The Large Hadron Collider
Precision cooling tubes supplied by Fine Tubes are helping scientists at CERN to understand the nature of our universe.
“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.
Background
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.
Challenges
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.
Solutions
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 110km of precision tubing for the Large Hadron Collider in straight lengths of up to 15.8m each.
Next steps
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. Plans are currently underway for an upgrade to the LHC which will improve the performance of CERN’s accelerator complex. For more information about the latest developments go to www.cern.ch
About CERN
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, and Israel is an associate member.
