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100$ Xray desktop CT scanner

A computed tomography scanner for your desktop

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I am building a volumetric 3D scanner based on X-ray computed tomography.
The goal is to keep the total material cost under 100$.

The scanner will have the size of a backpack and will run on batteries.

It will scan a true 3D image with features inside the object, so you will be able to virtually cut inside the object and see features an optical scanner can´t see.




SYSTEM DESIGN DOCUMENT

Computed tomography is still considered to be an overexpensive huge machine standing in hospitals.

I want to make this technology accessible to everyone.

This small version might be used to examine archeological artefacts or replicate complex objects that an optical scanner cannot view.

Basically, a volumetric 3D image can be obtained from a series of 2D X-ray images assumed the object is rotated by a few degrees for every picture.
The X-ray source is an old radio tube (available for 0.50$-3$) which is driven by a high voltage source made of two car ignition coils. There are still plenty of these tubes available online.

The X-rays are made visible by the so called "intensifying screen". It´s a sheet plated with a chemical that emits visible light when hit by X-rays.

I am currently using intensifying screens previously used in a veterinary clinic - but there is a way to make them DIY which I will not focus on.

I was able to generate X-rays with the radio tube:

The system is almost completetely assembled now in a transport box, including PCBs and wiring.

WORKING TOWARDS

I´ll finish assembling the system first and will start test runs to obtain the correct exposure times.

The filament of the radio tube has to be heated to increase the current. This will be done by induction.

  • 1 × X-Ray film cassette with intensifying screens (later DIY version) Intensifying screens emit visible light when radiated with x-rays
  • 1 × DRV8846 (Texas Instruments) Dual H-Bridge Stepper Motor Driver
  • 1 × ATMega8 (Atmel) AVR Microcontroller
  • 2 × Car Ignition coils The cylindrical type of ignition coil
  • 1 × Nema 17 Stepper Motor Or anything similar, can unscrew one from a discarded printer or scanner

View all 8 components

  • Connecting up

    Paul Kocyla08/08/2015 at 08:30 0 comments

    Many wires to connect... actually not so many in the end :)

  • New board soldered

    Paul Kocyla07/30/2015 at 18:30 0 comments

    New board soldered and running.
    Now I will wire all the system.

  • New control board

    Paul Kocyla07/13/2015 at 21:11 0 comments

    Here is the (hopefully) final control board and power switch board dsign. It´s sent for production.

    The controller board contains a relais for the camera trigger, a motor driver for the rotary table, a buzzer to warn you when the x-ray powers up and an interface for the switch buttons and the coil drivers.

    The power board contains two isolated power-mosfets to drive the ignition coils and the transformer for the tube´s filament heating.

    I decided to put the power board near the ignition coils & filament heater to reduce the EMI on the controller board. The coils spit lots of unwanted EMI, maybe I´ll need to replace the stepdown converter by a simple LDO, because it showed that switching converters get dizzy by the EMI (induction in the switching coils?) Let´s see. Chopping the coils induces high voltages on the primary side( (>400V) which are indended to occur to develop a high enough output voltage, so they should stay on short paths to the battery. Varistors are included for protection of the control board, just in case.

    ^^ The filament of the vacuum tube should be heated to ensure a higher current flow. Because two ignition coils are necessary to get a voltage that is high enough to generate hard x-rays, there is a potential of up to 30kv on the heated cathode against the supply rails. So if you want to heat up the filament, you can´ t just wire it to the control board. A solution would be inductive coupling by two air coils isolated by a plastic wall.

  • Mounting the Setup

    Paul Kocyla07/10/2015 at 17:18 0 comments

    Mounting of the setup is progressing.

    Left upper corner: Plate to which the intensifying screen will be glued

    Left lower corner: car ignition coils

    Middle low: Rectifying tube

    Right lower: Batteries

    The camera is protected from the X-Rays by a lead plate

    The rotating table is between the screen and the tube

  • Got X-Rays

    Paul Kocyla06/03/2015 at 21:58 0 comments

    Got X-RAYS, yeah :-D
    It works fine. I get a smooth nice green glow on the scintillator screens.
    It works with car engine ignition coils and an old radio tube (there are plenty of them on ebay, from 50 cents to 3€)

  • High Voltage source

    Paul Kocyla05/31/2015 at 11:34 0 comments

    The Xray-power source for the 100$ scanner version.
    Made of two car ignition coils, which you can even get for free when you´re lucky.

    I connencted them parallel (in reverse) to double the voltage. It is driven by a power mosfet.

    I read some nasty flame-comments about this project, regarding the "100$"-label :-D
    YES, this version WILL cost at max 100$. The other version with the commercial x-ray source is an additional bonus, but of course I want to make this project replicable for everyone.

  • Rotary Table Working

    Paul Kocyla05/16/2015 at 17:12 0 comments

    The board was working out of the box - nice :)

  • Controller Board Soldered

    Paul Kocyla05/16/2015 at 10:40 0 comments

    There it is - finally soldered.

    It contains a new motor driver from TI, an USB connector and two relais.

    I chose an ATMega8 as MCU. This will also make the board arduino compatible.

  • DESKTOP CT: rotary table, xray source

    Paul Kocyla04/24/2015 at 22:19 0 comments

    The aluminium box will be the mobile CT scanner case. I printed a rotary table and a NEMA17 stepper motor holder for the object to scan.
    The electron tube (a diode) will serve as an x-ray source.

  • Control Board Design finished

    Paul Kocyla03/21/2015 at 09:50 0 comments

    Just finished the Control Board design for the CT scanner. It´s based on an ATmega8 from Atmel.

    It uses a small form factor microstepping IC from TI with 1A current capability to drive the rotary table.

    Relais are included to control the X-Ray generator and the digital camera.

    An USB connector enables a terminal connection to parametrize the control board with a PC.

    Finally there is a switch to START/STOP the scan and two status LEDs.

View all 11 project logs

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Discussions

Jacob.R.Jennings wrote 10/19/2016 at 15:53 point

Could this approach translate for small scale to create a DIY solder inspection station (inspect hidden solder joints under ball grid array chips)

  Are you sure? yes | no

Paul Kocyla wrote 10/19/2016 at 19:36 point

Probably yes. The safety is another concern: The tube is radiating in all directions, there would be need for proper shielding with lead.
I didn´t  progress with the project due to an EMDrive+satellite project, don´t know when I will find time to finish this one.
Anyway there are still plenty of the x-ray sheets available on ebay, so it should be easy to rebuild this one.
 

  Are you sure? yes | no

Jacob.R.Jennings wrote 10/19/2016 at 21:46 point

Cool, thanks for the info

  Are you sure? yes | no

Gurban.Dan wrote 02/22/2016 at 08:54 point

Congratulations!

I want to create a portable and inexpensive-element analysis.

As ideas after I thought a lot-

- we can use radiation x-ray beam to excite x-ray induced in materials (portable XRF)

It is simple and there exists.

But if we succeed focused radiation X, we can get a map of the surface - a kind of microscopy.

- another idea would be to excite radiation X with an electron beam

Even extracted in air through a thin window, electron beam, I travel a certain distance in the air.

Enough to get a 3D picture of cells that here-


http://www.sciencedirect.com/science/article/pii/0168583X93957049

http://pubs.rsc.org/en/Content/ArticleLanding/2007/JA/B700851C#!divAbstract

I suggested an electron beam easy to obtain then proton beam.

Performance will not be as good, but at least miniaturized devices.

And yes, I want to collaborate and apply to present them at a scientific conference.

  Are you sure? yes | no

Jerry Biehler wrote 05/01/2015 at 05:20 point

And note that if you are in the US most states require licensing for X-Ray devices.

  Are you sure? yes | no

Paul Kocyla wrote 05/01/2015 at 20:42 point

Here´s the same. I´ll take care to fire it up under legal conditions - and still make it safe for people who want to run it at home - with many warning stickers :-D

  Are you sure? yes | no

hackworth wrote 04/10/2015 at 19:10 point

Just a couple of items:

1) Make sure you've got very good shielding.

2) You might want to investigate Fourier reconstruction as it's faster than filtered back projection. http://www.aapm.org/meetings/02am/pdf/8372-23331.pdf

3) If you're using a scintillator (you seem to plan to) use a mirror to keep the CCD out of the x-ray beam. Having the camera in the beam will lead to a lot of noise in your images.

Feel free to ping me if you have any questions. In a previous stage of my career I worked with x-ray tomography extensively.

  Are you sure? yes | no

Paul Kocyla wrote 04/10/2015 at 19:29 point

Thanx a lot. For this project, I´ll just use intensifying screens and will try to keep the camera away of the ray paths. The mobile version will get a lead-foil shielding.
Thanx for the link and your offer, I appreciate it - as it is my first try in that topic I´m sure I´ll have some questions in the future. I´ll check out the fourier reconstruction paper, too.

  Are you sure? yes | no

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