RE: Safety Gear (was: possible sources ... lead ... oil?)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 

see http://physics.nist.gov/PhysRefData/XrayMassCoef/tab4.html

mass attenuation coefficients (mu) are:
For Acrylic, 20keV, about .571 cm^2/g.  POlyethylene, etc. are all close

Pyrex (borosilicate glass) is about 2.3

compare, lead glass, at 65.7


Your own soft tissue is about .823, bone about the same.

You can convert to tenth thicknesses.. (see 
http://physics.nist.gov/PhysRefData/XrayMassCoef/chap2.html)
.1= exp(-(mu/rho)*x)

Assuming density of plastic is about 1 g/cc, I get a "tenth thickness" of 
about 3.8 cm.

Somehow I don't think those goggles are an inch and a half thick, so I 
don't think that David's comment:

"dramatically reduced"

is valid.

Assuming a lens thickness of 1mm, we might be looking at an absorption of 
around 5% (i.e. a transmittance of .945)

You'd be better off with lead glass, at 100 times the absorption


I used 20 keV here because it's a typical voltage for a NST.

Even a small TC will put out a lot more voltage, and the absorption 
coefficients drop off a LOT with higher energy, which bites you two ways... 
not only do more Xray photons get through, but the ones that do have higher 
energy.  Of course, your absorption also decreases, so maybe the Xrays just 
keep on going through.

This is why calculating "REM"s is difficult, because a lot depends on the 
energy of the particles.


At 08:18 AM 10/7/2004 -0600, you wrote:
>Original poster: "David Trimmell" <humanb-at-chaoticuniverse-dot-com>
>Even soft x-rays will not be 100% stopped, but they will be dramatically
>reduced with even a Polycarbonate lens. Certainly, the higher density
>the material the better.
>
>Regards,
>
>David Trimmell