At 03:34 PM 12/7/00 -0800, Eric Cordian wrote:
It appears that the tactical chemical laser the US has been hoping to
deploy to protect the Zionist Entity from rockets launched by Hezbollah
guerrillas in southern Lebanon is, in the words of its developers, "not
ready for action."

http://www.newsday.com/ap/text/international/ap796.htm

According to the defense department blurb on the system, called THEL
(http://www.smdc.army.mil/FactSheets/THEL.html), the system employs
deuterium fluoride as the lasing medium.

Since deuterium is somewhat more expensive to produce than ordinary
hydrogen, one wonders why the system has been designed to work with
deuterium.  Is it because the government does not want fuel for it to be
easily produced, should the design fall into enemy hands.

Or is there some engineering advantage to using deuterium?  Does excited
deuterium fluoride have some wonderful spectral line in exactly the right
place, that pedestrian hydrogen fluoride does not?

Any chemical or nuclear engineers here who could answer the question
of why deuterium is more desirable?

That's exactly it. Deuterium-Flourine (and I think Deuterium-Iodine) have a prominent emission line which matches up nicely with CO2.  In practice, the DeF/DeI are hypergolically combined in the combustion chamber (that is they combust immediately upon contact) producing an impressive power output.  Somewhere inside or just outside the nozzle CO2 is injected and turbulently mixed.  Two parallel mirrors perpendicular to the exhaust lase the pumped up C02 and other (tracking) mirrors direct it to the target.  Unlike most other high power lasers these babies are CW, not pulsed, and capable of generating multi-megawatt beams. (They work exceptionally well in space if you can keep the fuel/oxidizer from leaking and make sure the exhaust doesn't dissolve the weapon)

This was a major Naval project when I worked at TRW in the 80s called Mid-Infrared Advanced Chemical Laser (MIRACL)


See http://www.space.com/missionlaunches/launches/laser_shootdown_000926.html

or search under "TRW chemical laser"

steve