Sunday Evening in Bern

is dead. There is almost nothing open. I forgot how dead Switzerland is on Sunday. Almost everything in Geneva is also closed on Sunday. I don't how the Swiss amuse themselves on Sundays, or fit in all their shopping and errands on Saturday. I guess you are supposed to go to outdoorsy type things, but still, what happens if it rains?

Anyway, you may be wondering why I'm in Bern now, when I only just arrived in Geneva yesterday. I am here with my supervisor for an ATLAS Collaboration Overview Week, and it is one of the reasons that I'm over here this early, since my Swiss scholarship doesn't start until September. She wants to introduce me to other important people in the collaboration and have a chance to be trained up and present for first beam and collision. Personally, I wouldn't have minded no coming over here until September, but I'm kind of excited being around for it.


I think it's time for another physics interlude, one a little more relevant to my work. Maybe someday I'll actually explain what I'm working on. Anyway, today's interlude will be about ATLAS and the LHC.

The Large Hadron Collider, or the LHC as it is more commonly known, is a particle physics experiment built to explore very high energies, like what it would have been a fraction of a second after the Big Bang. This is done by colliding very high energy protons together in a 27km circumference tunnel which is located 100m under the French-Swiss border just outside Geneva. Incidentally, this same tunnel housed the LEP (Large Electron-Positron) collider in the 1990s. To bring the protons to the nominal collision energy of 7TeV, a series of linear accelerators and booster rings, and superconducting magnets are used.

ATLAS (which supposedly stands for A Toroidal Large AppartuS which is never used) is one of four major experiments on the LHC ring. The aim of ATLAS is to discover new physics and verify and improve existing measurements. There are three main parts to the ATLAS experiment, the first is the detector. ATLAS is a very impressive piece of equipment. It is cylindrically shaped, 44m long and 22m in diameter and almost every square inch within this huge amount is filled with either active detector or detector services like scaffolding, power and gas lines. The second part is all the computing involved. The LHC is built to have one collision every 25 nanoseconds and computers are used to decide which collisions to store to disk, to convert the electronic signals of the detector into something more understandable and to finally analyse the data. Scientists have developed what is known as the Grid to help them perform all of this computing. The Grid is kind of like the internet, in that it connects computing centres all over the world, but its only use is for science, to produce and analyse data. The third part of the experiment is the physics, which I think I'll leave for another time. Actually, I would say there is also another part to the experiment and that is the politics and administration. The collaboration consists of over 2200 physicists from 170 institutions in 37 countries. There is a lot that has to go on for things to run smoothly. And that's kind of what this week is about, people reporting on what they are doing and people discussing stuff with other people.

Anyway, that's enough about that for now. I will leave you all with the fact that the conference is being held in the Stade de Suisse, which is located at the Wankdorf Centre. *snickers*