DIY X-ray backscatter imaging system (airport body scanner)
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- Опубліковано 25 лис 2012
- I'll be presenting this work at EHSM: ehsm.eu/
I built an X-ray backscatter imaging system from parts found on eBay. This system works by scanning a very thin beam of X-rays across the target, and measuring the amount of backscatter for a given beam position. The beam is scanned mechanically by a rotating chopper (collimator) wheel, and by tilting the rotating wheel on an orthogonal axis. The output image is generated on an oscilloscope by matching the horizontal scan speed to the rotating wheel, and using a potentiometer to measure the vertical axis position. The scope's brightness (z axis) is controlled by the amount of backscatter signal received by a large-area detector. Thus, the image is constructed bit by bit. I used a long-exposure shutter on my camera to see the image formed by the moving oscilloscope trace.
www.google.com/patents/US5181234 - Наука та технологія
Making this video and information public is going to have such far-reaching benefits for aspiring hardware enthusiasts all over the planet, especially as the internet spreads out. Way cool! Congratulations on being part of an awesome societal project to break down the barriers of what just a handful of humans can do when information is shared! Woot!
Fantastic work, and crystal clear explanation! Thanks! Your use of a potentiometer for detecting the Y position (3:03) reminded me of how I tracked the X and Y positions of a pen for input to a TRS-80 computer for a high school science project.
Very interesting project- very solid overlap of physics, mechanics, electronics, and a hefty dose of clever.
A big RC servo would be a quick & easy way to do the tilt. But I'm sure you're the sort of guy who would prefer to machine your own gears out of plate....
Impressive job.
My thoughts on the application of this as the name of the channel stated:
1. Exposure - compton scattering or backscatter means that you need high exposure or at least, large area of exposure (to the human body). That means, higher radiation doses.
2. Cost - The SIZE of the detector you'll gonna have for practical application means a lot of costs.
3. Shielding - Imagine this on an airport. Since your dealing with scattering, it is literally scattered all over the place. that's why an appropriate shielding is needed for airports. Cost too.
Most of these machines were removed on public airports (US and UK) due to some of these reasons.
Source: I'm a Linear Accelerator Tech.
It just amazes me that someone is capable of building their own xray backscatter machine in their workshop. More impressive is the simple way in which you have been able to record the output
Very impressive skills Ben.
Yet another incredible DIY project! great job!
That is fantastic. Excellent work a lot of time went into this, I know because I've been watching you progress. Keep it up we all enjoy the videos. ~Russ
I am somewhat a recent subscriber of yours and was searching for xray optics or something that uses passive xray. You were years ahead XD
Interesting. I worked with X-Ray imaging for Food Systems both Conveyor and Pumped food through a detection Window and to the detector array. That technology involved using a Collimator (?) for not focusing but only allowing the X-Ray beam into a thin line. That matched the detector width and the scan rate of the Detector Array and was dependent on the speed of the Conveyor or speed of the substance with a Pump system. It was not a backscatter setup but Emitter and Detector synchronized image. Airline Baggage scanners used this technology 30 years ago.
Ben, you are the Renaissance man. You use physics, mechanics, electronics as if each was just a simple tool on your shelf. Every new video of yours is more impressive than the previous one.
Hey, thanks for telling me, you can learn something new everyday!
So well done I'm speechless!
Very impressed with your project.
Very nice!
After adjusting to Ben Kr'asnow level of awesomeness, this is still awesome.
Amazingly well done!
I have a very old version of SolidWorks at home. I use SolidWorks 2012 at work.
this gave me a couple of ideas: using x or gamma rays, make an imaging device using a: an old flatbed scanner with the lamp removed. should get very high res images if the carriage is slowed down enough for the rays to directly blast the linnear ccd pixels. b: make an image using an alpha emitter on the toner drum of a laser printer. alpha particles should nutralise the static and cause ink to fall off, producing a negative image of some kind
I recommend watching mikeselectric tear down of an airport xray scanner if you haven't already. It uses many small sensors to create a vertical line and then the scan rate is determined by the conveyor speed
Good idea! My original plan was to use an FPGA to fill a framebuffer, and output VGA or HDMI. I'd still like to do this, but the soundcard idea is probably more effective and easier in many ways. Hmm
You're correct with your assumption.
Most front-driven cars have two opposing tapered bearings on each drive shaft, and then one in the drum brakes/hub on the back wheels. Personally I've never replaced the wheel bearings of a rear-wheel driven car, so I don't know how it goes there, unfortunately.
Wish i had the patience you do. Really lets you do some frick'n neat things.
Oh my gosh this is amazing.
I remember reading in a physics book some years ago about using Iridium as a x-ray lens. I have a home made x-ray machine but I never been able to get a hold of Iridium to test it with. It would be neat to be able to build a x-ray camera because the traditional "shadow puppet" technique of X-ray imaging has it limits.
@Logician Writer because all you'd get each time you take a photo (assuming the camera is even sensitive enough) is a glowing area where x-rays are hitting the screen. There's no way to focus the x-rays being scattered back to the detector so you need the combination of scanning from the rotary aperture and the oscilloscope to do the same kind of "image processing" that an optical lens does. All the information you'd get without that processing is 'there's something in the way of the beam.'
Materials with a low atomic number (water, plastics, etc) will scatter lots of X-rays, so there will be more signal from them. High-Z materials like metals will absorb more X-rays and backscatter fewer, so they will emit less signal. Density is also a factor. My oscilloscope has a z axis input such 0V = full bright, 1.8V = dark. The PMT outputs a 0 to -2 V signal with 100K load resistor, which is just brought above 0 by the opamp without inverting.
could post your blue prints that help you make this ( the link) i think it would be to cool to see
Wow. That is an awesome project. I have thousands of thoughts going through my mind at the moment ranging from "Wish I had a cnc milling machine" to "does the tilt scan distort the actual imaging compared to a worm gear straight up and down scan?"
this is one spot on video buddy
top marks form me
Wow amazing 😮. So simple and it would never have come to my mind that way. But you could do the same with an IR-Laserdiode instead and no money IR-Sensor to create a lowcost structure-scanner, even the runtime-sigal could be additionaly derived to get 3D info out of it..... so I guess at least 😅
Way less sensitive as they are just photodiodes, and have a fairly small area - a photomultiplier is many orders of magnitude more sensitive, and Ben's detector has tens of thousands times more detection area - in all you're probably looking at maybe a million to a billion times more sensitivity.
the long exposure on the oscilloscope was smart as fuck.. wow
This is very rad. I was wondering, I know that the light from your scintillator is very dim, but could you do some crystallography or tomography by utilizing the angle of the reflected X-ray?
You use photo-multiplier tubes in several of your videos. Could you point me to some literature on these, or consider making a video on their operation and use?
I have a backscatter van with xray machine still inside and a 20 KVA genetator. I originally purchased it to turn the box truck into a food truck and when i broke the lock open, To my surprise i found the xray system still intact in prestine condition. Can I sale this? And where can i sale it? Thanks.
Keep working on this! Hope you achieve more resolution and less noise!
Are there any safety features at this point? For example, some way to stop the beam if the X or Y axis is not moving "suitably". I have no idea if you can turn x-ray tubes on and off easily, but it looks like a solenoid that pops a shutter into the beam path would work too.
Can anyone explain how the scintilator turns the signal into an image? What pieces it together or other components make it work?
Very nice!.. Is there any detailed tutorial?
A chikkin' in a jumper! The last thing i expected to see on applied science. i can't stop laughing 😂😂😂 Great intro :)
What can I say? This is awesome!
Ben Krasnow you are one top guy
That's up there in the upper echelon of amateur projects. Kudos.
Two-part answer for both questions: The amount of back-scatter you get is dependent on A) the density of the thing being scanned and B) the energy level of the x-rays. The tendency of denser (metal, especially heavy dense metals like tungsten) materials to scatter WAY more than lower-density lighter things (bones, flesh, clothing, plastics, etc) allows the TSA to find guns, knives, etc. easier. Also, back-scatter scanners can be lower-powered and can use lower-energy x-rays to get a good image.
What CAD program do you use ?
Most of these projects are pretty high tech and outside my pocket but of real interest .
One way to cook Christmas dinner :)
Awesome! Where do you find the time to get projects of this scope done?!?
Tapered bearing at the front supporting the wheel end of the axle and a tapered bearing at the rear in the differential supporting that end.
This guy is like a batman of real life!
how about using x-ray for your spectrometer for metal id
how will I make home made inspection full body analyzing system and software to read the info New at the manufacturing any electronics
Have you considered using a sound card and a Processing sketch to capture the data?
Amazing
very cool
No idea, I'm afraid.
Hey Ben, I'm a big fan of the channel. This video is a few years old but if you have any interest in discussing this technology further then let me know and we can prior art. I currently do mechanical design work on backscatter systems for Rapiscan/AS&E.
You could use an electric linear actuator from somebody like LINAK for a smooth controlled scan.
They are mirrored. Did you not see the shinyness at 2:07 ? The outside is black to prevent light from leaking INTO the detector.
But that was a transmissive scanner, you would need both the detector and and the x-ray source to move together or have the person get moved by on a conveyor :/ I wonder if the sensors in Mike's detector are any more or less sensitive though, being engineered for the job.
I have question, why are you so awesome?
Cool!
applied science I bought a really big x ray tube at military surplus store, I have a 1000 watt transformer that is also high in voltage and Im going to run the x ray tube with it, if I get to run with no problems what do you think about the radiation at that power level?
Owen Chase Wear your lead underpants. The X-ray tube voltage will determine how well the X-rays penetrate. Under 10KV, and the rays will be stopped by thin glass and aluminum. Above 30KV, you'll need lead shielding. Medical tubes that operate at 75KV and at high currents are a real hazard.
Applied Science o ok because I have a tesla coil that ran at 100,000 volts.
+Owen Chase science channel you may be able to put out 100kv, but good luck pushing any real current at that voltage
is it because of ohmic heating melting the conductor?
@@robmckennie4203 you don't need much current for xray... Besides, 100kv at the power of the transformer he has is about 10mA.
Why the photomultiplier tube and oscilloscope? Couldn't you capture a comparable image with a camera directly from the phosphor screen>
Genius. I got Smarter Today.
would you pls send me all the name of equipment's you used in the device if that possible , thank you soooo much
it should not be big problem to store data in form of image file?
But great use of oscilloscope and long exposure. Great idea.
For some reason this reminds me of early mechanical tvs
You could angle the screen so that it was tilted haf way between the xray and the camera to give less distortion?
+Donald Sayers That would only be harder to correct for as the projection itself will be distorted if the screen isn't perpendicular to the x-ray source.
+lgab But the distortions by symmetry, will cancel out.
Or view back of phosphor screen through a 45deg mirror
What was the approximate cost of this project?
It seems like your image is reversed - more backscatter causes a drop in intensity on the scope. Is this by design or an artifact of how your PMT + op-amp circuit works?
could you try to improve the sensitivity of your detector? i think an APD would do a better job
APD not good for large area. scintillator + pmt much better.
Awesome. I really thoung it was a DIY... I have to get my kitchen's oscilloscope.
Just found your channel. Awesome! You said there is lens for x-ray, but couldn't you build an x-ray pin-hole camera?
In theory, yes... you can. But, did you ever built pinhole imaging device? Just for fun, use aluminium foil, puncture it with sharp needle. Then place this hole over the incandescent light bulb, then project picture onto paper. Surely, you can see faint picture of the tungsten wire, but only that - nothing else. Imagine then how much x-rays will be needed for decent picture - even frozen chicken may get radiation sickness and die for a second time. :D
+Wild Maniac You can also use a zone plate, which works like a pinhole but lets more light through: en.wikipedia.org/wiki/Zone_plate
Oh, yes, thanks for reminder. Zone plate, that is right.
building your own airport without the TSA?
This is all cool and exciting, but... how would a sound card and stuff work? Could you do a video explaining this?
I love you stuff, but sometimes it flies right over my head! >.
i don't know much about the res or sensitivity, but i meant SNR
Would scotch tape work as an x-ray source?
Cool
Did the poultry submit to a "manual search" as well? Thank you for not filming that.
How many extra eyes and limbs does your cat now have? LOL
Awesome job, as always!
I miss-spoke, low-mass atoms scatter a lot, high-mass atoms absorb a lot. (water is a good reflector, lead is good at absorbing.)
I agree, but that's what engineers do. This is a little snicker at all the artsy people out there who think engineers are somehow "limited".
how about a low lux monochrome camera instead of the photo multiplier?
Why Xrays? Look at NLJD (Non Linear Junction detectors)
Is this safe ?
when you doubt your chicken for metal poising
and here I was all proud of the little tool organizer I just built... :\
"hold your hands above your head"
turkey proceeds to pull ak-47 out of body cavity
Very interesting...I have one question though...did the chicken squawk? ;-}
Safe? Yes, as long as you practice adequate safety. (He does, uses a Geiger counter to determine rad levels, gets the F out if they're too high, etc) Legal? Same answer, with the addition of warning and keeping bystanders safe/away from it when it's on. (He most likely does this or doesn't even turn it on when others are around)
Whoa..
My first question is, how are you not irradiating yourself? My second question is, are you suggesting the TSA is irradiating us in their detectors?
That's why I never got any, plus, it's takes over 2100'C to melt it. My kiln only goes to 1300'C
Well, that's OK I guess but I tied both of my shoes by myself today!!! Let's see ya top that dude!!! LOL
What blocks a back scatter from imaging our body?
I would love to hear a real report on what X-Rays can do to a person with long time exposure. You're dealing with x-rays see what you find.
The one thing that I find really puzzling about this video is why one man would need so many calipers.
Reminds me of Jeri Ellsworth's microwave scanner video.
DIY? Reeeeally? Very nice though