In an electron beam evaporation process, the samples can be placed in two different positions. Position 1 is very close to the target, position 2 further away. Can we also conclude in vacuum that the temperature is lower at position 2? Is there a physical/ thermodynamic law for this?
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$\begingroup$ Temperature of what? A sample closer to one target (equally hot targets) will get more radiation from the hot material. In vacuum, just how the sample is attached to whatever substrate it is on can have a huge effect on the actual temperature the sample reaches. $\endgroup$– Jon CusterCommented Nov 3, 2021 at 13:25
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Classical theory suggests that the free electrons in a metal are in thermal equilibrium with the atoms of the metal. In a heated filament (as in a cathode ray tube) some of the electrons can gain enough energy to break away from the surface into the vacuum of the tube. Another possibility is “field emission”. A very strong electric field can develop around the tip of a lightning rod (during a storm). This field (associated with a high density of electrons in the tip) can move electrons from within the metal into the surrounding air. This flow can reduce the induced charge in the surrounding ground (or water) and make a lightning strike less probable.
