Radiation-induced outgassing from Type 304 stainless steel

A Type 304 stainless-steel vacuum system has been designed and constructed to study radiation-induced outgassing when this material is exposed to 60Co gamma radiation. An analytical model has been developed that predicts the outgassing from Type 304 stainless steel to be 5 x 10-10 Pa.l/cm2.s per Mrad/h. Experiments determined the value for Type 304 stainless steel after bakeout at 3000C to be (1.03 +- 0.58) x 10-9 Pa.l/cm2.s per Mrad/h, in fair agreement with the analytical model predictions. Studies on thermally induced outgassing from Type 304 stainless steel showed that after bakeout at temperature T/sup */, thermal outgassing Δ obeys the relationship Δ = Δ0 exp(-anti Q/RT), where both the constant Δ0 and the average desorption energy anti Q are functions of T/sup */. Water vapor and hydrogen were the principal residual gases in a Type 304 stainless-steel vacuum system, with hydrogen being dominant at low pressures after bakeout