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Re: Laser Triggered Spark Gap



> Original Poster: "Steve Young" <youngs-at-konnections-dot-com>

> Lasers would have the advantage of being able to simultaneously trigger a
> bunch of aligned series gaps by aiming the beam through all the gaps.  I
> suspect some Marx generators are fired that way.  But where can the
> cash-strapped experimenter find a suitable laser which can sufficiently
> ionize the air to initiate spark breakdown?  The only potential cheap
> sources I am aware of would be to use a $15 laser pointer in a pulse mode.
> Would this work?  

An LTG for 30kV service would need a minimum of 1-2J
of optical energy per pulse in order to fire reliably, 
an expensive proposition indeed for the laser portion!

The optical energy does not have to be coherent however,
in order to trigger the gap.  Xenon strobes are typically
used in Back-Lit Thyratrons (BLT's) in order to initiate
an avalanche breakdown. Although BLT's are less expensive 
than LTG's, they're still out of the target price range 
for most coilers.

Solid State devices such as Mod GTO's are coming of age 
in this realm, but again they're a bit pricey at $1400 
per 4200 volt module.

Perhaps the only rapidly variable break rate switching 
device within the present grasp of the budget coiler is 
the ultra-low inertia rotary spark gap.  Slew rates of
3000BPS / sec are easily possible with a low-I rotor.


> In summary, isn't it time to move toward triggered spark gaps for
> disruptive TCs?

You would dare suggest that to a group that hand-rolls 
its own capacitors and winds its own transformers??  8)

I'm off to the garage now, to make a new pair of shoes! :)
-- 


-GL
www.lod-dot-org