gas laser enquiry

hi guys

for some projects I have in mind, I want you, if possible, to give me details about your tubes:

brand and model
discharge voltage
discharge current
triggering voltage
triggering current
filament voltage
filament current
optical output power
type of gas

this is only to make some statistics over the voltage and current ranges found on these tubes, according to optical output power and type of gas

more info when the project will be put on the table, in several months ;)

if some of the details are unknown, don't worry, the rest will still be worthy

you might also put the AC input characteristics and watts used by the PSU, which could also be useful

cheers!

This is specs list of my He-Ne @632.8nm "Spectral RMML505L"
http://www.photonlexicon.com/forums/...ead.php?t=6349

Greets:)
Steve

nearly everything ion is a either 3.2 or 2.6V AC cathode. Ranging from 25 to 50 amps, and this must be adjustable to match the power line. The tube current must be balanced off a center tap of the cathode transformer, or the arc favors one side and melts it. This transformer is designed to maintain a constant wattage. They are not cheap, in fact they are the most expensive part in most supplies.

I have tubes from 85 V @ 9 amps to 265V at 35 or more.

Steve

Steve,

are the transformers regulated by magnetic shunting or is there some active control involved?

Cheers, Ian

Quote:

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Originally Posted by shrad

I want you, if possible, to give me details about your tubes:

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Allow me to introduce you to Sam's Laser FAQ. Specifically, to the ion laser section. Lots of good information in there.

Adam

silly me, I didn't even think about sam, although I have been looking there each time I had something to learn

http://360.kombo.com/images/content/...2_20090622.jpg

anyway, if you have some hints about high power current AND voltage regulation, you may send me a PM ;)

[QUOTE=Doc;116187]Steve,

are the transformers regulated by magnetic shunting or is there some active control involved?

Old ones have the shunting, newer coherent ones are ferroresonant, lexel has 3 user adjustable taps, coherent medical has taps, JDSU uses a line side power control on some lasers. And a few really new coherents have phase control of some form.

A few rare units SP, Laserphysics, have HF or DC cathode drives for low noise in semiconductor processing, but they have to flip polarity or something to even the wear.

steve

Quote:

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Originally Posted by Doc

Steve,

are the transformers regulated by magnetic shunting or is there some active control involved?

Cheers, Ian

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I'm really sorry Ian...
I ignore it... also because I am not so expert in electronics...:o

The only thing I can tell you is: the first PSU I had (has gone burned because my guilt:o...) was a enough heavy and big box which inside was a medium size "classic" transformer and an electronic card (resistors, capacitors, triacs, etc. etc.).
At the present the PSU unit is much more light and smaller (5x5x15cm; about 600-700 grams of weight). I can remember when I bought it from the factory, they told me: "this new PSU is much better than the old one because it is a *switching* type".
It is sealed, so I can't open it to investigate what components inside are...:(

Greets!
Steve

brand and model: Spectra Physics 168
discharge voltage: ~240VDC

discharge current: 10-38A

triggering voltage: Not sure on this one... I know the there is a voltage doubler to put around 500V to the tube at startup, but I assume there is an actual pulse that goes through which is a bit higher, but again not sure on this (Pat? Steve?)

triggering current: I think around 8-10A is idle, not sure if there is a certain amperage the power supply goes to to start the tube though.

filament voltage: About 3V

filament current: My guess is 30A, but I haven't measured an exact value (Pat? Steve?)

optical output power: It was doing just under 8W @ 34A (tube max is 38A)

type of gas: Argon *retardo

thanks guys, your input is appreciated... I have now some work to do on a big gas laser, if it is intact...

original PSU was 3 phase 400V @ 60 amperes to get it to full power, and I doubt to be able to get it lase at 220VAC single phase @ 38A max...

I keep thinking about getting it to work before selling it though, and I really want to see it lase even if it is at one watt... a whitelight tube is something I want to make work one day, and I have now that opportunity, having one for free

Quote:

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Originally Posted by shrad

thanks guys, your input is appreciated... I have now some work to do on a big gas laser, if it is intact...

original PSU was 3 phase 400V @ 60 amperes to get it to full power, and I doubt to be able to get it lase at 220VAC single phase @ 38A max...

I keep thinking about getting it to work before selling it though, and I really want to see it lase even if it is at one watt... a whitelight tube is something I want to make work one day, and I have now that opportunity, having one for free

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Pulse it. Surplus electrolytic caps are cheap. Hum, driving the magnet though....... Ok magnet on the 220 line, big bank of caps,

Light the cathode, and then pulse the anode though a series injection ignitor.

coherent does that for their I70 sized medical tube........... 1-2 second pulses.

Steve

ya gots to deal with the magnet. probably 15 or more amps:eek: you could use a bridge rectifier with a bunch of amp capabilities:eek:

I would try to find a surplus power supply somewhere then you are golden...even tho it is still a crappy laser>:) i cant believe I just said that:eek:

hehe I have found the powwer supply, a SP model 270 exciter, which is still in pretty condition

all I hope now is they don't remember they had it mated to that tube in the past, and that they will let me take it as junk electronics

Steve, could you perhaps tell me about a basic chronogram for that pulsed operation? that would make its way easier to my mind, and it would help designing a prototype basic power supply in the future

also, I was thinking about that, are ion lasers excitable via RF power? if so, modification of a meduim power CO² power supply would maybe do a part of the job? what worries me are coatings and eventual metallic seals which could wear off because of that

if I see it correctly, the magnet would do 10~15 amps at a good 200V, which would leave a good 20 amperes for the rest of the PSU

heating the filament wouldn't be a problem as it would draw less than 5 amperes from a rewound microwave oven transformer, and I'd have a good 15~20 amperes for discharge purpose, optimal case... I couldn't find the idle current so no idea what I need

any idea about how to calculate discharge voltage and current versus length of tube?

I'll keep gathering information about that laser and its PSU (if I may find schematics it would be phenomenal) and see if I can do something... and maybe then change the optics as Steve suggested to get a stable cavity (or implement some kind of feedback to make this beamlock thing work...)