  Kinetic energies of light fragments A <= 10 from the decay of target
spectators in 197Au 197Au collisions at 1000 MeV per nucleon have been measured
with high-resolution telescopes at backward angles. Except for protons and
apart from the observed evaporation components, the kinetic-energy spectra
exhibit slope temperatures of about 17 MeV, independent of the particle
species, but not corresponding to the thermal or chemical degrees of freedom at
breakup. It is suggested that these slope temperatures may reflect the
intrinsic Fermi motion and thus the bulk density of the spectator system at the
instant of becoming unstable.
  PACS numbers: 25.70.Pq, 21.65.+f, 25.70.Mn
