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HeCd laser availability ...

aryntha

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So I know, the Gas forum doesn't get much love these days - but hey, I still love me some Gas. (Still building that collection, even.)

For a few years now I've been trying to get my hands on a decent working HeCd setup; (One ebay order ended in a shattered tragedy; and most of the other ones I see are $300 shipping + 'untested'.)

I know getting one of these that is in working condition is very tough, since they're incredibly fragile and have a lot of balancing factors that go out of whack, like tube pressure and temperature. But it still would be nice to try.

Was wondering if any members here knew any better... or more about them; Unlikely, but worth a shot.
 
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diachi

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I've owned a couple, as have several others. Can probably get some pointers if you see anything specific.
 

aryntha

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YES .... such lasers are real lasers....., thats it .

Um, thanks for the cynical response? I guess I *have* been gone too long. Sorry? Won't do it again?

Anyone, I was hoping some folks had some experience with them - looks like Diachi might so I'll probably run some questions by the folks who won't be inherently annoyed by it, if there are any.

Basically - what's the usual biggest problem on the used market with these; are they up to air, usually? Or is it an alignment or calibration issue? I know I likely don't want to buy one unless it's in working order before shipping...
 

diachi

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Basically - what's the usual biggest problem on the used market with these; are they up to air, usually? Or is it an alignment or calibration issue? I know I likely don't want to buy one unless it's in working order before shipping...

Usually either a high hours tube or a tube that has been sitting in storage for a long time and has high He pressure so won't light or will be tough to light. Sometimes you get lucky.

HeCds have a helium reservoir with a membrane that allows helium through when heated, in normal operation this keeps the helium pressure at the right level but if they're stored for long periods the helium can leak out and increase the pressure, if it gets too high the PSU won't be able to keep the tube lit. The other problem is old tubes that have depleted Cd. Cd moves from the Cd reservoir at one end to another reservoir at the other end, the supply is finite. Improperly maintained tubes can have the Cd build up inside the bore too, which can cause issues.

Often have to take a gamble unless you can find one that has been tested. IMO your best bet is an Omnichrome or Kimmon.

Shipping takes some careful packaging, some tubes are worse than others.
 

aryntha

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Yeah there's a good condition Onmichrome (cylindrical) for an OK price out there, verified working; but no PSU, and as far as I know these -need- the matched PSU to work... (though this guy apparently has it working on his...)

Oh well. I'll keep an eye open, and if anyone happens upon this thread and has a working HeCd system just burning a hole in their collection, let me know.
 

paul1598419

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You could try to contact Matt, Ultimatekaiser. He had several last time I talked with him.
 

CurtisOliver

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It is true. You don't hear that much of gas lasers on here atm. Laserbuilder is one that bought back some interest in them. He actually builds his own hence his username. I still like gas and solid states. Semiconductors are definitely taking over now though.
As for the availability of a system like that. I would imagine it would be pot luck in buying a second hand unit.
 

LSRFAQ

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KImmon.. Still makes them. Omnichrome not made for a decade and change, and no new Liconix for like 20 something years. Therefore, look at Kimmon… The recent Kimmons are beautiful instruments. I have no experience with the Russian design, which are few and far in between, and never really made it to the international market.

Typical beautiful Kimmon manual:

Domo Arigato

Steve
 
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diachi

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KImmon.. Still makes them. Omnichrome not made for a decade and change, and no new Liconix for like 20 something years. Therefore, look at Kimmon… The recent Kimmons are beautiful instruments. I have no experience with the Russian design, which are few and far in between, and never really made it to the international market.

Typical beautiful Kimmon manual:

Domo Arigato

Steve

Yeah, chances of getting a working Liconix are pretty low these days. Omnichromes are pretty durable in my experience, so you should have better luck there if you can find a fairly low hours head (less than 2-3000 is probably ideal). Mine was 16-17 years old with ~90 hours on it, ran like a dream. Not much data to go on but that says to me they're not so bad when it comes to having He pressure issues. Totally different design from the Liconix and Kimmon tubes, they have an outer jacket surrounding the bore, similar to a HeNe, where the Liconix and Kimmon tubes use a bare fused quartz tube (correct me if I'm wrong on the material Steve, been a while).

My Kimmon also ran great, though it was much newer than the Omni. AFAIR the Kimmons are all external mirror tubes, whilst the Omni heads are internal mirror tubes. Really fantastically made though, you can tell right away as soon as you open one up. No shortage of attention to detail.

Read the manuals if you get one, proper operating procedure is important. Takes 10 minutes or so to heat the tube up before the Cd vaporizes and lasing starts. Also supposed to follow a proper shutdown procedure, shutdown on a HeCd keeps the tube lit for a little while after turning off the Cd heater to make sure all of the Cd is out of the bore, otherwise it condenses in the bore, which you don't want. Not sure I still have a copy of the Omni manual, Steve probably does though.

Any luck you get a 442nm head, both of mine were 325nm. Beam quality was fantastic though, especially on the Kimmon. Omni was still good, but was TEM01* (donut mode).

Eidetic suggested a few good potential sources on Discord having seen your post. I'll quote it here in case you didn't see it.

He-Cd lasers are hard to find too because the Cd is used up during their lifetime. Also, Cd growths over time can obscure the beam, cutting output early. I'd ask for one on the holographyforum, or holography page on Facebook. Possibly contact members of the IHMA for used He-Cd lasers from those making hologram masters in photoresist. Here's the first one, the Spectra-Physics 185 from 1969.
 

ultimatekaiser

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I have a few omnichromes that are still running... I can tell you pretty much anything you wanna know about them. Definitely go with an omnichrome or Kimmon. Liconix ones are definitely dead by this point. It’s virtually guaranteed unless someone has serviced them recently. Unfortunately the biggest issue to getting one of these is that aside from the obvious issues of them sitting, most of them tend to break in the mail. They’re quite hard to ship effectively without damage or some level of alignment change.

alot of the power supplies are dead or dying now too
 




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