Irish researchers get first data in atomic collisions test


THE WORLD’S largest atom smasher has delivered its first information on atomic collisions using an experiment developed by researchers at University College Dublin.

The Irish researchers have been carrying out early tests on the €6 billion Large Hadron Collider (LHC), which is due to be fully switched on next month, firing atomic particles around a 27km circuit at close to the speed of light.

The LHC is based at Cern, the European Organisation for Nuclear Research, on the French-Swiss border.

Installed underground in a 27km-long ring-shaped tunnel, the LHC is designed to send two beams of particles in opposite directions and collide them to release energies comparable to two locomotives colliding head on. The purpose is to recreate the temperatures and conditions seen an instant after the Big Bang that created space-time and our universe.

UCD was central to the testing of the detector, known as Velo and part of a larger experiment called LHCb, and has been involved in its development since 2003, according to Dr Ronan McNulty of the School of Physics and head of UCD’s LHCb team.

Velo watches for the results of particle collisions, when two large particles collide to kick off still smaller particles. Velo tracks the paths taken by these smaller particles in very fine detail.

“When particles are given off then [Velo] can tell you where they went to about one 200th of a millimetre, about a tenth of the thickness of a human hair,” he explained.

Having such information tells the scientists about what kind of particle has been emitted and about its energy and path.

“Velo plays a very important role and is the detector that is closest to the beam, about one or two centimetres away.”

Velo uses 42 of these detectors positioned in pairs and UCD tested about a quarter of them, he said.

The results of this experiment came in last Friday.

Velo is an international collaboration led by the University of Liverpool with participation by Irish, Dutch, Swiss, Scotch and US participants.

University College Cork will be involved in the next version of Velo through its Tyndall National Research Centre.

Ireland is not a member of Cern because the Government has so far been unwilling to pay the fees required for participation in the world’s most important experimental physics centre.

UCD won the right to be involved, however, after long collaboration with group leader at Liverpool, Prof Themis Bowcock.

“The Irish have been deeply involved for the last seven or eight years and were involved in a large range of activities from computing through hardware,” Prof Bowcock said from Cern yesterday.

“It is fantastic to see Irish physicists fully involved in the LHC.”

The next milestone comes on September 10th when a beam is sent right around the 27km circuit. A beam will later be sent around in the opposite direction.

The first collisions caused by these circulating beams is expected to take place before the end of the year.