My first HeNe :D

I finally got one of Dave's(daguin) 543nm HeNe lasers and it arrived today. It's my first HeNe and I have to say I am HOOKED on gas lasers. It is unfortunate that it set me back $111 for a ~2mW laser but its totally worth it now that it is on my desk. I have had it turned on way too long today messing with the beam and looking at its wavelength compared to my 520nm and 532nm pointers. What I find to be the best about these lasers is they have such a displayable look. The smooth neon glow of the bore tube is awesome. I decided to take a few picks of my ghetto setup. I plan to build it a permanent acrylic case so I can display it safely. Anyway here are some pictures:

This first one shows the real color of the tube when its on the best:
















Now I need to get myself a small fog machine so I can get some beam shots of this beauty.

Also got my first Argon the very next day. The thread is here:
http://laserpointerforums.com/f43/my-first-argon-84463.html#post1222021

Ooh, those wires running some impressive voltage numbers are a *bit* to close to spinning fan blades for comfort!

Otherwise, damn. Can HeNe's be ran without duty cycle, if so how much electrical power does all of it (including the PSU) eat up?

If I ever get a gas laser, I'd have it as a lamp mounted on a wall or something. It looks pretty.

HeNe lasers definitely make quite an impression when compared to your standard variety laser pointer, especially from the light emanating along the length of the core tube where all of the lasing action is taking place.

You may consider housing the tube into a hand held container, like a clear acrylic tube as one option. I did this which made for one heck of a laser pointer. To help reduce the chance of breaking the glass tube, I mounted it using common window insulation foam, so that the laser would be cushioned on all sides.

This also had the added effect of eliminating potential electrical shock from accidentally touching either end of the laser attached to the HV power supply. Speaking of which, what power supply did you use, or did you build one up from scratch?

Congrats!! That is totally awesome. The main thing holding back a gas laser purchase by me is my lack of understanding how to power them properly, but you got me thinking about them again

Very cool.

Eudaimonium said:

Ooh, those wires running some impressive voltage numbers are a *bit* to close to spinning fan blades for comfort!

Otherwise, damn. Can HeNe's be ran without duty cycle, if so how much electrical power does all of it (including the PSU) eat up?

If I ever get a gas laser, I'd have it as a lamp mounted on a wall or something. It looks pretty.

Click to expand...

I had a small-ish 3mw HeNe light in the corner of the living room that ran for over 5 years solid - always on. Probably draws current in similar amounts to light bulb.

I think the power supply went out, but hard sealed HeNes are good for a LONG LONG time.

They were meant to run 20,000hr non stop. They only take 4-7mA on average. However, they do take ~2.5kV

They can get warm, but it's not a problem really. I'd be more worried about something knocking it or disturbing it/breaking it more than the tube overheating or some other catastrophic malfunction

Hard seal tubes hold in the gas very well, and all that's happening inside, doesn't "burn" the gas away. Just ionizes it to excite the atoms forcing the electrons to a higher level, and then letting them fall down, producing light.

I know there are some with the misconception that this is actually using plasma to burn the gas and cause light, this is actually not te case at all, so they can sustain a long life of abuse

That being said, they do get warm quick, keep in mind that plasma is around 4000K

Hey Kap! As long as you have a psu for the HeNe that gives the right current, and voltage, you're golden. Red HeNes are pretty forgiving for this as well, much more than a greene. A 0.5mA difference with my Greene and we've got problems, but reds can handle some variance mildly well. Easiest setup is getting a psu that works on your local, or preferred electrical setup (110V, 220, 24, 12, 9). After that, make sure it meets the requirements of the tube. Then it's just a matter of hooking up the psu to the tube, then psu to wall (or whatever you're powering it with) and enjoying the pretty lights

Let me know if you have any questions, or need help pairing tube to psu, I'd by happy to assist

My PSU is rated for 1.2-1.6KVDC at 4.5mA and a total power rating of 22W max. I was only able to feel the slightest bit of warmth from the PSU after about a half hour of runtime so I do not suspect that it will ever be an issue. The tube itself gets warm mostly at the anode during operation so I put the little fan next to it to counter that. The fan was about 2.5 inches from the tube so its far enough away not to have a risk of voltage jumping to it. Plus its a USB fan that has plastic blades that could never damage one of the wires.

I plan to build a small acrylic case for it so that I can safely put it in the open for display. I would build a portable unit for it but I feel that is just too much risk for right now. I do know of 5VDC PSUs that are made for this size tube but I would do that with a different tube I think. I don't think I am going to make a portable one though because the act of turning the tube on and off wears them out much quicker(from what I have read) but I may consider it in the future.

Honestly at first I was a bit scared of the voltages being utilized in this laser but now I feel pretty comfortable. Its a lot of voltage but at the same time the AC line running into the PSU is far more dangerous and I have worked with and around AC lines so much that they no longer worry me. I do respect it and I also know how to work around it so that's why I am not scared of it.

If anyone is interested HERE is the PSU I found on ebay. It is rated at 800-1200VDC at 3mA so AFAIK it should work for a small red HeNe but I'm not sure if it would work for this particular tube. Does anyone care to speculate on it it would work for this tube or for a small red?

That wouldn't work with your green, any green tube over .2mW is going to need 5-6.5mA.

It would work for a SMALL red, we're talking <1mW. That being said, the optimal for most small reds is about 3.5-4mA, so 3mA is pushing it. The voltage should work for again, a SMALL red. Most reds <1mW still need about 1-1.3KVDC for startup, after that it drops down a bit to maintain it, but that initial ionizing point needs to be reached.

If your tube starts to sputter/flicker, then more likely than not, the tube is fine but you should inspect the PSU.

Keep in mind it's a 5VDC so don't put this into your wall!

Good to know. Thanks for the info.

The PSU I have on my green works but do you think a slightly higher rated one would perform better/differently?

No problem

I know nothing about the PSU you're using

Top of post #7 bro

Well, there are .2mW 543nm tubes that run on 4.5mA. How long is your tube? Keep in mind that the highest rated 543nm greens are 2-2.5mW, so calling it 2mW is saying a lot. My 2mW 543nm is about 18in

Interesting. Not that it matters much but I was just rolling off what daguin said about what he guessed the output to be. I don't have a LPM capable of metering that low. Visually though its pretty damn bright and I would have guessed it to be about 2mW but its probably much lower then. My 543 tube is 8.5inches from mirror to mirror.

Huh, that's pretty short. It's quite possible, and I've seen 543's go to 4.1mW before, but it was a 2mW rated tube. It's quite possible that this is a much lower rated tube, but it's just overspec, and works with the 4.5mA. If it works, it works. If you notice it stays lit, but the spot goes out, or very dim. Red flag. Or if the tube starts to blink, sputter, or flicker, then another red flag. Both issues have to do with the current requirement not being met.

So far the laser has been rock solid. It has not sputtered or blinked once. I will see if I can find a way to meter it out because now I am really curious LOL.

You're going to need an optical (photodiode) LPM. Like this one

It gives you a raw number, then you use the enclosed conversion table to calculate the actual power