[RASMB] Sapphire windows

[Kristian Schilling]

Hi all,

I would like to get rid of some Sapphire windows, I am willing to sell them 
at 80 EUR per piece. Here's why:

We have been using Sapphire windows ever since because we have interference 
optics. However, we were never quite happy with the windows in question 
because they have significant fringe noise. It's mostly somewhere in the 
range between one fringe and half a fringe over that one cm we register.

Of course one can aquire a blank scan at the beginning of the experiment 
and subtract the time invariant noise from all subsequent scans, but it has 
turned out we rather use those cells all the time where the windows are 
better... Just to say you *can* work yourself around with these windows.

The fringe noise is due to inhomogenities inside the sapphire material. It 
will not influence the results of absorbance measurements, however, it is 
not recommended to use sapphire for measurements below 235 nm.

The windows are not Beckman originals but are geometrically identical, and 
they look exactly the same. I bought them directly from a Sapphire company 
but it turned out only one out of three were really satisfactory. I will 
try out other materials and sources and would like to do so until the end 
of the year, but for that I will need some cash, so here goes...

I have placed typical interference scans of a "good" and a "bad" window at 
the following link for illustration: 
http://www.nanolytics.de/scientific/sapphire.pdf

Best wishes,
Kristian



=================================
Nanolytics
Gesellschaft fuer Kolloidanalytik mbH
Dr.  Kristian Schilling

Hauptstr. 20
D-14624 Dallgow

Tel.:		+49/3322/24200-5
Fax:		+49/3322/24200-6
e-mail:	schilling at nanolytics.de
Internet:	www.nanolytics.de