Using Mylar (TM) to block radiation

[Plasmech]

Has anyone any experience using 2 mil Mylar film as a radiation block? Certainly more industrial than aluminum foil found in the supermarket...Does anybody have the "E' value of said Mylar film? Thanks.

-Plasmech

Mechanical Engineer, Plastics Industry

 

[Plasmech]

Another point...in someone else's post below, a reply states that the radiation barrier must "see" the heated product...it must be on the inside. I agree that this is true if one wants to kill the radiation leakage at the source so to speak, but if the reflecive film was on the outside of the vessel "facing in" would that not stop/reduce the radiated heat energy of the system as a whole in the long run? I'm pretty certain it would...

-Plasmech

Mechanical Engineer, Plastics Industry

 

[iainuts]

Aluminized mylar might be what you're looking for. It can be single or double sided, and is commonly used as radiations shielding inside vacuum jacketed equipment.

 

[dvd]

Facing the reflective surface on the outside surface of the vessel looking inward and against a solid surface would only be effective at reflecting the radiation being transmitted through the solid. The wavelengths of the electromagnetic energy responsible for heat transfer are much longer than the spacing of molecules in most solids and thus solids don't transmit radiation well. (Clear materials will behave differently to some extent, however.) Conduction is a much more dominant mode of heat transfer.

The point in radiation shields is to reflect the radiation back to the source, before it warms the entire vessel. The warmer vessel will allow greater convection heat transfer with outside ambient conditions as well. Additionally, by placing a reflective film on the outside of the vessel you subject it to more abuse and the possibility of damaging it.

 

[IRstuff]

Radiation is proportional to absolute temperature to the 4th power. Therefore, the higher the temperature difference at which you place the reflector, the bigger the impact overall. If the effect was linear, there would be no difference in where you put it.

TTFN

FAQ731-376

 

[Plasmech]

I experimented with the shiny Mylar on the OUTSIDE of a vessel today. It didn't do jack %&$!.

I think this is because, like you guys all say, it needs to go on the INSIDE where I'll get a lot more bang-for-the-buck. Also, when beyond the steel vessel wall, it's simply bouncing radiation back at the wall, heating it (the wall), and then that heat is conducted to the Mylar and out to atmosphere. It needs to be inside...

-Plasmech

Mechanical Engineer, Plastics Industry