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Author Topic: How good is one of those suits? Can it stop gamma radiation?  (Read 42794 times)

Offline CliffordK

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How good is one of those suits? Can it stop gamma radiation?
« Reply #25 on: 19/03/2011 18:24:40 »
This is why I think some basic science education should be mandatory in the US.

There was a piece on the TV this morning about this that was, frankly, awful reporting. The "Doctor" who is flogging this "stuff" did a demo where he shielded a Geiger counter from a radiation source with his amazing "wonder cloth".

Wow! The Geiger counter almost stopped counting. Did the reporter ask any questions at all - nope! If he had at least a basic understanding of science, he might have suggested substituting a sheet of paper, or a chunk of drywall. Alas, no.

So the good "Doctor" was able to get a huge free plug for his product. No doubt a bunch of scientifically challenged Americans will now rush out and buy these things. Probably the same ones that have bought up all the available supplies of potassium iodide.
Paper...  or water is good at blocking alpha and beta.  Not effective with gamma.

Hopefully the demo wasn't done with an alpah/beta emitter or sensor.

I was going to ask about cosmic rays...  but the discussion seems to indicate that the benefit would likely be minimal, but perhaps the material would augment spacecraft construction materials.
 

Offline CliffordK

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How good is one of those suits? Can it stop gamma radiation?
« Reply #26 on: 19/03/2011 18:31:17 »
so they really need suicide volunteers for the most dangerous jobs.
Usually what OSHA does is gives you an annual dose limit.
They don't care if you get that dose in 15 minutes, or 365 days.

So, the really hot work is done with a relay team in very short shifts.

The other alternative is robotics. 
 

Offline yor_on

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How good is one of those suits? Can it stop gamma radiation?
« Reply #27 on: 19/03/2011 18:38:53 »
So, no studies known then?

That I can't accept, I will have to look some more, there should be some at least. And I agree, above possibly 2 MeV (Compton scattering) the suits seems to give little protection for Gamma radiation. Still, it seems the best there are, for the moment. It seems also able block all kinds of bacterias, virus etc, according to some sources, so yeah, it should definitely be watertight. Still, having a gamma-protection up to that level seems better than using nothing?  
 

Offline wolfekeeper

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How good is one of those suits? Can it stop gamma radiation?
« Reply #28 on: 19/03/2011 19:29:03 »
Here's the old puzzle. You've got an alpha source, a beta source, a gamma source and a neutron source. You've got to throw one away, swallow one, put one in your pocket and hold the other at arms length. Which one do you do what to?
 

Offline Geezer

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How good is one of those suits? Can it stop gamma radiation?
« Reply #29 on: 20/03/2011 00:14:40 »

Hopefully the demo wasn't done with an alpah/beta emitter or sensor.


It sure looked like one! It was sitting on a table in the middle of a factory, had no apparent shielding, and nobody was wearing any sort of protective gear at all.

As far as I could tell, the only thing that seemed to be missing was a big label saying "P. T. Barnum".

Oh yes - I forgot to mention - the "Doctor" also threw in some nanoparticle mumblespeak too. Of couse, we know that Florida is a also major center of resarch in that field.
 

Offline Geezer

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How good is one of those suits? Can it stop gamma radiation?
« Reply #30 on: 20/03/2011 00:25:50 »
Still, it seems the best there are, for the moment.

No it ain't. If the level of protection is provides is little better than a plastic bunny suit, but it gives people a false sense of security, it's worse than a plastic bunny suit, and even worse, it's making somebody rich.
 

Offline yor_on

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How good is one of those suits? Can it stop gamma radiation?
« Reply #31 on: 20/03/2011 03:43:25 »
Geezer if you trust the research it seems to take care of the gamma radiation at the normal x-ray level for hospitals at least. So they should be better than nothing. Also they seem very impregnable for all other biological substances, saw that a lot of different forces was buying them in the States.

I totally agree in that they won't protect, as a guess that is, at all over 2 MeV and so won't allow people any closer than they already can come maybe. But there they will protect better than what they had I think.
 

Offline Geezer

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How good is one of those suits? Can it stop gamma radiation?
« Reply #32 on: 20/03/2011 18:14:34 »
On the TV clip I saw no evidence that they are able to block any kind of X-rays. The fact that the guy demonstrated its "effectiveness" with an alpha or beta source makes me highly skeptical.

Are there any test reports available from reputable independent test agencies?
 

Offline syhprum

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« Reply #33 on: 20/03/2011 19:36:03 »
Radiation is a very loosely used term in relation to nuclear mishaps, to my mind radiation means electromagnetic energy such as gamma rays but it is used for Alpha and Beta particles and even microscopic particles of Plutonium etc.
 

Offline yor_on

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How good is one of those suits? Can it stop gamma radiation?
« Reply #34 on: 21/03/2011 02:44:41 »
Radiation testing on Demron fabric samples was performed by the US Department of Energy at Lawrence Livermore National Laboratory (2003?).

Here. 

" Demron is effective as a radiation shield, comparable to lead in terms of g/cm2 and tantalum according to the mass attenuation coefficient, against gamma, x-ray and beta emissions. For example, for 100 keV photon radiation, the mass attenuation coefficient is about 3.8 cm2/g, which means that the transmission will be down to the l/e point for a thickness of 1/33 = 0.26 g/cm*.

For Demron, with a density of 3.14 g/cm3, the thickness would be 0.8 mm corresponding to 2 layers for the present sample. For lead with a density of 11.3 g/cm3, the thickness would be 0.2 mm."

But it is old, I would have liked to find a newer one.
 

Offline Geezer

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How good is one of those suits? Can it stop gamma radiation?
« Reply #35 on: 21/03/2011 03:05:19 »
Gee whizz! Those boys at Lawrence Livermore really know their stuff.

"Demron is effective as a radiation shield, comparable to lead in terms of g/cm2**."

Perhaps the fact that the material is infused with elements with "high atomic numbers" has something to do with it.

 
Well, he's certainly been busy on the patent front.

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=0&f=S&l=50&TERM1=Meridian+Research+and+Development+&FIELD1=ASNM&co1=AND&TERM2=&FIELD2=&d=PTXT

Claims from the most recent patent -

3. The article of clothing of claim 1 wherein the nano-material is formed from one or more nano-sized substances selected from the group of tungsten, barium, boron, tantalum, bismuth, silver, gold, platinum, aluminum, copper, depleted uranium, cerium oxide (CeO.sub.2), yttrium oxide (Y.sub.2O.sub.3), lanthanum oxide (La.sub.2O.sub.3) and neodymium oxide (Nd.sub.2O.sub.3).

4. The article of clothing of claim 1 wherein the nano-material is formed from one or more radiopaque substances including nano-sized lead or tin.

Hmmmm? Nano-sized lead or tin....



** WTbleep does g/cm2 (grams per square centimeter presumably) mean?
« Last Edit: 21/03/2011 04:16:54 by Geezer »
 

Online Bored chemist

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How good is one of those suits? Can it stop gamma radiation?
« Reply #36 on: 21/03/2011 06:55:10 »
g/cm ^2 is what's called areal density.
since the suit has to have enough area to cover a person that area is pretty much fixed.
So, for a given areal density it's a measure of how heavy the suit is.
As explained earlier lead is better shielding on that basis than most things.
If the suit was better than lead I'd be surprised.
As it turns out, it's comparable with lead.
Gosh! That's because of the lead in it.
 

Offline yor_on

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How good is one of those suits? Can it stop gamma radiation?
« Reply #37 on: 21/03/2011 12:53:21 »
So, there should be a be newer test somewhere. Why not find a test to prove your views? After all, I was the one asking :)

I do not find Lawrence Livermore National Laboratory incompetent, or this test incomprehensible, but I would like to see another, newer one too, or was the material already in its final state 2003?

 

Offline Geezer

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How good is one of those suits? Can it stop gamma radiation?
« Reply #38 on: 21/03/2011 18:30:44 »
The latest patent was filed in 2004, so they were probably still developing it.

There is nothing wrong with the Lawrence Livermore report. But it seems to conclude that, if the material is as heavy as lead, it will provide the same protection as lead, which is hardly surprising if the material is full of lead. However, the stuff I saw on the TV obviously did not have much lead in it, if it had any lead in it at all.

The patents tell us that Meridian is combining various elements with polymers to produce a flexible fabric, but when it comes to X rays, they really have to use lead or something with an even higher atomic number. I took a quick look to find out why nano-sized lead would be any better than any other variety of lead, but I didn't see much, so I'm inclined to think it's largely hype, although I did not crawl through all the patents in depth, so I may have missed something.

My basic objection to all of this is that Meridian would like us to believe that they have invented a material with special shielding properties, but it seems the bottom line is, if you want to block gamma radiation, you better get behind a bunch of lead, whether it's built into a suit or not.
 

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How good is one of those suits? Can it stop gamma radiation?
« Reply #39 on: 21/03/2011 22:12:07 »
Finely powdered lead might affect the flexibility of the garment less and blend into the polymer more easily.
 

Offline yor_on

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« Reply #40 on: 21/03/2011 22:23:53 »
"At first the small research group studied metal shielding, but that turned out to be just one of numerous dead ends. Lead is toxic, heavy and bulky, so that was out. Says DeMeo: “Copper and aluminum showed some [shielding] response, but nothing overly useful. Later we worked on embedding metal particles in fabric and obtained a few patents in that area. Then we got involved with trying to find polymers that attenuate radiation.” After considerable fruitless effort, the RST team came up with a polymer composite of polyurethane and polyvinylchloride that incorporates a variety of organic and inorganic salt particles that block radiation.

Constituents of these salts have high atomic numbers (the number of protons in an atom of a particular element), so they tend to arrest radiation more effectively. “Our material looks and behaves like a heavy, dense rubber,” DeMeo says. Demron works in two ways, depending on the type of radiation. When x-rays or gamma rays meet these dispersed salt particles, DeMeo explains, they are either absorbed (via the photoelectric effect) and their energy dissipated through the generation of heat, or they are scattered at an altered energy level (via the Compton effect) and then absorbed or deflected by surrounding particles. This cascade of absorption and scattering stops harmful radiation from penetrating to body tissues. When alpha and beta particles strike Demron, intervening electrons in the salt atoms deflect and slow them down, whereupon they are absorbed into the material."

So it seems to be some types of salt?
=

Btw: this should mean they they are one time wear item, to be discarded after that too, right?
Makes me think of the German salt mines /nuclear waste deposits. Wonder if this was a consideration they made?
« Last Edit: 21/03/2011 22:30:53 by yor_on »
 

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How good is one of those suits? Can it stop gamma radiation?
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