AVS 45th International Symposium
    Vacuum Technology Division Tuesday Sessions
       Session VT-TuA

Paper VT-TuA9
Hydrogen Pumping Simulation for Cryopumps

Tuesday, November 3, 1998, 4:40 pm, Room 329

Session: Drag Pumping and Transition Flow Phenomena
Presenter: L.C. Wagner, IGC-APD Cryogenics Inc.
Authors: S. Nesterov, Moscow Power Engineering Institute, Russia
J. Vasiliev, Moscow Power Engineering Institute, Russia
L.C. Wagner, IGC-APD Cryogenics Inc.
M. Boiarski, IGC-APD Cryogenics Inc.
Correspondent: Click to Email
Cryopumps are an effective way to create clean, high vacuum. When designing a new cryopump, it is desirable to have some tool to predict cryopump performance for the different cryopanel geometries that are being considered. Monte Carlo simulation is a method that has been used for evaluating the pumping speed of a cryopump when it has not yet accumulated any gas. The simulation of hydrogen pumping has its own challenges due to the typical location of the hydrogen pumping sites and interactions with other gases. As gases accumulate on the pumping surfaces, the passageways for hydrogen gas are restricted. This paper describes the work that was done, using Monte Carlo simulation, to study the hydrogen pumping speed and capacity of a typical cryopump as it accumulates hydrogen, water and argon. The hydrogen pumping speed is predicted as a function of the amount of other gases that have been accumulated.