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2mW 543.5 Green bare tube HeNe from Meredith Instruments (Many pics)

LtKernelPanic

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First of all a big thanks to Helios to pointing out the awesome deal on these tubes. Also for some reason Flickr likes to say some photos are not available when they really are. You can either try a "super reload" which is usually option/alt-reload or just click on the image to view on flickr.

First of all some specs as provided by MI.

Manufacture / Part Number: Melles Griot, model LGR192
Output Power: 1.4mW minimum, 1.7mW typical, 2.5mW maximum.
Wavelength: 543.5nm GREEN
Polarization: Random
Mode: TEMoo
Beam Diameter: 0.80mm
Beam Divergence: 0.86mRads.
Light Exit: Cathode end of tube.
Operating Voltage: 2800 VDC (with 75K ballast).
Start Voltage: >12KV.
Operating Current Range: 6 to 7mA, 6.5mA Ideal.
Recommended Ballast Resistor: 75K Ohms, 5 Watt.
(Add in series to the anode lead within 3" of the tube.)
Dimensions: 19" long x 1.5" diameter.


The tube arrived via USPS priority mail in one of their triangular "tube" mailers. Inside was what looked like a giant white fuse from one of my multimeters with some packing peanuts on the ends to keep it from sliding around. I forgot to take a picture before unwrapping the tube but it looked more or less like this. The wrapping around the tube was nice and snug and the end caps were stuck on farther but this gives you an idea of the quality packing job they did.


2011-05-27_08-34-10pm by ltkernelpanic, on Flickr


2011-05-27_08-37-22pm by ltkernelpanic, on Flickr

The tube came with a 5W 75K ohm ballast resistor and solder clips on the tube to solder your leads to. The Alden style connector with cables I bought separately from another seller on ebay.

Setup was simple so I didn't bother with any pics. I stripped a little more off the end of the HV cables, soldered the resistor to the positive lead then to one of the clips. The negative lead was soldered right to the clip.



2010-12-09_09-45-34pm by ltkernelpanic, on Flickr

The power supply I used is the one that came with my green HeNe head and is seen powering the head using a 12v power brick and my home made power adapter. (I wish the seller had more of those. $95 for the head and PS was a steal! Anyhow back to the subject of this review.)

The last thing to do was to attach the clips to the proper end of the tube and fire it up. Note on most longer tubes light exits via the cathode end of the tube where most of the short 6" red tubes you see exit the anode end. This is important because a reverse polarity can take a brand new tube which should have a long life ahead of it and ruin it in a matter of minutes. When in doubt don't guess . Try looking up its data sheet on google or ask the very knowledgable folks over in the gas lasers forum for guidance.

Now for the all important action shots.


2011-05-27_10-56-53pm by ltkernelpanic, on Flickr



2011-05-27_10-57-06pm by ltkernelpanic, on Flickr

Note the 75K ohm ballast on the anode.


Beam shots! I was surprised even with ~300w of overhead lights on that I could see the beam. I haven't had a chance to measure it but I suspect it'll be more than 2mW.


2011-05-27_11-02-50pm by ltkernelpanic, on Flickr

A couple shots with my 6" 632.8 red HeNe bare tube.


2011-05-27_11-12-51pm by ltkernelpanic, on Flickrr

Even with a long exposure the red beam is very faint. Exposures over about 5 seconds don't help either since the plasma glow will still over power it.



2011-05-27_11-14-04pm by ltkernelpanic, on Flickr


And the money shot from the series of pics I took last night....





2011-05-27_11-15-54pm by ltkernelpanic, on Flickr
 
Last edited:

icecruncher

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very nice pics and great to see you got it up and running right away.

beam shots are beautiful.

Big tube isn't it? :)
 

LtKernelPanic

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Yeah it's a monster compared to the little red tube. The plasma can light up the room nicely. The beam looks brighter than my other greenie but I haven't had time to LPM it yet. My other one was made in March 1999 so who knows how much milage it has on it already.

Also I have no idea why flickr insists on being stupid so I'm going to try and relink the busted pic above.


2011-05-27_11-12-51pm by ltkernelpanic, on Flickr
 

Helios

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That last picture is awesome. :drool:


I wish I didnt have a move on the horizon so I could have gotten one myself! I dont trust myself packing and moving 3 HeNes 3000 miles.


Its a great looking tube and a clean looking PSU I must say

+1
 




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