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ArcticMyst Security by Avery

A little piece of history...and my quest to find it... [pic heavy]

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I've been quiet for a while...school keeps me busy, but I had to share this tonight to get it off my shoulders. I think you'll all enjoy it :) as it's quite exciting! Also I'd like to shout out at Bloom, as it's his B-day soon.

Happy B-day man!

Spectra-Physics....possibly one of the greatest laser manufacturers, as well as one of the most veteran. Anyone who's into gas knows that the SP lasers are top notch. Many of them being old style lasers however...the early ones are known for having leaked, so a lot of the older lasers no longer function. A large number of them are just thrown out from sitting for so long that they've leaked up to air, and they no longer produce parts or plasma tubes for their old stock. This makes finding surviving stock hard. VERY hard.

While I love my SP model 127 (43 mW) it is a BEAST. It's monstrous, sitting at about a meter long and weighing in at over 40+ lbs! It's one of the largest HeNes out there, and anyone who owns one can attest that this thing is huge, and inconvenient to move around, but it is a great HeNe, powerful...and has a long life, is hard sealed and they're double brewster tubes. However, due to the massive length, they are hard if not impossible to get other colors from simply due the size, and brewster tube HeNes are not really produced any more by anyone, and most of them are weak. so they're mostly only good for red in practicality.

So we turn our gaze to one of my favorite lasers. Back in the day, it was a simple little tube, and often a bit thankless...but I rather enjoy the quality of this thing compared to modern ones. While coaxial tubes are generally Frit-sealed (Hard seal) so they don't leak, and generally more modern and compact, and the mirrors don't require cleaning internally ever, etc...I love old side-arm tubes....to death...

The SP-120.

This is one of the SP-127s younger sisters, and is based as a double side-arm tube in a V shape. The main bore runs the axis of the laser, with the ballast and anode above it, and the cathode off to the side. It is mounted in SP's patented 'stabilite' lightweight rigid laser tube 'frame and resonator isolation' build style, and the machining is most excellent! It also has a huge variety of options for alignment adjustment. It is a double brewster tube, about 14" in length window to window, and has a very narrow bore. it is spec'd at >5mW with healthy tubes doing generally 6-7mW+ or so with a good alignment. Magnets run along the underside of the bore to kill the 3.39um line gain to help with stability as well. The whole thing is mounted in a strong rigid aluminum resonator frame, which is suspended in the outer frame in the center bottom and at each end. The catch? it's soft-seal. The brewsters are epoxied on, rather than optically contacted, and the ballasts and anode are glass sealed in the tube. so most of them have leaked by modern day. precious few of these are around, and the only one I've heard of still working is held by Dr. Sam for about $1500. pretty pricy...so as I've waited, I've come across several obviously dead. and eventually happened across an IR one, and a stubborn seller. so I bought it, if nothing else for the mirrors.

Indeed it was up to air with a magenta/purple glow, and on the verge of failing and the getter was turning white. The seller happily refunded me after a short conversation due to a deal i'd cut out before buying it, and I got my money back, and he let me keep the tube. Great! free mirrors, and a great decoration item...
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Removed tube:
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Super old brewster windows:
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Turns out it was a great purchase regardless. The original 120s use the 256 exciter, which uses a coax style cable for power. newer ones, use a 3 pin style, that screws on like an argon cannon connector. and use an entirely different exciter, the 249! These are in short supply, and the tubes use the same power...so what to do....I frantically search around as I find a 120S a model that has the shutter added to the front, and it is overseas, so I wonder if it's worth shipping over, as it has this alternate connector and 249s are very pricy. Eventually I give in and ask about it, and after a few photos I get to see the inside, and the getter is BLACK! I get quite flustered and buy it anyway. It arrives, like the other, looking quite new, but no guarantee as to it working due to age, but this one looking substantially more promising.

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Problem is....no power. so, after a bit of fidgeting, I remove the tube from the old one and work hard to remove the blocks from the old cable and slip it out of the old resonator, and do the same to the newer tube, careful not to bust the anode pin off. After carefully fighting for a couple hours I successfully swapped the cables and plug it into the 256 exciter and hold my breath...and flip the switch. I am instantly greeted with orange glow, and a red beam, and literally proceed to nearly pass out (emotionally) in disbelief.

Good thing I bought the old one afterall! :) the 256 was only 120 bucks or so, compared to the guy who wanted 250 for the 249 :(

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Truly a beautiful laser, and I'm glad to own it! presently it is outputting around 7mW or so of power but i'm not sure i'm running it on its proper settings, but with time in the future, I'll tinker with the alignment and current, and set it up correctly. I feel like I found a lost treasure :) and unlike other double brewsters...its not a weak little 1mW tube. :tinfoil:

*correction as of 2/5/2016 - its doing 6.5mW, as my meter was off at the time.
 
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upaa27

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That's so cool to have one of their older models and even cooler that it works. I wish I were alive during that time..
 
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Thanks, this is one of my favorite lasers.

Been running it since noon, and adjusted the current up a bit to where the tube should be much more comfortable. somewhere probably near 6.5-7mA ish. it's slowly risen in power up to almost 8mW now. sitting at a lofty 7mW ish at the time I'm writing this.
 
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Awesome. Seems like an incredibly decent price as well. Good background info on SP- explains why I don't see really old SP hene's FS anywhere, although tbh I hadn't even thought about it until seeing this. So how is it that the send one you got is still lasing, if they are both soft seal? Or had the seller ran it occasionally?
 
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Unknown. It's been in storage, as the previous owner doesn't have a 249 exciter. Some of these for reasons unknown just happen to keep working...sam and I are the only people I know that have one still healthy and like new. I'm beginning to understand more so why he still wants 1500 bucks for his... Though mine has the shutter and arm holder, I don't think his does. It's a very very nice tube. It's nothing like modern coax tubes at all. It's a marvel to watch work. Like a mini 127.
 
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Simply beautiful laser, quite the prize! Also, lovely documentation of the whole story.

One thing though, UK. You are KILLING ME LEAVING THAT LOR TUBE ON THOSE DINKY "STANDS". Gah! I can't stop mentally picturing it rolling, and hearing that spineshattering "clunk, tink!".

=P

Oh, and any plans for the up-to-air tube?
 
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Simply beautiful laser, quite the prize! Also, lovely documentation of the whole story.

One thing though, UK. You are KILLING ME LEAVING THAT LOR TUBE ON THOSE DINKY "STANDS". Gah! I can't stop mentally picturing it rolling, and hearing that spineshattering "clunk, tink!".

I can't tell if you're teasing me or not... But it's definitely not rolling and falling off with those things. Actually, they're quite nice and they even have a hole through the middle so that they can be bolted to an optical breadboard/table.

Oh, and any plans for the up-to-air tube?

Nope not yet.... it would make a nice decoration... :) or I might sell it, it might be able to be reconstructed for a do it yourself tube... If someone had good glassblowing skills and a vacuum pump and ultra pure gasses.
 
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I can't tell if you're teasing me or not...

Nah, not teasing. I know it won't roll on its own, but an inadvertent bump is all it would take. I'm paranoid about unmounted tubes. With tie downs and those stands bolted, it's excellent. Just sitting there though... /anxiety.


ultra pure gasses.
There's your kicker. Pump, annealing kiln, and skills are easy to acquire. Simple thing to pop a filling port on the anode, simple to seal off, a nightmare to fill.
 
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It's a wide desk, it's not going anywhere. But yeah it'd be fun to try though. Unseal and bake it to release the bad contaminates and purge it a few times then back fill it and blow it shut with a CO2 laser or a torch and the fire the getter again. It'd probably work if done well.
 
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upaa27

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It's a wide desk, it's not going anywhere. But yeah it'd be fun to try though. Unseal and bake it to release the bad contaminates and purge it a few thrones then back fill it and blow it shut with a CO2 laser or a torch and the fire the getter again. It'd probably work if done well.

If only microwaves we're hat big... Oh well.

You could also just make an electric kiln for pretty cheap.
 
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Very nice! You should contact Dr. Sam and let him know of your success. He likes to aggregate this kind of info and pictures like this he'd love. PM me if you need his contact info, but I think you have it.
 
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Just a quick add-on, rather than starting a new thread....I put the 1153nm mirrors from the other dead 120 in the working one, and after some tweaking, I got it up to just over 1mW. pretty neat....though like my 1523nm tube, it makes a really lousy laser pointer :tinfoil:
 
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Just a quick add-on, rather than starting a new thread....I put the 1153nm mirrors from the other dead 120 in the working one, and after some tweaking, I got it up to just over 1mW. pretty neat....though like my 1523nm tube, it makes a really lousy laser pointer :tinfoil:

I have never understood the want for IR hene's...What is the point (hobbyist wise)?
 
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Crazy ---
It is not just a hobby, It is the science!!!!
Everyone wants to burn something BUT
there are some tempted to actually experiment.
HMike
 

upaa27

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I have never understood the want for IR hene's...What is the point (hobbyist wise)?

Lol I have to agree on this. It becomes a lamp at this point.

I guess it's just an accomplishment for science like Hemlock said!
 




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