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Vacuum cadmium chamber fluid dynamics

I'm trying to find some information on the fluid dynamics of a vacuum cadmium chamber. Moreover, I'd like to know whether turbulent flow in the chamber will ensure a more uniform coating thickness. I've calculated the Reynold's number of our chamber to be 2165, which is in the transitional range (turbulent flow occurs when Re>10,000, and laminar flow occurs when Re<10), but I cannot find any published information to compare my calculations with. Any information would be very much appreciated.

Sam Laranang
plating - Torrance, California, USA
2004

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What pressure are you depositing cadmium at? I ask because at low pressure traditional fluid dynamics equations don't work. This is because the flow transitions from viscous flow (traditional fluid flow) to molecular flow. In molecular flow atoms travel long distances before they hit another atom or the wall of the chamber. For instance if you have a pressure of 1 mTorr an Argon atom will travel about 5cm on average before running into another atom.

The whole motion calculation gets even worse for Cadmium because it doesn't bounce off the vacuum chamber walls. Cadmium will sublime/evaporate off from hot surfaces and condense on cold surfaces. Most modeling at low pressures is done by Particle in Cell or Monte Carlo programs.

John Davis
- Berthoud, Colorado, USA
2004

WHAT KIND OF EQUIPMENT DO YOU NEED FOR VACUUM CADMIUM?

IGNACIO YANES
- MIAMI, Florida, USA
May 7, 2009