An electron optical system has been developed for a low energy electron beam proximity projection lithography tool that is capable of scanning a field of 40 mm square with a beam current up to 20 AA. By using a beam current of 18 mu A the system has successfully resolved a dense 46 nni hole pattern with 90 nm pitch near one corner of the field. This article introduces a double-pinhole technique to monitor and measure the telecentricity of the electron beam (or e-beam) of such a system. Other related areas covered in the article are the simulations of space charge effect and of deflection aberration: also discussed here is the linearity of the subdeflection system used for correcting the mask distortion. (c) 2005 American Vacuum Society.