New Old He-Cd Laser

[Eidetic]

I spent this nice sunny day cleaning up the 1974 Liconix Model 401 Helium-Cadmium laser below. Liconix was formed in '73 by Mark Dowley, after leaving Coherent Radiation because they didn't want to build this type of laser. I'm pretty certain this is their first model.

Notice the windows on the tops of the Brewster window covers! Must've been an alignment thing. The rubber boots are all in good shape, but the rear mirror holder and bezel are missing. There's no helium reservoir, typical of all other He-Cds I've seen, and no cadmium heater. You can see the cadmium reservoir near the anode pin. The tube is centered by three nylon screws at each end and supported on the cathode end by the connection to the ballast tank underneath (which is glued in place). The anode end is apparently aligned by the nylon screws. I can imagine trying to keep that in place!

The power supply is from 1976 so I don't think it's original to the head. Other than the Spectra-Physics Model 185 (same 6' long head as their Model 125), this is about as old as He-Cd lasers get.

[mixedgas]

Bob, bug me in a week or so. I have or had a 401 manual some place. Cd pressure is set by placing a card in the roof vents to adjust the heating. I had a head like that, but like a idiot I loaned it to some one who did not handle it correctly.

My manual has a final test report is signed with the initials "WTS", that should mean something

Steve

[142laser]

Wow that is an oldie! I recently bought an old Metrologic HeCd laser that is aparently self contained like their HeNe's. The tube seems intact but someone has butchered the power wiring and I may send it to lasersam Goldwasser to see if he can undue what they did to the poor thing. Not that I really expect it to actually wrk but... Anyone have information on the Mettrologic ML 442? Phil, 142laser

[Eidetic]

That must be the one recently on Ebay that I missed biding on because I got home too late! Was there a year date on it somewhere? He-Cd is a doomed laser because of the new diodes. I know the location of an SP-185 that I've got dibs on, but don't look forward to dealing with. Be great to find a similar vintage He-Se laser too! Liconix made those briefly.

[142laser]

No year is on the laser unfortunatly. I am thinking 1980's. They may have only made one production run; after they all failed under warranty... If anyone has a ML 442 manual please let me know. Metrologic knows nothing about that laser. Phil

[mixedgas]

I have a pound of Selenium in the basement and had a glassblower make me a tube three years ago. I have not followed up on it yet. The idea of getting 28 lines across the visible spectrum at close to 300 mW really, really intrigued me. HeSe is one of those lasers you want to see, just once.

Steve

[142laser]

Hi Steve,
If anyone has one of these lasers still working it is Bob Arkin at Holo Spectra. He has about the most impressive collection of antique lasers I have ever contemplated. I will ask him about the Liconix HeSe and see what he says. It is not the pounds but the purity that is probably important for laser use. I have never see one of these alive or dead. If tens of mW and 28 lines are available why did these not catch on commercially...any idea? Best, Phil

[shrad]

if anyone's interested I have some useful liconix information (power supply and wiring)

I have 3 tubes awaiting for revival, and for some HV BNC connectors

anyone has some to sell?

[mixedgas]

If tens of mW and 28 lines are available why did these not catch on commercially...any idea? Best, Phil[/QUOTE]

HeSe is highly documented, needs a bit more current then Hecad, and the dominate lines are Green, Red, Yellow, and then the blues and violets are weak. Blue was what was needed for reprographics, more then any thing else, so HeCad won.

Xerox and the Russians went after HeSe and Hecad with a passion, but in the end Xerox went with air cooled argon.

There is a RGB HeCad as well, but it needs a hollow cathode tube, not a long positive column bore like a HeNe or blue Hecad.

HeSe was looked at mainly for displays, but for some reason CRTs always ended up winning, and I imagine the shift in memory production allowing HiRes raster CRTs finally sealed HeSe's fate.

RGB Hecad with a high quality white beam made it into production in late 1990s early 2000s by Cooke corporation, however DPSS finally finished that one off.

I'd love to own a Cooke RGB Hecad, but 15-20 mW and 10,000$ new cost was just not going to meet my criteria for cost effectiveness. It had a very specific imaging application which is why they developed it, but that application was never disclosed. Quite a few made it into labs, the ultra high quality beam had its uses.

Some weird combinations were tried, HeCad/Hene in the same tube, and Cd/Se mixtures, as well as split tubes that had CD at one end, Se at the other and a common bore.

Steve

[Eidetic]

Wow that is an oldie! I recently bought an old Metrologic HeCd laser that is aparently self contained like their HeNe's. The tube seems intact but someone has butchered the power wiring and I may send it to lasersam Goldwasser to see if he can undue what they did to the poor thing. Not that I really expect it to actually wrk but... Anyone have information on the Mettrologic ML 442? Phil, 142laser

I just got one of those too Phil, and know the location of another that has a smashed tube. The tube in mine is broken off where the reservoir tube ends in front, but I have the piece and will be glueing it back in place. Neat plasma tube, aint it? I like the hand tied asbestos cover over the tube. Mine is cut open a bit already, so I have a window in it to see the disks inside the tube.

I just did a little Google search and found a paper in November 1975 Analytical Chemistry that mentions using this model laser. The earliest ad I've found for LiConix He-Cd lasers is in February of '73. There's no dates or other markings on mine, so I'm going with c1975 as the date.

I'll post pics after cleaning!

Bob