CERN Open Days

The CERN Open Days are already fading away, even though it was an adventure that already started in July 2018. I had the pleasure of coordinating the ATLAS activities for this 75k-visitors event together with Anna Sfyrla, Laetitia Bardo and a great team of about a dozen ATLAS members that helped us by coordinating one of our activities.

During the Open Days, which started with an underground-only family day on Friday afternoon and lasted until Sunday evening, almost 300 ATLAS members joined as volunteers to make the ATLAS activities – as far as I am concerned – a huge success.

We offered exhibits and activities at both Point 1 and in the ATLAS detector workshop on the Meyrin site of CERN.
In the Photo Corner visitors could get a photo print-out of themselves in front of the ATLAS detector dressed up with helmets. In our Computing Corner they could learn everything about ATLAS@HOME, data analysis in ATLAS and the grid infrastructure behind all our computing activities. Our Higgs Corner took visitors on a journey to learn all about the production, decay and classification of Higgs events by spinning the “Higgs Wheel of Decay Channels” and digging through a box of ‘background gravel’ to finally end up with a button of their Particle Zoo decay particle of choice. Mostly – but not exclusively – for our younger audience we offered to learn about protons and their constituents in our Proton Cookies Corner (spin-off from the fantastic PhysicsCakes) or build what they think a particle detector does/should look like in a Build Your Own Particle Detector competition. For all topics not addressed in either of these activities, visitors had the chance to sit down with an ATLAS physicist, get a coffee (in one of our ATLAS cups) and ask their questions in our Science Café. And of course we offered tour to the ATLAS Control Room and the detector itself at Point 1.
At the ATLAS detector workshop, we set up an exhibition showing examples of nearly all detector components of ATLAS giving visitor of all ages the chance to get a close look and an in depth description by our volunteers. The obvious highlight were the two nine-meter-diameter New Small Wheels currently being constructed in the workshop. Together with the ColliderScope and a “Making a Splash” water-balloon collisions activity this site more than made up for the about two kilometres walk from Point 1. A path that several of us took multiple times – sometimes with up to a hundred visitors – on one of our spontaneously arranged “ATLAS Walking Tours”.

It was certainly an educative, sometimes exhausting, but on the ATLAS side always enjoyable adventure. To put the event in numbers …

  • about 1800 proton cookies were served
  • about 3800 visitors got a tour underground
  • about 1500 visitors got a tour to the AVC
  • 267 LEGO models were registered in the BYOPD competition
  • about 15 ATLAS walking tours from P1 to B191 were made
  • more than 1150 photos were printed
  • about 2900 ATLAS cups were given out
  • about 2000 coffees were served (including about 1000 sugar bags)
  • I made more than 66k steps on the weekend (more than 100k include setup and dismantling)

Here is some impressions from the weekend …

Find some more at