I made a TEA laser and it isn't working

[Brutus]

The dielectric is 4 sheets of .05millimeter paint-drop cloth, the capacitor plates are aluminum foil, the electrode is a s are aluminum v angle stock, and the power supply is a 2n3773 flyback driver. The electrod rails are readily firing but just not lasing. I have tried just about every rail configuration and still no lazing. I have some pictures here.

 

[Brutus]

bump.

 

[qumefox]

Firstly.... Don't bump something just because nobody replies immediately... You waited a WHOLE 16 minutes.....

Secondly.. you know TEA lasers are CO2 devices right? I see no gas source or containment.. They don't work open air... unless you sucked all the air out of the room, and replaced it with CO2... which I doubt you did since your in there taking pictures..

 

[ElektroFreak]

^TEA lasers are Nitrogen lasers, and IIRC they do in fact run on open air...

 

[qumefox]

Hmm.. I was going by this.

TEA laser - Wikipedia, the free encyclopedia

 

[GBD]

The dielectric is 4 sheets of .05millimeter paint-drop cloth, the capacitor plates are aluminum foil, the electrode is a s are aluminum v angle stock, and the power supply is a 2n3773 flyback driver. The electrod rails are readily firing but just not lasing. I have tried just about every rail configuration and still no lazing. I have some pictures here.

Looks to me like the same one you posted on 4HV

TEA lasers do run in open air, the nitrogen is formed from the spark gap.
is the gap firing properly?

also, the discharge rails need to be pretty much PERFECT and uniform for this to work properly.
I made mine out of some 1/8" aluminum L brackets and a copper wire.
if it still fails to lase, another thing to try out is messing with that inductor's value a bit.

also, since you said you are using a flyback for this,
care to post a picture of it?
most modern flybacks have an internal diode, so they are DC output
the older ones with a disk shaped secondary output AC.

You will need DC for this to work.

 

[ped]

qumefox << busted

Also what driver are you using for the FBT?

 

[qumefox]

qumefox << busted

Also what driver are you using for the FBT?

Only half way.. The problem stemmed from there being multiple types of TEA lasers, and the CO2 variant was the only one I remembered, and it didn't help that the CO2 TEA laser wiki article was the first one that popped up when I googled either. :cryyy:

And from his pics, it looks like a fairly typical TV flyback. Though I would certainly recommend he heatsinks the drive transistor properly, instead of halfway like it is.

 

[Brutus]

FBT driver is a 2n3773. Yeah, I did post on 4hv. It just doesn't seem like anyone knows how to fix this. I have found several people who have had the same problem, but none of them have been able to fix it. I got the firing rate pretty stable using a resistor, but no lazing at all.

 

[phenol]

A couple of years ago I made a TEA laser like that and it worked. My build was a lot sloppier than yours, it was also somewhat smaller but it did lase, albeit not spectacularly. There are a couple of key points you need to consider carefully: 1. Minimize all parasitic inductances and 2. Align the electrodes properly. A few tens of microns woth of offset can readily kill it.
As concerns 1, use the thinnest dielectric possible with sufficient breakdown voltage (I used overhead projector plastic sheets), make sure your spark gap is 'beefy' enough (two pieces of wire facing each other's tips wont do; it has got to have large cross-section for low inductance. I actually used two cologne cylindical metal caps (real metal, not metallized plastic) spaced around 2-3mm apart. The low inductance mantra is valid for the electrodes as well-they must be in perfect contact with the Al foil. Put a heavy non-conductive object on them (a jar filled with water, for instance) to press them against the foil as much as possible. Better yet, get a different pair of electrodes with lower inductance (those v-shaped angles seem to touch the foil only along one of their rims, the contact area is rather small and the overall inductance high), for instance L brackets or just wide enough flat (2-4mm) bars on which you can stack weights.
The gap between the electrodes seems somewhat insufficient. with my own setup it lased only when the gap was some 2-3mm wide. To register the presence of 337nm output I used plain white paper sheets. They are bleached and produce bright blue light when bombarded with UV.
I have Rhodamine-B, but i never got it to lase with that thing. I didnt have a cyl. lens to properly focus the beam on the cuvette

 

[Brutus]

i got it working for about 5 seconds and then it stopped and I can't get it back

 

[Brutus]

bump.

 

[qumefox]

You might get more replies if you give more information on how exactly it quit.

 

[Brutus]

It began arcing through the di-electric.

 

[Brutus]

Sorry to be pushy, but bump

 

[Brutus]

Bump, I need help. I changed the di electric to overhead projector film and although it's not arcing through, it has still yet to laze.