Kimball Physics lanthanum hexaboride 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:

Standard tip with 90° cone and 15 µm micro-flat for standard SEM and standard TEM applications
Long life, high stability tip with 90° cone and 20 µm micro-flat for Microprobes and analytical SEM applications
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.

Design and features of Kimball ES-423E LaB6 cathodes

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)

Specifications of the different Kimball ES-423E LaB6 cathodes

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

Kimball ES-423E LaB6 cathode selection table

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

Ordering information for the Kimball ES-423E standard LaB6 cathode with 90° cone and 15 µm micro-flat suitable for most SEM and TEM applications

14-AE3501

Kimball ES-423E LaB6 cathode, AEI

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Kimball Physics lanthanum hexaboride LaB6 cathodes

Design and features of Kimball ES-423E LaB6 cathodes

Specifications of the different Kimball ES-423E LaB6 cathodes

Kimball ES-423E LaB6 cathode selection table