CERN - A Brief Summary of What They Are Doing There

CERN - What are they actually doing there?

Early November of 2016 lead to me to visiting CERN in Switzerland on a school trip. Before this however, it sort of struck me that “wait a minute, what are they actually doing there?” Last time I’d heard they were discovering “Higgs Boson” and in 2012 they were going to destroy the universe - according to social media that is. The prospect of actually going to visit what could be debatably labelled “the coolest science project ever” (advancing science in multiple aspects, and best of all, birthing the modern internet as we know it) - having next to no prior knowledge on it made me feel quite ignorant.

So the idea here is that I’m going to fill you in with everything you need to know about CERN and the mass hadron collider - BUT- without all the waffle. I’m going to try and keep it concise… Which is actually close to impossible, but you’ll be better off than before.

Despite it being referred to as the pinnacle of science today, the project actually started soon after the second world war when European scientists came together to answer some big questions. The first particle accelerator was probably only the size of your living room, but after new ones were built and improved it has become the “Large Hadron Collider” (or LHC as you will more commonly see it referred to as) that we know today. In fact, the next one is being designed already.

Okay, so what does it actually do? Well, a few things actually, which is handy. Spending $13.25 billion to find something that we weren’t even sure existed sounds a bit pricey. In fact, in terms of cost, it’s about $1 billion per year in total. Ouch. The Large Hadron Collider is a) large and b) a collider. There you go. That’s all you need to know.

Okay but seriously, what it does is super-cool particles to accelerate them close to the speed of light then smash them together in order them to form new particles. They use Hydrogen particles because there is only one electron to remove from it and then it’s good to go. When the particles collide there is a lot of energy released. Well, I say that, but you yourself could create that much energy right now. You ready?

1. Hold your hands in front of you like you’re about to clap.
2. Clap once.
3. Done.

You just created a similar amount of energy in that clap as the collision of two particles travelling near to the speed of light. “Whaaat??” you exclaim?! Well, imagine all that energy across the millions of particles in your hand on just two particles. That’s a lot.

They collide and it shoots out new particles at different stages. Some form straight away, some further away from the initial collision, hence they have multiple different sensors to detect the variety of particles. This includes matter and antimatter. The two sound crazy, in fact you’ve probably watched enough Sci-Fi to hear “antimatter rocket launcher” and think “sh*t is about to get real”. Unfortunately, it’s not as exciting as you think, it’s just another standard particle that is a byproduct of the collision.

The three big hurdles are: accelerating the particles, detecting the particles and storing the information from them. Firstly, accelerating the particles, as mentioned before there are multiple “layers” to it, as shown by this diagram:

At each “ring” the particles are accelerated by different means. Pb and b are “linear accelerators” where the particles are electronically accelerated - the technology for this was first proposed in 1924 and has given way to lots of useful technology around the world generating X-Rays and being used for radiotherapy.

PS is “Proton Synchrotron”. No, it is not a Transformer that fights alongside Optimus Prime, but accelerates the particles using very powerful magnetic rings. It is the oldest accelerator on the CERN site, and has operated since the 1950s - having lots of upgrade of course - still using the original magnets.

SPS - “Super Proton Synchrotron” - not only sounds badass but measuring at 7km long, it has served as the workhorse for CERN since it’s launch in 1976. Using it, they have made numerous discoveries including the Nobel-prize-winning discovery of W and Z particles in 1986.

Finally, the piece-de-resistance being the LHC - “Large Hadron Collider”. First launched in 2008, the LHC is the world's most powerful particle accelerator having a length of 27km made of superconducting rings. This peaks the acceleration of the particles using the supercooled electromagnets at -271.3°C/-456.34°F - which is colder than outer space which is (-270.45°C/-451.81°F).

[The LHC accelerating magnets - Source: CERN website]

Once they are in this ring, there are 4 main sensors picking up data: ALICE, ATLAS, CMS and LHCb - each having their own roles. You’ve most likely seen ATLAS (see below) as it is often used to represent the CERN experiments. 100m below the little village of Meyrin on the Swiss-French border lies the 7000 tonne beast that is ATLAS. It has been used for multiple physics researches from searching for Higgs Boson to dark matter - even new dimensions - that run day-in-day-out.

Layers of sensors pick up different things like heat, momentum and size to determine what sort of particle is produced by matching them with the properties of particles we can already distinguish to a very precise level. A stream of data is produced using a computer system that decides what data to keep and what to throw away. This data is then stored all across the world using “the grid computing” which is effectively a sophisticated internet. About 1 petabyte of data is created at the LHC every second (about 210,000 DVDs every second) which is all sent out as “packets” that are then reassembled when needed through a clever computer algorithm.

ATLAS [Source: www.oastories.org]

Most of CERN is underground with exception of the control buildings, offices and museums being above ground. There a couple of reasons for this, one being that it is protected from exterior damages (it would be a costly loss if it were to be targeted by terrorists) and also that a lot of it would be obstructed by all the people living on the surface.

Interestingly, it is shut down only once every 4 years. This is because it takes more energy to shut it down and start back up that to just leave running. It is at this point when they shut it down and do check ups and repairs that it is possible for people to visit the underground parts.When they do bring it back to life again, the power demand causes a bit of a shortage in the town of Geneva. Unfortunately when I visited it was not one of these times, but the exceptional museum and tour guides are still worth the trip.

Some question whether the costs of running this whacky science project is worth it. You could argue that the discoveries are leading us towards a better future and it must also be considered that the money does come back into the economy with the wide variety of people being paid from office workers, to tour guides and even the miners for example who are obtaining the raw materials. A debate for another day perhaps.

To summarise: the idea is to collide particles in order to obtain a better understanding of the world around us and even beyond the world we know. I hope this was informative for you to read and that it wasn’t too much or too little.

Let me know what you think,

Seb