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Kimball laB6 cathodes

Kimball lanthanum hexaboride LaB6 filaments are the industry standard, high quality LaB6 cathodes and  available for most makes of electron microscopes and other E-beam instruments.

Kimball LaB6 cathodes improve results when used for:

  • SEM for low voltage and long term EDS mapping applications
  • TEM imaging and analysis
  • Electron probe micro analyzers (EPMA or Microprobe)
  • E-beam lithography

Kimball LaB6 cathodes are available with three types of LaB6 tips:

  1. Standard tip with 90° cone and 15 µm micro-flat for standard SEM and standard TEM applications
  2. Long life, high stability tip with 90° cone and 20 µm micro-flat for Microprobes and analytical SEM applications 
  3. High brightness, sharp tip with 60° cone and 6 µm micro-flat for high resolution TEM applications

LaB6 sources require a higher operating pressure than standard tungsten sources which generally requires an additional ion-getter pump at the electron source. The required vacuum is in the 10-7mbar range.

The lifetime of an LaB6 cathode is much longer than a tungsten source providing a stable high brightness source over a longer period.

The standard LaB6 cathode comprises a 90° tip angle and a 15µm flat made from a <100> oriented single crystal. This provides a long lifetime, high brightness source coupled with excellent stability.  The special version with sharper 60° tip angle and smaller 6µm flat is available for TEMs.

Kimball Physics uses the purest, high quality lanthanum hexaboride crystals for the Kimball ES-423E LaB6 cathodes.

The standard Kimball LaB6 tip provides a 10x higher brightness as the standard tungsten source, resulting in better resolution with clear images and less noise.

Kimball Physics ES-423E (extended life) LaB6 cathode is a high performance, resistively heated, thermionic electron source. It is based on a well proven carbon rod heater structure with improved stability, improved reliability and less exposure of the LaB6 crystal to reduce contamination of the Wehnelt aperture. There is heating current through the LaB6 crystal; there are no high-temperature current carrying joints. The LaB6 crystal is held in place by a carbon ferrule. The design results in a small physical size which fits most Wehnelt cylinder with ease.   Benefits of this unique construction are:

  • Suitable for SEM, TEM, Microprobes and E-Beam lithography systems

  • Resistively, indirectly heated high purity LaB6 crystal, resulting in lower heating current

  • High thermal stability to eliminate drift problems

  • Carbon ferrule with less exposure of LaB6 crystal to reduce Wehnelt contamination

  • low vapour pressure with reduced evaporation loss

  • High brightness; about 10 x higher than tungsten filaments (even 20x for the sharper tips)

  • Stable sources; due to its sturdy construction, the standard Kimball LaB6 cathodes comprise a stability of better than 3%/hour at 1550°C

  • Long life; at 10-7mbar vacuum and 1550°C operating temperature, >500 hours lifetime can be expected for the standard Kimball ES-423E LaB6 cathode

  • Low work function of 2.66ev (compared to 4.7ev for tungsten)

Please consult the following table for the correct type of Kimball LaB6 source or cathode for your SEM, TEM or Microprobe. The Kimball Physics LAB6 cathodes are available for Thermo, FEI, Hitachi, JEOL, Amray, CamScan, ISI, ABT, Topcon, Philips, Tescan, Zeiss, LEO, Leica, Cambridge Instruments and Leica electron microscopes. 

Type

Standard tip

Long life, high stability tip

High brightness sharp tip

Tip shape

90°tip angle with 15µm flat

90°tip angle with 20µm flat

60°tip angle with 6µm flat

Brightness
Value

10 x times than tungsten tip
1 x 106 A/cm2.Str

2 x less than standard tip
0.5 x 106 A/cm2.Str

2 x times than standard tip
2 x 106 A/cm2.Str

Saturation

Mono spot at around 1550°C

Mono spot at around 1550°C

Mono spot at around 1550°C

Crossover

Small: 7-10µm

Small: 7-10µm

Small: 7-10µm

Angular distribution

Sharp: 1.6 x 10-2 rad

Sharp; 1.6 x 10-2 rad

Sharp; 1.6 x 10-2 rad

Lifetime

Long > 500 hrs

Longer than standard tip

Shorter than standard tip

Ease of operation

Moderate

Easy, due to larger spot

Difficult, due smaller spot

Stability

High, better than 3%/hr

High, better than 3%/hr

Lower, due to smaller spot

Vacuum

10-7 mbar or better

10-7mbar or better

10-7mbar or better

Work function

2.66 ev

2.66 ev

2.66 ev

Application

SEM & TEM

Analytical SEM / Microprobe

TEM

 

 

Electron Microscope Type or Filament base

Product number

Ceramic Disc mm

Pin Diameter  mm

Pin Pitch mm

AEI

14-AE3501

12.0

1.0

6.45

AmRay /AMR (except 1200 series)

14-AM3502

26.0

1.0

5.0

Cambridge Instruments (except S4-10)

14-AE3501

12.0

1.0

6.45

CamScan with AEI conversion

14-AE3501

12.0

1.0

6.45

FEI TEM and SEM

14-FP3503 / 14-FP3568

26.0

1.0

5.0

Hitachi S-Type

14-HI3504

9.8

1.2

2.7

JEOL K-Type metal ring – SEM – standard tip

14-JL3508

28.0

1.2

8.0

JEOL K-Type metal ring – TEM – sharp tip

14-JL3568

28.0

1.2

8.0

Leica

14-AE3501

12.0

1.0

6.45

LEO 400 and 1400 Series SEM

14-AE3501

12.0

1.0

6.45

LEO1450 (except AEI conversions)

14-ZS3510

19.8

1.0

5.0

LEO TEM

14-ZS3560

19.8

1.0

5.0

Philips SEM and TEM (except XL-30)

14-FP3503 / 14-FP3563

26.0

1.0

5.0

Philips XL-30 SEM

14-AE3501

12.0

1.0

6.45

Tescan

14-TN3509

19.8

1.0

5.0

Thermo SEM and TEM

14-FP3503 / 14-FP3563

26.0

1.0

5.0

Zeiss DSM SEM and TEM

14-ZS3510 / 14-ZS3560

19.8

1.0

5.0

Further details and specifications of the Kimball ES423E LaB6 can be found in the PDF:Kimball ES-423E Extended Life LaB6 Cathode Specifications

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