Isospin dependence of the isotopic distributions from ${^{36}Ar}$ and ${^{40}Ar}$ fragmentation at about 60 MeV/nucleon

Fragments produced in the reactions of 69 MeV/nucleon ${^{36}Ar}$ and 55 MeV/nucleon ${^{40}Ar}$ on a Be target have been measured experimentally. The isotopic distributions from fragmentation reaction for both projectiles are compared with modified statistical abrasion-ablation model calculations. A strong isospin effect exhibits in the fragment distributions produced in ${^{36}Ar}$ and ${^{40}Ar}$ fragmentation. Experimental evidence for the disappearance of the isospin effect in the isotopic distributions produced by projectile fragmentation is observed with the increase of the violence of nuclear reaction