This is the largest system with four levels of operation. The uppermost level is the analyzer level where the sample can be characterized by XPS, ISS, LEED, QMS/TPD. The next level is a preparation level where the crystal can be cleaned using Argon ion sputtering and prepared in situ by deposition of metals and gases. The third level is an analysis level for HREELS - screened in a mu-metal box. The lowest level is a combined high pressure cell and PM-IRAS system for detection of intermediates on single crystals under elevated temperatures and pressures, typically up to an atmosphere. 
The combination of various surface characterization techniques with the high pressure cell makes this apparatus valuable for studies of reactions under conditions relevant to industrial applications. The system is used for preparation and characterization of (sub)surface alloys. After characterization, including reactivity and stability investigations, the samples are transferred out of the chamber for subsequent tests in the electrochemistry laboratory.