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I made a TEA laser and it isn't working

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Zack

Mon Jan 17 2011, 01:14AM

Registered Member #3624 Joined: Mon Jan 17 2011, 01:08AM
Location:
Posts: 25

There was someone on a previous thread who was having the exact same problem I am. When the spark gap fires, the rails arc but don't lase. I don't know why this is happening. I've spent hours and hours trying new things, but nothing is working. I have a couple pics here.

You can see in the pictures that the rails are firing but not lazing.

Bjørn

Mon Jan 17 2011, 01:23AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

I presume you have read this:

The discharge between your rails does not seem very uniform, it might be the problem.

Zack

Mon Jan 17 2011, 01:37AM

Registered Member #3624 Joined: Mon Jan 17 2011, 01:08AM
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Posts: 25

Yeah, I read the hv wiki. But the problem is the discharge not being uniform is what I'm trying to solve. The rails are smooth and pretty equidistant from each other, but still no lazing. Here's the other thread I was talking about.

radhoo

Mon Jan 17 2011, 09:31AM

Registered Member #1938 Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701

Hi Zack, this is Radu, welcome to 4HV!

Zero

Mon Jan 17 2011, 11:12AM

Registered Member #3588 Joined: Sat Jan 08 2011, 11:19AM
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Posts: 36

You should use at least one adjustable rail/electrode for your laser...and you have to be sure the alu-foil lays smooth on the isolator.

Mine was lasing like right away:

There are a few close ups...might help.

Electroholic

Mon Jan 17 2011, 12:55PM

Registered Member #191 Joined: Fri Feb 17 2006, 02:01AM
Location: Esbjerg Denmark
Posts: 720

Is your current path going up the alu angles? The extra inductance might be the problem. Also, try polishing the gap edge, and weight the electrodes down to improve contact. Any other specs? voltage? rep rate?

Zack

Mon Jan 17 2011, 02:26PM

Registered Member #3624 Joined: Mon Jan 17 2011, 01:08AM
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Posts: 25

Rep rate is 2hz. The current might be the problem. But I've done all of this but it just doesn't want to laze. It makes hot blue sparks that aren't working. I think that the sparks are supposed to be purple. Also, I just realized the rails were anodized, but I removed the finish and still no luck.

EDIT: I took the inductor away and it does the exact same thing. wonder what it could be...

klugesmith

Tue Jan 18 2011, 04:13PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

Zack wrote ...
Also, I just realized the rails were anodized, but I removed the finish and still no luck.

Yes, anodize coating is a good insulator. Did you expose the metal uniformly along the gap, and also where the angles touch the base plates?

cedric

Tue Jan 18 2011, 05:06PM

Registered Member #2941 Joined: Fri Jun 25 2010, 08:08AM
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Posts: 143

tea nitrogen laser are not easy to tune ,a lot of parameter are important : the dielectric have to be really fine,like one layer of over head projector film ,the aluminum paper have to be lying very flat on the dielectric .on your first foto it look like your spark gap is next to the middle near the electrode,normally it's on the side of one of the capacitor ,the hole process last less than two nanosecond so the spark you see in your channel is not very important but if it's always append at the same place you know that your rail are not parallel . the contact in between the rail and the aluminum paper have to be pretty good to, so you need to put some thing heavy on them .
finally even with a perfect set up lasing can take some time .
advise : a clean set up with nicely cut dielectric and aluminum foil,the spark gap on the side of the laser ,not necessarily in the middle ,
a good dielectric is very important ,typically ,for a tea to work you need a dielectric witch is on the edge of breakdown ,unless you can afford kapton or some Teflon material,for mine I use for instance some strong trash bag witch are use for demolition ,I think they are made of hdpe, from the five in the bag they are always one or two who have visible defecte,over head projector sheet work as well and some x-ray film but for higher voltage.
for a overhead projector sheet the voltage have to be in between 5kv to 10kv.
once every thing is in place ,you can get the rail very close to each other and once the spark gap is firring you can use a dielectric material to take the electrodes apart,the ideal distance depend of the voltage and the shape of the electrode but most of the time is around one millimeter.what you want to see first is a nice corona discharge in between the electrode ,from one side to the other,once you get this you mus be getting close.and of course you need a fluorescent target .

Conundrum

Sat Jan 22 2011, 11:02AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

GITD paint or EL phosphor makes a good target

If its any help I can send some pieces.

-A

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