*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****
Hello Aryeh,
I recently have been seeing black (actually only darker, as in your
images intensity does not drop to zero as well) lines or bands
in Ar laser 488nm line excited scans on our LSM510. It turned
out that one of the fans in the VIS laser unit was failing. The unit
houses all visual lasers, AOTFs with control electronics, and beam
combiner. Replacing the failing fan fixed the problem which likely
was related to the overheating of laser power supplies and/or AOTF
control electronics. This was very quick and cheap fix (after
somewhat prolonged diagnostics) .The additional oberved characteristic feature was that
the black lines started appearing after 1 hr after the start of cold
machine, and progressively have been yielding more fluctuation.
I am not well familiar with Leica confocals, and your tiff images
do not provide complete hardware settings so I cannot translate
my LSM510 diagnosis to your SP5. However, based on common confocal
machine principles I would suggest to check the temperature/cooling
regime and stability for your confocal. In my case lines were not
periodic but maybe overheating leads to some periodic oscillations
in SP5 electronics (or laser as Guy suggested earlier).
By the way take a plastic fluorescent slide (which is uniform and not easy to bleach)
and check if the dark lines still appear periodically. Starting with simple
test objects sometimes helps the diagnostics.
Good luck,
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.: 315-464-7997
fax: 315-464-8014
email: [log in to unmask]
>>> Aryeh Weiss <[log in to unmask]> 8/31/2012 8:35 AM >>>
*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
*****
We see (apparently) periodic horizontal dark lines with our Leica SP5,
when using the argon ion laser. Images that show these lines can be seen
at the following link:
http://cl.ly/2m2h0R1u1J2w
There were some some posts on the list about this, with the suggestion
that the laser is dying. However, when last I checked (a few weeks ago),
that laser was putting out plenty of power (although the 488nm line was
relatively weak compared to the 514nm line). Also, the lines have some
periodicity (50Hz?). Faster scan rates increase the line spacing, but it
does not appear to be linear with scan speed.
Frame averaging will average it out, so it is not correlated with the
scanning system. So the lines are annoying, but average signal seems fine.
None of the other lasers do this, and it is independent of detector.
Therefore, we assume that the problem is upstream of the vis laser
combiner/AOTF. That leaves the fiber, laser head, and power supply.
We suspect the laser, but it would be more satisfying to understand what
causes this behavior. Understanding the cause may lead to knowing how to
fix it without replacing the laser, but even if not, I like to know why
things work (or dont work) the way they do.
Has anyone has seen something similar?
Thanks in advance
--aryeh
--
Aryeh Weiss
Faculty of Engineering
Bar Ilan University
Ramat Gan 52900 Israel
Ph: 972-3-5317638
FAX: 972-3-7384051
|
