# Suggestions for 200-600 nm range transmitting polymers/materials

I am a student of physics who is doing research related to Cherenkov measurements. For that purpose, I need suggestions for some materials that have the following properties:

• $80\%$ transparency in the range of $200$-$600$ $\mathrm{nm}$

• Low scintillation light produced from electrons

• Relatively lower density

• A high refractive index

Some materials in this regard that I have tested are PMMA, TPX, NAS, LURAN, TOPAX, and Plexiglass. I want to test more materials to see if something does better; what polymers or other materials might I try to achieve these properties?

• Photons with wavelength around 200 nm are highly damaging to almost any kind of organic matter (not only do the photons get absorbed, they trigger molecular decomposition rather than just being turned into heat). Depending on the photon flux around this wavelength, your parts could degrade quickly. Inorganic materials are a must. Jan 13 '17 at 20:21

No plastic of any practically useful thickness$^\dagger$ has $80\%$ transparency down to $200~\mathrm{nm}$. Period.

Below is a UV transmission chart for various materials from a marketing brochure published by BrandTech, a manufacturer of disposable UV/Vis cuvettes (click image to enlarge):

The chart only goes down to $210~\mathrm{nm}$; extrapolating the trend, not even quartz is $80\%$ transparent at $200~\mathrm{nm}$, but it's probably a decent choice for your purposes as long as it sufficiently meets your other criteria.

Beyond that, fluorite $\left(\ce{CaF2}\right)$ is the only specific material I know of with better UV transparency; it appears to have better than $90\%$ transparency down to around $200~\mathrm{nm}$ (figure is from ThorLabs online catalog):

A chart at that ThorLabs link indicates two additional candidate materials: $\ce{MgF2}$ and sapphire. As with quartz, the choice among these will boil down to how well they meet your other criteria.

$^\dagger$ As a caveat to the above: If a very thin plastic film ($\leq 100~\mu \mathrm{m}$ or so) is acceptable, a specialty material might give sufficient transmittance. You would have to convince the manufacturer of such a material to make it for you, however, which would probably not be trivial, or cheap.

• Ah thanks a lot, really appreciate the material insight you gave as well as the insight into the transmission rates. Jan 18 '17 at 8:21