Low brightness and high emittance electron gun for a reducing image projection system

Abstract

An electron gun for an accelerating voltage of 100 kV to be operated under space charge limited condition is designed, and its emittance and brightness are calculated. To obtain low brightness, a Pierce-type electron gun with a Wehnelt electrode and a control anode is adopted. Choosing a low value of the ratio between anode and cathode curvatures reduces the electric field strength at the cathode. A maximum emittance of 1.8 mm mrad and a minimum brightness of 350 A/(cm2 sr) are obtained under the above conditions with a cathode diameter of 1.66 mm. The radius of the Wehnelt aperture and its axial position are optimized. The effects of deviations of the shapes of the Wehnelt and control electrodes from concentric sphere are studied. It is found that in the space between the anode and the control anode the electrodes must be spherical up to an angle of at least 55°, whereas in the space between the Wehnelt electrode and the control anode the electrodes must be spherical up to an angle of at least 21°.

Feasibility Study of Multiple-Beam Scanning Electron Microscopy for Defect Inspection

“…For brightness and emittance, there is measured value for 20 keV of beam energy. 3) The brightness can be measured using this experimental electron optical column. In this optical column as seen in Fig.…”

On the Estimation of the Termination Effect in Fourier Synthesis in X-ray Structure Analysis

“…La atoms order on the simple cubic sites as trivalent ions with the boron octahedra on the body-centred cubic sites constituting divalent molecules in the CsCl-type structure (Longuet-Higgins & Roberts, 1954). The specimen is widely used as a thermo-radiated material and also as a characteristic material in studying physical properties (Nakasuji & Wada, 1980). An LaB 6 single crystal has been investigated in detail by X-ray diffraction by Korsukova et al (1986).…”