[RASMB] Am I missing something?

[Borries Demeler]

Dror,

Keep in mind that the limiting factor here is the flash lamp. You can only
fire the lamp so many times, which means several rotor revolutions pass before
you can take the next measurement. The idea you have requires a constant light
source and a very fast acquisition chip which can integrate in timesteps shorter
then the width of the channel sector (there are two). Each recording requires a 
lamp flash.

No matter how you scan it, it will still take the same number of
(relatively slow) lamp flashes to get the same number of scans. A lamp
flash doesn't last long enough to illuminate all cells at all speeds.
Right now, the only way to scan with the current technology is a cell at a time.

There are new optical systems under development that allow so called "rapid
scanning" using constant light sources and fast integration circuits. Tom Laue
may have some more information on this topic.

Best regards, -Borries


> 
> Dear all,
> I'm running sedimentation velocity experiments on our XLA where a 
> typical scan (no replicates, r=6.0 to 7.2) takes about 1 min. If I try 
> to scan two cells or more, the time interval between scans increases 
> proportionally because the XLA software scans the cells one at a time 
> (i.e. scans the whole radial range for cell 1 then cell 2 etc.). This 
> makes scanning several cells unreasonably slow. Does anybody know if 
> it's possible to scan multiple cells simultaneously a radial step at a 
> time (i.e. measure at r=x for all the cells then for r = x+dx for all 
> cells etc.)?
> Thanks,
> Dror
> =========================
> Dror Noy, Ph.D.
> Structural Biology Dept.
> Weizmann Institute of Science
> Rehovot 76100
> Israel
> 
> e-mail: dror.noy at weizmann.ac.il
> Tel: (972)-8-934 2525
> Fax: (972)-8-934 4154
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