Ultramicroscopy, Год журнала: 2025, Номер unknown, С. 114167 - 114167
Опубликована: Май 1, 2025
The strong electric field between the sample and extractor is at heart of cathode lenses a crucial factor for high resolution. However, fields in range 3-10 kV/mm can be source complications. Local enhancement sharp edges or microscopic protrusions cleaved samples lead to emission flashovers. In addition, slow background electrons drawn into microscope column contribute space charge effects. A novel objective configuration, optimized by ray-tracing simulations energies from few eV 6 keV, significantly reduces sample. One more annular electrodes concentric shape front formation 'gaplens' values below 1 range. Tuning zero advantageous 3D structured samples. Retarding repel electrons, suppressing properties different lens modes are investigated using ray tracing determination aberration coefficients. Despite its much lower field, gaplens mode exhibits smaller aberrations enables larger view both momentum real imaging. At as low 1200 880 V/mm, accessible solid angle interval three times than (with start energy 100 k-resolution 10-2 Å-1). Due elimination effects retarding mode, XPEEM resolutions 25 nm predicted. results confirmed spherical chromatic coefficients real-space k-space images.
Язык: Английский