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Re: [ATM] Quartz blanks
On Tue, 7 Feb 2006, Mel Bartels wrote:
> > quartz pieces for much less than $1500 USD. Can he used
> > so-called fused silica, BTW?
>
> I thought they were essentially the same - is this correct/wrong?
>
> Mel Bartels
Mel,
Looks like others got to this before me. Basically, as mentioned,
these are structurally not the same. Optically they are very
similar. In fact, at the wavelengths we most often interested
in, you won't find much difference even compared to low iron
plate and borosilicate. The real difference in terms of transmission
is in the very low UV (around 240 nm, but let's say below 300 nm)
and NIR. Somewhere at/below 300 nm, fused silica is markedly
superior than quartz. If you want to see some transmission curves,
I can dig some up. Alternatively, Beckman Instruments makes
spectrophotometers (DU7500) commonly used by biochemists. They
have manuals, etc that discuss the choice of different cuvettes
(quartz, fused silica, etc) for different applications and show
typical transmission curves. We pay a huge premium for low UV
cuvettes (more than 1000 dollars), but only because we have
specific applications that absolutely require these. For all other
applications, we use other, much cheaper ones (about 1 USD
each, disposable).
Dominic-Luc Webb
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