Date: Tue Nov 6 22:08:21 2007

Author: Bernard Cleyet

Subject: Re: x-ray issues with DIY "plasma globes"

Post:
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Thanks for the references, etc.

The Cu activation reminds me of my first job. (1961/62!) I made CdS
photo-conductors and added a little Cu. (I think
CuCl.)

That was a joke, nicht wahr?

bc thinks the ionization of the G-M tube changes the Z so the hum is
more evident.

William Beaty wrote:

>On Mon, 5 Nov 2007, Bernard Cleyet wrote:
>
>
>
>>Like NaI, I suspect the ZnS is "activated" w/ another element(s).
>>
>>
>
>A few years ago we bought a 50lb sack of the common "glow-in-dark"
>phosphorescent paint. It is spec'd as ZnS:Cu.
>
>
>
>
>>I used phosphor from a kinescope
>>
>>
>
>Good idea! Unmodified oscilloscope screen.
>
>
>
>
>
>
>>http://www.viewsfromscience.com/documents/webpages/radioluminescence_NS.html
>>
>>
>
>Warning: the above URL features an animated head of Sir William Crookes.
>He talks!
>
>
>
>
>>p.s. a home made ionization chamber might be better for detecting soft
>>x-rays. A kapton window would be suitable.
>>
>>
>
>
>Here's someone who has built numerous different ion-chamber devices
>
> http://www.techlib.com/science/ion.html#Better%20Version
>
>One thing I noticed with the alpha-window counter: the audio clicks have a
>distinct 60Hz hum modulation, and this wasn't apparent when I ran the
>handheld Tesla coil from 120V batteries. Which leads me to suspect that
>if I built an audio-modulated Tesla coil, I could stick one of these bulbs
>on top, and use it to transmit voice over x-rays! :)
>
> Transistor-based Tesla coils w/audio modulation
> http://www.youtube.com/watch?v=BiUlqecQKUo
> http://www.youtube.com/watch?v=3ff_AXVlo9U
>
>
>
>
>>
>>William Beaty wrote:
>>
>>
>>
>>>I heard from a couple of hobbyists that most small light bulbs contain a
>>>hard vacuum. I finally got around to testing this. Sure enough, nine out
>>>of ten small bulbs at Home Depot do *not* exhibit plasma streamers when
>>>operated as a "plasma globe" or touched to a handheld Tesla coil. These
>>>are aquarium bulbs, very small appliance bulbs, exit-sign replacement
>>>bulbs, etc. Even the #48 2V pilot lamps in my junk drawer are hard
>>>vacuum.
>>>
>>>Sure enough, their glass fluoresces when connected to a small Tesla coil.
>>>Most lit up sky blue, a few were white, and only one was green. And sure
>>>enough, an alpha-window geiger counter shows that they put out x-rays.
>>>Their x-ray output might be pretty feeble though. Even for dark-adapted
>>>eyes it won't give the slightest flicker on phosphorescent ZnS paint, when
>>>the bulb is held against the paint. (I used black electrical tape to
>>>block the visible glow.) Now I'm wondering if ZnS sulfide paint is far
>>>less sensitive to x-rays than the material used for old-style medical
>>>fluoroscope screens. It might not be good for crude testing for x-ray
>>>hazards.
>>>
>>>And as I expected there was no GM counter readings from any of the more
>>>common larger bulbs with "edison" screw bases. These all displayed purple
>>>plasma streamers coming from their filament assembly.
>>>
>>>
>>>(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
>>>William J. Beaty SCIENCE HOBBYIST website
>>>billb at amasci com http://amasci.com
>>>EE/programmer/sci-exhibits amateur science, hobby projects, sci fair
>>>Seattle, WA 425-222-5066 unusual phenomena, tesla coils, weird sci
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>
>(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
>William J. Beaty SCIENCE HOBBYIST website
>billb at amasci com http://amasci.com
>EE/programmer/sci-exhibits amateur science, hobby projects, sci fair
>Seattle, WA 425-222-5066 unusual phenomena, tesla coils, weird sci
>
>
>
>

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Thanks for the references, etc.

The Cu activation reminds me of my first job. (1961/62!)=C2=A0 I made CdS=

photo-conductors and added a little Cu. (I think
CuCl.)=C2=A0

That was a joke, nicht wahr?

bc thinks the ionization of the G-M tube changes the Z so the hum is
more evident.

William Beaty wrote:

On Mon, 5 Nov 2007, Bernard Cleyet wrote:



Like NaI, I suspect the ZnS is "activated" w/ another=
element(s).



A few years ago we bought a 50lb sack of the common "glow-in-dark"
phosphorescent paint. It is spec'd as ZnS:Cu.




I used phosphor from a kinescope



Good idea! Unmodified oscilloscope screen.






http:/=
/www.viewsfromscience.com/documents/webpages/radioluminescence_NS.html



Warning: the above URL features an animated head of Sir William Crookes.
He talks!




p.s. a home made ionization chamber might be better fo=
r detecting soft
x-rays. A kapton window would be suitable.




Here's someone who has built numerous different ion-chamber devices

http://www.techlib.com/science/ion.html#Bet=
ter%20Version

One thing I noticed with the alpha-window counter: the audio clicks have =
a
distinct 60Hz hum modulation, and this wasn't apparent when I ran the
handheld Tesla coil from 120V batteries. Which leads me to suspect that
if I built an audio-modulated Tesla coil, I could stick one of these bulb=
s
on top, and use it to transmit voice over x-rays! :)

Transistor-based Tesla coils w/audio modulation
http://www.youtube.com/watch?v=3DBiUlqecQKUo
http://www.youtube.com/watch?v=3D3ff_AXVlo9U





William Beaty wrote:



I heard from a couple of hobbyists that most small l=
ight bulbs contain a
hard vacuum. I finally got around to testing this. Sure enough, nine ou=
t
of ten small bulbs at Home Depot do *not* exhibit plasma streamers when
operated as a "plasma globe" or touched to a handheld Tesla coil. These
are aquarium bulbs, very small appliance bulbs, exit-sign replacement
bulbs, etc. Even the #48 2V pilot lamps in my junk drawer are hard
vacuum.

Sure enough, their glass fluoresces when connected to a small Tesla coil.=

Most lit up sky blue, a few were white, and only one was green. And sure=

enough, an alpha-window geiger counter shows that they put out x-rays.
Their x-ray output might be pretty feeble though. Even for dark-adapted
eyes it won't give the slightest flicker on phosphorescent ZnS paint, whe=
n
the bulb is held against the paint. (I used black electrical tape to
block the visible glow.) Now I'm wondering if ZnS sulfide paint is far
less sensitive to x-rays than the material used for old-style medical
fluoroscope screens. It might not be good for crude testing for x-ray
hazards.

And as I expected there was no GM counter readings from any of the more
common larger bulbs with "edison" screw bases. These all displayed purpl=
e
plasma streamers coming from their filament assembly.


(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
William J. Beaty SCIENCE HOBBYIST website
billb at amasci com http://amasci.com
EE/programmer/sci-exhibits amateur science, hobby projects, sci fair
Seattle, WA 425-222-5066 unusual phenomena, tesla coils, weird sci











(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
William J. Beaty SCIENCE HOBBYIST website
billb at amasci com http://amasci.com
EE/programmer/sci-exhibits amateur science, hobby projects, sci fair
Seattle, WA 425-222-5066 unusual phenomena, tesla coils, weird sci







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