Vacuum requirements are more stringent for hexaboride emitters than for tungsten in order to minimize carbon contamination. In order to image materials we must first generate an electron beam. - Tungsten - Molybdenum - stainless stell - Aluminium - Graphite Yttria coatings are used in a wide range of applications, as well as separating layer or non-stick coating. 0004168565 361..396 A heated filament made from the metal tungsten. Much in the way that an incandescent lightbulb works, the high voltage that is fed through the filament causes electrons to be kicked off the filament. The amount of energy required is known as the work function. The LaB 6 filament is also a thermal filament. vs tungsten LaB6 Filament Basic Knowledge For Using The SEM Keywords | Glossary of SEM Terms | JEOL Field emission gun (FEG) is used to produce an electron beam that is … Lifetime around 40-100 hours Failure is usually due to mass transfer/melting Over heating the filament causes this to happen faster and greatly decreases the filament life Lanthanum Hexaboride (LaB6) Filaments Thorium oxide coating - HME This is the purpose behind the electron gun; to provide a continuous beam of electrons which can be adjusted by the user. Tungsten vs CeB6 - Desktop SEM - Accelerating Microscopy