Applied Physics Technologies (APTech) lanthanum hexaboride (LaB6) and cerium hexaboride (CeB6 or CeBix) cathodes are now available from Electron Microscopy Sciences.
LaB6 and CeBix cathodes are ideal for many small-spot-size applications, such as SEM, TEM, surface analysis and metrology, and for high-current applications such as microwave tubes, lithography, electron-beam welders, X-ray sources and free electron lasers.
The properties of hexaboride crystals provide stable electron-emitting media with work functions near 2.5 eV, yielding higher currents at lower cathode temperatures than tungsten, and resulting in greater brightness and longer cathode life.
In electron microscope applications, this translates to more beam current in a smaller spot at the sample, improved resolution, and less frequent cathode replacement.
For applications with large beam spot sizes, where high total current and current density are required, LaB6 and CeBix can be the cathodes of choice rather than dispenser cathodes.
Both cathodes are robust and resistant to chemical poisoning, have modest vacuum requirements and long shelf life, and need only be brought up to operating temperature to provide emission, eliminating the activation procedure required of dispenser cathodes.
They can provide long-term, stable operation at current densities up to 50A/cm2, and can be fabricated in a variety of shapes and with diverse heating and mounting configurations.
