# What materials can X-Rays not pass through?

## Recommended Posts

bridgey    10

I've been researching for a while now but i can't find anything that answers my question.

I'd like to know what are the radiopaque materials? That is, which materials can x-rays not pass through?

##### Share on other sites
5614    27

I don't know but a google search came up with barium sulphate.

##### Share on other sites
YT2095    591

yeah, Barium Sulphates a good one, but the original question is still too vague in the respect that theres no mention of Power levels or Type, such as Hard or Soft X-Rays, one could argue that Lead is another Blocker, but then thats only partly true also, as its efficiency depends upon many other factors.

##### Share on other sites
5614    27

You could also argue that a blackhole is radiopaque

##### Share on other sites
YT2095    591

Ill bring that up the next time I see a Radiologist for an X-Ray

##### Share on other sites
swansont    6248

As YT said, the energy matters, but nothing is actually opaque, really; it's a matter of being more or less transparent. In terms of e.g. taking an x-ray picture, you get contrast so the film is more or less exposed, and materials like lead will be better at shielding, but some fraction of x-rays will pass through, depending on the thickness (it's an exponential function, $e^{-\lambda L}$ ).

If you want materials that are good at stopping x-rays, you want a large linear attenuation coefficient, $\lambda$

##### Share on other sites
RyanJ    34
I've been researching for a while now but i can't find anything that answers my question.

I'd like to know what are the radiopaque materials? That is' date=' which materials can x-rays not pass through?

Theoretically anything as long as there is enough of it

Cheers,

Ryan Jones

• 1

##### Share on other sites
sunspot    10

When I worked in Oak Ridge, our sister plant, the National Lab, had a swimming pool where they put hot/radioactive stuff from their experimental reactor. It was sort of weird walking along the catwalk and seeing the things glowing blue under the water. I believe about 20 ft or so of water is sufficient as an radiation shield including X-rays. This taught me a strategy if there ever was a nuclear incident nearby. If deep water is available, dive as deep as possible.

Another good shield is lead. If one gets an X-ray, this provides the family jewels some protection. Berylium is also good.

##### Share on other sites
swansont    6248
Another good shield is lead. If one gets an X-ray, this provides the family jewels some protection. Berylium is also good.

Berylium? Is this the same Berylium that has an attenuation coefficient of about 0.25/cm at 100 keV (as compared to Pb, with a value of 50/cm)?

• 1

##### Share on other sites

I think he meant barium.

##### Share on other sites
jdurg    31

Pretty much any heavy, dense metal (or in some cases metal salts) will be good at blocking radiation. Uranium metal is actually VERY good at blocking gamma rays and x-rays, ironically enough.

##### Share on other sites
YT2095    591
I think he meant barium.

or perhaps Bismuth? I think Ide trust that alot more out of the "B" letter metals

##### Share on other sites
ecoli    369

about a foot of concrete would work too.

##### Share on other sites
washim    10

I want no about materials which has very low X Ray absorbing property. The material should be transparent like glass. It has to be safe for medical instrument

##### Share on other sites
swansont    6248

X-rays are ionizing radiation. You'll want something with a low atomic density and low atomic number to minimize the number of potential targets.

##### Share on other sites

I just thought I'd drop in a possibly interesting note about X-Rays ...

... that X-Rays are highly useful in medical applications because they don't pass through all materials equally well.

##### Share on other sites
J.C.MacSwell    181

I want no about materials which has very low X Ray absorbing property. The material should be transparent like glass. It has to be safe for medical instrument

I know that for composites, carbon fibre is preferred over glass fibre in the X-ray range. Quite the opposite of the visible range.

##### Share on other sites

I just thought I'd drop in a possibly interesting note about X-Rays ...

... that X-Rays are highly useful in medical applications because they don't pass through all materials equally well.

That's correct, but also causes problems. When the dentists took an XRay of my tooth, they could see inside of the roots just fine, but they could not see inside the upper part of the tooth that was covered by a metal crown.

Also, Doctors and Dentists don't use photographic film any more. The X Rays are captured by solid state sensors.

Edited by Bill Angel