Re: Van de Graaff generator safety question (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 16 Jan 2004 16:01:02 -0200
From: Antonio Carlos M. de Queiroz <acmq@xxxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Van de Graaff generator safety question (fwd)

High Voltage list wrote:

> From: Dr. Resonance <resonance@xxxxxxxxxx>

> I forgot to mention --- in a tank with SF6, not in open air.

Ok. In a compressed gas the possible surface charge density is much
higher (increases almost proportionally to the pressure). It's
easy then to make a machine with many mA of charging current.
The large currents in pelletrons are due to high chain speed,
and maybe more stable operation due to the charge transport by
metal sectors instead of in a dielectric surface.
Charging by induction is natural in this case, as it is not necessary
to spray charge over a chain of conductors. They can be charged
directly by conduction when put in electrical contact with a
high-voltage supply. A very efficient charging system can be made
in this way.

Antonio Carlos M. de Queiroz