Mission: frustrating. Getting a 168 Ar/Kr lasing again.

[GooeyGus]

Hey guys,
It looks like in the very near future I'm going to be trying to get my mixed gas 168 lasing again. In the past I've checked the tube voltage, which was exactly where it should be (cant remember the exact numbers) and spent numerous hours trying to get it aligned, with no luck. I also shot the bore with a HeNe and was able to get a clean shot through to the other side. Unfortunately the setup I made to shoot the bore wasn't super stable, so it wasn't useable for alignment. When I get this set up again, it WONT be on top of my washer and dryer, as seen below ALso, I'm pretty sure I cleaned the brewster windows, but it is something I will probably do again once I get it all set up again.

I guess I'm just looking for tips on what I should try first. I got the whitelight optics from dsli_jon, and I think he mentioned that they were from a coherent laser of the same size, although its been a while so I could be wrong.

Can I use the multi-line argon optics that I have for my other 168 for alignment purposes? I just want to eliminate the optics as a problem. Once it's lasing I can toss in the WL optics and see what happens. I guess for alignment this time I'm going to use a series of adjustable mirror mounts and shoot the bore on a much more stable work surface.

Lastly, a concern I have. Everything in the laser seems healthy. The plasma color looks picture perfect, everything is clean and looks almost new, but there is one thing that puzzles me. At the anode end of the laser, there seems to be a tiny bit of debris inside the tube. It almost looks like a couple tiny tiny grains of sand. The brewsters look clear, so I doubt this would completely kill lasing, but I just have no idea of what it could be. I can tap the stem to get the tiny bit of debris to move to a less critical area, but they move when the laser is powered on again which leads me to believe the the debris may be magnetic. I've incuded a (somewhat blurry) picture of what I'm talking about below. I'll take a better picture soon.

Any tips you guys may have that would help me get this laser lasing again would be awesome. I usually dont have too much trouble aligning an ion laser, but I've only ever had to align one end. I've never had it where the whole thing is completely out.

Here are some pics of the laser tube, as well as a picture of the debris I was talking about. Sorry the first couple pics are so bad, I think I took them with my cell phone. The last two were taken with a camera, even though the debris shot didn't come out well.







Here's the picture of the anode end. The debris in the tube can be seen as those tiny light spots. I'll get a better picture soon!

[mixedgas]

The junk in the tube is not magnetic. The electrostatic field in the tube pushes them to the location with the opposite or least field, in this case, the window stems.

You need a very large, very stable table to align on or your wasting your time.

Typical first alignment takes a newbie four to eight hours or more.

You can try the "Spots in the plasma" method with your whitelight mirrors.

If the laser is NOT on a strong, sturdy, surface, the alignment will drift like mad.

If you really cannot get going, try the two high reflectors, do not try switching to the argon output coupler, it has too much transmission on the 488 line for that laser.

Steve

[GooeyGus]

I've done the 'spot in the plasma' trick for hours on end with no luck. I can get an obvious dot in the light that is coming out the OC end (mirror removed) when I get the HR mirror lined up. Then I toss the OC back in and do the "rock and scan" but I cant get a flash.

[LaserWizard]

I have done the laser through the bore alignment many times in a variety of stable and unstable situations, and it usually does not work the first time. But it works. Just repeat, repeat, repeat, try to get more stable and more perfect as you go along, and I believe you will get it. Have faith bro!

[Laserman532]

where do you live these days jason. If it will light it will lase. are you able to run it on three phase and get a full 35 amps out if it? looks like a house current which might be marginal source

[GooeyGus]

Still living close to marysville (about 6 hours away from ya )

Its running on a 10hp phase converter, I can get a stable 20-25A out of it with no cathode or artificial leg voltage sag or anything like that. I can get it up to 35A but the breaker blows pretty quickly. Not ideal, of course, but even at 20A it should have enough gain to lase on even a not-so-great alignment, right?

[Laserman532]

that is your problem right there, it wont lase at 20 amps. I can prove that by taking a perfectly running whitelight small frame and turn down the current to 20 amps and there will be no beam...for all practical purposes (with a whight light sp small frame) 20 amps is idle. You will need a constant source of three phase that can deliver 35 amps especially if you need to go through an alignment procedure. ESPECIALLY if you are using optics that are not designed for that gain and blah blah blah. Get a stable source of 35 amps and a dark room and a shadow box, get the HR dialed in center first, rock the front plate and FLASH! get the flash stable and then peak the tube on the aperture and thats it...bingo. You should have no problem getting an argon going at 20 amps but a whitelight is a whole different animal....thats what i gots.

ps.... if you get cathode sag...your effedddddd.

[Laserman532]

I have done the laser through the bore alignment many times in a variety of stable and unstable situations, and it usually does not work the first time. But it works. Just repeat, repeat, repeat, try to get more stable and more perfect as you go along, and I believe you will get it. Have faith bro!

shooting small frames with henes are for rookies (you know im kidding tim)