The biggest toy in the world was delivered to physicists at 10:28 in the morning on 10 September 2008. The first beam in the Large Hadron Collider (LHC) at CERN (the European Organization for Nuclear Research) was successfully steered around the full 27 kilometers of the world's most powerful particle accelerator on the Swiss/French border. It is expected that the huge and extremely complex machine will allow scientist to reproduce the conditions following the Big Bang and improve their understanding of subatomic particles.
Deciphering the name, it is clear why it is called Large. Hadron is used in the name because it accelerates hadrons - in this case protons. Since the function of the machine is to accelerate two beams of particles traveling in opposite directions, which collide at four points where the two rings intersect - it is a collider.
There is a lot that can be learned from working on a large particle accelerator. The complete system includes thousands of individual elements that have to be synchronized to under a billionth of a second, and beams finer than a human hair have to be brought into head-on collision.
To get an idea of the LHC, we neet to consider the facts that there are a total of 9300 magnets inside, cooled down to -271.3°C (1.9 K) by the largest cryogenic system in the world. At full power, trillions of protons will race around the ring 11245 times/second, traveling at 0.999999991 times the speed of light. Two beams of protons will each travel at a maximum energy of 7 TeV (tera-electronvolt), corresponding to head-to-head collisions of 14 TeV. To produce all that, the LHC consumes a total of 120 MW electric power provided primarily by the French company EDF.
When two beams of protons collide, they will generate temperatures more than 100000 times hotter than the heart of the Sun, concentrated within a minuscule space.
To sample and record the results of up to 600 million proton collisions/sec, engineers have built gigantic devices that measure particles with micron precision. The trigger system registers the location of the particles to millionths of a meter. Six experiments are installed at the LHC: A Large Ion Collider Experiment (ALICE), ATLAS, the Compact Muon Solenoid (CMS), the Large Hadron Collider beauty (LHCb) experiment, the Large Hadron Collider forward (LHCf) experiment and the TOTal Elastic and diffractive cross section Measurement (TOTEM) experiment.
The data recorded by the experiments at LHC is expected to be about 15 petabytes (15 million gigabytes) of data annually - enough to fill more than 1.7 million dual-layer DVDs. The data analysis will be performed by the Grid - tens of thousands of computers located around the world being used in a distributed computing network.
The LHC will recreate the natural phenomena of cosmic rays and is expected to produce microscopic black holes, as well as different hypothetical particles. The unknowns related to the behavior of the black holes have raised concerns about the safety of the project. Further information on these issues can be found in the Legal Issues section on page 53.