From: arno@utu.fi (Arno Hahma)
Newsgroups: rec.pyrotechnics,alt.engr.explosives
Subject: Re: C2H2/02/Xe
Date: 29 Jan 1999 12:02:21 GMT

In article <78qfdf$eln@news5-gui.server.cableol.net>, Dirk Bruere
<artemis@kbnet.co.uk> wrote:

>wrong) by displacing 10% of the vol with Xenon gas, and then filling the
>remainder with C2H2/02.
>
>Question is, does the explosion/detonation pump the Xenon sufficent to
>convert a substantial portion of the energy into a brilliant flash?

It would probably flash, but not with high efficiency. The energy
density in a gaseous, detonating mixture is not that high and the
temperature isn't high enough to excite atoms in significant amounts.

However, there is a way to produce extremely powerful flashes out of
noble gases. One only has to use solid explosives to generate the
shockwave. The so called argon flash is more or less standard
procedure, when bright, short flashes are needed, for instance, when
photographing detonations.

In a simplest form, an argon flash is a balloon filled with argon and
some detonating cord taped onto the balloon. When the shockwave from
the detonating cord hits argon, it heats up to extremely high
temperatures (in the order of 10000 K and more) and emits very strong
UV and visible radiation. The intensity can be scaled with the amount
of explosive.

Any other gas will light up as well. However, noble gases with high
ionisation potentials can heat up to much higher temperatures than,
say, air. Molecules dissociate and restrict the temperature, while
atomaric gases can only ionize to consume the energy. Ionized gas is
pretty hot and bright.



ArNO
    2