[RASMB] AUC windows

John Philo jphilo at mailway.com
Mon Nov 28 16:41:15 PST 2005


Casey,

You should read the recent RASMB discussion of window suppliers and window
breakage in the archive. Unless you really must have excellent transmission
at the lowest possible wavelengths, I'd recommend using sapphire rather than
quartz simply because it is so much more durable.

One point that I don't think was really brought out in that recent
discussion is that these very inexpensive windows are FUSED quartz, not
single-crystal quartz as manufactured by Meller Optics and supplied by
Beckman. I'm not going to defend Beckman's $600 price, but the prices from
the non-Beckman/Meller suppliers are not really for equivalent products.

I can't say for certain to what extent fused versus single-crystal quartz
makes a difference with regard to breakage, but I would suspect the
single-crystal is much stronger. The single crystal ones will be more
homogeneous in refractive index and therefore MIGHT actually produce
somewhat lower noise, although I suspect surface smoothness is more
important in that regard.

John

-----Original Message-----
From: rasmb-bounces at rasmb.bbri.org [mailto:rasmb-bounces at rasmb.bbri.org] On
Behalf Of cjohnson at salk.edu
Sent: Monday, November 28, 2005 3:13 PM
To: rasmb at rasmb.bbri.org
Subject: [RASMB] AUC windows


dear all,
i recently ordered some quartz windows for analytical ultracentrifuge from
>a company other than beckman coulter.  these windows cost 1/10 of the 
>price per window as compared to beckman.  however, 3 out of 6 windows 
>broke on the first run.  obviously this scenario will not work long 
>term. i would like to know which type of quartz windows you prefer?  i 
>thought i would ask around before plunking down the $600/window for 
>beckman quartz. thanks for the help.


Casey D. Johnson x1976
Salk Institute
Structural Biology Lab - Choe
10010 N. Torrey Pines Rd.
La Jolla, CA 92037 _______________________________________________
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