Collisions of112 Sn and 124 Sn nuclei, which differ in their isospin asymmetry, provide information about the rate of isospin diffusion and equilibration. While several different probes can provide accurate diffusion measurements, the ratios of the mirror nuclei may be the simplest and most promising one. Ratios of the mass seven mirror nuclei yields are analyzed to show the rapidity, transverse momentum and impact parameter dependence of isospin diffusion. [4][5][6][7] for its determination. Recently, constraints on the density dependence of the symmetry energy were obtained from measurements of isospin diffusion in peripheral nuclear collisions [6,8]. In this paper, we identify a set of experimental observables, specifically observables constructed with yield ratios of mirror nuclei, that provide consistent measures of the isospin diffusion and extend those experimental investigations to a wider range of rapidity, transverse momentum and impact parameter.In a heavy ion collision involving a projectile and a target with different proton fractions, Z/A, the symmetry energy tends to propel the system towards isospin equilibrium so that the difference between neutron and proton densities is minimized [7].The isospin asymmetry A Z N − = δ of a projectile-like residue produced in a peripheral collision reflects the exchange of nucleons with the target; significant diffusion rates should lead to larger isospin asymmetries for collisions with neutron-rich targets and smaller isospin asymmetries for collisions with proton-rich targets [6].To isolate the isospin diffusion effects from similar effects caused by preequilibrium emission, Coulomb or sequential decays, relative comparisons involving different targets are important. In recent studies, isospin diffusion has been measured by "comparing" A+B collisions of a neutron-rich (A) nucleus and a proton-rich (B) nucleus to symmetric collisions involving two neutron-rich nuclei (A+A) and two proton-rich (B+B) nuclei under the same experimental conditions [6]. Non-isospin diffusion effects such as preequilibrium emission from a neutron-rich (A) projectile should be approximately the same for asymmetric A+B collisions as for symmetric A+A collisions. 2Similarly, non-isospin diffusion effects from a proton-rich (B) projectile in B+A collisions and B+B collisions should be the same.The degree of isospin equilibration can be quantified by rescaling the isospin asymmetry δ of a projectile-like residue from a specific collision according to the isospin transport ratio R i (δ) [6,9] given by ( )In the absence of isospin diffusion, the asymmetry B A+ δ of a residue of a neutron-rich projectile following a collision with a proton-rich target has the limiting values 1 ) (. On the other hand, if isospin equilibrum is achieved for roughly equal sized projectile and. By focusing on the differences in isospin observables between mixed and symmetric systems, R i (δ) largely removes the sensitivity to preequilibrium emission and enhances the sensitivity to isospin diffusion.Id...