1. Isotopically resolved residues from the fragmentation of projectiles with largely different N/Z
Daniela Henzlova for CHARMS collaboration
GSI-Darmstadt, Germany
(on leave from NPI Rez, Czech Republic)

2. Motivation nuclear liquid-gas phase transition caloric curve
high excitation energies introduced in nuclear reaction -> abundant production of small fragments
nuclear liquid-gas phase transition
caloric curve
THeLi (MeV)
liquid-gas phase transition?
<E0>/<A0> (MeV)
J. Pochodzalla et al., Phys. Rev. Lett. 75 (1995) 1040
DPG Berlin
D. Henzlova for CHARMS

3. Basic idea to determine nuclear temperature
thermally equilibrated nuclear system
particles emitted by such a system carry information on the temperature
methods:
similarities:
slope of the kinetic energy spectra
based on thermodynamics
double isotopic ratio
focused on IMFs and light fragments
population of excited states
3H, 3He yield ratio
DPG Berlin
D. Henzlova for CHARMS

4. New experimental investigation
fragmentation of 136Xe (N/Z=1.52) and 124Xe (N/Z=1.30)
isotopic identification over the full nuclear charge range
alternative approach – the isospin thermometer method
freeze-out
evaporation
final fragment
N/Z
N’/Z’
follow the isotopic composition of the heavy fragment during the evaporation process back in time to reconstruct its excitation energy
DPG Berlin
D. Henzlova for CHARMS

5. Fragment Separator (FRS), GSI Darmstadt
136Xe + Pb 1A GeV
136Xe Z N
resolving power A/ΔA ~ 400
DPG Berlin
D. Henzlova for CHARMS

6. <N>/Z in full nuclear charge range
full isotopic identification for projectiles with extreme N/Z difference obtained for the first time
difference between the final <N>/Z preserved in full nuclear charge range
memory on the N/Z of the projectile preserved even at the end of evaporation
DPG Berlin
D. Henzlova for CHARMS

7. Evaporation as a diffusion process
mass, E* and N/Z of the nucleus changes in each evaporation step due to the emission of the nucleon or light cluster (X.Campi, J.Hüfner, Phys. Rev. C24 (1981))
excited fragment follows certain rather well defined path in the chart of nuclides
136Xe
experimental data
abrasion
evaporation
break-up
knowing the final and intermediate N/Z the excitation energy may be traced back
DPG Berlin
D. Henzlova for CHARMS

8. The isospin thermometer method
explores the change of N/Z in evaporation process to trace back the E*~T2 of fragment entering evaporation
136Xe+Pb 1AGeV
136Xe
break-up
abrasion
E* ~ T2
evaporation
temperature at freeze-out after break-up
T = 5 MeV
Tf= 3MeV
Tf= 4MeV
Tf= 5MeV
Tf= 7MeV
DPG Berlin
D. Henzlova for CHARMS

9. Summary
isotopic composition in the complete Z range was measured for residues from 136Xe (N/Z=1.52) and 124Xe (N/Z=1.30) projectiles
freeze-out temperature of 5 MeV in the broad Z range was deduced from the isospin thermometer method
temperature extracted using evaporation of the heavy residues is consistent with values extracted from light and IMFs
DPG Berlin
D. Henzlova for CHARMS