Electron Sources

 

Tungsten Filament

Lanthanum Hexaboride (LaB6)

Field Emission

Emission

Thermionic

Thermionic

Field

Operating vacuum

10-4 - 10-5

10-6 - 10-7

10-9 - 10-10

Brightness (nA/cm2)

10+4 - 10+5

10+5 - 10+6

10+7 - 10+9

Source size (Ám)

100 Ám

20 Ám

<10 nm

Energy spread (eV)

1-5

0.5 - 3

0.2 - 0.3

Probe current varies

0.1 - 1.0%

0.2 - 2.0%

2 - 10% / min

Operating life (hrs)

> 20

> 100 (> 600)

> 300 (> 2000)

Cost (each)

$12

$1,000

$1,500