Measurements of the nucleon structure function in the range 0.002 < x< 0.17 and 00.2 < Q2< 8 GeV2in deuterium, carbon and calcium

Small angle scattering of 280 GeV positive muons by deuterium, carbon and calcium has been measured at scattering angles down to 2 mrad. The nucleon structure function F2extracted from deuterium does not show a significant xdependence in the measured range of Q2and its Q2dependence is linear in logQ2. For calcium, a depletion of F2is observed at low xby 30% as compared with the values at x= 0.1 where F2(Ca) and F2(D) are not significantly different. This depletion is attributed to shadowing. The carbon structure function exhibits a similar, but less pronounced, xdependence. Such behaviour is observed to be independent of Q2. The data are consistent with those obtained from other charged lepton experiments both at similar and higher values of xand Q2and considerably extend the range of the measurements down to the low values of xto be measured in forthcoming experiments at HERA.