Re: Breakdown voltage at submillimeter distances?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Robert Clark <bobbygc2001@xxxxxxxxx>

 Thanks for that. I will take a look at that Review of
Scientific Instruments report.


   - Bob Clark

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: Bert Hickman
> <bert.hickman@xxxxxxxxxx>
>
> Tesla list wrote:
> >Original poster: Robert Clark
> <bobbygc2001@xxxxxxxxx>
> >  Thanks for the detailed response. I was thinking
> of
> >creating small capacitors using very small gap
> spacing
> >based on the idea that the breakdown voltage would
> >start rising again at the left end of the Paschen
> >curve. Your references seem to put the scotch on
> that
> >idea.
> >  However, I've read that the shape of the
> electrodes
> >has an effect on the measurements: pointed ones
> give
> >off more electrons than flat ones.
> >  What would be the result if we used flat plates
> >(atomically flat even)?
> >
> >    Bob Clark
>
> Bob,
>
> The left side of Paschen's curve does not apply even
> when using
> optically smooth surfaces. It has been observed in
> optical reticles
> and MEM devices. Anomalous breakdown originates from
> points of high
> E-field concentration (and these are always present
> even on
> "optically flat" surfaces). "Conditioning" (the
> removal of high-field
> points by evaporation via low energy discharges)
> helps to slightly
> increase breakdown voltage of the gap, until the
> next, slightly
> lower, field concentration point initiates another
> breakdown.
>
> In one series of experiments (1) thin layers of
> evaporated gold were
> applied to optically polished sapphire in order to
> create a very
> smooth air-insulated flat plate capacitor. Similar
> anomalous
> breakdown behavior was observed. Similar behavior
> was observed in
> chrome reticles (as well as a new phenomenon -
> Electric Field Induced
> Migration). See:
>
http://www.sematech.org/meetings/past/20031212/Paper2.pdf
> and
>
http://www.sematech.org/meetings/past/20031212/Paper3.pdf
>
> 1. Emmanouel Hourdakis, Brian J. Simonds, and Neil
> M. Zimmerman,
> "Submicron gap capacitor for measurement of
> breakdown voltage in
> air", Review of Scientific Instruments, 77, 034702
> (March, 2006)
>
> Bert
>