DELONG INSTRUMENTS a.s.

Schottky Emitters

Schottky Emitters

ZrO–100 W monocrystal is used in the manufacture of Schottky emitters. Thanks to a high angular current density, high brightness and small virtual source, they are ranking among the most powerful electron emitters used for TEM and SEM field emitter guns (FEG).

At presents schottky cathodes are used in LVEM5 project. All pictures are taken in LVEM5.

The cathode crystal

The cathode tip after activation

The cathode tip after etching, annealing, and before activation

The cathode emission pattern on the screen

 

Technical Specification

tip diameter [µm]
0,2–0,5
angular current density [mA/sr]
0,1–1,5
extraction voltage [kV]
2–5
total emission current [µA]
50–200 (800)
temperature [K]
1,800
virtual source size [nm]
20
source brightness at 5kV [A/cm2sr]
5×107
energy spread [eV]
0.4
life time [hours]
>4,000
vacuum required [mbar]
<1×10-8