Abstract
Breakup temperatures in central collisions of at bombarding energies to 200 MeV were determined with two methods. Isotope temperatures, deduced from double ratios of hydrogen, helium, and lithium isotopic yields, increase monotonically with bombarding energy from 5 to 12 MeV, in qualitative agreement with a scenario of chemical freeze-out after adiabatic expansion. Excited-state temperatures, derived from yield ratios of states in , , and , are about 5 MeV, independent of the projectile energy, and seem to reflect the internal temperature of fragments at their final separation from the system.
- Received 17 December 1997
DOI:https://doi.org/10.1103/PhysRevLett.80.3928
©1998 American Physical Society