Defining a molecular beam source in molflow

General discussion
1

Hi,

I am trying to model the steady-state pressure conditions of a vacuum setup with an effusive atom beam source. Is there a way to define one of the facets of the imported geometry as an emissive source within molflow. Please let me know if you need any additional information.

Thanks

2

Not only it is possible, it’s obligatory to define a source, in the “Particles in” groupbox on the right side facet parameters.

In general about setting up a simulation: https://molflow.docs.cern.ch/guide/molflow/general/quickstart/

For molecular source you might want to define an angle map: https://molflow.docs.cern.ch/guide/molflow/features/anglemaps/

Or you can just use the Cosine^N diretion type.

3

To model a molecular beam source, I currently define a circular facet (2 mm dia) within my geometry and set its desorption to Cosine^N with a ridiculously large value of N (1E+05 or 1E+06). However, when I monitor the speed distribution 100 mm away from the facet along its normal, I see a very narrow speed distribution.

4

Please give more information. How do you monitor the distribution, what do you expect and what do you get?