[en] Upgrades of the RIKEN heavy-ion linac (RILAC) involving a new superconducting linac (SRILAC) are undergoing to promote super-heavy element searches at the RIKEN Radioactive Isotope Beam Factory (RIBF). Stable ultra-high vacuum (<10^-8 Pa) and particulate-free conditions are strictly necessary for keeping the performance of the superconductive radio frequency (SRF) cavities of the SRILAC. It is crucially important to develop neighboring warm sections to prevent contamination from the existing old RILAC and beamlines built almost four decades ago. In the present study, non-evaporable getter-based differential pumping systems were newly developed to achieve the pressure reduction from the existing beam-line vacuum (10^-5-10^-6 Pa) to the ultra-high vacuum within very limited length (<80 cm) ensuring the large beam aperture of more than 40 mm. They are also equipped with compact electrostatic particle suppressors. (author)