Reduction of stainless-steel outgassing in ultra-high vacuum

Effect of surface polishing and vacuum firing on electron stimulated desorption from 316LN stainless steel

“…The data available from the literature demonstrate that the outgassing rate [g t ; molecules/(sÁm 2 )] depends upon many factors such as material selection, surface roughness, cleaning procedures, the temperature and duration of bakeout and the pumping time, etc. [1][2][3][4][5][6][7][8] In the design of a large vacuum system, stainless steel is the most common material selected for the vacuum chambers because it can routinely achieve a value of g t ¼ 10…”

“…À12 mbarÁl/(sÁcm 2 ) for hydrogen (and much lower for other species) after a 24-h bakeout at 300 C. 1 Further reduction can be achieved using the methods of an air bake, vacuum firing, and surface polishing. The best outgassing results of g t ¼ 10 À15 mbarÁl/(sÁcm 2 ) have been obtained after performing either an air bake or a very fine polish and subsequent vacuum firing at a pressure better than 10 À6 mbar.…”

Void nucleation and growth in heavy ion and electron bombarded pure metals. Progress report, March 1--December 1, 1974

“…9) are held by the sample holder as shown in Fig Typical partial pressure composition of the residual gas during an anneal, at the temperature of a typical irradiation, and at room temperature are shown in Figure 11. In all cases the bulk of the residual gas is hydrogen, (42) presumably from the stainless steel components of the sample chamber. The only beam transport elements located between the tandem exit and the sample are magnetic devices.…”

An XPS study on the evolution of type 304 stainless steel surface during routine TCSU operation

“…These correspond to H 2 , DH and D 2 and/or He, respectively. It is well known that type 300 stainless steels contain large amounts of hydrogen [10], while deuterium was trapped in the chamber walls during plasma discharges. It can therefore be speculated that these residual hydrogenic species might have played a role in the reduction of the metal oxides, by reacting with the free oxygen/carbon bonds created by the He-glow discharge.…”