Dear folks,
        I would be grateful to receive feedback regarding the stability or
fragility of the red 647nm excitation line of the krypton-argon lasers. Our
use of it here with an MRC-600 has been frustrating for the following
reasons.
(1)     It seems to only emit when the available power is more than 80-90%
of maximum i.e. an LCV of > 4.0Volts. When we have managed to have it
emitting at the lower end of this range it invariably cuts out and may
sometimes be reinstated as we turn the power output up.
(2)     The laser mirror Allen key adjustment at the rear of the laser head
is so exquisitely sensitive that adjusting for the red line seems
impossible. If one does fluke it the stability of the gymbals does not seem
to match the rigourous positional requirements of the laser mirrors for red
line production and in no time at all there seems to be fractional movement
of the gymbals, hence the mirrors, and no red line apparent.
(3)     When we do manage to have the red line shining the raw Cy5 image
will have, to a greater or lesser extent, horizontal banding across it
which in my simplistic way I am assuming to be a "reflection", for want of
a better word, of the fluctuating intensities of an unstable red excitation
line. This can generally be improved by Kalman filtering but is not
something I see when using the blue or green line with their fluorescent
probes.
 
During this travail if I check the blue and green line they will emit very
strongly and, in fact, will  do so at 50% power output. While I'm here is
the argon gas solely responsible for the blue and greeen line production
and krypton gas the red or some other combination?
 
Input from krypton-argon red line excitation users would be much apprrreciated,
                Cheers,  Colin
 
 
 
 
 
The Hielander
Colin Macqueen      [log in to unmask]
Confocal Facility   The University of Queensland