Measurement of the Ratio of the Neutron and Proton Structure Functions F(2) in Inelastic Muon Scattering

The ratio of the neutron and proton structure functions F_2 has been measured to very low x_{bj} using inelastic muon scattering. Data were taken in 1990 using 475 GeV muons incident on hydrogen and deuterium targets. Electromagnetic calorimetry has been used to remove radiative backgrounds and muon-electron elastic scattering. Results of the measurement are presented which cover the kinematic region 0.0001 <= x_{bj} <= 0.4 and 0.1 GeV^2/c^2 <= Q^2 <= 100.0 GeV^2 /c^2.