Let's play "can you id this HeNe tube"

Hi y'all, I scored a couple HeNe tubes on eBay for el cheapo dinero. All the seller could tell me about them was he purchased them about 30 years ago, be thought they looked similar to coherent tubes, and the he never got around to powering them up. The only markings on them are a couple stickers saying 15mW max output. I can't find any other markings or serial numbers. They are aprox 15 1/8 inches from mirror to mirror and aprox 1 1/2 inches in diameter. Anybody recognize these or able to point me in the right direction.















I tried using a psu from my other HeNe, it is a laser drive inc model 105e01720 that is rated @ 1500v 5 mA. I used the resistors that came with the new tube, I didn't remove the heat shrink to check the values. I got plasma and it lased but the psu made a ticking sound so I quickly shut it down.

A few questions:

Do longer tubes require higher starting and running voltages?
Could the ticking noise in the psu be caused by improper values on the limiting resistors?
Does age effect HeNe's?

I've been googling these for hours and havent made any headway so I figured I'd throw it out to the forum. I do t usually purchase items without proper intel but these were so sexy I couldnt pass them up. The price was right even if they became a lamp I would've been happy. I'd like to get them up and running mounted in acrylic. Apologies for the upside down pics.

That tube will need more than that to run correctly. Over on Sam's site there's a section on estimating the power needs of a tube.

That is an adjustable mirror tube, sweet! Yeah at 15mW max (don't expect more than 7mW out of it in reality) I would expect at least 6.5mA to be needed, more so if it were at end of life.

LtKernelPanic said:

That tube will need more than that to run correctly. Over on Sam's site there's a section on estimating the power needs of a tube.

Click to expand...

I had looked all around that Sam's FAQ, but didnt see anything like that. I'll try take another look around.

Sigurthr said:

That is an adjustable mirror tube, sweet! Yeah at 15mW max (don't expect more than 7mW out of it in reality) I would expect at least 6.5mA to be needed, more so if it were at end of life.

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7mW Woo hoo! No really that's awesome I can't wait to get these running. What is the deal with adjustable mirrors? Any idea on the make?

ionize said:

A few questions:

Do longer tubes require higher starting and running voltages?
Could the ticking noise in the psu be caused by improper values on the limiting resistors?
Does age effect HeNe's?

Click to expand...

1) yes
2) yes
3) yes

longer and more powerful tubes need more voltage and current to run, if your psu is making a buzzing/ticking noise it's probably not supplying enough voltage

old HeNes that were sealed more or less with glue tend to leak helium and stop lasing over time, newer ones are contact hard sealed and can pretty much sit on the shelf forever

MarioMaster said:

1) yes
2) yes
3) yes

longer and more powerful tubes need more voltage and current to run, if your psu is making a buzzing/ticking noise it's probably not supplying enough voltage

old HeNes that were sealed more or less with glue tend to leak helium and stop lasing over time, newer ones are contact hard sealed and can pretty much sit on the shelf forever

Click to expand...

How do you figure out the starting voltages? Spec sheets for tubes only list the maximum starting voltage, not the minimum, and a lot of PSUs don't list starting voltages on the spec sheet at all.

The starting voltage shouldn't matter as long as it is capable of ionizing the tube. I'm not aware of any easy way to find the minimum voltage you'll need to start the tube other than just the general length of the discharge. Really the only thing that matters is the tube voltage once it's lit and the current. After you have that you could ignite it with a BBQ sparker or a plasma ball if you wanted to heh

MarioMaster said:

longer and more powerful tubes need more voltage and current to run, if your psu is making a buzzing/ticking noise it's probably not supplying enough voltage

Click to expand...

Any idea what kind of running voltage I should be looking for in a psu on the tube of that size and power?

ionize said:

Any idea what kind of running voltage I should be looking for in a psu on the tube of that size and power?

Click to expand...

I would guess around 2500 VDC, but this is only a guestimate as all I know is the length of the tube.

kumowoon1025 said:

I would guess around 2500 VDC, but this is only a guestimate as all I know is the length of the tube.

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That works for me :thanks:

Anyone recognize these/this style of tube?

what color is it? if red, at that output and length it may be multimode and take around 2.4 kV, i need to look at the p/s for my tube. from what i've gathered, the voltages needed for a particular tube are pretty broad and can be inferred from color and tube length.

cheech226 said:

what color is it? if red, at that output and length it may be multimode and take around 2.4 kV, i need to look at the p/s for my tube. from what i've gathered, the voltages needed for a particular tube are pretty broad and can be inferred from color and tube length.

Click to expand...

Yep it's a red one, about 15 1/8 inches from mirror to mirror :thanks:

ionize said:

Yep it's a red one, about 15 1/8 inches from mirror to mirror :thanks:

Click to expand...

Sam's Laser FAQ - Helium-Neon Lasers

About 1/3rd of the way down the page, are some tube length tables for the other companies products.

Yours looks like a Hughes, or NEC from the glasswork. Those will not be listed, but you can assume/interprolate.
Scroll down about 20 mouse-wheel-clicks from my link.


Steve

this may work
JDSU HeNe laser power supply 12v to 2450 volt 6.0 ma | eBay

cheech226 said:

this may work
JDSU HeNe laser power supply 12v to 2450 volt 6.0 ma | eBay

Click to expand...

Has an alden connector tho. Might have to pick up an alden plug if your wiring a bare tube to this psu.

Please post some pics once you get it up and running, I have faith in you!