CERN

Happy 2016! I hope everyone had an interesting and vaguely relaxing break.

I was actually wrong in my last blog to say that nothing particularly interesting would happen before the end of term—I ended up helping out in the Science Museum lates for Tim Peake’s launch. Some people from Astrophysics had a pop-up planetarium and an infrared camera and I entertained (and scienced) the people waiting for it by showing them how to make a spectroscope out of a DVD. (It actually works surprisingly well.)

Two years ago I won an Imperial Essay competition and part of the prize was a trip to CERN. Due to various complications the trip was postponed and postponed, but a couple of days ago it finally happened! I’ve always wanted to go to CERN, ever since I first heard about it, when I was too young to even know what a hadron was!

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The trip was even better than I imagined however, as we were shown round by  Prof. Sir Tejinder Virdee who as well as being a professor at Imperial, was one of the founding members and head of CMS (Compact Muon Solenoid) one of the detectors on the LHC. Having overseen the planning, construction, testing and finally results of the detector, he had some amazing stories to tell, for example how he travelled to the Soviet Union to help convert top secret military factories into places to grow the lead tungstate crystals used in part of the detector.

He was also incredibly thoughtful, giving us an introductory talk, getting and signing us a picture book of the construction of the detector, introducing us to everyone, and even arranging our own very fancy lunch in the CERN restaurant. He also tipped us off on the possible discovery of a new, never-before-hypothesised particle which may be starting to emerge from the recent high energy runs… Something to watch out for!

The atmosphere at CERN was lovely, with people from all nationalities and different sets of expertise working alongside each other. We saw the main site of CERN, with accommodation, offices and restaurant, and then drove to the other side of the LHC ring, into France, to go down into CMS and see the detector for ourselves.

As I mentioned I am slightly obsessed with CERN, so have seen hundreds of pictures of the detector, but I couldn’t imagine the scale of it until I was standing right above it. It is huge and vastly complex and did I mention huge, and it isn’t even the biggest detector in the Collider—ATLAS is six times larger in volume! (Though CMS is of course the best detector as Professor Virdee assured us.)

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Due to a water leak a few weeks before, part of the detector was slid apart so we could see some of the inner workings. All the parts of the detector can be slid separate to work on—nothing is ever unplugged to prevent faulty connections.

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Inside CMS

We followed the huge mass of wires into another underground room where the initial data is taken and most of it is instantly discarded. Each second there are 40 million collisions when the LHC is running—too much data to ever work on, so instantly all except 100 000 of the most high energy collisions are discarded.

The whole time we were escorted by another guide, who I think was keeping an eye on us to make sure we weren’t tempted to try and pull out a cable!

We saw the server rooms where the data is processed, and the control rooms with open links to other control rooms all over the world where people watch the data come in live to instantly spot any problems. I had no idea this was the case!

In the afternoon we visited the museum which has parts of the insides of the detectors on display as well as some of the old detectors used in the history of particle physics, and I bought a lot of CERN memorabilia!

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The tiny beam-pipe!

It was an amazing trip to a beautiful place. CERN is right next to Geneva and the LHC ring is surrounded by snow-capped mountains and Lake Geneva, and CMS itself is striking, buried at the bottom of this vast cylinder and brightly multi-coloured so it looks an impossibly intricate children’s toy.

I am incredibly grateful that I had a chance to visit it, and look forward to hearing about the collider starting again soon!

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Sadly, Geneva fountain wasn’t on when we were there

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