The recently described tests of the synchrotron imaging photoelectron spect
romicroscope MEPHISTO (Microscope a Emission de PHotoelectrons par Illumina
tion Synchrotronique de Type Onduleur) were complemented by further resolut
ion improvements and tests, which brought the lateral resolution down to 20
nm. Images and line plot profiles demonstrate such performance. (C) 1999 A
merican Institute of Physics. [S0034-6748(99)04902-3].