Large Hadron Collider nears completion

By Leon Engelbrecht, ITWeb senior writer

Johannesburg, 09 Nov 2007

Physicists are a step closer to proving some key theories underlying their science, with the completion of another phase of the construction of the Large Hadron Collider (LHC).

This is being done at the European Laboratory for Particle Physics, known by its French acronym CERN (Centre Europ'ean pour la Recherche Nucl'eaire).

South African scientists are involved in the project that will help confirm or deny aspects of the Standard Model of physics, mostly in the field of grid computing. Once operational, the LHC is expected to generate data in the petabyte range.

When activated this coming May, it is hoped the LHC will produce the elusive "Higgs boson", the observation of which could confirm predictions and "missing links" in the Standard Model of physics, and explain how particles acquire properties such as mass.

CERN officials, led by director-general Robert Aymar, this week held a brief ceremony in the French countryside to mark the completion of the construction of the collider, now the world`s largest cryogenic system and most powerful particle accelerator.

The LHC`s cryogenic system - which uses services-orientated architecture provided by Progress Software - has the task of cooling 36 800 tons of material to a temperature of just 1.9 degrees above absolute zero (-271.3^0C), colder than outer space.

To do this, over 10 000 tons of liquid nitrogen and 130 tons of liquid helium will be deployed through a cryogenic system, including over 40 000 leak-tight welds.

This week`s ceremony marked the end of a two-year programme of work to connect all the main dipole and quadrupole magnets in the LHC. This complex task included both electrical and fluid connections.

"This is a huge accomplishment," says Lyn Evans, LHC project leader. "Now that it is done, we can concentrate on getting the machine cold and ready for physics."

Careful testing

The LHC is a circular machine, 27km around and divided into eight sectors, each of which can be cooled down to its operating temperature of 1.9 degrees above absolute zero and powered-up individually.

One sector was cooled down, powered and warmed up in the first half of 2007. This was an important learning process, allowing subsequent sectors to be tested more quickly, says Evans.

"Over the coming months, we`ll be cooling down the remaining sectors," Evans adds. "Five sectors will be cooling by the end of 2007, with the remaining three joining them early next year.

"There is no big red button, and there are inevitable hurdles to be overcome as we bring the LHC into operation," says Aymar. "Every part of the system has to be brought on stream carefully, with each sub-system and component tested and repaired if necessary."

"There have been no show-stoppers so far," adds Evans. "For a machine of this complexity, things are going remarkably smoothly and we`re all looking forward to doing physics with the LHC next summer. If, for any reason, we have to warm up a sector, though," he cautioned, "we`ll be looking at the end of summer rather than the beginning."