To be sure, there are still applications for thermionic emission, especially in power electronics and specialized switching applications. But by and large, progress has left vacuum tubes in a ...

The Thermo Fisher Apreo 2 Variable Pressure Field Emission Scanning Electron Microscope (FE-SEM) is a thermionic field emission high resolution scanning electron microscope. The Apreo 2 FE-SEM is an ...

However, [Nick Poole] wanted to investigate an alternative method, using thermionic converters for solar power generation. [Nick] has been gearing up to produce various styles of vacuum tubes ...