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climatex

Wed Jan 04 2012, 12:36PM

Registered Member #2012 Joined: Sat Mar 07 2009, 10:22AM
Location: Slovakia
Posts: 45

First x-ray pictures I've got with a Chirana X-ray tube setup at 45-50 kV, from a modified ZVS+DST driver (here's the distance where the arc strikes, 7cm)
The pictures were made with an american intensifier screen CRONEX RAPID 800 + a long exposure photograph (3 seconds).

Here's an X-ray of a flat remote control, plus the grayscale inverted (negative) photograph.

Retractable meter

Relay

Microchip

.. and, a radiometer goin' crazy.

Currently, X-ray experiments are temporarily halted; I'm in progress of making another x-ray setup with some Soviet x-ray tubes, those with a Be window.

randommscience117

Wed Jan 04 2012, 10:20PM

Registered Member #4274 Joined: Mon Dec 19 2011, 03:10AM
Location:
Posts: 47

Check out Teravolt.org, he has a pretty sweet X-ray setup you might want to check out.

climatex

Thu Jan 05 2012, 12:12AM

Registered Member #2012 Joined: Sat Mar 07 2009, 10:22AM
Location: Slovakia
Posts: 45

Hah, neato'. I've seen it and I'm afraid there's nothing to check out to inspire, since the principle stays still the same. Yes, donate me a real singlephase x-ray transformer and I will obtain the same output pictures, if not better... My x-ray is powered with a single DST flyback, since it's the best choice for a ZVS and I don't have interest in building multipliers and sealing them with epoxy afterwards.. after all, they provide lesser current than directly from the transformer anode conn..

And, in addition, I doubt how much money he had spent on his setup. I have obtained my x-ray tube and intensifier screens through barter trade, I paid just the shipping fees. And the DST flyback, or the driver itself... you know, semi-free access to the scrapyard makes wonders.

klugesmith

Fri Jan 06 2012, 03:50AM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

Nice work; thanks for sharing. Mind your millisieverts!

Are we seeing digital photographs of the intensifier screen,
or chemically developed film or photo paper?

climatex

Fri Jan 06 2012, 10:27PM

Registered Member #2012 Joined: Sat Mar 07 2009, 10:22AM
Location: Slovakia
Posts: 45

Thanks Klugesmith; Intensifier screen. However I think sometimes I'll try photosensitive paper, the old fashioned method of developing it. :)

Wolfram

Sat Jan 07 2012, 02:33AM

Registered Member #33 Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971

Good to see more people entering this interesting hobby. What sort of camera were you using? Your setup has the potential to give much better results than the picture. This

is the sort of result that is possible with this technique. That photo was even taken with a 7 year old DSLR, I am sure a modern camera could give much better results.

Using directly exposed film is going to give much sharper images with less effort. Even relatively fast film (320 ISO in this example) film can give extremely sharp results

. Using film in a cassette requires much less radiation for a given exposure, at the sacrifice of resolution, the results will still be very good however.

I wouldn't recommend photo paper to start with, even though I know other people here have used it with great results. The main issue is the very low sensitivity. An other common issue is that fixed-contrast photopaper is plain silver-halide emulsion without sensitizing dyes, so it won't be very sensitive to the green light from a typical Gd2O2S:Tb (by far the most common today) x-ray cassette screen. I see your cassette has a blue-emitting screen so this will not be an issue, just something to be aware about. An other potential issue is with the use of multigrade photo paper, which is the only kind available in many places. Multigrade paper is sensitive to both green and blue, but contrast is determined by the light color. I know multigrade paper in a green x-ray cassette often results in images with very contrast, it might work better with a blue cassette.

Direct exposure of photo paper works well, but it requires very long exposure times.

Don't take my words for it though, experiment, try new things, report back to us and remember to stay safe.

radhoo

Sun Jan 08 2012, 05:39PM

Registered Member #1938 Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701

Nice work, congrats. Try improving the picture quality. I almost got better results using a 2x2 tube:

climatex

Mon Jan 09 2012, 07:12PM

Registered Member #2012 Joined: Sat Mar 07 2009, 10:22AM
Location: Slovakia
Posts: 45

Folks, I have been in contact with a Russian, who has made a nice fluoroscope with 40-50 kilovolts, utilising his Soviet BS-1 x-ray tube intended for crstallography (the anode had a beryllium window).

(He got 4th degree burns shortly afterwards, since he didn't shield the soft xrays, however no amputation was needed.)

Well, I don't have the chance to try a tube like this, I have found the nearest equivalent being the BH-4, which Proud Mary did a review of it:

The only difference is that this tube has a smaller anode cap, bigger voltage/wattage rating (up to 10 W, the BS1 had 6W continuous) and I would pick the model with golden anode /Au/. However, Proud Mary warned me about this particular tube that it has its focal point of 2x4mm, in comparision with the BS1 (0.1mm or so?)

The reason I got interested in these Soviet xray tubes was because one needs a hefty supply, usually over 60-70kV under load, to get some nice (and fluoroscopic, i.e. in real time) pictures with classic medical Coolidge-style tubes. With these Be-windowed ones, the rays do not pass through glass, they do through the window instead. :)

If anyone has any hints or remarks which would assist me with these Soviet tubes, please share them with all of us.

And Anders, congrats! Perfect "FullHD" x-ray setup you've got there, hats off to that!

Proud Mary

Mon Jan 09 2012, 09:50PM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

climatex wrote ...

The only difference is that this tube has a smaller anode cap, bigger voltage/wattage rating (up to 10 W, the BS1 had 6W continuous) and I would pick the model with golden anode /Au/. However, Proud Mary warned me about this particular tube that it has its focal point of 2x4mm, in comparision with the BS1 (0.1mm or so?)

In fact I told you 2mm x 2mm. The reason an anode spot of this size is unsuitable for general imaging purposes is shown in this illustration of geometric unsharpness:

Knowing the dimensions of a focal spot allows you to calculate geometric unsharpness at a given distance by simple geometry.

Aside from the issue with the focal spot, I would not reccommend use of an Au anode in general radiography, as its two characteristic emission peaks are at - from memory - about 10 keV and 12 keV respectively. This could be very good for small biological specimens, but no use at all for making images of mobile 'phones and all the techno bits most often shown in 4HV.

In my opinion - old killjoy that I am - you should learn a lot more about X-rays, buy a modern X-ray dosimeter, and a big roll of 2mm lead sheeting before you go any further.

climatex

Tue Jan 10 2012, 07:44AM

Registered Member #2012 Joined: Sat Mar 07 2009, 10:22AM
Location: Slovakia
Posts: 45

Proud Mary wrote ...
In fact I told you 2mm x 2mm.

Yes, you've told me that. In fact, you're wrong.

Proud Mary wrote ...
... I would not reccommend use of an Au anode... characteristic emission peaks are about 10 keV and 12 keV respectively....

Now let's look at the copper specto-graph, of a similar (BS-5) Soviet tube. Now, the emission spectrum seems to have a peak even below 10 kEv, and AFAIK that fat dark-red thing which was in my medical Chirana was also copper anode... Could you explain why is copper used even in medical tubes then?

Proud Mary wrote ...
..for small biological specimens...

Like human fingers ? :)

Proud Mary wrote ...
old killjoy that I am

Age doesn't matter. I'm 18 and my friends that I personally know, from the same age group, show no slight interest even in high voltage electronics. And I could go now and brag to them that I have constructed X-rays at home and therefore I'm superior. I won't do it, however, and thank God he didn't award me with such boneheadness.

Proud Mary wrote ...
...buy a modern X-ray dosimeter, and a big roll of 2mm lead sheeting...

Yes and you have forgot to include the newest modern ion-camber-based scintillation detector to my checklist. One can't rely on his GM-tube-based radiometer when working with soft x-rays, even if the tube is equipped with a mica window (through which soft gamma, and even alpha particles easily pass through)... can he?

Sorry Proud Mary for a comment like this, however please don't underestimate my experience with X-rays, if you don't mind. I'm always open to helpful hints, but there's no need to instruct me what I should and shouldn't do. As you have seen I have succeeded to make X-rays with a classic coolidge-type medical tube. And I'm still here, alive and kicking. No burns, no radiation sickness, no possibility of increased cancer and no radiography of my body parts. I always keep a safe distance.

All I wanted were hints how to get on with these Soviet tubes (or reasons why I should avoid them wide-range), or else I will have to find myself a real 50Hz x-ray transformer, to get such nice pictures as Anders M. obtained.
The real reason why I started looking after those Soviet tubes was the Russian video.

Thanks for understanding.

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