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Spectra-Physics 155 Side-arm He-Ne (pics)

Greenmechanic

Greenmechanic

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A while back I was looking thru Sam's Faq's photos of antique He-Ne's
All He-Ne tubes look pretty much the same. But I did come across one that caught my eye. It was the Spectra-Physics side-arm tube. I decided I had to have one of these unusual tubes in my collection. I looked and looked on eBay. After a month or so I finally found one that didn't look like it had been run over by a tank. LOL:yh:

Long story short I won it and here's some pics. Will post beam shots later(when the wife is not home, she hates my fog machines)

First 3 are of the complete case.
S-PsidearmlaserPics025.jpg

S-PsidearmlaserPics026.jpg

S-PsidearmlaserPics028.jpg


Next the insides. I just love the look of that side-arm tube!!
S-PsidearmlaserPics003.jpg

S-PsidearmlaserPics014.jpg

S-PsidearmlaserPics017.jpg

Close-ups of tube
S-PsidearmlaserPics001.jpg

S-PsidearmlaserPics005.jpg

In the dark
S-PsidearmlaserPics004.jpg

S-PsidearmlaserPics016.jpg

If this laser wasn't so rare I'd make a lamp out of it. That tube is to pretty to be covered up. I'm looking for a beat-up one to make a lamp, but they are getting hard to find.
Thank for looking!!
 





Maybe you could get some plexi and create a transparent cover for the head
Click to expand...
I was thinking along those lines too. Maybe cut a 6"X2" hole in the top of the case and glue some Plexi. over it. A little Alum. trim work, and it would look almost factory.
I am not going to do anything untill I find another one although.
I wouldn't feel so bad about cutting up a beat-up case, but this one is mint
In 20 or 30 years from now it might be worth a fortune.
I read on Sam's, that you are hard pressed to find one that works now, let alone one that looks like it just came out of the box.It outputs like new also,1.2mW after a 20 min. warmup.(It's only rated at .95mW)
 
^ NICE :cool: I have never seen a side arm HeNe before, its rather cool looking
 
Cause the arc is from the electrodes only ..... and probably the tube s not lasing.

I have a Spectra-Phisics one made in the same system, lost on some shelf collecting dust (the original PSU burned, and i never found another and had no time for build it myself) ..... the only difference is that mine is the type with external mirrors, and is long around a meter (or also a bit more :p)
 
HIMNL9
Cause the arc is from the electrodes only ..... and probably the tube s not lasing.
Click to expand...
What do you mean by the tube is not lasing, the large (not the side-arm) tube?
If you mean the laser tube as a whole, it is most certainly lasing at 1.2mW.
Please clairfy what you mean by tube.
Being as this is my first side-arm, I'd like to learn as much as possible about it.
I found this on Sam's FAQ's
The HeNe laser tube is the classic Spectra-Physics side-arm design but with the anode electrode mounted about halfway along the length of the bore. The same tube with the anode mounted at the end would produce around 4 to 5 mW. In fact, the Spectra-Physics 157 (3 mW) and 159 (4 mW) lasers are virtually identical except for the tube's anode location and the use of a larger power supply.
Click to expand...
 
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The plasma doesn't go all the way down the bore in a HeNe with this electrode configuration. Normally it does because the end cap of the HeNe also serves as the electrode. It doesn't hurt it that there's no plasma in the ends of the tube.
 
I don't know much about gas lasers, but that really looks awesome. Nice deal you got on it, too.
 
Greenmechanic said:
What do you mean by the tube is not lasing, the large (not the side-arm) tube?
If you mean the laser tube as a whole, it is most certainly lasing at 1.2mW.
Please clairfy what you mean by tube.
Being as this is my first side-arm, I'd like to learn as much as possible about it.
I found this on Sam's FAQ's
Click to expand...

EEK .... your font hurt, you know ? ..... :p :D

Seriously ..... from the pictures, you can see the arc from the anode (the electrode in the middle of the tube) to the cathode (the big aluminium cylinder offside the main tube), and when Cyparagon asked "Why isn't the whole bore being excited? ", i replied considering that there you can see the arc only in half of the tube ..... from the pics, you cannot see the beam in the rest of the capillar tbe, nor the output beam, so i said that, maybe, the tube was not lasing (and, ofcourse, if it's lasing at a level that is too low for show up in the pics, i can be in error saying this, also if mine was only a supposition)

As for gas tubes, usually "tube" is referred to the entire assembly, including the ones that you call "off-side arm" types, like your one ..... but, technically, the bigger part of your tube is only the cathode container (and gas reservoir), where the lasing tube in fact is the "off-side arm" itself, where there is the cavity and the mirrors ..... in the central tube models, the cathode is usually around the real capillar tube with the mirrors, giving probably the impression that is the main part ..... in fact, the cathode is so big, compared with the anode, just cause is the electrode that get more hot, and need to dissipate it, otherwise it can become damaged, and a large surface is required for this (practically, 95% or more of the heat generated from a He-Ne laser is generated from the cathode) ..... and also for another reason, being more precise, i mean that in any DC system, where a flux of current is involved, the cathode is the electrode that give electrons, and that phisically consume itself more quick than the anode, especially where plasma is involved (but this is less important, in lasers ..... much more in arc lamps).
 
Wow. Cool find! I never get that lucky... Used gas lasers are hard to come by in my neighborhood, and when they do, they're usually outrageously expensive and utterly crappy. :(

But I still have two brand new unused HeNe tubes for future builds, and thanks to Daguin, a nifty little brick PS for one of them. Now if I could only find the time... or find a nice argon laser! ;)

Robert
 
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