Visit to CERN

18 Nov. 2006

Twenty eight MIT club members and friends met at the “Globe of Science and Innovation” (the beautiful, wooden, spherical building offered to CERN by the Swiss Confederation on the occasion of its 50th anniversary – it used to be the “Palais de l’Equilibre” in Neuchatel during Expo 02).

The group was welcomed by our club member and distinguished CERN physicist, Dr. Jean-Pierre Revol, who started by introducing the CERN and its fascinating fundamental research that also drives technological developments as diverse as medical applications and the Internet: the “word wide web” was invented at CERN to allow easy communications between its scientists. Dr. Revol presented the entire zoo of particles and anti-particles that make up matter and the four forces that bind these together. One of the last challenges in filling the gaps in the so-called “standard model” of matter is to confirm experimentally the existence of the Higgs particle: Peter Higgs proposed that the entire space is permeated by a field, similar to the electromagnetic field, and that the various particles appear to have mass as they move through this field. As all fields are associated in quantum physics with particles, there should also be a Higgs particle: the experiments that CERN will conduct in the new accelerator it is building, the Large Hadron Collider or LHC, will hopefully produce the Higgs particle and observe the traces it leaves in its detectors.

The LHC has a 27 km long circular ring – some 8.6 km in diameter – expanding, 100 meters underground, into neighboring France. At the heart of the device two circular beams of protons will travel in opposite directions at almost the speed of light. These extremely energetic beams are crossed at four points, underground, in the middle of huge detectors that catch the showers of particles created by these collisions.

The group could not see the ring and the huge shafts that drop down to the cathedral-size cavities where the four large detectors are located, but had the truly unique opportunity to see and touch one of the detectors, the CMS (the Compact Muon Solenoid) that in spite of being “compact” has a diameter of 15 m, with a length of 20 m and weighs 12’500 tonnes. Indeed the CMS is constructed as several vertical slices above ground; the slices will be lowered into the shaft and assembled as a huge horizontal cylinder underground; from that point on nobody will see them again as the group has, thanks to Dr. Revol. The detector slices, beyond being impressive, are beautiful in size, color, shape, true works of art. The visitor realizes the importance of international collaboration in the LHC project by the multitude of labels with the names of worldwide collaborating laboratories on the equipment. The CMS hardware alone has a price tag of 550 million CHF.

After the CMS visit, the group boarded the bus again (yes, you need a bus to visit the LHC) to visit next the Magnet Testing Laboratory. This is where the LHC superconducting magnets (a couple of thousand of them, each with a price tag of one million CHF) are tested before installation in the ring.

Everything the group has seen was at the limit of the state of the art and beyond. The extremely heavy and large, industrial size of the laboratory equipment contrasted the extreme precision needed and the smallness of what the detectors were built to observe: the microcosm at the heart of matter. In fact, a visit of the CERN “Microcosm” permanent exhibit closed the day.

Dr. Revol was kind enough to guide us and answer questions through the day; we heard first-hand about the challenges that the Laboratory is facing in building this huge LHC project: scientific, technical, organizational, but financial also as support from the member countries diminished at the same time that building of the LHC was approved. Many thanks to Dr. Revol for organizing and so graciously hosting the visit, and to the CERN for its hospitality.