Fragment Kinetic Energies and Modes of Fragment Formation

Abstract

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

11 pages, with 4 included figures; Accepted by Phys. Rev. Lett.; Also available from http://www-kp3.gsi.de/www/kp3/aladin_publications.html

References in corpus (9)

• Universality of Spectator Fragmentation at Relativistic Bombarding Energies
• Breakup Temperature of Target Spectators in Au + Au Collisions at E/A = 1000 MeV
• Temperatures of Exploding Nuclei
• The multifragmentation of spectator matter
• Temperatures of Fragment Kinetic Energy Spectra
• Breakup Density in Spectator Fragmentation
• Microcanonical studies concerning the recent experimental evaluations of the nuclear caloric curve
• Spectator and participant decay in heavy ion collisions
• Breakup Conditions of Projectile Spectators from Dynamical Observables

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• Comparative Study of Multifragmentation of Gold Nuclei Induced by Relativistic Protons, ${}^4$He, and ${}^{12}$C
• Thermal and Chemical Freeze-out in Spectator Fragmentation
• Transverse Velocity Scaling in Au+Au Fragmentation
• Thermal and transport properties in central heavy-ion reactions around a few hundred MeV/nucleon
• Bimodality - a general feature of heavy ion reactions
• Two characteristic volumes in thermal nuclear multifragmentation
• Fragment Formation in Central Heavy Ion Collisions at Relativistic Energies
• Improved Thermometer from Intermediate Mass Fragments in Heavy-Ion Collisions with Isobaric Yield Ratio Difference
• Dispersion of longitudinal momentum distributions induced in fragmentation reactions
• Projectile fragment emission in fragmentation of ${}^{56}$Fe on C, Al,and CH${}_2$ targets at 471 A MeV
• Light fragments from (C + Be) interactions at 0.6 GeV/nucleon