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Adam Munich

Wed Apr 27 2011, 10:53PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Now most people just use lead metal when shielding x-rays, but lately I've been thinking of alternative methods of shielding radiation.

One method I have dreamed up would be to dissolve some lead nitrate or acetate in water, then add some xanthan gum to thicken it up a little. This goo could then be poured in a plastic bag or another container, and aside from being an x-ray sheild it would also be a neutron moderator.

Another method I've dreamed up would to be to mix some lead powder with plasticine clay, but since lead powder is expensive iron filings could be a possible substitute, even if more clay is needed. Also, one could mix lead sulfide powder with clay and that would be a non-toxic shielding clay, but I can't seem to find lead sulfide for sale anywhere.

So, does anyone else have any ideas? This is mainly just a discussion thread.

magnet18

Wed Apr 27 2011, 11:07PM

Registered Member #3766 Joined: Sun Mar 20 2011, 05:39AM
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I would think that dissolving the lead or otherwise doing something along those lines would lower the density too much, but i've never tried it, so it's probably worth a shot.
From a chemistry standpoint, acetate is a rather large polyationic ion, so something along the ines of lead iodide might work better, and allow a higher density, though lead iodide is insoluble...
Lead paint? many, many layers? It would be both more dense and have a higher ppm than anything dissolved.
I think one problem may be that anything added that doesn't stop x-rays will only make it a less effective shield. I'm attempting to think of things that would be liquid and leave behind pure lead once cured..., like bubbles coming out...

James

Wed Apr 27 2011, 11:08PM

Registered Member #3610 Joined: Thu Jan 13 2011, 03:29AM
Location: Seattle, WA
Posts: 506

Leaded glass is used in CRTs. I have a dental x-ray tube that has some sort of ceramic shielding sleeve around it, so alternates have been used.

Proud Mary

Thu Apr 28 2011, 12:08AM

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

Lead shot can be poured into moulds or forms of any needed shape. It can be cast with resins or silicones, or used 'dry' so it can be re-used again later in some different shape. Obviously the average density per ml is less than solid lead.

Lead is so often chosen because it provides high density at a good price, and is easily cut, worked, and painted.

Where shielding compactness is not central to a design, there is no reason at all not to use other, cheaper materials such as steel and concrete, provided there is enough of it.

Lead has only limited self-support capability, so can usefully be combined with sheet steel in a laminate combining the density of lead with the structural strength of steel. I have found both industrial epoxy and rivets quite satisfactory for making laminates of this kind. The steel sheet may be placed on the outside, so the lead is securely sealed off from the environment.

The use of steel and lead composites is mandatory for immediate X-ray tube housing in some radiation safety protocols.

I would strongly advise against having anything to do with any toxic lead compounds.

magnet18

Thu Apr 28 2011, 12:17AM

Registered Member #3766 Joined: Sun Mar 20 2011, 05:39AM
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Proud Mary wrote ...
I would strongly advise against having anything to do with any toxic lead compounds.

Because x-rays are so safe?

Wolfram

Thu Apr 28 2011, 05:11AM

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

They are, if proper safety precautions are taken. No need to add potential lead poisoning through soluble lead salts, if there are other viable options.

Lead poisoning is a real concern, and while there is a lot of talk here about radiological protection, there is very little talk on working safely with lead.

Proud Mary

Thu Apr 28 2011, 08:01AM

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

Anders M. wrote ...

They are, if proper safety precautions are taken. No need to add potential lead poisoning through soluble lead salts, if there are other viable options.

Lead poisoning is a real concern, and while there is a lot of talk here about radiological protection, there is very little talk on working safely with lead.

Quite right, Anders. In this thread, as in others like it where I have raised the problem of lead toxicity over these last years, the need for precautions has been greeted without enthusiasm.

I don't recall a single case where someone has asked about the lawful disposal of hazardous lead waste, how does one arrange it, and how much does it cost.

cedric

Thu Apr 28 2011, 08:47AM

Registered Member #2941 Joined: Fri Jun 25 2010, 08:08AM
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what's about sand-bag?it's not expensive ,non toxic and it does protect against x-ray...
by the way ,I use lead shielding for x-ray as well but I don't like to use lead directly after the tube because lead reflect also a lot of x-ray .I think an absorbing material like dense wood before the shield can help to reduce secondary emission...

Bored Chemist

Thu Apr 28 2011, 11:44AM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

A nice thing about the solution of lead acetate is that it transparent. If you put it in a flat walled container you have a window that is opaque to X-rays but transparent to visible light. I know you can get lead glass for that, but it's hardly easy to get unless you are breaking up a TV set.

magnet18

Thu Apr 28 2011, 02:38PM

Registered Member #3766 Joined: Sun Mar 20 2011, 05:39AM
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Posts: 624

Proud Mary wrote ...

Alright, lead wastes can be problematic, but lead is commonly used all the time, IIRC some parts of the country such as older sections of cities actually have lead plumbing (only in return pipes, I hope).
As long as it is used responsibly, and not dumped down drains, it can be perfectly safe. If you were to use lead paint, it would still be safe, especially if you painted over it again. It's not sitting outside, and no-ones licking it, so it should be safe. Just be sure not to spill any and wash your hands well and you should be fine.

Grenadier, does your x-ray machiene currently work? If so, try making the solutions you suggested and x-raying them, see what happens.

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