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Re: Jellys - Geissler
>
> Those are geisller tubes (one version of them). They are very collectable
> however they produce many many x-rays. I have access to one. Its real neat to
> watch it work. A standard transformer works well with them.
>
> Do you know if they are still being made?
>
> Howie Cohen
>
Dear Howie,
these geissler tubes are still beeing made for physical demonstrations.
(One Company is the german Leybold Lehrmittel ).
The dark rooms in the positive coloumn stems from the use of molecular gases
instead of atomar noble gases. When run for a longer time, these gases react
with electrodes and the glass, so the tube life is very short compared
to neon. The electrodes are mostly planar ones instead our hollow shells.
So sputtering and gas consumption is very important for reducing tube life.
They should be run on DC - or an old inductor delivering AC with
an energy relation of the positive impulse to the negative one of 80% vs 20%.
The gas pressure is low, ignition voltage very high, and depending on the
glass they produce only SOFT X-rays. No danger when using less than 9kV transfo.
All X-ray then absorbed in the glass.
Marcus Thielen, DL1EHM,
Student of physics at duisburg University.
email: marcus@ttphysik.uni-duisburg.de
References: