Tungsten SEM Filaments

EBS Tungsten EM Filaments

High quality, high stability EM cathodes

EBS Tungsten Filaments | Tungsten Filament Selection Table | Electron Source Performance Table

Introduction

The tungsten filaments manufactured by Energy Beam Sciences are used in all major brands of scanning and transmission electron microscopes. These high quality, high stability tungsten EM filaments, also called cathodes or electron emitters, are manufactured to excede the specifications of the original equipment manufacturers. These superior cathodes are made using high quality ceramic dics, exact size contact pins and high grade tungsten filament wire. Special tools are used to produce the correct shape of the tungsten filament. All EBSciences 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 EBS 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

→ Please consult the following table for the correct type of tungsten filament for your SEM, TEM or Microprobe. The EBS tungsten filaments are available for FEI, Hitachi, ISI, JEOL, Philips, Tescan, Zeiss, LEO, Cambridge Instruments, Leica, AmRay and CamScan Electron Microscopes.

Tungsten Filament Selection Table

Electron Microscope Type or Filament base	Product number	Ceramic Disc mm	Pin Diameter mm	Pin Pitch mm
AEI	AU-14-AE1201	12.0	1.0	6.45
AmRay /AMR (except 1200 series)	AU-14-AE1202	26.0	1.0	5.0
Cambridge Instruments (except S4-10)	AU-14-AE1201	12.0	1.0	6.45
CamScan with AEI conversion	AU-14-AE1201	12.0	1.0	6.45
CamScan with new Tescan Column	AU-14-TN1209	19.8	1.0	5.0
FEI	AU-14-FP1203	26.0	1.0	5.0
Hitachi S-Type	AU-14-HI1204	9.8	1.2	2.7
Hitachi with Cartridge TM series tabletop 3400N, 3700N, SU1500, SU3500	AU-14-HT1205	9.8	1.2	2.7
ISI /ABT / Topcon 2-Pin	AU-14-I21206	23.4	1.2	12.0
JEOL K-Type with metal ring	AU-14-JL1208	28.0	1.2	8.0
Leica	AU-14-AE1201	12.0	1.0	6.45
LEO 400 and 1400 Series SEM	AU-14-AE1201	12.0	1.0	6.45
LEO1450 (except AEI conversions)	AU-14-ZS1210	19.8	1.0	5.0
LEO TEM	AU-14-ZS1210	19.8	1.0	5.0
Philips V-Loop (PSEM500/EM200 and later)	AU-14-FP1203	26.0	1.0	5.0
Tescan	AU-14-TN1209	19.8	1.0	5.0
Zeiss DSM and TEM	AU-14-ZS1210	19.8	1.0	5.0
Zeiss EVO	AU-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