Dear Kim,

We have a graveyard of sample chambers of bewildering
dimesions.  The bottom line is that if you have a large
chamber, it takes more time to sweep all of the CO2 gas
out of the chamber into the line.  Also, if you have
larger samples, there is a much longer time to degas them.
 All in all, I think the solution is a small chamber.
 Take your large sample and break it up into smaller
pieces, loading one at a time.  With a small chamber, the
flushing time after exposure to air is so short, that you
should be able to change samples and be up-and-running
again in just a few minutes.

Sincerely,

Zach

On Thu, 9 Jun 2005 12:22:45 +1000
  Kim Baublys <[log in to unmask]> wrote:
> Isogeochemists,
>
> We are currently running a laser carbonate system
>(CF-IRMS with a 75watt
> CO2 Merchantek laser ).  We need to redesign the laser
>cell to be able to
> handle larger sample sizes.  We would like any
>information/advice on the
> properties and costs and people's experience with
>different cell windows
> and cell designs.  I've searched the archives and laser
>ablation of
> carbonates was last mentioned way back in 1995.
>
>
> Thanks
> Kim
>
>
> Kim Baublys
> Stable Isotope Laboratories
> Department Of Earth Sciences
> University of Queensland 4072
> Australia
>
> Ph:   +61 7 3365 1131
>Fax: +61 7 3365 1277
> http://www.uq.edu.au/geochem/