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NUBM08 decaned by accident,lets do some testing then

Alaskan

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+Rep next time I can, good thread.
 

Benm

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this is a nubm08 diode,we run those at 4+ Amps on our builds and im just testing it at 1.5A to be able to meter it on my hyperium cuprum.

maybe oxygen or something that oxygen contains makes a very slow degradation.i'll definetly keep testing it and don't forget that the can placed and sealed again so im expecting the degredation to stop at some point
That should be okay, it's rated for 3.0 amps continuous operation so you are well in the safe zone. Perhaps even a bit too far as the threshold is already 0.5 amps or so, and varies with temperature as well.

I'm not sure what you have set up in terms of heatsinking and/or a constant ambient temperature, but if there is any variation in that it could skew results quite badly.

Another thing to consider is measuring slope efficiency instead of power output at a relatively low current: when heatsinked well you could measure power at 2 and 3 amps forward current and keep track of the ratio between optical power output under those conditions. This may give you more information about performance (degradation) than raw power readings at a single current.
 

paul1598419

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this is a nubm08 diode,we run those at 4+ Amps on our builds and im just testing it at 1.5A to be able to meter it on my hyperium cuprum.

maybe oxygen or something that oxygen contains makes a very slow degradation.i'll definetly keep testing it and don't forget that the can placed and sealed again so im expecting the degredation to stop at some point
Not trying to admonish you, but oxygen, or O2, is just that and contains nothing else. Maybe you meant to say "air" as it contains several gasses....mostly nitrogen and oxygen. There are also particulates suspended in air that could be contributory. +rep
 
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Not trying to admonish you, but oxygen, or O2, is just that and contains nothing else. Maybe you meant to say "air" as it contains several gasses....mostly nitrogen and oxygen. There are also particulates suspended in air that could be contributory. +rep
yea you are right,(air not oxygen)i meant mostly the other gasses and also some other items like dust that air can contain. :thanks:
 
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Since oxygen is very reactive,

it can be sometimes be very usefull as a part of the sealed diodes gas mixture. Some other stuff that has been created inside the can due to the high energy of the blue laser photons (or what ever else)
will react with the O2 first. This is not bad as the second choice is something in the diodes front apperture. By sacrifying oxygen, we can save or increase the life time of the diode. Other active gases can
be used depending on the chemestry involved. The residual atmosphere should be a dry inert gas like argon or s.e..

Singlemode
 

RedCowboy

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One factor could easily be moisture/humidity that as well as dust and smoke is one reason many light engines are sealed with heat being carried away to remote fan forced radiators.

With the facet being so tiny just removing the can and replacing it could be enough to reduce MTTF

Here's a pic of a 32 Gball diode unit, you can see the seal where the top was removed.

https://laserpointerforums.com/f44/...lumens-laser-projector-99031.html#post1448328
 
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One factor could easily be moisture/humidity that as well as dust and smoke is one reason many light engines are sealed with heat being carried away to remote fan forced radiators.

With the facet being so tiny just removing the can and replacing it could be enough to reduce MTTF

Here's a pic of a 32 Gball diode unit, you can see the seal where the top was removed.

https://laserpointerforums.com/f44/...lumens-laser-projector-99031.html#post1448328
Nice picture you have here (from a huge beamer I assume). As I see the complete housing has one
common seal. This is pretty standard and even a must in such systems in the ~ 10W and higher range to protect all optical surfaces from beeing burned by a small particle like dust f.e..

All the points you are talking about can be accomplished with technical vacuum only. No need for inert gases or other ingredients (to seal under an artificial atmosphere you need to evac. anyway) so why the extra work if it is not needed?
Especially if anything else than vacuum increase the heat transfer to the diode can window and reduces the one to the rear of the can, that serves as a heat sink.

Especially blue laser light is nasty since with high intensity it can drive 2-photon transitions in the deep UV ionizing all the stuff around. O2 likes to create a bond with this nasty ones.

I can lool for some theses that are not sensitive if needed.

Singlemode
 

deadshadow

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hello everyone im updating the thread with a new reading after a total of 5 months from the first decan and instant recan.



my main theory that if the diode resealed it will degrade at some point due to air that trapped inside but the degradation will stop after a certain point, seems that came true.

as you can see the reading from 2 months total time vs 5 months total time is almost identican and the degradation seems to have stopped at this point.
 

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Alaskan

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Very interesting. I would also like to see run time factored in, the power degradation might increase more when exposed to oxygen when running. This test doesn't factor that in, does it?
 

deadshadow

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Very interesting. I would also like to see run time factored in, the power degradation might increase more when exposed to oxygen when running. This test doesn't factor that in, does it?
you mean air* as air contains others than pure oxygen(i made the the same spelling mistake in the past ;) ) yes you are right the testing is made with the diode in off state,it could be a a different result if the diode was in 'on' state the whole time
 

Alaskan

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Yep, I bet run time exposed to the air causes more degradation to the diode too. A given, they normally loose power over time when canned too, but I'm wondering if more rapidly when exposed to the air.
 

RedCowboy

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Who removes a GBall can then puts it back on and uses it like that ?

Basically nobody, what people do is remove the GBall and use a G2/G7/G9/3E lens that they can focus.

Will removing the GBall produce premature optical output loss compared to a unmolested GBall intact diode, my experience is that removing the can causes accelerated wear while powered but not while in storage.

Replacing the can and testing at low power once in a while over months proves nothing except what I have said before, that is there is no degradation while in storage.

Run a vacuum seal broken and glue the can back on 08 diode for 60 seconds on and 300 seconds off next to an unmolested 08 diode for 60 seconds on 300 seconds off for 50 hours and track the output, make sure to drive both diodes at the same current and in the same size/type heat sink.

You will discover that breaking the vacuum seal on the can introduces nitrogen/oxygen/moisture that erodes the facet where the beam exits the P/N junction and you should see a large reduction in optical output compared to the unmolested diode after just a few hours of total runtime observing a reasonable duty cycle to prevent overheating.
 
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