Electron Beam Source Management
Electron beam sources are available in a variety of configurations, but the flexibility provided by a multi-pocket source make it the most common choice for research and development. Ensuring that each of the materials in the source are deposited properly requires careful management of the pocket carousel.
Different materials require different electron beam distributions to ensure a successful deposition. For materials that melt, like many metals, a concentrated beam spot will provide a tightly defined evaporation point. For materials that sublimate, like many ceramics, a concentrated beam spot would result in uneven and uncontrolled evaporation. A solution to this problem is to rapidly sweep the beam in a pattern which covers all surfaces of the material to evenly distribute the heat and provide a uniform deposition flux. Beam sweep controllers are standard on all multi-pocket electron beam sources.
Integrating multiple pockets to a single source requires motorized pocket indexing to change materials. During pocket indexing, it is possible for material which has accumulated on the source to break away and cause a pocket jam. If left undetected, a pocket jam can lead to material contamination and permanent damage to the deposition source. Angstrom’s solution to this problem involves using a pocket indexer with torque sensing pocket jam detection; should a pocket jam occur, the motor will disengage and operator will be notified to clear the jam prior to carrying out further processes.