About Molflow

A test-particle Monte-Carlo simulator for ultra-high-vacuum systems

Developed at CERN



Molflow+ allows you to calculate the pressure in an arbitrarily complex geometry when ultra-high vacuum condition is met. The name comes from molecular flow, the condition when the mean free path of molecules is so long compared to the geometry size that collisions can be neglected. In this case, particles fly independently, which makes this physics particularly suitable for Monte Carlo simulations. The first version of this program was written by Roberto KERSEVAN in 1990. In 2008 a new version called MolFlow+ was written, that uses the original algorithm in a modern environment. It uses OpenGL acceleration and can use multiple cores. Further improvements were added in 2012. Geometries can be imported from most CAD programs that support the STL file format.

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SynRad+ is a mod of the previous program. Instead of molecules, it traces photons to calculate flux and power distribution on a surface caused by synchrotron radiation. The user can define magnetic regions where the trajectory of the beam is calculated. From this beam photons are emitted, and when they hit surfaces, their reflectance or absorbance is calculated, helping the design of machines where SR induced heat or gas desorption is important. It has been writtent in late 2012 and has been released to the public in 2013. The file formats are compatible with MolFLow+.



Authors & Contact

For support (bug reports and help with the codes), we prefer that you open a post in the forum, which others may learn from. Otherwise, feel free to get in touch with us:

Original Molflow and algorithm:
Roberto KERSEVAN - roberto.kersevan@cern.ch

Code and website:
Marton ADY - marton.ady@cern.ch
Pascal Rene BAEHR - pascal.baehr@cern.ch

"SDL App" GUI Framework:
Jean-Luc PONS - pons@esrf.fr


See this dedicated page


If you publish results computed with our codes, we kindly ask you to include a reference to this IPAC'19 proceeding:

Recent developments of Monte-Carlo codes MolFlow+ and SynRad+
M. Ady, R. Kersevan
10th Int. Particle Accelerator Conf., Melbourne, Australia -  doi:10.18429/JACoW-IPAC2019-TUPMP037


Keywords: CERN UHV vacuum simulator ultra high vacuum test particle monte carlo