極高真空用電離真空計の無収差偏向器の設計
1991 年 34 巻 1 号 p. 5-9
詳細
1991 年 34 巻 1 号 p. 5-9
A noble electrostatic deflector in the ionization pressure gauge for extemely high vacuum has been proposed. In stead of the deflector in Helmer gauge, a cylindrical electrostatic deflector with the deflection angle of 255° has been used in order to get the perfect focus of the ion beam at the exit slit of the deflector, and additionally it presumably reduces the noises due to both soft X-ray photoemission current and electron stimulated desorption (ESD) ions generated at the ionization grid, which determine the lowest limit of the pressure measurement of the present gauge. From the calculation of the ion trajectories inside the deflector, the optimum deflection angle has been discussed in the realistic electric field including the fringing effect.
