How to host an event

Here you can find an overview on what it takes to run a BYOPD event at your institute/lab.
In any case, feel free to get in touch with me and to find out more and ask whatever question you have!

The basic idea of “Build Your Own Particle Detector” events is to have visitors (mostly children) design and build their own particle detector out of building blocks (mostly LEGO). For this purpose, I have organised about 45 kilograms of random LEGO pieces that we just spread out onto tables in the tent.

Typically, this activity is connected to a competition for the best idea and implementation of a model (including a good name). For the purpose of the competition, we take a picture of each contestant’s model clearly showing the ticket number on the picture. After that they have to disassemble their model again.

To carry out the event we need people for two tasks: someone to take the pictures of the models/tickets (paparazzi) and a few people that just walk around, hand out tickets and talk to people about physics (floaters).

Besides the actual activity we might have screens showing ATLAS/physics videos and a time-lapse video of the construction of the large ATLAS model, or might have the latter on display. We’ll also have a computer for people to register their models for the competition (they can also do it at home).


  • several kilograms of LEGO pieces (get in touch with me if you don’t have any)
  • one, two, ideally more volunteers at any given time
  • some prizes and ideally give-aways
  • a computer (ideally) with internet connection
  • a camera (could be your phone as well)
  • a printer (only before the event)


  • get in touch with me via or +41764416428/+4917648199660
  • get your LEGO pieces (I might be able to join and bring LEGO pieces if needed)
  • I will set up an event page and a registration form for your event at
  • print the tickets
  • print a poster with the BYOPD logo and put it up

Running the event

  • general workflow
    • visitors enter the tent and will most likely either go to the tables or the model directly (there’s a strong correlation with age)
    • before they get started on building something, a volunteer should introduce them to the competition (idea, rules, etc.)
    • when done, each contestant has to get a ticket and a picture taken (just his/her model – avoiding people – with the ticket number visible on the picture)
    • each contestant has to register their name and email address for the competition (using a dedicated event page on this website and supported by a volunteer)
    • participants that registered get a take-away/souvenir
    • each contestant has to disassemble his/her model and put the pieces back on the table for others to use again (typically it’s fine, but the floaters should have a eye)
  • visitors (usually) don’t get to keep their models / LEGO pieces!!!
  • while people build volunteers should talk to people (most likely parents of the contestants) about the experiment, the physics, what they are building and how that differs to the real experiments, what they with their ‘detector’ and what we do with ours
  • winners of the competition will be announced a few days later (you can take part in the decision)
  • prizes are typically send out by regular mail or can be picked up somewhere
  • visitors/participants do not need any LEGO skills – doesn’t hurt though 😉 – and they don’t necessarily need to know anything about the ATLAS model (they will learn from the posters and volunteers)
  • also volunteers don’t need to LEGO experts, but it’s advantageous to know a bit about CERN, the experiments and maybe the physics to keep people entertained
  • please advertise this webpage ( / and share/mention our twitter page @BYOPD

Wrapping up

  • I collect the pictures and connect them with the registration entries
  • I will upload the pictures to the website
  • you can decide on the winners
  • winners can be announced on your channels and I will put them on this website
  • contact the winners to get postal addresses
  • send out prizes