What is the Atlas particle detector?

The ATLAS experiment is a collaboration of 3000 physicists from over 174 universities and laboratories in 38 countries around the world. Its purpose is to study the basic forces of physical reality in such detail as has never been possible before. At the hub of this collaborative is the ATLAS particle detector; a 45 metre long, 25 metre high, 7,000 ton precision piece of machinery located in a section of the underground collision hall of the Large Hadron Collider (LHC) in Geneva Switzerland.

What does ATLAS do?

ATLAS is an acronym for “A Toroidal LHC Apparatus”, toroidal meaning torus or doughnut shaped. Contrary to popular reports, ATLAS is not a particle accelerator, it is an apparatus positioned within the LHC’s 27km underground accelerator ring. The placement of the apparatus is such that millions of particle collisions take place per second at its centre. It is the largest of six particle detectors on the ring, each run by similar individual collaborations. The detector’s four major components measure the momentum, energy and identity of each new particle produced in the collisions. ATLAS is also capable of bending the path of these particles with its huge system of magnets in order to measure their altered momentum. Of the 1000 million events detected per second, 100 of the most interesting or unusual are analysed, recorded and stored for future study.

ATLAS discoveries

The quest for a unified theory to explain all the forces of the universe has continually expanded the boundaries of physics and cosmology. It is envisaged that the data collected from the ATLAS experiment will blow those boundaries wide apart, filling in many of the missing links that have baffled scientists for so long.

In late 2009, the LHC and ATLAS were powered up for the first time. Two years later, in December 2011, ATLAS detected its first brand new particle chi b(3P) , a boson never before encountered in any particle collider. The discovery of chi b will advance study in the area of the strong nuclear force which holds matter together.

Of particular interest is the discovery by ATLAS in July 2012 of the elusive Higgs boson, a particle theorised for over 50 years, which is believed to exert energy/mass on other matter in the universe. This discovery led to a Nobel Prize being awarded to François Englert and Peter Higgs “for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles”.

In years to come, the great mystery of the universe in all its glory will slowly unravel. From black holes to dark energy, the big bang and extra spatial dimensions, scientists are gradually fitting more pieces into the puzzle. In all probability, the ATLAS experiment will play a major role in advancing and rewriting what is currently known about the physical world we live in.