Author/Authors :
M.J. Fransen، نويسنده , , E.P.N. Damen، نويسنده , , C. Schiller، نويسنده , , T.L. van Rooy، نويسنده , , H.B. Groen، نويسنده , , P. Kruit، نويسنده ,
Abstract :
The electron optical brightness and the virtual source size of an ultrasharp field electron emitter were determined by an analysis of Fresnel fringes occurring in point projection microscopy images. Simulating the Fresnel diffraction pattem by taking into account the influence of the source size, the source diameter was determined as 5.2±1 nm. From additional current density measurements, using the same model, the reduced brightness was calculated. The brightness values obtained ranged from 1 × 107 to 3 × 109 A/m2 • sr • V for currents between 1 pA and 5 nA. A comparison of our results with the work of other authors is given.
