 |
 |
|
 |
||
CeBix™ Cathodes
Overview & Advantages:
For years, LaB6 has been the industry standard thermionic emission cathode material. APTech has a material, CeBix™ (cerium hexaboride) that can be used as a direct replacement for LaB6. CeBix™ has several advantages over LaB6 cathodes, including:
Longer Lifetime
Faster Start-up
Lower Work Function
Higher Brightness
Lower Evaporation
Rate
Capability to Recover
from Contaminates
Reduced Effects of O2
Faster Stabilization after Air Exposure
Lower Temperature Operation at the Optimum Filament Setting
CeBix™ cathodes are a simple, direct replacement for LaB6 cathodes in nearly every instrument currently using LaB6.
Applied Physics Technologies exclusively offers CeBix™ cathodes. CeBix™ cathodes are ideal for many small spot size applications such as SEM, TEM, sterilization, surface analysis and metrology, and for high current applications such as microwave tubes, lithography, electron-beam welders, X-ray sources and free electron lasers.
CeBix™ & LaB6 Comparison
In laboratory tests on-site at Applied Physics Technologies, CeBix™ has proven to be more resistant to the negative impact of carbon contamination than LaB6, which gives it an edge in potential cathode lifetime. Additionally, the evaporation rate for CeBix™ at normal temperatures near 1800 K is less than the rate for LaB6. As long as the cathode is being operated below 1850 K, CeBix™ should maintain the tip shape longer and therefore last longer.
CeBix™ has a significantly lower evaporation rate under certain conditions than LaB6. Studies have shown that the material loss rate for LaB6 is almost 75% greater than that of CeBix™ at 1750 K in a vacuum of 2 x 10-8 torr. Thus, CeBix™ can be expected to last 30-75% longer than a LaB6 cathode when operated under proper vacuum and temperature conditions.
In some applications, carbon contamination from pumping oils, solvents, or samples can effect the surface properties of LaB6 cathodes, resulting in severely decreased electron emission. In a case of mild contamination, the operator is often unaware of the problem and only sees that it is necessary to increase the cathode heating current in order to maintain emission current. This increase in cathode temperature results in shortened lifetime. In the case of severe contamination, the emission current may be completely lost.
CeBix™ cathodes are also effected by carbon contamination, but this contamination is removed by thermal desorption at normal operating temperatures. If there is a carbon bearing gas in the system, it will not adhere to the cathode surface at operating temperature; therefore it will not harm the CeBix™ cathode.
View this information in our PDF brochure or Contact Us for more information on CeBix™.
