Tungsten dispenser cathodes have been Semicon Associates’ core business
for more than 50 years. Semicon has extensive experience in supplying not
only dispenser cathodes, but various other cathodes and cathode assemblies.
20,000 cathodes are produced each year for virtually any application or
customer requirement. These cathodes consist of a porous tungsten matrix
impregnated with a barium based emission enhancing material.
Additional structures such as support sleeves, mounting flanges, heat shields,
emission shields , high voltage insulators and grids, all the way to the complete
Electron Gun, are added per customer requirements (See Electron Guns.)
The cathode matrix may also be a mixed metal such as tungsten iridium or
tungsten molybdenum (Sembo).
Dispenser cathodes are used in all types of vacuum devices and in inert and reducing atmospheres.
The most common applications include TWTs, klystrons, magnetrons, and plasma devices.
Semicon controls the entire cathode manufacturing process beginning with basic raw materials
and including the manufacturing of critical components. The standard manufacturing process
includes chemical cleaning of the emitting surface which ensures open porosity and verification
using scanning electron microscopy. Cathode heater assemblies are also 100% tested for proper heater operation.
Semicon has quality systems in place that can provide full flight qualified cathode assemblies with all required
backward and forward material and process traceability.
Semicon's engineering staff is ready to assist in any custom design requirement.
Our specialists can assist with a design that will satisfy customer requirements while maintaining manufacturability.
Assistance with establishing tradeoffs needed to obtain required emission, limit barium evaporation rate and adequate
lifetime is also provided.
Commercial, Military, or Space Qualification
0.010" - - 8.00" (0.25 mm - 200 mm)
74% - 84%
4:1:1 (S), 5:3:2 (B),6:1:2,3:1:1, or any other required type
Osmium Ruthenium (M), Iridium. Other coatings possible.
Tungsten, molybdenum, molybdenum-ruthenium, rhenium, tungsten-rhenium, Kovar,
nickel, stainless steel, Monel, and others.
To +/-.0002" (+/-0.005 mm)
||Ranging from molybdenum-ruthenium (mp 1980°C) to low temperature alloys such as
copper-gold (mp 910°C)
||From 910°CB to 1200°CB
||Continuous, as high as 20 A/cm2, typically 2-5 A/cm2; pulsed, as high as 120
A/cm2, typically 30-70 A/cm2
||From 3,000 hours to 150,000 hours
Beyond technical expertise, we offer a market and team driven approach. Semicon
Associates will partner with you to develop customized solutions tailored to
your needs. Our partnership continues after the sale is completed to ensure you
get maximum benefit from your purchase.
||Porous tungsten impregnated with 5:3:2 Ba)-Ca)-Al2O2
||As above (4:1:1)
||Above coated with Os/Ru
||Porous tungsten iridium with Ba)-Ca)-Al2O2