Journal of Vacuum Science & Technology B, Vol.12, No.1, 26-31, 1994
Realization of Limited-Area Cathodes and Their Performance in an Electron-Optical Column
Limited-area cathodes based upon impregnated dispenser cathode material have been investigated in an electron optical column at accelerating voltages of up to 30 kV. A peak axial brightness of about 6 x 10(5) A/cm2 sr was obtained at this voltage using a flat cathode. Brightness values greater by a factor of 10 were measured using a conical limited-area cathode with a tip radius of curvature of 0.075 mm. The latter measurements were affected by space-charge spreading in the beam.