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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...
Removed tube:
Super old brewster windows:
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.
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
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.
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...
Removed tube:
Super old brewster windows:
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.
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
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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