Experimental and theoretical search for a phase transition in nuclear fragmentation
A. Chbihi1 - O. Schapiro2 - S. Salou1 - D.H.E. Gross2
1 GANIL, P.B. 5027 F-14021 Caen Cedex, France
2 Hahn-Meitner-Institut, D-14109 Berlin, Germany
Received: 30 November 1998 / Revised version: 8 March 1999 Communicated by B. Povh
Phase transitions of small isolated systems are signaled by the shape of the caloric equation of state e*(T), the relationship between the excitation energy per nucleon e* and temperature. In this work we compare the experimentally deduced e*(T) to the theoretical predictions. The experimentally accessible temperature was extracted from evaporation spectra from incomplete fusion reactions leading to residue nuclei. The experimental e*(T) dependence exhibits the characteristic S-shape at e* = 2-3 MeV/A. Such behavior is expected for a finite system at a phase transition. The observed dependence agrees with predictions of the -model, which simulates the total accessible phase-space of fragmentation.
05.70.Fh Phase transitions: general aspects - 21.10.Ma Level density