Denka M-3 LaB6 EM cathodes
High brightness, direct replacement electron sources
Denka M-3 LaB6 EM cathodes | Denka LaB Filaments Selection Table | Electron Source Performance table
Introduction
Denka M3 LaB6 cathode. LaB6 crystal with standard 90 degree tip and 15µm flat. |
The Denka M-3 LaB6 filaments are the industry standard, high quality LaB6 cathodes. The standard cathode with the round tip has a 90° tip angle and a 15µm flat, which provides a high brightness source coupled with excellent stability. Special version with sharper 60° tip angle and smaller 5µm/10µm flat are available for TEMs.
Denka uses the purest , high qulaity LaB6 crystals for the Denal LaB6 cathodes. The Denka LaB6 tip provides a 10x higher brightness as the standard tungsten source, resulting in better resolution with clear images and less noise. The lifetime of the LaB6 cathode is much longer than a tungsten source providing a stable source over a longer period. See electron source performance table for more details. The Denka LaB6 cathodes improve results when used for:
- SEM for low voltage and long term mapping applications
- TEM imaging and analysis
- Electron probe micro analyzers (EPMA or Microprobe)
- E-beam lithography
The LaB6 sources require a higher vacuum than standard tungsten sources which generally requires an additional ion-getter pump at the electron source. The required vacuum is in the 10-7 mbar range.
Design and features of the Denka M-3 LaB6 EM cathodes
The Denka LaB6 EM cathode construction is similar to the tungsten cathodes. It uses the same base with tungsten wires attached to the contact pins. Instead of a full tungsten loop, the LaB6 crystal forms the tip with the tungsten wires cemented against the LaB6 crystal. In this design the LaB6 crystal is directly heated by the filament current through the tungsten wires and the LaB6 crystal. This unique construction has the a number of features and benefits:
- Interchangeability: Denka M-3 LaB6 cathodes are designed as direct replacement for tungsten filaments
- Suitable for SEM and TEM
- Direct heating design with tungsten wired cemented at the high purity LaB6 crystal
- High brightness; about 10x higher than tungsten filaments (even 20x for the sharpere tips)
- Stable sources; due to its durable and simple construction, the standard Denka M3 LaB6 comprises a stability of better than 3%/hour at 1550°C
- Long life; at 10-7mbar vacuum and 1550°C operating temperature, 500-2000 hours lifetime can be expected for the standard M3 LaB6 cathode
- Low vapour pressure; reduced evaporation loss
- High melting point and stability at operating temperatures
- Low work fubction of 2.66ev (compared to 4.7ev for tungsten)
Specifications of the Denka M-3 LaB6 EM cathodes
Please consult the following table for the correct type of LaB6 source for your SEM, TEM or Microprobe. The Denka LaB6 EM cathodes are available for FEI, Hitachi, JEOL, Amray, CamScan, Philips, Tescan, Zeiss, LEO, Leica, Cambridge Instruments and Leica electron microscopes..
Type |
Stand tip |
Sharp tip |
Tip shape |
90°cone angle with 15µm tip flat |
60°cone angle with 5µm tip flat |
Brightness Value |
10x times than tungsten tip |
2x times than standard tip |
Saturation |
Mono spot at around 1500°C |
Mono spot at around 1500°C |
Crossover |
Small; 7-10µm |
Small; 7-10µm |
Angular distribution |
Sharp; 1.6 x 10-2 rad |
Sharp; 1.6 x 10-2 rad |
Lifetime |
Approx. 500 - 2000 hrs |
Shorter than standard tip |
Ease of operation |
Moderate |
Difficult due to spot adjustment |
Stability |
High, better than 3%/hr |
Lower, due to smaller spot |
Vacuum |
10-7 mbar or better |
10-7 mbar or better |
Work function |
2.66 ev |
2.66 ev |
Denka M-3 LaB6 EM cathode selection table
Electron Microscope Type or Filament base |
Product number |
Ceramic Disc mm |
Pin Diameter mm |
Pin Pitch mm |
AEI |
AU-14-AE3301 |
12.0 |
1.0 |
6.45 |
AmRay /AMR (except 1200 series) |
AU-14-AM3302 |
26.0 |
1.0 |
5.0 |
Cambridge Instruments (except S4-10) |
AU-14-AE3301 |
12.0 |
1.0 |
6.45 |
CamScan with AEI conversion |
AU-14-AE3301 |
12.0 |
1.0 |
6.45 |
FEI TEM and SEM |
AU-14-FP3303 |
26.0 |
1.0 |
5.0 |
Hitachi S-Type |
AU-14-HI3304 |
9.8 |
1.2 |
2.7 |
JEOL K-Type metal ring - SEM - standard tip |
AU-14-JL3308 |
28.0 |
1.2 |
8.0 |
JEOL K-Type metal ring - TEM - sharp tip |
AU-14-JL3318 / AU-14-JL3328 |
28.0 |
1.2 |
8.0 |
Leica |
AU-14-AE3301 |
12.0 |
1.0 |
6.45 |
LEO 400 and 1400 Series SEM |
AU-14-AE3301 |
12.0 |
1.0 |
6.45 |
LEO1450 (except AEI conversions) |
AU-14-ZS3310 |
19.8 |
1.0 |
5.0 |
LEO TEM |
AU-14-ZS3310 |
19.8 |
1.0 |
5.0 |
Philips TEM and SEM (except XL-30) |
AU-14-FP3303 |
26.0 |
1.0 |
5.0 |
Tescan |
AU-14-TN3309 |
19.8 |
1.0 |
5.0 |
Zeiss DSM and TEM |
AU-14-ZS3310 |
19.8 |
1.0 |
5.0 |
Electron Source Performance Table
The electron source performance table is porvided to give additional information into the performance and requirements for different type of electron emitters. Tungsten cathodes are still used in the majority in SEMs. Improved results can be obtained with LaB6 cathodes and the highest resolution can be obtained with either Schottky or cold Field Emission Sources
Emitter Type | Thermionic | Thermionic | Schottky FE | Cold FE |
Cathode Material | W | LaB6 | ZrO/W (100) | W (310) |
Operating Temp (K) | 2700 | 1800 | 1800 | 300 |
Cathode Radius (nm) | 60,000 | 10,000 | <1000 | <100 |
Effective Source Radius (µm) | 25 | 10 | 0.015 | 0.0025 |
Emission Current Density (A/cm2) | 3 | 30 | 5300 | 17,000 |
Total Emission Current (µA) | 200 | 80 | 200 | 5 |
Brightness (A/cm2.sr.kV) | 1x104 | 1x105 | 1x107 | 2x107 |
Maximum Probe Current (nA) | 1000 | 1000 | 10 | 0.2 |
Energy Spread @ Cathode (ev) | 0.59 | 0.4 | 0.31 | 0.26 |
Energy Spread @ Source Exit (eV) | 1.5 – 2.5 | 1.3 – 2.5 | 0.35 – 0.7 | 0.3 – 0.7 |
Beam Noise (%) | 1 | 1 | 1 | 5 – 10 |
Emission Current Drift (%/h) | 0.1 | 0.2 | <0.5 | 5 |
Operating Vacuum (hPa/mbar) | <10-5 | <10-6 | <10-8 | <10-10 |
Typical Cathode Life (h) | 100 | >1000 | >5000 | >2000 |
Cathode Regeneration (h) | None | None | None | 6-12 |
Sensitivity to External Influences | Minimal | Low | Low | High |
Denka LaB6 Cathodes
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Sharp Denka M3-LKSH60S LaB6 cathode, JEOL K-type Base with metal ring, 60 degrees/5µm round tip for JEOL TEMsSKU: AU-14-JL3318Units Per Package: 1From: $2,203.50
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Sharp Denka M3-LKSH60 LaB6 cathode, JEOL K-type Base with metal ring, 60 degrees/10µm round tip for JEOL TEMsSKU: AU-14-JL3328Units Per Package: 1From: $2,193.75
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Denka M3 LaB6 cathode, Tescan base, 90 degrees/15µm round tip for Tescan SEMsSKU: AU-14-TN3309Units Per Package: 1From: $1,745.25
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Denka M3 LaB6 cathode, Zeiss Base, 90degrees/15μm round tip for DSM series SEMs, TEMs, LEO TEMs and LEO 1450 SEMSKU: AU-14-ZS3310Units Per Package: 1From: $1,745.25
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Denka M3 LaB6 cathode, AEI Base, 90 degrees/15µm round tip for Zeiss EVO, LEO, Leica, CamScan, Cambridge Instruments and Philips XL-30 SEMsSKU: AU-14-AE3301Units Per Package: 1From: $1,745.25
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Denka M3 LaB6 cathode, AEI Base, 90 degrees/15µm round tip for Zeiss EVO, LEO, Leica, CamScan, Cambridge Instruments and Philips XL-30 SEMsSKU: AU-14-AM3302Units Per Package: 1From: $1,940.25
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Denka M3 LaB6 cathode, FEI/Philips base, 90 degrees/15µm round tip for FEI TEM/SEM and Philips EM200 TEM & PSEM 500 and later (except XL-30)SKU: AU-14-FP3303Units Per Package: 1From: $1,940.25
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Denka M3 LaB6 cathode, Hitachi S-Type base, 90 degrees/15µm round tip for Hitachi S-, SU, H- and X-Series SEM and TEMSKU: AU-14-HI3304Units Per Package: 1From: $1,745.25
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Standard Denka M3-LKS LaB6 cathode JEOL K-Type base with metal ring, 90 degrees/15µm round tip for SEMsSKU: AU-14-JL3308Units Per Package: 1From: $1,745.25