Model dependence of charge densities determined from electron scattering

A new method is used to analyze recent experiments on electron scattering on ³He in the high momentum transfer region. The accuracy of the new measurements is very high so that the charge density can be determined with much higher accuracy than before. We find that further reduction of the error in charge density can only be achieved by a more accurate measurement of the region 3 < q < 6 fm^?1. Continuing the previous work of Hetherington and Borysowicz, a very useful approximate relation is derived between the error of charge density and the error of measurements of form factor. We find that linear expansion methods lead to similar results as the present method. They require, however, stronger asymptotic assumptions about ?(r).