Tungsten and radiation

Eskir

Hey guys, I'm quite a noob in physics.

Okay, here's my idea: We use lead to protect us from gamma radiation because it's dense enough to somewhat absorb the tiny wavelenght.
As I take it, tungsten is more dense than lead, right? Wouldn't it be safer to use tungsten instead of lead? (Looking away from the price aspect, of course...)

kurros

Looks like the answer is yes, in the sense that you need less of it to provide the same shielding:

http://en.wikipedia.org/wiki/Hot_cell

"This shielding can be ensured by the use of lead (common) or materials such as concrete (very large walls are therefore required) or even tungsten..."

"Lead loaded gloves are often used in conjunction with tongs as they offer better dexterity and can be used in low radiation environments (such as hot cells used in hospital nuclear medicine labs). Some companies have developed tungsten loaded gloves which offer greater dexterity than lead loaded gloves, with better shielding than their counterparts..."

Also:

http://en.wikipedia.org/wiki/Gamma_ray#Shielding

"Gamma rays are better absorbed by materials with high atomic numbers and high density, although neither effect is important compared to the total mass per area in the path of the gamma ray. For this reason, a lead shield is only modestly better (20–30% better) as a gamma shield, than an equal mass of another shielding material such as aluminium, concrete, water or soil; lead's major advantage is not in lower weight, but rather its compactness due to its higher density."

"When a gamma ray passes through matter, the probability for absorption is proportional to the thickness of the layer, the density of the material, and the absorption cross section of the material. The total absorption shows an exponential decrease of intensity with distance from the incident surface"

daveb

Osmium is even better (density around 22.6 compared to tungsten at 19.3), but osmium is even rarer than tungsten (and incredibly toxic from what I understand)

Bob S

Iridium might be best, but gold is a good second. Bismuth is sometimes used. Other choices are platinum and tantalum.

daveb

I've seen some estimates that put the density of Hassium (element 108) around 41!

M Quack

Of course you would have to then shield the Hassium....

Tungsten and Tantalum are sometimes preferred to Lead because of their mechanical properties, e.g. when pieces have to be machined to be put into UHV or inside tight detector housings.