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Home made x-ray machine.

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plazmatron

Fri Jan 18 2008, 01:21AM

Registered Member #1134 Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351

After some very positive comments by the user Mates, I`m starting up this little thread, with one or two radiographs taken with my home made x-ray machine`s.
I first built one back when I was 17 using a radio valve connected to a Tesla coil, but have now moved on to `real` x-ray tubes, and am now using flash radiography at energies exceeding 200keV

Radiograph of shells taken on `instant` Polaroid film at 50keV and 1 min exposure.

Radiograph of a spark plug and feeler gauge taken at 80keV, 1 min exposure with variable contrast paper loaded into a Kodak Lanex fine cassette.

1 minute exposure of V3i mobile phone at 50 keV using variable contrast paper, in kodak Lanex fine cassette.

I currently use only three tubes in my setup. One dual filament medical tube, sunk in oil, which is run upto a maximum of 90keV.
A vintage Matchlett tube, with a thin glass window, which is run in air at 10-20keV (for radiographing plants (below))

X-ray of a foxglove taken at 10keV on raw (no cassette) variable contrast paper 25 minutes exposure.

And last but not least, a flash-xray tube (pictured below) for radiographing with energies exceeding 200keV.

I will be happy to answer any questions!

Leslie

IamSmooth

Fri Jan 18 2008, 02:15AM

Registered Member #190 Joined: Fri Feb 17 2006, 12:00AM
Location:
Posts: 1567

I think they are very nice. You are protecting yourself, and keeping a safe distance when generating the xrays?

plazmatron

Fri Jan 18 2008, 02:22AM

Registered Member #1134 Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351

Thanks! All the tubes are adequately shielded, and housed in their own room with a remote control. I run a personal dosimetry program too, to be on the safe side. Like anything else on these forums, its safe for as long as you choose to respect it!

Leslie

ConKbot of Doom

Fri Jan 18 2008, 05:06AM

Registered Member #509 Joined: Sat Feb 10 2007, 07:02AM
Location:
Posts: 329

very interesting, especially seeing the feeler gage and the different leaves on that.

Mates

Fri Jan 18 2008, 07:03AM

Registered Member #1025 Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566

Hi Leslie,
I had the feeling that your work deserves its own threadâ€¦

My questions:

Could you somehow specify the total energy (dose) you need for taking some of the pictures? The energy of photons you are mentioning only defines the penetrability of the X-rays. The total dose is usually measured in Gy. In case you canâ€™t measure it directly (the meters with radiation chamber are rather expensive) it would be helpful to know not only the voltage but also the amps. Or alternatively what is the total power sucked by your machine form the wall plug.

What the contrast paper means? Can I use for making similar pictures standard X-ray film and the irradiated object only place on it? Are there any hidden problems with this setup?

Are you using any filters (Al or Cu) for removing the low energy photons?

And finally â€“ maybe some people who have not the possibility of having such third X-ray eye at home would like to know the guts of some other things. I have one which Iâ€™d like to order for your next photographic series. I was always very curious where the HV diode in the modern fly-backs is localized (I tried to remove it twice and after hours of crazy work with hammer and chisel I had to give it up without finding it).

Thanksâ€¦

ragnar

Fri Jan 18 2008, 11:43AM

Registered Member #63 Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425

[snip]
Why would Leslie want to go out of his way to trivialize his hard work, his costs and his research and his experiments, to put himself out of business? Guys, try it yourself, if you want to appreciate how it's done.

Mates wrote ...

And finally â€“ maybe some people who have not the possibility of having such third X-ray eye at home would like to know the guts of some other things. I have one which Iâ€™d like to order for your next photographic series. I was always very curious where the HV diode in the modern fly-backs is localized (I tried to remove it twice and after hours of crazy work with hammer and chisel I had to give it up without finding it).

Send him an offer, man; put your flyback in the post!

Mates

Fri Jan 18 2008, 12:54PM

Registered Member #1025 Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566

I have the feeling that for Leslie the X-ray photography is a hobby. The nice thing about hobbies is that usually you share the knowledge with other people regardless the costs. At least Iâ€™m this kind of personâ€¦

Chris Russell

Fri Jan 18 2008, 02:41PM

... not Russel!
Registered Member #1 Joined: Thu Jan 26 2006, 12:18AM
Location: Tempe, Arizona
Posts: 1052

Leslie does have an excellent site with all sorts of information that you may wish to peruse before asking any questions.

My two cents: very nice work, and excellent pictures. Evokes memories of Steven Busic's experiments from some time back.

c4r0

Fri Jan 18 2008, 04:52PM

Registered Member #151 Joined: Sun Feb 12 2006, 02:53PM
Location: Poland
Posts: 153

Hi!
Great photos! I have a few questions too :) By for example 80keV you mean maximum energy of photons, so you are powering x-ray tube from 80kV, right? Or is it average photon energy? You said that you have a dual filament tube. Does different filaments give visible difference in radiograms sharpness? I have double filament tube too, 1mm and 2mm focal spot, and i'm using the bigger one. My radiograms looks a bit blury, is it worth to take apart my oil filled tube casing and switch the filament to smaller focal spot for better radiograms?

Mates wrote ...
What the contrast paper means?

Here you'll find the answer:

And here some of my radiograms :)
Intensifying screens comparison: Dr.goos LGY 200 (blue) and Fuji UM Mammo fine (green):

Mobile phones: N6310, N6610 and N5110 on photographic b/w paper:

Part of TV remote on x-ray film, lcd display as backlight (you can see pixels :) ):

plazmatron

Fri Jan 18 2008, 05:50PM

Registered Member #1134 Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351

Hi everyone! Relax its all good, I have no secrets!

Ok where to start!
I dont use filters, since I`m not radiographing anything thats alive, (normaly done to reduce patient dosage since 10-40keV easily absorbed by tissue, and hardly makes it to the film) and every photon counts! (+plus it vastly improves contrast!) Besides the inherent filtration of glass, plastic and oil removes a large portion of everything below 30keV.
The beam currents used for the above x-rays are between 200 and 800 micro-amps, which puts dissipation at the anode at not more than 100W.
I generally run the tubes at as low current as I can get away with, since the exposure time of paper compared with film is quite large, and heat dissipation is by convection (ie not active).

Beam current varies inversely with supply voltage on my setup, as the increased load at high current drains the WC multiplier (the caps are a little small! ) so exposure times
are adjusted to suit my subjects.

C4r0:
The photon energy quoted is the supply voltage, so the vast majority of x-ray photons would probably be around 50-60keV with the most energetic at 80keV.

The dual filament tube I use had one of those integral switches in the base, so I removed it, and have 3 leads to the cathode, h1, h2, and common. It is well worth using the fine filament, though you will have to adjust your beam currents and/exposure times.

You have made some excellent radiographs, I spent many an hour in old.4hv and older.4hv reading your posts!

Leslie

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