We describe in detail the procedures used for the preparation of ultrathin (∼10 nm) free-standing membranes for(e,2e)spectroscopy. Such a thin target is needed to minimize electron multiple scattering before and after an(e,2e)event. The development of a rf plasma source which allowsin situthinning and thickness monitoring is of key importance to the success of the target preparation. Materials (C, Si, Ni, Cu, Al2O3,SiO2,CuO) with different properties and structures are usually prepared in different ways. For insulating targets it is important to have a conducting sublayer to avoid the charging problem. A well prepared target usually has a thin area larger than the(e,2e)beam size(∼0.2 mm in diameter) and yields high quality(e,2e)data from which the electron energy-momentum density in a chosen direction is determined. Efforts demonstrated in this article indicate that the preparation of ultrathin free-standing films is a challenging area where significant technical development is needed.©1997 American Institute of Physics.