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| Home Page | Abbreviated Contents | Customer Login | Quick Order / View Order | |
|---|---|---|---|---|
| Contact Us | Search | Indexes | Finish Order | |
Tungsten Filaments |
Kimball LaB6 Filaments |
Denka LaB6 Filaments |
YPS Schottky FE source |
Tungsten Filaments / Cathodes for EM |
|
Tungsten hairpin filaments are the standard type filaments widely used in Scanning Electron Microscopes, Transmission Electron Microscopes and Microprobe systems. Tungsten filaments are also called cathodes or electron emitters or electron sources. The high quality filaments we offer are made to the original equipment manufacturer's specifications using special tools to guarantee the correct shape for the filaments and to generate the optimum electron beam. The filaments are annealed in vacuum, stress-free and precisely aligned before they are shipped. Please consult the list below for the correct type of filament for your SEM, TEM, or EPMA. The tungsten filaments are manufactured from high grade tungsten. Of all metals in pure form, tungsten has the highest melting point (3422°C / 6192°F), the lowest vapor pressure at temperatures above 1650°C (3000°F) and has the highest tensile strength. Tungsten also has the lowest coefficient of thermal expansion of any pure metal. This combination of properties makes tungsten the ideal material. |
| Instrument | New Filament # | |
|---|---|---|
| AEI | 1403 | |
| AMR / AMRAY (except AMRAY 1200 series) | 1421 | |
| AMRAY 1200 (Siemens style) | ---- | |
| ARL - 0.004" W Wire | 1404 | |
| ARL - 0.005" W Wire | 1405 | |
| Cambridge Instruments (except and S4-10) | 1403 | |
| Cambridge Instruments S4-10 (Siemens style) | ---- | |
| Cameca | ---- | |
| CamScan standard Siemens style | ---- | |
| CamScan with AEI conversion | 1403 | |
| CamScan with new Tescan column | 1427 | |
| ETEC | 1406 | |
| FEI / Philips | 1412 | |
| Hitachi S-type | 1428 | |
| Hitachi HU-type | ---- | |
| Hitachi W/Ring | ---- | |
| ISI / ABT / Topcon 2-pin | 1425 | |
| ISI / ABT / Topcon 3-pin | 1426 | |
| JEOL GC-type older style JSM35, JXA50 | ----- | |
| JEOL K-type type modern style | 1407 | |
| Leica | 1403 | |
| LEO 400 and 1400 Series | 1403 | |
| LEO 1450 (except systems converted to AEI) | 1427 | |
| MAC Probe | ---- | |
| NORAN (ADAM) | ---- | |
| Novascan (SEMCO) | 1403 | |
| Philips S Loop (early system, improves resolution) | 1429 | |
| Philips V Loop (PSEM 500 and later, EM200 and later) | 1412 | |
| RCA | ---- | |
| Tescan | 1427 | |
| Siemens | ---- | |
| ZEISS | 1427 | |
| ZEISS EVO® | 1403 | |
| Emitter Type | Thermionic | Thermionic | Schottky FE | cold FE |
|---|---|---|---|---|
| Cathode material |
W |
LaB6 |
ZrO/W (100) |
W(310) |
| Operating temperature [K] |
2,800 |
1,900 |
1,800 |
300 |
| Cathode radius [nm] |
60,000 |
10,000 |
< 1,000 |
< 100 |
| Effective source radius [nm] |
15,000 |
5,000 |
15 (*) |
2.5(*) |
| Emission current density [A/cm2] | 3 | 30 | 5,300 | 17,000 |
| Total emission current [µA] | 200 | 80 | 200 | 5 |
| Normalized brightness [A/cm2.sr.kV] | 1.104 | 1.105 | 1.107 | 2.107 |
| Maximum probe current [nA] | 1000 | 1000 | 10 | 0.2 |
| Energy spread @ cathode [eV] | 0.59 | 0.40 | 0.31 | 0.26 |
| Energy spread @ gun 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 | < 1.10-5 | < 1.10-6 | < 1.10-8 | < 1.10-10 |
| Typical Cathode life [h] | 100 | > 1000 | > 5000 | > 2000 |
| Cathode regeneration | not required | not required | not required | every 6 to 8 hours |
| Sensitivity to external influence | minimal | minimal | low | high |
