Abstract
The chevron baffle with the two-stage type thermo-module could be kept at -47°C when the hot side of the module was cooled to 11°C by water. The final pressure was reduced by about one order and reached ca. 1 × 10-8 Torr with this baffle. The main residual gas component was the vapor of diffusion pump oil, DC-704. When the baffle was cooled by water with-out thermo-electrical cooling, the vapor of rotary pump oil was predominant. Radio-frequency mass spectrometer was used for the residual gas analysis.
