Re: Argon ion laser - age/noise and effect on images..?

Posted by Craig Brideau on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Argon-ion-laser-age-noise-and-effect-on-images-tp7586010p7586013.html

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As Rosemary says, it could be your alignment through the system generally. I would also check that the alignment and tuning of your AOTF is still ok. Otherwise grainy images are indicative of low signal, so the laser may just not be producing enough power. I recommend that equipment managers regularly measure the laser power at the sample plane of the microscope to determine long-term drift. If you have historical data available you can compare the current power out of the objective with power levels from when the system was operating better. This helps you diagnose if it is an excitation problem or an emission problem.

It is also possible to get Argon lasers refurbished for reasonable cost. This is typically half the price (or better) of a new laser and essentially brings it back to factory spec. I have had two Argon lasers in our lab sent out for refurbishment with excellent results.

Craig

On Thu, Nov 17, 2016 at 5:26 PM, <[hidden email]> wrote:

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Hi Jacqui,

Could your laser have just gone out of alignment? This happens quite regularly on our old SP2.

cheers,

Rosemary

Dr Rosemary White

CSIRO Black Mountain

GPO Box 1700

Canberra, ACT 2601

Australia

T 61 2 6246 5475

E [hidden email]

From: Confocal Microscopy List <[hidden email]> on behalf of Jacqui Ross <[hidden email]>
Reply-To: Confocal Microscopy List <[hidden email]>
Date: Friday, 18 November 2016 11:19 am
To: "[hidden email]" <[hidden email]>
Subject: Argon ion laser - age/noise and effect on images..?

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Hi everyone,

 

I’m hoping that someone can help me to confirm whether an effect I am seeing with one of our confocal  microscopes is likely to be due to the ageing of an argon ion multiline laser.

 

The laser is about 8 years old and the power level has dropped to about 1/3 of the original output but we are still able to excite the fluorophores very well at AOTF controlled percentages <5%.

 

What I’m noticing is that when I use the argon ion laser, e.g. 488nm line, the images look much more granular than when using other lasers when similar voltages are being used at the PMT. I’ve checked the other detectors and it doesn’t seem to be related to the PMTs.

 

Much slower speeds and more averaging do improve the images but I’m puzzled by this as the issue is there even when the Master gain/voltage is at a level which I wouldn’t normally need to go slower/average as much.

 

Can anyone tell me whether the age of the laser can cause issues like this? I’m wondering if we should just replace it. We only normally replace lasers when they expire.

 

Or if there are some tests that I can do to further define the issue?

 

The last measurements were as below for 8A with two different beam splitters;

 

488nm              0.51mW (NT 80/20)                    2.31mW (MBS488)        

Thanks in advance for any ideas.

 

Cheers,

 

Jacqui

Jacqueline Ross

Biomedical Imaging Microscopist
Biomedical Imaging Research Unit (BIRU)
School of Medical Sciences 
Faculty of Medical & Health Sciences
The University of Auckland
Private Bag 92019
Auckland 1142, NEW ZEALAND

Telephone: Ext 87438; DDI:  [phone]

Website:    http://www.auckland.ac.nz/biru