Since 1965 Energy Beam Sciences is specialized in manufacturing cathodes, filaments and many other components for electron beam applications. EBS has been OEM supplier for companies like Amray, Thermo Scientific, Axcelis for many years. EMSIS ASIA represents EBS in the Asian market and their products have shown high performance, stability and cost efficiency.

Lab6 Tip

LaB6 Cathodes

Various LaB6 cathodes for all TEM and SEM models are available at the EMSIS ASIA website with Standard Round Tips, Flat Tips and Sharp Tips

Standard (Round) Tips: Provided with a 90° cone angle and 15µ radius round tip.

Flat (Truncated) Tips: Flat tips are recommended for applications where stability and long lifetime are the prime considerations, and where some degree of brightness can be sacrificed.

Sharp Tips: Sharp tips are recommended for applications where initial brightness is the foremost consideration and where shorter lifetime can be accepted. Sharp tips are available in two configurations: 60° Cone Angle, 5µ radius and 60° Cone Angle, 10µ radius

 Lab6 cathode 2 Lab6 cathode 1

Features of LaB6 Cathodes

  • Low potential barrier (work function)
  • High melting point and stability at high temperatures
  • Low vapor pressure so as to reduce evaporation loss
  • Chemical stability
  • High Brightness: A LaB6 beam is ten times brighter than tungsten, has superior resolution, and features a wide range of acceleration voltages. It provides sharp, clear pictures down to the smallest detail. The initial brightness of a Denka Model 3 cathode (1 x 106 A/cm2 str) is substantially better than that of competing, minivogel type cathodes (typically 5 x 105 A/cm2)
  • Long Life: Heat and vacuum are the final determinants of any cathode tip´s life, but at 1550°C and a vacuum of 10-7 Torr, a service life of about 500 hours can be expected.
  • Stability: Due to its durable construction, Cathode has stability of > 3% per hour at 1550°C.

Specifications

 

Flat Tip

Standard (Round) Tip

Sharp Tip

Brightness

About 5 times that of tungsten, 2-5×105 A/cm2· Str

About 10 times that of tungsten, 1×106 A/cm2· Str

Twice as bright as standard tips 2×106 A/cm2· Str

Saturation

Mono spot at about 1,400°C

Mono spot at about 1,500°C.

Almost the same as standard tips

Crossover

Large (11-13µ)

Small (7-10µ)

Small (7-10µ)

Angular distribution

Broad, 3.3-4.2×10-2 rad

Sharp1.6 x10-2rad

Sharp1.6 x10-2 rad

Used Temperature.

Low temperature

Low temperature

High temperature.

Lifetime

Long life. Usable at low temp. Crystallized end changes slowly.

Long life but shorter than flat tips.

Short

Operation

Easy: Due large spot size and broad adjusting range.

Not so difficult.

Difficult; Point adjustment needed

Stability

High

High

Sensitive to thermal expansion or vibration. Adjustment sometimes necessary.

Technology Needed

Ordinary

High

Very high

Note: There are other LaB6 configurations available upon request.

 

MET Thermal Field Emission (Schottky) Cathode

The most commonly used Thermal Field Emitters are the MET-C (Denka 174C equivalent) and the MET-A (Denka 174 equivalent).

TFE1

 Specifications

 

 

Models

MET-C, MET-A

Operating Temperature

≤ 1850K. 1800K recommended

Filament current at 1800K

≤ 2.6A

Operating pressure

≤ 1.3×10-6Pa (1×10-8Torr).

2.7×10-7Pa (2×10-9Torr) recommended

Tip radius

0.4 to 0.7µm. Standard tolerance +/- 0.05µm

Cone Angle

>15°

Note: Other TFE Models are available, please contact for required tip radius of <0.4µm or >0.7µm.

 TFE drawing1