An Electron Ion Collider (EIC) with suitable forward detection capabilities would enable unique experimental program of deep inelastic scattering (DIS) from polarized light nuclei (deuteriu easurements promise significan advances in several key areas of nuclear physics and QCD: (a) neutron spin structure, by usin polarized deuterium and eliminating nuclear effects through on-shell extrapolation in the spectato proton momentum; (b) quark/gluon structure of the bound nucleon at x > 0.1 and the dynamica mechanisms acting on it, by measuring the spectator momentum dependence of nuclea structure functions; (c) coherent effects in QCD, by exploring shadowing in tagged DIS on deuteriu at x 0.1. The JLab MEIC design (CM energy radic;s = 15-50 GeV/nucleon, luminosit ∼ 1034 cm-2 s-1) provides polarized deuterium beams and excellent coverage and resolution fo forward spectator tagging. We summarize the physics topics, the detector and beam requirement for spectator tagging, and on-going Ramp;D efforts.
