2003/05/31 by G. A. Souliotis, D. V. Shetty, M. Veselský +6 · 6 citations
Physics and Astronomy · #Astronomical and nuclear sciences #Atomic and Molecular Physics #Nuclear physics research studies #nucl-ex
paper · pdf · doi:10.1103/physrevc.68.024605
published as Phys.Rev. C68 (2003) 024605 · 8 pages, 6 figures, submitted to Phys. Rev. C
arxiv created 2003/06/04 · openalex publication_date 2003/08/25 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The scaling of the yields of heavy projectile residues from the reactions of 25MeV/nucleon 86Kr projectiles with 124Sn, 112Sn and 64Ni, 58Ni targets is studied. Isotopically resolved yield distributions of projectile fragments in the range Z=10--36 from these reaction pairs were measured with the MARS recoil separator in the angular range 2.7\ifmmode^∘\else\textdegree\fi--5.4\ifmmode^∘\else\textdegree\fi. For these deep inelastic collisions, the velocities of the residues, monotonically decreasing with Z down to Z\ensuremath≃26--28, are employed to characterize the excitation energy. The ratios R21(N,Z) of the yields of a given fragment (N,Z) from each pair of systems are found to exhibit isotopic scaling (isoscaling), namely, an exponential dependence on the fragment atomic number Z and neutron number N. The isoscaling is found to occur in the residue Z range corresponding to the maximum observed excitation energies. The corresponding isoscaling parameters are \ensuremathα=0.43 and \ensuremathβ=\ensuremath-0.50 for the Kr+Sn system and \ensuremathα=0.27 and \ensuremathβ=\ensuremath-0.34 for the Kr+Ni system. For the Kr+Sn system, for which the experimental angular acceptance range lies inside the grazing angle, isoscaling was found to occur for Z<~26 and N<~34. For heavier fragments from Kr+Sn, the parameters vary monotonically, \ensuremathα decreasing with Z and \ensuremathβ increasing with N. This variation is found to be related to the evolution towards isospin equilibration and, as such, it can serve as a tracer of the N/Z equilibration process. The present heavy-residue data extend the observation of isotopic scaling from the intermediate mass fragment region to the heavy-residue region. Interestingly, such high-resolution mass spectrometric data can provide important information on the role of isospin and isospin equilibration in peripheral and midperipheral collisions, complementary to that accessible from modern large-acceptance multidetector devices.