The CERN site of Prevessin is located next to the French village Prevessin-Moens. This is the second large experimental CERN site, apart from the main CERN site of Meyrin. Unlike the Meyrin site, which is located on the French-Swiss border but in practise is as if in Switzerland, the Prevessin site is fully in French territory.

The site was built on the north end of the 6.9km SPS accelerator ring
https://home.cern/science/accelerators/super-proton-synchrotron
https://en.wikipedia.org/wiki/Super_Proton_Synchrotron

which was the accelerator at which, among other things, the W and Z bosons were discovered 40 years ago. Nowadays the SPS is a pre-accelerator for the LHC, but at the same time also several secondary beams are extracted that feed quite a few experiments, like NA62 (NA stands for “North Area”).

Given this concentration of activities, it is not a surprise to find the CERN Control Centre (CCC) there, the main hub from where the complex CERN accelerator system is steered. The site also hosts the control centre of the AMS experiment (an anti-matter experiment on the ISS), a large are for CMS activities including muon labs; (and a very enjoyable barbecue area :) ).

Also the VUB has had recent activities on this site: a few of the silicon tracking modules that were recently constructed in our labs were tested for an extended time in a high-energy muon beam. A picture with one of our postdoctoral researchers working on this is below:

In the map below, you can see the Meyrin and Prevessin sites, and the circular SPS accelerator between them. The small circle in the Meyrin site is the PS accelerator, an even smaller (and older) accelerator that is the step before protons enter the SPS. The biggest circle which we only partially see on this picture is the LHC tunnel.