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Although Molflow is developed for Windows, the WineSkin wrapper allows running it on Mac in non-native mode with a slight performance overhead. You can give it a try through the Downloads section and let us know how it works.

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Synrad+ and Molflow+ were meant to be use together as a package. The latest beta versions allow you to do a SR simulation in Synrad+, then import the absorbed flux map to Molflow+, convert it to a desorption map, and do a standard vacuum simulation, this time having the walls as outgassing source. Follow the steps below for the whole procedure.

Part 1: Synrad+ simulation

In this example, we will use a short sample tube which receives SR light from an upstream dipole.

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With MolFlow 2.3.5, two long-requested features have been added to the expressions that you can use in Formula Editor.

1) Mean Free Path / Mean Pumping Path

Adding the "MFP" or "MPP" variables will display the mean free/pumping path in centimeters, that is, the total length travelled by particles in the system divided by the number of hits / number of absorbed particles.

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2) Sums for selection groups

MolFlow now fully supports defining part of the geometry as selection groups. In the formula editor, it is now possible to refer to a group of facets and perform sum operation on them. The syntax is the following:

sum(prefix,Sn)

where prefix can be:

  • AR (area of facets)
  • A (number of absorbed particles)
  • H (nimber of hits on the facets)
  • D (number of particles desorbed from the facets)

Examples:

  • SUM(A,S3) will calculate the total number of particles absorbed on facets that are part of selection group 3
  • SUM(AR,S1) tells the total area of all facets in selection group 1
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The best way to start using SynRad is to set up a simple sytem with two dipoles and interpret results. There is a 10-minute quick start guide to do just that:

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You can also see how eactly the tutorial is solved on this Youtube video (set quality to 720p to see text):

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SynRad is a new MC simulator for calculating flux and power distribution of synchroton radiation in geometries of arbitrary complexity. It has a similar interface to Molflow and both programs read each other's file formats. You can also export the flux distribution and use it as an outgassing map in Molflow.

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Try it out in the downloads section.

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Recently two MolFlow users have been facing a similar problem:

One of them wanted to simulate outgassing due to beam loss, others had outgassing due to electrons in the system. In both cases, they had a distribution of outgassing that changed depending on the location. The only way to enter it to MolFlow was to create a matrix of facets, and define the outgassing rate one-by-one. A rather long and boring process.
 
So I decided to create a way of defining a spacial outgassing distribution. The key is the Explode command that existed already in Molflow.
 
First, you have to define how fine the outgassing matrix is by defining a regular mesh:
 
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Then we select the facet and issue the new "create outgassing map" command:
 
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Below you see a map of the facet. For each mesh element, you can manually set the outgassing value. Note that the edited cell's location is highlighted on the geometry (similar to texture plotter):
 
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Click image to magnify)
 
You can also paste values from the clipboard from Excel. The values are pasted to the right and bottom from the actual cell. Then you can define the desorption type (Uniform, Cosine, Cosine^N). Finally, if everything's ready, click Explode.
 
The exploded geometry highlights those facets that have a desorption now:
 
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To test that everything was well defined, add a mesh that counts desorbed molecules, and you'll see a nice colormap of the values you just entered:
 
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That wasn't hard, was it? Happy outgassing! ;)
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If you have carefully selected a group of facets, let's say all part of a given structure, then you probably won't want to select them once again.

That's why the Memorize selection function was added, allowing you to create facet groups, which are saved with the geometry file.

To use it, simply select some facets, then use Selection menu / memorize selection (shortcut: CTRL+W), and give your selection a name.

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In the current version of Molflow, it is possible to insert a GEO, TXT or STL file to the current geometry. It is useful if we want to assemble a system from parts that are each represented by a file.

However, snapping the pieces together might be difficult, thus there is a new Facet align option.

To use it, select the object that we want to align.

Then open the Facet align dialog. Upon opening, the selection will be memorized:

 

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You can now select one or more facets, and rotate them by a given number of degrees, around an arbitrary axis:

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If you want to use the "define by 2 selected vertex" mode to define the rotation axis, you will have to select two vertices using the vertex selector tool.

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When CAD programs export STL files, sometimes they include "null" polygons that have all nodes on a single line. This is a bug of the exporting program, most probably caused by the fact that coordinates can be stored with more precision in the memory than in a file.

For example, the following two polygons are NULL polygons:

Polygon1:

  • Point1 (0,0,0)
  • Point2 (1,0,0)
  • Point3 (1,0,0)

This is invalid because point 2 and 3 are on the same coordinates, thus it is not a triangle.