EM-Tec Tungsten EM Filaments
High quality, high stability EM cathodes
Introduction
Tungsten filaments are used in all major brands of scanning and transmission electron microscopes (SEM / TEM). These high quality, high stability tungsten EM filaments, also called cathodes or electron emitters, are manufactured to exceed the specifications of the original equipment manufacturers. These superior cathodes are made using high quality ceramic discs, exact size contact pins and high grade tungsten filament wire. Special tools are used to produce the correct shape of the tungsten filament. All tungsten filaments are precisely aligned and annealed in high vacuum to reduce stress in the filament. This will guarantee optimum stability, maximum brightness, longer lifetime and overall lower running costs.
Exclusive features of the EM-Tec tungsten EM filaments are:
- Minimum tip radius for coherent beam
- Rigid attachment of filament wire to post to increase stability
- Fully stress relieved for enhanced cathode lifetime
- Polished post ends
- Precise dimensions
- Better long term economy
General tips for using and handling tungsten SEM/TEM filaments:
- Tungsten filaments are fragile – handle with care and make sure that when replacing a filament that the tip is not touched by the Wehnelt cylinder.
- Adjust the filament so that the tip is central in the opening of the Wehnelt cylinder.
- Be careful not to over saturate the tungsten filament. Lifetime is longer when the filaments are operated just under full saturation. Check after a few days; to achieve saturation, the heating current reduces over lifetime.
- If possible, ramp up the heating current in small and slow steps. Same for ramping down.
- If possible, wait until the filament is cooled down before venting the SEM. Venting with dry nitrogen is preferred
Please consult the following table for the correct type of tungsten filament for your SEM, TEM or Microprobe. The EM-Tec tungsten filaments are available for TFS, FEI, Philips, Hitachi, ISI, JEOL, Tescan, Zeiss, LEO, Cambridge Instruments, and Leica Electron Microscopes
Tungsten Filament Selection Table
| Electron Microscope Type or Filament base |
Product number |
Ceramic Disc mm |
Pin Diameter mm |
Pin Pitch mm |
AEI |
14-AE1201 |
12.0 |
1.0 |
6.45 |
| Cambridge Instruments (except S4-10) |
14-AE1201 |
12.0 |
1.0 |
6.45 |
| CamScan with AEI conversion |
14-AE1201 |
12.0 |
1.0 |
6.45 |
| CamScan with new Tescan Column |
14-TN1209 |
19.8 |
1.0 |
5.0 |
| FEI |
14-FP1203 |
26.0 |
1.0 |
5.0 |
| Hitachi S-Type |
14-HI1204 |
9.8 |
1.2 |
2.7 |
Hitachi with Cartridge TM series tabletop
3400N, 3700N, SU1500, SU3500 |
14-HT1205 |
9.8 |
1.2 |
2.7 |
| ISI /ABT / Topcon 2-Pin |
14-I21206 |
23.4 |
1.2 |
12.0 |
| JEOL K-Type with metal ring |
14-JL1208 |
28.0 |
1.2 |
8.0 |
| Leica |
14-AE1201 |
12.0 |
1.0 |
6.45 |
| LEO 400 and 1400 Series SEM |
14-AE1201 |
12.0 |
1.0 |
6.45 |
| LEO1450 (except AEI conversions) |
14-ZS1210 |
19.8 |
1.0 |
5.0 |
| LEO TEM |
14-ZS1210 |
19.8 |
1.0 |
5.0 |
| Philips V-Loop (PSEM500/EM200 and later) |
14-FP1203 |
26.0 |
1.0 |
5.0 |
| Tescan |
14-TN1209 |
19.8 |
1.0 |
5.0 |
| Zeiss DSM and TEM |
14-ZS1210 |
19.8 |
1.0 |
5.0 |
| Zeiss EVO |
14-AE1201 |
12.0 |
1.0 |
6.45 |
Electron Source Performance Table
The electron source performance table is provided to give additional information regarding the performance and requirements for different type of electron emitters. Tungsten cathodes are still used in the majority in SEMs and in general use TEMs. Improved results can be obtained with LaB6 cathodes, whereas the highest resolution can be obtained with either Schottky or cold Field Emission Sources which can only be used in suitable EMs.
| 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 |
Ordering information for EM-Tec Tungsten EM Filaments
*Prices without VAT, but within the EU, we have to check for valid VAT-ID.
| AEI Base Tungsten Filaments |
 |
AEI base filaments compatible with Zeiss EVO, LEO, Leica, and Cambridge Instrument SEMs
Ceramic Disc Diameter: 12.0mm - Pin Diameter: 1.0mm - Pin Pitch: 6.45mm |
| Product # |
Unit |
Price* |
Add to Quote / Order |
| 14-AE1201 |
AEI Base Tungsten Filaments |
|
| Box/10 |
€125,00
|
|
| FEI-Philips Base Tungsten Filament |
 |
FEI / Philips filaments for FEI SEM/TEM and Philips PSEM 500 and later and Philips EM200 TEM and later
Ceramic Disc Diameter: 26.0mm - Pin Diameter: 1.0mm - Pin Pitch: 5.0mm |
| Product # |
Unit |
Price* |
Add to Quote / Order |
| 14-FP1203 |
FEI-Philips Base Tungsten Filaments |
|
| Box/10 |
€331,50
|
|
| Hitachi S-Type Base Tungsten Filaments |
 |
Hitachi S-Type Filaments for S-, SU-, H- and X-Series SEM and TEM
Ceramic Disc Diameter: 9.8mm - Pin Diameter: 1.2mm - Pin Pitch: 2.7mm |
| Product # |
Unit |
Price* |
Add to Quote / Order |
| 14-HI1204 |
Hitachi S-Type Base Tungsten Filaments |
|
| Box/10 |
€887,00
|
|
| Hitachi S-Type Base pre-aligned Tungsten Filaments with Metal Cartridge. |
 |
Hitachi S-Type pre-aligned Tungsten Filaments with Metal Cartridge for S-3400N, S-3700N, SU-1500, SU1510, SU-3500, FlexSEM and the TM-series Table Top SEMs: TM4040plus, TM4040, TM3030plus, TM3030, TM3000 and TM1000
Ceramic Disc Diameter: 9.8mm - Pin Diameter: 1.2mm - Pin Pitch: 2.7mm |
| Product # |
Unit |
Price* |
Add to Quote / Order |
| 14-HT1205 |
Hitachi S-Type Base pre-aligned Tungsten Filaments with Metal Cartridge. |
|
| Box/10 |
€1563,00
|
|
| ISI 2 Pin Base Tungsten Filaments |
 |
ISI 2-Pin Filaments for ISI / ABT / Topcon SEM and ABT TEM
Ceramic Disc Diameter: 23.4mm - Pin Diameter: 1.2mm - Pin Pitch: 12.0mm |
| Product # |
Unit |
Price* |
Add to Quote / Order |
| 14-I21206 |
ISI 2 Pin Base Tungsten Filaments |
|
| Box/10 |
€725,00
|
|
| Jeol K-Type Base Tungsten Filaments with Metal Ring |
 |
JEOL K-Type Filaments with Stainless Steel Alignment Ring for SEM and TEM |
| Product # |
Unit |
Price* |
Add to Quote / Order |
| 14-JL1208 |
Jeol K-Type Base Tungsten Filaments with Metal Ring |
|
| Box/6 |
€381,00
|
|
| Tescan Base Tungsten Filaments |
 |
Tescan Filaments for Tescan SEMs and Camscan SEMs with new Tescan Columns
Ceramic Disc Diameter: 19.8mm - Pin Diameter: 1.0mm - Pin Pitch: 5.0mm |
| Product # |
Unit |
Price* |
Add to Quote / Order |
| 14-TN1209 |
Tescan Base Tungsten Filaments |
|
| Box/10 |
€424,00
|
|
| ZEISS Base Tungsten Filaments for Zeiss DSM REM/Zeiss TEM und LEO 400/1400 Serie REM/LEO TEM |
|
Zeiss Tungsten Filaments for Zeiss DSM SEMs/Zeiss TEMs and LEO 400/1400 series SEMs/LEO TEMs
Ceramic Disc Diameter: 19.80mm - Pin Diameter: 1.0mm - Pin Pitch: 5.0mm |
| Product # |
Unit |
Price* |
Add to Quote / Order |
| 14-ZS1210 |
ZEISS Base Tungsten Filaments for Zeiss DSM SEMs/Zeiss TEMs and LEO 400/1400 series SEMs/LEO TEMs |
|
| Box/10 |
€424,00
|
|
