TEA co2 laser turns air into plasma

[Benm]

So yeah, 35 million watts focused down to an area about 1mm across. You can see why it makes the air explode.  
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Any more and it will rip holes in spacetime itself?

 

[Hemlock_Mike]

EH --- Did you get a look in that laser?? Is the chamber round ??? What do the capacitors look like?? Round, flat ??? How many Kv??

I read that round caps induce too much inductance into the circuit. Are these big flats on the sides???

Mike

 

[Event_Horizon]

I didn't get to take a peek inside the laser itself. The laser had been set up so the voltage inside the tube is adjustable, we were running it at around 20kV at the time. It can do up to 40kV but around there you start having problems where the ionizing spark actually arcs right across the tube and that supposedly causes some tube damage. The ionizing spark gap in this case is a sort of metal grating/screen that runs along one of the electrodes, which has pins that stick out near the screen. The entire voltage is placed across the tube and the ionizing sparks jump from the pins to the screen, which quickly becomes charged with the same voltage as the electrode, and then the actual discharge goes through the screen to the other electrode.

The only photo I could find of the inside of the laser is a picture in the SOP posted on the schools technology website, get it here:

http://technology.niagarac.on.ca/sop/SOP-LumonicsTEA.pdf

The caps are along the bottom of the picture, they look like simply huge electrolytic caps to me. Sorry I can't get you anything more detailed about them.

 

[Event_Horizon]

Do I see a spectra physics argon laser back there?

It very well could be. I wasn't really paying attention to that laser on account of the atmosphere exploding in my face! The lab has well over 20 lasers, everything from pulsed CO2s like that, to Excimer lasers, several argon ions, two kryptons, three large frame YAGs, two CW dye lasers, a couple CW CO2 lasers, two Helium-Cadmiums, a couple other metal vapour lasers, and the second most awesome setup apart from that TEA co2, is this:

40kW goes into a very very large Coherent multiline argon laser, which outputs about 7 watts that pumps a tunable Titanium Sapphire laser, which has an output of a few hundred mW, which THEN pumps a frequency doubled Nd:YVO4 crystal, which outputs a couple mW. So all in all you have a percent efficiency of 0.00001%! That's seven orders of magnitude!

 

[Hemlock_Mike]

As I figure, at 20 kV I need .03 mFd of capacitor. Sound right??

Mike

 

[Event_Horizon]

I couldn't say. I was only shown a very basic schematic of the firing circuit. If you are building one then I'd just try the best guess. If it's too much, back it down, if its not enough, add more. Sorry.

I'll ask the laser maintenance guy about it next time I see him.