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Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
I've made a plasma globe from a big incadescent bulb, and about 30kV@20kHz from AC flyback. It works very nice, producing multiple white-purple-blue streamers inside the bulb.
Picture:
However, I'm a little worried about it emitting x-rays. The glass 'stick' that held the filament (the filament is no longer there) is hollow and probably with vacuum inside. It glows dark green (it is not obvious from the picture; the camera didn't capture it properly) and continues glowing even after power is removed for about half second. My question is, does it really emit x-rays and if so is it safe to look at it?
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
x-rays are created when high energy electrons are accelerated into a metal target. i doubt you will have anything like that occuring within a plasma globe.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
EastVoltResearch wrote ...
x-rays are created when high energy electrons are accelerated into a metal target. i doubt you will have anything like that occuring within a plasma globe.
Glad to hear this, so it is safe to look at it for long periods of time? Also, what then causes the strange green glow? It looks dangerous!
Registered Member #229
Joined: Tue Feb 21 2006, 07:33PM
Location: Romania
Posts: 506
I think it is a fluorescence/ phosporescence phenomenon, not X-ray emission. The glass can contain different ion metals, that are excited by the streamers and can emite light (with a lower frequency, longer wave lenght), after the electric discharge stops.
Registered Member #256
Joined:
Location:
Posts: 124
ive had this happen as well, i put a small fridge bulb on my tc and the whole bulp glowed green after turned off! i was sondering bout it it looked cool i wouldnt say there is any problem with viewing it, just be careful not to peirce the thin glass envelope!
Registered Member #190
Joined: Fri Feb 17 2006, 12:00AM
Location:
Posts: 1567
If you are concerned about x-rays from any experiment you might be able to obtain an X-ray radiation badge. Put it near it for several minutes/hours and send it in to the lab for analysis. They can tell you the roentgen levels it was exposed to leaving no doubt about its safety. This would hold true for anyone doing experiments where they suspect ionizing radiation.
If you are seriously interested, I can inquire at work where these can be obtained/submitted for anaysis.
Registered Member #53
Joined: Thu Feb 09 2006, 04:31AM
Location: Ontario, Canada
Posts: 638
I have a really good pic of that green glow that seems to last a little after the power is shut off. There is a refection under the bulb from the HD platter is is sitting in.
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Nice plasma globe - does emit x-rays?
It looks dangerous! 
