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The Particle Identifier

Introduction

Welcome to the Particle Identifier! A game that puts you in the control room of one of CERN’s particle physics experiments. A series of particle tracks will appear on our detector display and we need you to identify what they are.

Press next to learn more…

CERN

The Large Hadron Collider at CERN is the world's largest and most powerful particle accelerator. Experiments here are designed to test the limits of particle physics, to try and better understand the building blocks of the universe.
In the LHC, particles are accelerated to almost the speed of light, and then they’re collided at one of the detectors creating a huge burst of energy and a vast number of particles - some of which have never been seen before!

Many of the particles created are very unstable and will decay within a fraction of a second - often into one of five types of particles that scientists can detect.

The Particles

The CERN experiments can detect and track five types of particles. These are: photons, electrons, muons, neutral hadrons, charged hadrons. These all have different properties (such as mass, electric charge etc.) which means they behave differently in our detector - this is how physicists (and you) can tell them apart.

Look through the information in the side panels to learn more about what these particles will look like and how the different parts of the detector work.

How to play

Check the info tabs on either side for info on what the particles should look like. Once you press start a random particle track will appear – use the buttons to enter the particle you think it is and press SUBMIT to see if you’ve got it right!
If you choose right you’ll go up a level and gradually more particles will appear. You can get five wrong before the game ends – see how many particles you can correctly identify!

☰ INFO


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Subdetectors

Silicon tracker

Silicon pixels make a tiny electrical signal when a charged particle passes through it, we can detect this and see where these particles have been. This can also let us know their momentum, which is pretty handy for calculations.

More on the silicon tracker here!

ECAL

This is the electromagnetic calorimeter; it is an example of what's known as a scintillator. This means when particles like electrons or photons go through it, it produces a flash of light. We can measure this light and from that calculate the energy of the photons and electrons.

More on the ECAL here!

HCAL

The hadron calorimeter measures the energy of hadrons – these are particles that are made of quarks (like protons or neutrons). The hadrons will go into a thick absorber layer so the hadrons break down into particles that can be detected by a scintillator layer, just like in the electromagnetic calorimeter.

More on the HCAL here!

Magnet

Magnets are incredibly important in particle detectors; they can control the path of charged particles. This is a very large solenoid magnet which makes a magnetic field that is 100,000 times stronger than the Earth’s!

More on the magnet here!

Muon tracker

Muons are like electrons but a lot heavier, so they aren’t stopped by the calorimeters. The final part of the detector is designed just to detect muons. The muon trackers show us where the muons have been, then based on how curved the path is we can find the momentum.

More on the muon tracker here!

Particles

Photon

Photons are particles of light. They have no mass, no electric charge and they’re elementary which means they’re not made up of smaller particles. Photons interact with matter a lot, their interactions with the eye allow you to read what’s on the screen right now! When they pass through a detector at CERN they’re detected at the electromagnetic calorimeter.

Electron

Electrons are small, stable, electrically charged, elementary particles. They are the foundation of electronics and are also produced in particle collisions at CERN, where the electromagnetic calorimeter can detect them.

Muon

Muons are like electrons except they’re much bigger and much less stable. The detector can’t stop the muons, so they travel right through and it’s only at the outer edge they can be detected in the muon tracker.

Neutral Hadron

Hadrons are particles made up of quarks – these are just another type of elementary particle. They can be found in pairs and triplets (or sometimes more!). Neutrons are an example of a neutral hadron; these are found in the nuclei of the atoms which make up everything around us. In our detector they get stopped at the hadronic calorimeter.

Charged Hadron

Hadrons are particles made up of quarks – these are just another type of elementary particle. They can be found in pairs and triplets (or sometimes more!). Protons are an example of a charged hadron; these are found in the nuclei of the atoms which make up everything around us. In our detector they get stopped at the hadronic calorimeter.