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 ---------- 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
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