CERN’s Large Hadron Collider
Particle physics does not usually hit world headlines. But in July 2012, physicists at CERN, the European Organization for Nuclear Research near Geneva, achieved what could be billed as the discovery of the century. Using the Large Hadron Collider (LHC) they found the strongest evidence so far to support a major theory of the structure of matter at a sub atomic level.
This most recent success has come after decades of development on the LHC. And over more than fifteen years, Fine Tubes have been developing and supplying high precision stainless steel tubes for the all-important cooling system.
It is an extraordinary breakthrough, pinpointing a sub atomic particle, assumed to be the Higgs boson. They may have isolated one of the most elusive building bricks of the universe, whose existence was predicted by Peter Higgs in 1964 - but whose existence has until now been impossible to demonstrate.
“Fine Tubes as a company are very constructive and open to new challenges - like performing the high sensitivity leak testing of the tubes. They ensure their products are of the highest specification which is vital, as these tubes carry supercritical helium inside the ultra high vacuum in which the particle beams circulate. Even the smallest leakage of Helium into the vacuum would perturb the functioning of the LHC machine.” Nicolaas Kos, Mechanical Engineer, Technology Department, CERN – the European Organization for Nuclear Research.
The Large Hadron Collider (LHC) is a particle accelerator considered to be the most powerful experimental physics apparatus ever built. Using it to smash sub-atomic particles helps scientists to understand more about the origin of the universe. It can be found at CERN’s facility, buried underground on the Franco-Swiss border.
Our present knowledge of particle physics leaves many unanswered questions. Cosmological and astrophysical observations have shown that all of the visible matter in the universe accounts for only 4 per cent of its composition. Physicists are searching for the particles or phenomena responsible for dark matter (23 per cent of the universe) and dark energy (73 per cent). A popular theory is that dark matter is made of neutral - but still undiscovered - supersymmetric particles. It is hoped the LHC will answer many questions about the make-up of the universe. It might prove the existence of dark matter and antimatter, helping determine the origin of mass. The results in July 2012 look set to confirm current thinking about sub atomic particles, in particular by isolating the Higgs boson.
The LHC produces head-on collisions between two beams of particles of the same kind - either protons or lead ions. The beams are created by a chain of accelerators and then injected into the LHC, where they travel through a vacuum comparable to interplanetary space. Superconducting magnets operating at extremely low temperatures guide the beams around the ring.
The technology uses superconducting twin-aperture magnets which operate in a superfluid helium bath at 1.98 degrees Kelvin (equivalent to -271 °C). Superfluid helium has a very high thermal conductivity, which makes it an ideal coolant for the refrigeration and stabilisation of large superconducting systems.
You could say that the central part of the LHC is the world’s largest, coldest fridge. At a temperature colder than deep outer space, it contains iron, steel and the all important superconducting coils. The challenge for Fine Tubes was to supply extremely precise tubular components for the LHC beam vacuum system, capable of withstanding the demanding conditions. The cooling tubes had to be made from a material that could handle the extreme temperatures and pressures involved, while providing high metallurgical cleanliness, very strict leak tightness, and exceptionally low levels of inside and outside diameter halogen contamination.
Fine Tubes started making the first prototypes for CERN in 1995. We manufacture the components using a specially formulated stainless steel which provides high mechanical strength and very low magnetic permeability at cryogenic temperatures.
The cooling tubes are 4.76mm outside diameter with a wall thickness of just 0.53mm. They form part of the Beam Screens, which are inserted into the beam pipes of the collider’s superconducting magnets. These cooling tubes carry a flow of supercritical helium with a temperature between 5 and 20 degrees Kelvin at a pressure of up to 2.6MPa (380 Psi). We supplied a total of 130km of precision tubing for the Large Hadron Collider in straight lengths of up to 15.8m each.
The LHC is now operating and data is successfully being collected and analysed using a worldwide network of computers called The Grid - tens of thousands of computers that help CERN’s scientists process data from the experiments and create a vast global computing resource for the LHC experiments. After the most significant success in July 2012, the teams will be working at replicating the experiments and validating the results using The Grid – and input from the most extraordinary worldwide community of scientists.
CERN announced in December 2012 that the LHC will go into a two year hiatus from March 2013. After completing its first three years of proton runs, the world’s largest particle accelerator will go into hibernation until 2015, as engineers carry out a revamp to help it reach maximum energy levels that could lead to more important discoveries. This break will allow engineers to install 10,000 redesigned superconducting cables that connect between the magnets, vastly improving its capacity to simulate the conditions after the big bang. "It will bring you more collisions. Which means that the more collisions you have, the more likely you are to see rare events," commented James Gillies, chief spokesman for CERN. "The Higgs particle was just one of many on the wish list that we'd like to find, so higher energy increases your discovery potential."
For its last run, the LHC will collide protons with lead ions before the two year shutdown. For more information about the latest developments go to www.cern.ch
CERN, the European Organization for Nuclear Research, was founded in 1954. Based near Geneva, it is the biggest particle physics laboratory in the world and has become a prime example of international collaboration with currently 20 member states contributing. Researching at the frontiers of science, CERN helps to push back the boundaries of technology and the results, in areas from computing to materials science, will have much broader applications. For instance, the World Wide Web was invented at CERN to help particle physicists around the world to communicate.
At present, member states include Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is currently a candidate to enter the collaboration. Cyprus, Israel and Serbia are associate members in the pre-stage to membership. India, Japan, the Russian Federation, the United States of America, Turkey, the European Commission and UNESCO have observer status.