laser stability

Posted by Arvydas Matiukas on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Glicerin-labeling-tp7265984p7266641.html

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Dear list,
 
Please advice what is the most efficient/cheap way to deal
with confocal laser instability. Our LSM 510 is 7 years old
but  Ar and Hene 543 lasers have been replaced two years
ago and have been used no more that 2000-2500 hrs.
Users started complaining about 488nm and 543nm laser
line stability, and I measured it using Chroma fluorescent
plastic slides and 10x objective. The frame- averaged fluorescent
signal is reduced by 40-50% in 1hr after laser start. The decline
curve is quite steady after first 3-5 min with some fluctuations.
 
The  most disturbing  are intermittent large scale signal fluctuations (2-4 fold)
occurring on about a minute timescale. They kill dynamic (e.g. FRET) or
long-term imaging. They happen irregularly, on average once in 4-5 days,
and always after 2-3 hrs after the lasers are started.
 
In a related post several years ago laser cooling, laser polarization, AOTF cooling,
and AOTF driver stability were listed as the key factors. I am quite confident that cooling
is not an issue as the fans within the equipment boxes are working well, and whole room
has a powerful local conditioning system which maintains ambient temperature very stable.
Zeiss engineer checked the fibers recently, and suggested that maybe AOTF drivers are
not stable. As we are not on service contract and have to pay for every replacement I
would be interested to do more testing myself to identify the failing component.
 
Any suggestions/advices are very welcome. I can provide the measurement curves if
somebody is intersted (contact me off list).
 
Thanks,
Arvydas
 


 
 
 
Arvydas Matiukas, Ph.D.
Director of Confocal&Two-Photon Core
Department of Pharmacology
SUNY Upstate Medical University
766 Irving Ave., WH 3167
Syracuse, NY 13210
tel.: [phone]
fax: [phone]
email: [hidden email]