MASS SPECTROSCOPE

PROBLEM TO BE SOLVED: To provide a mass spectroscope having high robustness, and capable of high sensitivity low noise analysis.SOLUTION: A mass spectroscope has an ion source generating ions, a vacuum chamber for analyzing the mass of ions evacuated by evacuation means, and an ion introduction electrode 12 for introducing ions into the vacuum chamber. The ion introduction electrode has a pre-stage pore 35 on the ion source side, a post stage pore 36 on the vacuum chamber side, and an intermediate pressure chamber 33 between the pre-stage pore and post stage pore. Cross-sectional area of the ion inlet of the intermediate pressure chamber is larger than that of the pre-stage pore, central axis of the pre-stage pore and central axis of the post stage pore are located eccentrically, and cross-sectional area of the ion outlet is smaller than that of the ion inlet of the intermediate pressure chamber.SELECTED DRAWING: Figure 2 【課題】ロバスト性が高く、高感度かつ低ノイズな分析が可能な質量分析装置を提供する。【解決手段】イオンを生成するイオン源と、真空排気手段で排気されイオンの質量を分析する真空室と、イオンを真空室に導入するイオン導入電極１２を有し、イオン導入電極は、イオン源側の前段細孔３５と、真空室側の後段細孔３６と、前段細孔と後段細孔との間の中間圧力室３３を有し、中間圧力室のイオン入口の断面積は前段細孔の断面積よりも大きく、前段細孔の中心軸と後段細孔の中心軸とは偏心した位置にあり、中間圧力室のイオン入口の断面積よりもイオン出口の断面積の方が小さいことを特徴とする。【選択図】図２