Xray Lasers

>From Clay Bush:
   I've encountered x-ray lasers in a campaign setting. My research attached:
if I'm wrong or anyone can add anything, please do so. (I'm fishing for more
information.)

X-RAY LASERS
 ============
   The regular laser works by exciting a crystal. The material used limits
what input and output can be handled.
    Note: U.S. materials refer to output levels that can be repeated: the
material in the crystal is not ruined. Some Russian firsts actually represent
a one-shot use that burned out the crystal -- which anyone could have done.
Some of those high figures found their way into SDI threat estimates.
   Thus, characters can improvise the "one-shot laser weapon" by altering a
device (defeating safeguards) and burning out its crystals. These are always
one-shot devices.

   An X-ray laser is at a higher wavelength than regular lasers, and catalyst
materials do not operate reliably at those frequencies. The energy input
causes an energy release before the intended frequency is achieved.
   Consequently, SDI (and 2300AD) look at using nuclear explosions and one-
shot crystals to generate X-ray laser beams. (The higher frequency requires
much more power in the same time span, so you need a actual nuclear explosion
to power it.)

EFFECTIVENESS
 =============
   The higher energy levels in an X-ray beam make the weapon _several times_
more lethal.
   The wider wavelength limits penetration: X-ray lasers would be ineffective
below 100 km in the Earth's orbit. (Limits use in planetary bombardment, and
cannot be used in thin or thicker atmospheres.)
   The limited penetration and higher energy combine to act as a physical
impact on the target. Instead of a hole through the craft, you have concussion
damage and equipment shaken up.
   The beam would be wide, so so an orbital battle station could hit multiple
targets with one shot. This applies mainly to hit decoys and the protected
item, because otherwise things wouldn't be close enough together. The decoys,
being lighter, would react more to the X-ray hit, permitting identification of
the protected target even if it is not destroyed.