Re: He-Cd UV laser
Howard Shapiro (hms@shapirolab.com)
Fri, 19 Apr 1996 17:59:46 -0400 (EDT)
>we have problems with our UV laser.
>We use a Coulter Elite ESP with a He-Cd laser
>from Omnichron for DNA measurements.
>We start with a full CV measured with beads from
>Coulter - DNA check - about 2.5 to 3. After half
>a year, the CV increased to 5/6 and get worth.
>
In all likelihood, the laser has become noisy due to increased helium
pressure in the tube. This process can be slowed, but not stopped, but
running the tube for an hour or so a week, but it can't be reversed. Since
neither Coulter nor the other flow cytometer manufacturers have elected to
provide the relatively simple noise compensation circuitry which could
readily allow users to get better CV's from noisy lasers, you'll probably
have to replace the noisy plasma tube, even though power may be adequate.
However, call Omnichrome first; maybe they've found a magic fix.
--Howard
CD ROM Vol 2 was produced by staff at the Purdue University Cytometry Laboratories
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If you have any comments please direct them to Dr. J. Paul Robinson, Professor & Director, PUCL,
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EMAIL robinson@flowcyt.cyto.purdue.edu
