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Thread: Co2 Laser Re-Gas discussion

  1. #41
    Join Date
    Jul 2009
    Orlando, FL


    Your vacuum setup is going to need a ton of work to pull off successfully re-gassing an RF CO2 tube.

    A welch duoseal is a pretty good backing pump, but it won't provide a clean or deep enough vacuum for RF CO2 tube work. You need AT LEAST one other stage in your pump cascade to achieve and maintain low enough pressures and a way to ensure you don't backstream oil and contaminate your tube. A cryotrap is a straightforward and relatively inexpensive way to do this, but it's not ideal for this type of vacuum work. Next best+cheapest option would be your duo seal backing a diffusion pump with a cryotrap, then you get into the beautiful but expensive world of turbomolecular, sorption, and ion pumps.

    Do you have a way to measure or monitor the quality of your vacuum?

  2. #42
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    A lab with some dripping water on the floor.


    Krypton was studied as a replacement for the 1 tp 5% Xenon additive professionally. . No Go! Decreases power. Same for Argon. I am the one who tried Argon. I could get it to lase, but 50% loss of design power was evil to say the least.

    Flowing gas tube does not have the regenerative catalyst materials in the laser bore. If you closely examine a flowing gas tube compared to a RF tube, you will find the structural materials are far cheaper, because you are not reusing the gas. Flowing gas depends on convection in the laser mixture for cooling the tube and optimizing the lasing power. Hot gas or a hotter tube wall, does not lase well. Sealing if off will make you far less power, if it lives long at all.

    Concur on the better vacuum, and if you want decent lifetime you either need the 3200$ pinch tool (was 1700$ ten years ago) or a cryo-valve actuator. Cryo is just the brand.

    Even the best Swagelok bellows valve is a No-Go for long term operation.

    3He:1N2:1C02 +5 % Xe + 1 % H2 plus a trace of H2O Then Co as needed, is a start, but will not give you good steady state power. Each tube design is different and the Helium content is critical. Mixtures are the result of years of R and D, and no two companies use the same mix. For most tubes, this mix is too much He to attain peak power.

    Without the catalytic surface, regen agents, and Xenon the laser will fall to 50% of rated power in an hour or less.

    You do not want to see what happens if the tube pressure is too low, either. Easy peasy catastrophic failure. I once tore down an SL, it had some very interesting structures in it.

    Got Tig? Got RGA? Got Capacitance Manometer.

    It is difficult enough mixing two gases for Ion Lasers or HENE, let alone five or six.

    For the record, I am well aware of certain Catalyst Free metallic tubes being in existence.
    Last edited by mixedgas; 03-03-2022 at 11:04.
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  3. #43
    Join Date
    Jan 2015

    Default Mélanges de gaz pour laser CO2

    Pour ma part j'ai une trentaine de lasers CO2 continu, pulsé, TEA etc.... et comme je les utilise uniquement pour des expériences de courte durée alors je les équipent avec des vannes à soufflet Swagelok ce qui me permet de les remplir à chaque fois que j'en ai besoin donc sur une courte période 1 à 2 jours je n'ai pas de problème de perte de puissance dû à la modification chimique du mélange gazeux avec les électrodes et les parois.

    Photo d'un laser TEA CO2 de 6 Joules
    Attached Thumbnails Attached Thumbnails 20220208_144613.jpg  

    Capture d’écran 2022-04-19 212514.jpg  


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