Hiroshi Hirose

A simple double-focusing mass spectrometer

Abstract A revolutionary double-focusing mass spectrometer is constructed and the focusing property investigated. The instrument consists of an electric parallel plate condenser (6.3×4.2 cm2), a double electrostatic Q lens and a small magnet having pole pieces of rectangular shape (128×45 mm2, rm = 25 cm, φm = 30°, ϵ1 = ϵ2 = 15°). This arrangement facilitates adjustment, because the double-focusing conditions can be satisfied by electrical adjustment of the double Q lens. Therefore, no mechanical adjustment is necessary. The highest resolving power obtained is 1600 for a 10% valley separation.

Detection of SiO2- Ions from SiO2-Si Interface by Means of SIMS

Analytical conditions for sensitive detection of molecular ions are examined using thin oxide films grown naturally in air on silicon single crystal surfaces. This is carried out to clarify the behavior of these ions in SIMS. It is found that molecular ions can be detected more sensitively under the condition of the low energy primary ion beam incident at large angles. Secondary molecular ions have energies several electron volts lower than elemental secondary ions. SiO2-, and SiO3-, ions are hardly detected in 1500 ? thick CVD oxide layers, but are sensitively detected at the SiO2-Si interface and also in naturally oxidized layers. This result suggests that the chemical composition of the CVD oxide interface is similar to that of the natural oxide on silicon single crystals.

Second-order image aberration correction of double-focusing mass spectrometers by electrostatic hexapole lens

Abstract Ion optical properties of an electrostatic hexapole lens are described. The correction methods for second-order image aberrations of double-focusing mass spectrometers are also examined. As an experimental example, the second-order image aberration of a Hitachi double-focusing mass spectrometer are observed, and reduced by the electrostatic hexapole lens of 40 mm length. It is confirmed by photographic plates that the second-order image aberration of curved image lines is corrected by this hexapole lens.