RE: Attention dye laser jockeys

Kevin Holmes (KHOLMES@atlas.niaid.nih.gov)
Fri, 22 Aug 1997 18:48:12 -0400

We've also have a Coherent 599 dye laser on our FACS Vantage. The
biggest tip I can give you concerns a maintenance trick that we've
recently found which can greatly improve the overall consistency of
the dye laser output. We noticed that a puddle of dye was always
visible in the bottom of the dye head. We talked with BD and Coherent
and got recommendations on different methods to start and stop the dye
pump. But the biggest difference was found when we pulled the rubber
boot over that covers the dye jet nozzle and starting looking. It
seems that after you turn off the dye pump and flow of the dye is
stopped, there is apparently still residual pressure within the
tubing. If you carefully clean the tip of the nozzle with a methanol
soaked swab and wait.... you find that a droplet of dye forms on the
end of the nozzle! This droplet formation can still be seen even when
the dye has been off over 2 or 3 days. What we routinely do now is to
swab the nozzle with methanol both after shutting down and before
starting up. The results of this little trick is that we no longer
have a puddle, our power output is more consistent and we need to
tweak the dye less to get the same amount of power.
We think that if you don't clean the nozzle, when you start the dye
pump some of that dye droplet is probably sprayed in all different
directions (creating the puddle over time), and also some of the dye
may have dried in the orifice, changing the direction of the dye jet
and therefore the alignment of the pump laser beam with the dye jet.
As you run, the dried dye may actually dissolve, again changing the
direction of the jet (which explains why we sometimes had to tweak the
dye laser after it had been running a while)

BTW, we also have a Spectra Physics model 355 dye laser, which
curiously has a vertical dye jet/catcher tube design and doesn't have
the above problem.
I'd be happy to share any other dye laser info/questions. Dye lasers
are somewhat finicky, but we've operated them for over 10 years and
are happy with the wavelengths and flexibility they give you.

Kevin L. Holmes, Ph.D.
Head, Flow cytometry Unit
Office of the Scientific Director
Bldg 7, Room 01
NIAID, NIH

Phone: 301-496-9071
FAX: 301-402-4532
Email: kholmes@atlas.niaid.nih.gov

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From: Joseph Webster[SMTP:J.Webster@centenary.usyd.edu.AU]
Sent: Thursday, August 21, 1997 10:51PM
To: cyto-inbox
Subject: Attention dye laser jockeys

I wish to share hints, tips & ideas with other dye laser users,
especially with BD sorters.

I have a FACStar Plus and a Coherent 599 dye laser, and I'm feeling
a bit isolated.
I have some experience and expertise as well as lots of questions.

Many Thanks, Joseph.

Joseph Webster, Flow Cytometry Facility manager
Centenary Institute
Locked Bag No.6, Newtown, NSW 2042, AUSTRALIA.
Ph: 61-2-9565-6110 Fax: 61-2-9565-6101