Takeo Oguri

The Static Operation Mass Spectrometer

A mass spectrometer has been designed for the studies on the adsorption of CO, CO2 and O2 in a closed system. The spectrometer is a 60° sector type of 10 cm in radius, and made of Pyrex glass. The electrodes are made of gold and silver, and a tin-oxide coating is adopted as the conductive coating. The field emission cathode operated at room temperature is used as the electron emitter of the ion source in stead of a glowing tungsten filament. The above construction is based on the results of the experiments on the activity of O2 on semi-clean surfaces of the electrode materials. The spectrometer can be operated statically in ultrahigh vacuum of 6×10-10 Torr. The static operations for Ar, H2, N2 and CH4 can be made in the best condition, and those for n–C4H10, CO, CO2 and O2, which could not be analyzed statically using a spectrometer with a glowing filament, can be also made in good condition. The detectabilities for the above gases are about 5×10-8 cc N.T.P., which are satisfactory for adsorption experiments in a closed system.

Angular Distribution of Scattered Electron and Medium Energy Electron Spectroscopy for Metals

The angular distribution (AD) of scattered electrons produced by medium energy incident electrons ( E P =50∼300 eV) from polycrystalline Ti, Fe, Ni, Cu and Au were obtained by the angle-resolved medium energy electron spectrometer. The AD of the energy loss peaks are similar figures to AD of the elastically reflected electron peaks. Therefore, the exchanged electrons produced by the knock-on collision between the incident electrons and those of metals without momentum transfer are observed as the energy loss spectra (ELS). This interpretation differs from the inconsequent interpretation by the dielectric theory or the interband transition. The information depth and penetration length are obtained from AD of the Auger electron peaks. The contribution of the surface to spectra is 3% at the maximum for E P =50 eV. The true secondary peaks representing the secondary electron emission spectroscopy (SES) are caused by the emissions of the energetic electrons (k T e ≧4 eV), and SES is the inversion of ELS. The e...