# Thermodynamics in an ion beam?

#### Harperchisari

Hi there,
I'm trying to design an ion beam source, but having some issues with the thermodynamics of it. I'm no expert in thermodynamics, but I do understand some. I'm trying to find an equation which I can use to find the amount of energy I need to put into a set mass of a set material in order to turn it all into a gas at a set pressure at a set initial temperature. This equation would have constants that change depending on the material of course.

I'm trying to figure out the energy to make an ion beam, so I assume the energy required to make the beam would be the energy to separate the mass from the main mass ( the thermodynamic part) as well as the energy required to strip the outer electron away from the mass and accelerate the mass forward. The energy should be able to be separated thermally (by heating it), electrically (by applying a potential), or, ideally, a mixture of both, but the total energy binding the particles should be the same.

In the end, it should be an equation like Etotal = Eacceleration + Eelectron stripping + Eseparation where Eseparation = Ethermal + Evoltage. In this case Eseparation should also be the same amount of energy required to turn the set amount of material directly into a gas (i.e. it could be done entirely through thermal means) which would be easier at lower pressures, but I also need to have a voltage component as well, as I am trying to accelerate it away anyways.

I'm trying to do this without taking a full course in thermodynamics, but if I must I will. I just figured I'd pose this here in case someone knows the equation mentioned (or equations) mentioned in paragraph 1.
Thanks for any response,
Harper

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#### nsaspook

I can't help much with the theoretical equations but I can supply some background information that might help.

The ion sources commonly used in the semiconductor industry use electron bombardment (directly heated filaments or indirectly headed cathodes) with a externally piped in process gas (or a crucible vaporizer to generate that gas inside the source) to generate the positive ions needed for source extraction.

https://inis.iaea.org/collection/NCLCollectionStore/_Public/26/001/26001458.pdf

"Thermodynamics in an ion beam?"

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