Dynamical and statistical fragment emission properties in image 20Ne + 40Ar collisions Original Research Article

Dynamical and statistical fragment emission processes in 200 A MeV 20Ne + 40Ar collisions are well probed by measurements of charge (Z), mass (A) and momentum vector (View the MathML source) of all fragments in large parts of the available momentum space. We present such data obtained at the cluster-jet target of the CELSIUS storage ring, for the first time with an internal, ultra-high vacuum (UHV) compatible detector system (CHICSi). Energy and angular dependence in Z and A distributions are not reproduced by a single-step model, e.g., those based on molecular dynamics (MD), but require a complete three-step model. We use here the intranuclear cascade + statistical multifragmentation + secondary evaporation model (CFEM). The angular dependence of isobaric ratios, like 6He/6Li at low emission velocities and temperatures extracted from isotopic (double) ratios, do exhibit differences, even from this model. These differences, which call for adjustment of model parameters, are discussed.