The creation of hot Ca-like fragments was investigated in the 40Ca +40Ca reaction at 35 AMeV.Using the AMPHORA 4π detector system, the primary projectile-like fragment was reconstructed and ...itsproperties were determined. Both primary and secondary distributions are compared with the predictionsof a Monte Carlo code describing a heavy-ion collision as a two-step process. Some of the nucleons whichare identified as participants in the first step are transferred in the second step to these final states, whichcorrespond on the average to the maximum value of entropy (thermodynamic probability). The modelallows for competition between mean-field effects and nucleon-nucleon interactions in the overlap zone ofthe interacting nuclei. The analysis presented here suggests a thermalized source picture of the decay ofthe projectile-like fragment. The validity of the reconstruction procedure for projectile-like fragments isdiscussed. (Springer)
The shape of the velocity distributions of charged particles projected on the beam direction can be explained if emissions from the hot projectile-like fragment and the target-like fragment are ...supplemented by an emission from an intermediate velocity source located between them. The creation of this source is predicted by a two-stage reaction model where, in the second stage, some of the nucleons identified in the first stage as participants form a group of clusters located in the region between the colliding nuclei. The cluster coalescence process is governed on the average by the maximum value of entropy, although its fluctuations are also significant. The properties of the intermediate velocity source are precisely described, including the isotopic composition of the emitted particles. (Springer)
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