High Vacuum Pump
Use the High Vacuum Pump node to represent a high vacuum pump such as a turbomolecular pump or a diffusion pump in the molecular flow regime (Knudsen number, Kn>10).
If the pump flux is specified directly then  Jpump is user specified. Otherwise, the fraction of incident molecules that are pumped, f, is specified either directly or through a pump speed, S, such that f= √ (2πMn/RT) S/A (here Mn is the molar mass of the species, R is the universal gas constant, T is the temperature, and A is the area of the pump). This condition applies pointwise across the surface of the pump.
Care should be taken with the specification of Jpump to ensure that the value is never negative.
High Vacuum Pump
Select an option from the Specify pump flux list: Directly (the default), Fraction of incident molecules (the default), or Pump speed. The emitted flux J is given by J = G − Jpump.
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For Directly enter a value or expression for the Molecular flux Jpump (SI unit: 1/(m2·s)). The default is 0 (1/(m2·s)).
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For Fraction of incident molecules enter a value or expression for the Fraction of incident molecules pumped f (dimensionless). The default is 0.
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For Pump speed enter a value or expression for the Pump speed S (SI unit: m3/s). The default is 0 m3/s.