大気圧開放時の水分抑制によるべーキング不要の高速超高真空排気と節電効果

摘要

中高真空への高速排気やべーキングを実施せずに超高真空へ高速排気する技術の確立は，実験設備や生産ラインにおける排気時間の短縮，人的コスト削減および節電によるコストの削減，更には地球温暖化の原因となる二酸化炭素排出の削減にも繋がる.それに加え，ベーキング不要であることは，ベーキングの準備や温度管理などの手間の排除，ベーキングにより生じる待機時間の排除，ベーキングヒーター，断熱材，コントローラ一等のハードウ；Cァの排除，ベーキングにより生じる問題点の排除（配線の損傷および腐食，チェンバーの加熱•冷却の繰り返しにより生じるリーク等)にも繋がる.%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 CO_2 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.