Azimuthai 2α correlations and projectile-residue distributions selected by neutron and charged-particle multiplicity measurements

The resolution of reaction filters for intermediate-energy heavy-ion collisions based upon charged-particle and neutron multiplicity measurements with 4\ensuremath{\pi} coverage is compared for ${}^{112}\mathrm{Sn}{+}^{112}\mathrm{Sn}$ and ${}^{124}{\mathrm{S}\mathrm{n}+}^{124}\mathrm{Sn}$ collisions at $E/A=40$ MeV. The quality of event characterization is inferred from the azimuthal correlations of \ensuremath{\alpha} particles emitted at intermediate rapidity and from the Z distributions of projectilelike fragments emitted at forward angles. For central and midimpact parameter collisions, the associated charged-particle multiplicity appears to provide better impact-parameter selection than the associated neutron multiplicity.