| 摘要 |
PURPOSE:To obtain a highly sensitive miniaturized ion source facilitated in degassing and sharply reduced in ion energy of unevenness of space charges produced by oscillating electrons. CONSTITUTION:A positive electrode 1 is constructed into a semispherical shape with use of a metal qauze capable of transmitting electrons therethrough, and further integrally finished by backing welding a substantially flat mesh gauze on the side of a semisphere cross section. In addition, a hot negative electrode 4 is arranged on the outer periphery of the positive electrode 1 on the semisphere side while an ion delivery electrode 3 arranged on the opposite side. Hereby, gas molecules are ionized by oscillating electrons in the vicinity of the positive electrode of closed type. Only ions thereamong produced within the positive electrode are taken out to the flat mesh side by making use of unevenness of space charges produced by oscillating electrons, whereby energy dissipation of the produced ions is made minimum while facilitated in degassing with a simple structure for improving the resolution of a mass analysis. Hereby, any analysis for residual gas of about 10<-8>Torr can be assured without employing a secondary-electron multiplier. |
