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Thread: Helium 3

  1. #1
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    Default Helium 3

    A friend of mine is looking for helium3 to bring an old HeCd back to life. Anyone got a source? Need the Cd isotopes as well.

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    Quote Originally Posted by kecked View Post
    A friend of mine is looking for helium3 to bring an old HeCd back to life. Anyone got a source? Need the Cd isotopes as well.

    112 and 114 have the most gain, Isoflex or Urenco sell them....

    Helium Three is a national strategic reserve material. Now that the cold war is over, its price has skyrocketed, as there are no more bomb production reactors making it as a byproduct. You can try, but it ranges from 1500 to 5000$ a litre depending on purity... Spectra Gasses sells it, as does one or two other companies.

    Quoting Isowiki:

    The even numbered Cd isotopes (mainly Cd-110, Cd-112, Cd-114 and Cd-116) are used to improve the power output and coherence length of HeCd lasers.

    Laser Fundamentals by William Silfvast, available on Google Books, Page 117 has the graph of what Isotope does what.

    Some one's insane to try this without a LOT of money. Natural mix of isotopes does lase, and so does regular helium. Only if you want a single frequency laser or the highest possible power do you do that.

    Silfvast invented the HeCad.

    Steve
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    Quote Originally Posted by mixedgas View Post
    112 and 114 have the most gain, Isoflex or Urenco sell them....

    Helium Three is a national strategic reserve material. Now that the cold war is over, its price has skyrocketed, as there are no more bomb production reactors making it as a byproduct. You can try, but it ranges from 1500 to 5000$ a litre depending on purity... Spectra Gasses sells it, as does one or two other companies.

    Quoting Isowiki:

    The even numbered Cd isotopes (mainly Cd-110, Cd-112, Cd-114 and Cd-116) are used to improve the power output and coherence length of HeCd lasers.

    Laser Fundamentals by William Silfvast, available on Google Books, Page 117 has the graph of what Isotope does what.

    Some one's insane to try this without a LOT of money. Natural mix of isotopes does lase, and so does regular helium. Only if you want a single frequency laser or the highest possible power do you do that.

    Silfvast invented the HeCad.

    Steve
    Yea this is for Dale. He can't afford that. We were thinking to recover the Cd from older tubes but I can't find a good way to do it that is safe. I had thought to plate I out though but didn't go further.

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    if he needs replacement why not use dpss? or is it just pure nostalgia?

    http://www.powertechnology.com/concerto-442-150.html

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    Quote Originally Posted by dzodzo View Post
    if he needs replacement why not use dpss? or is it just pure nostalgia?

    http://www.powertechnology.com/concerto-442-150.html
    totally for fun.

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    Why this specific helium isotope? Would the atomic energy levels not be equal for the various isotopes? Or does the missing neutron and the including slight change in the nucleus' magnetic moment have such an impact?

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    Quote Originally Posted by colouredmirrorball View Post
    Why this specific helium isotope? Would the atomic energy levels not be equal for the various isotopes? Or does the missing neutron and the including slight change in the nucleus' magnetic moment have such an impact?
    from what I was told 50% of the power comes from using the CD isotopes and than 20% more from the He3

    So say you used regular mixed Cd and He4 and got 10mw. That could have been 17mw Almost double the power.

    100mw=170mw big difference.

    Physics of it? Try wiki.?

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    I cant find any scientific reference to He3 being used for a power boost. I can find plenty of references for using a mix of even numbered Cadmium isotopes, because odd isotopes evidently have an odd spin which contributes to a gain bandwith curve with three spikes and three dips in it. Whereas even isotopes have a smooth gain bandwidth curve.
    +

    Single isotopic Cadmium also triples the coherence length.
    +

    Evidently there is a expensive little solid state laser at 442 with a long 100 meter Coherence length that has replaced HeCad for holography.
    +
    +
    Kecked, Google "Isotopic Cadmium Laser ", pick a few papers, and all will be revealed.
    +
    Winning numbers, 114,112,110, 116 in that order...
    +
    Mutimode high power lasers would use a mix of the four isotopes listed above.
    +

    Steve
    Last edited by mixedgas; 11-18-2015 at 13:28.
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    Quote Originally Posted by kecked View Post

    Physics of it? Try wiki.?
    I could not find anything. Are you sure you need this isotope?

    Sams laser FAQ says you get a better coherence length if you use only one Cd isotope but does not explain why.

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    I used to buy hene and argon bulbs from Midwest Sign and Screen Supply, St. Paul MN, you might want to check with them.

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