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anakin_nEo
Belliger luminis

Inscrit le: 07 Janvier 2004
Messages: 18575
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Posté le:
Mer Jan 02, 2008 2:17 am |
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anakin_nEo
Belliger luminis

Inscrit le: 07 Janvier 2004
Messages: 18575
Localisation: gg
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Posté le:
Mer Jan 02, 2008 2:26 am |
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http://www.steelypips.org/principles/2005_12_04_principlearchive.php
The wavemeter doesn't have good enough resolution to tune the laser perfectly into resonance, so at this point, I moved on to the ultimate test: comparing the frequency to the krypton resonance line. For this, I've got a small krypton cell (pictured here) that I run an RF plasma discharge in to produce metastable atoms as a reference. I shine a bit of the laser light through, and look for absorption of the light with a photodiode. Finding these absorption lines can be a hugely time-consuming process, if you don't know exactly what you're looking for (ask my summer students), but I've adjusted this laser to this particular line a half-dozen times before, so it wasn't that difficult. Here's the scope trace showing absorption-- the triangle wave is the signal I use to sweep the laser frequency back and forth, while the big dips in the lower trace show the laser light being absorbed.
http://www.steelypips.org/principles/labweek/scopetrace.jpg
et le point foindateur
Somewhat surprisingly, this is a feature, not a bug, at least when it comes to measuring krypton as a background contaminant. The energy needed to excite the atoms to the metastable state is about 10 electron volts (eV), which sounds like a trivial amount of energy to particle physicists (who regard energies of a million eV as beneath notice), but is pretty significant in atomic physics-- another way to think about it is that 10 eV is roughly equal to the kinetic energy of an atom in a gas at a temperature of about 12,000 Celsius. In other words, there aren't a lot of ways for a krypton atom wandering around my lab to end up in the metastable state. And since we can only trap and detect atoms that are in the metastable state, this eliminates a lot of the worries you might otherwise have about contamination in the system. Any krypton atoms in the air in the lab (air is about one part per million Kr) would need to both get into the system somehow (not a trivial matter) and also acquire 10 eV of internal energy before they could possibly be detected and compromise the measurement.
je ressort
The energy needed to excite the atoms to the metastable state is about 10 electron volts
entendez....le krypton s'excite facilement au point dans la manip ici en anglais de pouvoir perturber les mesures de ce test d'aligenement laser ou plutot d'affinage dela frequence des lasers par comparaison a un etalon krypton
les physiciens adorent compliquer tout
mdrrr
bref en gros ce gars essaie de moduler la puissance de ses lasers de maniere totalement controlee avec pourmesure un etalon krypton mais s'inquiete du fait que le krypton etant aisement excitable , sa norme puisse etre "betement" influencee par un peu d'ev electron volts "en l'air"
si l'adn possede du krypton et que le krypton possede un seuil "electrique" d'excitation si bs c'est poeut etre parce que le "voltage" du cerveau (et des cellules du corps) particulierement bas
voir topic adn ummo
http://www.objetvolant.com/html/modules.php?name=Forums&file=viewtopic&t=5673 |
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anakin_nEo
Belliger luminis

Inscrit le: 07 Janvier 2004
Messages: 18575
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Posté le:
Mer Jan 02, 2008 2:32 am |
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anakin_nEo
Belliger luminis

Inscrit le: 07 Janvier 2004
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Posté le:
Mer Jan 02, 2008 2:33 am |
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anakin_nEo
Belliger luminis

Inscrit le: 07 Janvier 2004
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Posté le:
Mer Jan 02, 2008 2:35 am |
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Manu
Amiral de Terre


Inscrit le: 12 Août 2003
Messages: 523
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Posté le:
Mer Jan 02, 2008 2:37 am |
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Manu
Amiral de Terre


Inscrit le: 12 Août 2003
Messages: 523
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Posté le:
Ven Jan 04, 2008 11:11 pm |
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Bonsoir,
Je viens de faire un petite mise à jour concernant GAA (le carré), pas pour l'aire de la pyramide, mais pour 711 (G-A-A), comme vu plus haut.
Sans tout lire, cherchez "
Atterrissage de 1967
" et voyez ce qu'il ya autour de ça, en appréciant la CAD-oeuvre d'art des Xanmoo! (ordinateurs là-bas) :=))
Le lien est la signature. |
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Manu
Amiral de Terre


Inscrit le: 12 Août 2003
Messages: 523
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Posté le:
Ven Jan 04, 2008 11:54 pm |
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| anakin_nEo a écrit: |
pour retomber sur le topic et puisque la pyramide semble une clef
se demander quel diable peut etre le lien entre une pyramide.. metallique et le krypton
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Numéro atomique du Krypton =
36
+
1967
=
2003
Email
: "I'm a time traveler stuck here in
2003
..."
Dé-Krypton!!! |
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