Two surface treatments for stainless steel, E.P. (electropolishing) and E.C.B. (electro-chemical-buffing), were studied for the outgassing properties. These stainless steel surfaces were investigated with mechanical surface profile meter, SEM and AES. Measurement of surface profiles indicated the roughness of Rmax=0.2 μm for the E.P. treated surface and Rmax=0.04 μm for the E.C.B. treated surface. SEM images showed grain boundaries for the surface treated with E.P. but showed many traces by abrasive grains for the surface treated with E.C.B. AES depth profiling showed thinneroxide film and more enrichiment of Cr for the surface treated with E.P. than for the surface treated with E.C.B.
We fabricated two stainless steel chambers treated with E.P. and with E.C.B. and measured pressure and outgassing rate in the chamber as a function of pumping time. It was found that UHV in the order of 10-7Pa was achieved within 9 hours without baking for the both chambers.
