抄録
The development of a quick pumping scheme into medium vacuum or ultra high vacuum (UHV) reduces not only the cost and the duration of pumping down, but it also reduce CO2 emission that is known as one of serious cause of global warming. In this study, we aim for quick pumping into UHV without baking but with both introduction of well dried nitrogen gas into a chamber and improvement in the operation of the vacuum system. Baking and purging of a nitrogen gas line made of stainless steel have been applied in order to exclude water vapor, resulting in a dew point of −92℃ (0.065 vol. ppm) in the gas line. For practical reason we carried out nitrogen gas showering onto an open flange of the chamber, which reduced the pumping duration to achieve a pressure of 1×10−6 Pa to 3 hours, while it took 9 hours without showering. It turned out that the quick pumping of a UHV system with no baking operation was successfully achieved and could reduce the electric power consumption.
