are standard transmission X-rays. Spectrometry would be awesome -- too many cool projects!

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  4. Very impressive, great quality.

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  5. Any idea why the lenses in the DSLR pic are blocking the x-rays so much? Are they coated with with something or is that just too much glass to go through?

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  6. Anonymous, yes the glass is pretty dense and the X-ray beam is only 50KV at 1mA. It would be nice to have an X-ray beam with higher energy.

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  7. Ok, I would like to build an x-ray but safety is an issue. Are there some good references that I could start looking at? I have a friend that has an old dental x ray unit and it might make a good source but it all comes back to safety. Maybe a thick concrete box (12 or 16 inches) and leaving the room would be a good start (operating the machine remotely).

    Thanks for all the work you have done I really have enjoyed your posts.

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  8. tocs, I don't know of any good introductory safety references for X-rays. Lead is a very effective shielding material, but steel is good too. Notice how the airport baggage scanners are built: It's a tunnel, but the ends have to be fairly open to allow the baggage to pass through, so the manufacturers use lead-coated fabric strips. You don't need 12 inches of concrete -- 3mm thick lead will stop 99.97% of 80KeV X-rays. There is a handy android app that calculates attenuation for all elements. You can get lead sheet at mcmaster.com. Also, you can use a Geiger counter to detect stray X-rays, but a scintillation counter or ion tube would be even better.

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  9. Thanks for the information. Doing some research on radiation shielding, I came across the wikipedia article on the subject (Radiation_protection). There is a small table about Halving thicknesses. It says that the halving thickness for lead is 1cm (0.4 in). How does this relate to the 3mm of lead stopping 99.97% of 80KeV X-rays?

    I do not mind the idea of doing my own research but it is like having to learn a whole new disciple. I suppose this is why so much commercial equipment is so expensive. You pay for some one to tell you "This is safe" or "This will do what you want."

    I just put in a bid on ebay for an x-ray film cassette. It might be a little while before I feel comfortable using it but I think I can get there.

    By the way I also really like your tomography set up. I became interested in tomography years ago after seeing it in the hospital. When ask how it worked I was told by every one "Its just like an x-ray." That was a little frustrating because the CAT scanners use x-rays but they are not like a regular x-ray. A few years later I saw a nice demonstration of how cat scanners work at Auto Rib Cage Projection, in case any one is interested.

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  10. I goofed up an got the "Auto Rib Cage Projection" wrong.
    This should work http://www.colorado.edu/physics/2000/tomography/auto_rib_cage.html

    It was nice a few years ago but right now it is not working on my Linux machine. Will have to look for the proper plug-in.

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  11. Did the xrays corrupt the data on your netbook harddrive? Also is there any chance that xrays might induce some current in electronics that could damage them?

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  12. timelessbeing, X-rays will not induce currents or corrupt data on a hard drive. X-rays can expose photographic film -- especially sensitive high-ISO film.

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  13. tocs, the "radiation halving distance" from Wikipedia is probably referring to much higher energy gamma rays. The 80KeV X-rays do not penetrate mass as easily as gamma rays, so less shielding is needed. Use the android calculator or get the data yourself online from NIST (free).

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  14. All right, clearly I'm an idiot... what's the last image of?

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  15. Anonymous, the items are:

    TV remote control

    Canon DSLR camera

    Wireless headphones

    Asus netbook computer

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  16. Hi Ben,

    Do you think you can you do a post showing some examples of photos taken at different voltages? I'm putting together my own xray setup but I'm starting out with just a 25kV power supply and want to know what if anything I can capture with such low voltage. I haven't found much info on the web relating to this, and think it'd be an interesting experiment.

    Thanks!

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  17. Unknown, that is a really good idea. It would be a sort of "color" image showing penetration of different wavelengths.

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  18. fwiw, recent x-ray renovation where I work involved installation of new lead lined gypsum (drywall) board.
    This stuff is available. I have no idea of price.

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  19. Hello Ben, how did you take the picture? Are you aiming the camera straight to the x-ray tube, with the item in the middle? Pic taken in the dark? Or is there a phosphor screen in between the camera and the item?

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  20. Admin, the camera is on the same side of the fluorescent screen as the X-ray tube. I've corrected the perspective distortion in the image in Photoshop since the camera will not get a straight head-on view with this arrangement. The picture was taken in a very dark room, and the exposure was about 30 seconds at ISO800.

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  21. Hi Ben, your xray of the camera is a fantastic image. Would you mind if I printed it out and used it in the backdrop of a short video? I would really appreciate it.

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  22. Philip, you can use the image for educational or non-commercial use.

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  23. Where did you get the fluorescent screen and how much did it cost?

    The pictures look phenomenal!

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  24. Anonymous, I bought a few different screens on eBay ($30). Search for X-ray cassette, or Lanex, or Cronex, or other terms you find via general searching.

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