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Linas

Sat Dec 22 2007, 09:16PM

Registered Member #1143 Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721

hi
i have very big x-ray tube, and have 200Kv sstc, is it posible make good x ray machine??
and how tu know, how many pm or nm (nanometre)electromagnetic radiation ?
some photos

Shaun

Sun Dec 23 2007, 04:17AM

Registered Member #690 Joined: Tue May 08 2007, 03:47AM
Location: New Jersey, USA
Posts: 616

I'm pretty sure X-ray tubes need DC, not HF AC. Plus they are usually fired by a large capacitive discharge, producing a high-energy burst of X-rays. You will probably get some radiation with that tube on an SSTC, but I doubt it will be significant.

Dr. Dark Current

Sun Dec 23 2007, 10:31AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

I don't know how much voltage it needs but 80-100kv is achievable with a DC flyback

c4r0

Sun Dec 23 2007, 12:14PM

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

I think driving real x-ray tube (especially heated cathode type) directly from SSTC is not a good idea. To get preety good radiograms you need at least 50kV (medical diagnostic x-ray machines usually uses about 50-100kV range). DC would be the best, but actually x-ray tube is a vacuum diode, so it will self-rectify the current. In some x-ray machines (in my x-ray machine too) this self-rectifying is used and x-ray tube is connected directly to the HV mains transformer winding, but it's 50Hz, not hundreds of kHz like in SSTC. Anyway, you can try it, but you absolutely need a geiger counter

Linas

Sun Dec 23 2007, 12:39PM

Registered Member #1143 Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721

how to detect x-ray in house ?

ConKbot of Doom

Sun Dec 23 2007, 03:55PM

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

Shaun wrote ...

I'm pretty sure X-ray tubes need DC, not HF AC. Plus they are usually fired by a large capacitive discharge, producing a high-energy burst of X-rays. You will probably get some radiation with that tube on an SSTC, but I doubt it will be significant.

Some of the X-ray machines Ive seen at work use 2 capacitors, each about the same hight as and 3/4 the diameter of a 55 gallon barrel.

c4r0

Sun Dec 23 2007, 04:33PM

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

Linas wrote ...

how to detect x-ray in house ?

With geiger counter or suitable ionising chamber. I'm preety sure that you can easily find a cheap geiger counter on internet auction in Lithuania, just be patient (i hope you have an internet auction website there

). Or you can make one just like Uzzors did:

Linas

Sun Dec 23 2007, 04:51PM

Registered Member #1143 Joined: Sun Nov 25 2007, 04:55PM
Location: Vilnius, Lithuania
Posts: 721

c4r0 wrote ...

Linas wrote ...

how to detect x-ray in house ?

I'm preety sure that you can easily find a cheap geiger counter on internet auction in Lithuania, just be patient (i hope you have an internet auction website there

). Uzzors did:

no :(

uzzors2k

Sun Dec 23 2007, 09:06PM

Registered Member #95 Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308

Why not? It works okay.

I've actually been doing some x-ray experiments lately, but so far the radiation has been pretty weak. I haven't seen any fluorescence yet, but my geiger counter will overflow when brought within a few cm of the tube. This is with the 0.4R/h GM tube... At least it proves the geiger counter works, and x-rays are present! If only I had a real x-ray tube and not some crummy HV rectifiers.

As for driving your tube (which you are lucky to have) I think your TC would work alright, at least to see that it works. As said earlier the tube will rectify anyway, and being a tube it can handle the frequency easily.

Proud Mary

Wed Jan 16 2008, 11:33PM

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

Unless they are specifically designed for detecting the low energy X-rays likely to be produced here, GM tubes are not at all a good way to detect them.

X-ray sensitive GM tubes are constructed much like a longer version of an end-window alpha tube, but with a thicker mica window. A heavy fill gas like argon or krypton is usually used, and at a much higher pressure than in other types of GM tubes - typically 600 - 650 torr.

Some 'general purpose' beta/gamma GM tubes will fail to detect low-energy X-rays altogether, and none but those specially designed for the job should be relied upon for a meaningful indication of dose.

Low energy X-rays are the most hazardous to human health, so one can't afford to not detect them!

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