PhysicsTechnology

My week at CERN

It has been almost a year since I managed to get up on the stage at the 21st EU Contest for Young Scientists in Paris, to be presented with the EIROforum CERN Prize. I still can’t believe how I got there from a six week Nuffield Bursary project at the University of Sheffield, via the inaugural Big Bang Fair, and even less how I ended up getting a week-long all-expenses paid trip to the largest particle physics laboratory in the world this summer. Still, I am very grateful for all the opportunities that my project, which involved analysing background noise and performing simulations for a neutrino detection experiment, has given me.

I arrived at into Geneva on a July Sunday evening, and the next day I met with Catherine Brandt, who works in the EU Projects office at CERN, and who was responsible for organising much of my trip. During my week-long visit I spent the mornings attending lectures, along with the CERN summer students – a project-based scheme that attracts undergraduate students from around the world. The lectures proved a useful way of getting a good general idea of the sort of things that are important for a particle physicist to know.

Monday afternoon had a distinct neutrino flavour, starting with a visit to the CERN Neutrinos to Gran Sasso (CNGS) experiment. CNGS involves shooting a beam of muon neutrinos through the earth from CERN to a laboratory in Gran Sasso, Italy, where they are detected. The aim is to determine whether these muon neutrinos change or ‘oscillate’ into tau neutrinos. I met Ans Pardons, a mechanical engineer who showed me a spare CNGS ‘horn’, and took me through how it worked. The horn is used to focus a muon beam using magnets – a simple idea, but very complex in execution. My neutrino afternoon concluded with a talk with Ilias Efthymiopoulos, an experimental neutrino physicist, about the next generation of neutrino experiments. It was very exciting to hear how much work there is ahead for the researchers of the future.

My next afternoon of visits began with a trip to the new Universe of Particles exhibition in the Globe, a spherical wooden building bequeathed to CERN by the Swiss Government. The exhibition itself would not have looked out of place in London’s Science Museum – it was futuristic in design as well as in content. My favourite exhibits were the spark chamber, which lit up to show the tracks of cosmic rays, and a multi-touch screen that allowed you to find out more about the different sections of CERN, and even ‘see’ the Large Hadron Collider (LHC) in action.

After this I went with Christoph Rembster and one of his summer students to the ATLAS (A Toroidal LHC ApparatuS) experiment. ATLAS is one of the two main all-purpose experiments at the LHC, and is used as a sort of ‘camera’ for particles – including, potentially, the elusive Higgs boson. I was allowed into the control room – an area normally closed to the public – where the experiment is monitored and controlled.

 

The afternoon was rounded off by a meeting with Rolf Heuer, CERN’s Director General. He was very friendly, and as we talked I learned that we shared similar experiences as young physicists: we were both the first members of our families to go to university, and neither of us had been interested in physics until the right, inspiring, teacher came along. I told Prof Heuer about the Nuffield Bursary Scheme, and he seemed very impressed, saying that it should be used as a model for other countries.

Wednesday brought more visits to detectors, again guided by Christoph, and accompanied by his summer students. Obviously, it isn’t possible to visit experiments when they’re turned on, but I was still treated to a tour of a number of different areas. First came one of the three linear accelerators (Linacs), where protons are accelerated from rest before being injected into the ring accelerators. Thereafter, the visits to various experiments came thick and fast.

We saw the Low Energy Ion Ring (LEIR), used to produce lead ions for the LHC; the Cosmics Leaving Outdoor Droplets (CLOUD) experiment, which is looking at possible links between cosmic rays and cloud formation, and hence climate change; the Antiproton Decelerator (AD), which stores antimatter before it is sent to other experiments; finishing with a visit to an experiment looking at the possibility of using antiprotons in cancer treatment – the sort of thing that makes it harder for people to claim that basic research is pointless. After so many experiments, it was almost a relief to visit the CERN Computing Centre, taking in the sights of both the servers currently being used and a small exhibition of old computer accessories, including one of Tim Berners Lee’s original Grid servers.

Finally, I was taken to see the CERN Axion Solar Telescope (CAST), which is searching for hypothetical particles from the Sun called axions. If discovered, axions could solved what is known as the strong-CP problem, and could have important implications for theories about antimatter and dark matter. I spent a long time learning the intricacies of both the theory and the apparatus from technical co-ordinator Martyn Davenport, and received a great piece of advice from the CAST spokesperson Konstantin Zioutas: “Go into particle astrophysics – you get everything for nothing!”

On Thursday afternoon I visited SM18, where the superconducting magnets placed around the ring of the LHC were made and tested. In addition to learning all about how they worked and why they were needed, engineer Zornitsa Zaharieva, gave me an in-depth account of the accident that stopped the LHC for months, following its initial switch on.

On Friday afternoon began with a meeting with Director for Research and Computing, Sergio Bertolucci, who, like Prof Heuer, was very friendly. I was thrilled when he told me that I’d be very welcome to come back to CERN as a summer student. My last CERN Visit was to the Press Office, where information from the laboratory is disseminated around the world. While CERN does not yet have an official Facebook page, it uses its own website and Twitter to communicate its work to the wider world. Finally, I was photographed and interviewed for the CERN Courier, the internal newsletter of the lab.

My weekend was spent trying to take in everything I had learnt, before making my way back to my home near Lincoln. It was an intense but fascinating week, and I am very grateful to all the CERN staff who were so helpful to me. There was much to enjoy, but what I think what I enjoyed the most was learning how all the detectors I’d read about actually worked from the experts directly responsible for their operation. What made the trip even more exciting is that the LHC is now running, with the first experimental results going into publication.

 

Hopefully, my experiences will help enthuse others with the excitement of particle physics. Personally, I can hardly wait until September, when I can apply for next year’s summer student program!

 

Originally published in the Autumn 2010 issue of E&T Education

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