The odd–even effect of fragmentation cross sections produced in the de-excitation process

Abstract

The odd–even effect of fragmentation cross sections is studied by improved quantum molecular dynamics model and the GEMINI statistical decay model for reactions 36Ar and 40Ar on C, Al, Cu and Pb targets at 400 A MeV. The odd–even effect is produced in the de-excitation process. The pairing energy plays an important role for the odd–even effect. The odd–even effect disappears without the pairing energy. The excitation energy of prefragments is researched. The odd–even effect for proton is produced obviously at low excitation energy for 36Ar projectile. The odd–even effect is stronger for the neutron fragmentation than the proton one.