| 摘要 |
1,213,534. Ion beam apparatus. APPLIED RESEARCH LABORATORIES Inc. 28 Oct., 1968 [30 Oct., 1967; 12 July, 1968], No. 51066/68. Heading H1D. In a method of chemical analysis by bombarding a material to be analysed with a beam of primary ions to sputter atoms of the material from its surface as secondary ions and mass spectrometrically analysing the secondary ions, the primary ions are ions which are chemically reactive with the material to be analysed under the conditions of bombardment, e.g. ions of C, N, O, F, Cl or I in order to increase the availability and stability of yield of ions for analysis particularly in comparison with the use of primary ions of one of the inert gases, e.g. A or Xe. Graphs are given showing ion output against time in respect of the bombardment of aluminium, zinc and stainless steel targets with positive atomic or molecular oxygen ions to produce aluminium ions, zinc ions and chromium, iron, nickel or silicon ions respectively. Also mentioned are targets of Ti, Si, Mg, Fe, Ag, Mo, C, W, Zr, Mn, Cr, Sn, Pb, Bi, Ni and Cu. The analysing instrument may comprise an ion microscope or ion probe system coupled to a mass spectrometer. The ion source for the primary ions comprises a duoplasmatron in which the aperture 90 in intermediate electrode 86 is offset slightly from coaxial alignment with the cathode 80-a favourable arrangement for the production of negative ions. The tubular cathode 80 has electron emissive material on its inner wall. The source also includes an anode plate 94 having its aperture aligned with the axis of the cathode 80 and fixed upon an iron plate 94, a tubular acceleration tube 108 and a shielding tube 110 which supported on a bellows assembly 112 for axial adjustment. Dynamic air cooling is provided by a fan 104. A constricting magnetic field between intermediate electrode 86 and anode 92 is produced by annular ceramic permanent magnets 114 mounted between iron plate 94 and an iron plate 116. The reactive element used in the source is preferably diluted with an inert carrier gas e.g. A or N. |
