ATLAS Experiment CERN

What is ATLAS?

ATLAS is a particle physics experiment at the Large Hadron Collider at CERN. The ATLAS detector is searching for new discoveries in the head-on collisions of protons of extraordinarily high energy. ATLAS will learn about the basic forces that have shaped our Universe since the beginning of time and that will determine its fate. Among the possible unknowns are the origin of mass, extra dimensions of space, microscopic black holes, and evidence for dark matter candidates in the Universe.

ATLAS site
The ATLAS detector

What is the schedule of ATLAS?

ATLAS Schedule

Late 2009 -- Startup of LHC and first event collisions at a total energy of 0.9 TeV and later at 2.36 TeV (above the previous world record).

March 2010 -- Event collisions at a total energy of 7 TeV. This led to about eight months of data taking before a few weeks of heavy ion collisions and the usual winter shutdown. Many papers with early results have come as a result of the 2010 run.

March 2011 -- A year of intensive data taking was followed by a few weeks of heavy ion collisions and a winter shutdown. Event collisions at a total energy of 7 TeV. (Dec. 2011 - Apr. 2012).

April 2012 -- Event collisions at a total energy of 8 TeV. A year of intensive data taking will be followed by a few weeks of heavy ion collisions.

2013 -- A long shutdown to prepare for an increase of the total energy towards 14 TeV.

Next 15-20 years -- Continued data taking with publication of results on an ongoing basis.

ATLAS site
Simulated Higgs event

Who are the 3000 physicists in ATLAS?

ATLAS is a virtual United Nations of 38 countries. In this troubled world, it is inspiring to see people from many lands working together in harmony. International collaboration has been essential to this success. These physicists come from more than 177 universities and laboratories and include 1000 students. ATLAS is one of the largest collaborative efforts ever attempted in the physical sciences.

ATLAS collaboration
ATLAS collaboration

What is the LHC?

The protons are accelerated in opposite directions in the Large Hadron Collider, an underground accelerator ring 27 kilometres in circumference at the CERN Laboratory in Geneva, Switzerland. Crashing together in the center of ATLAS, the particles will produce tiny fireballs of primordial energy. LHC recreates the conditions at the birth of the Universe -- 30 million times a second. Relics of the early Universe not seen since the Universe cooled after the Big Bang 14 billion years ago will spring fleetingly to life again. The LHC is in effect a Big Bang Machine. (Portions of this text are paraphrased from an article written by Dennis Overbye in the New York Times on May 15, 2007, with permission.)

ATLAS site
ATLAS Experiment and LHC

How big is ATLAS?

ATLAS is about 45 meters long, more than 25 meters high, and weighs about 7,000 tons. It is about half as big as the Notre Dame Cathedral in Paris and weighs the same as the Eiffel Tower or a hundred 747 jets (empty).

Notre Dame Cathedral

How much data will be recorded?

If all the data from ATLAS would be recorded, this would fill 100,000 CDs per second. This would create a stack of CDs 450 feet high every second, which would reach to the moon and back twice each year. The data rate is also equivalent to 50 billion telephone calls at the same time. ATLAS actually only records a fraction of the data (those that may show signs of new physics) and that rate is equivalent to 27 CDs per minute.

ATLAS site
Data aquisition

Why is there so much excitement?

We will be re-writing our children's science textbooks, chapter by chapter. This experiment is the culmination of a lifetime of effort, and the excitement is unlike anything we have experienced as scientists. It may well be a monument to mankind.

ATLAS brings experimental physics into new territory. Most exciting is the completely unknown surprise - new processes and particles that would change our understanding of energy and matter.

ATLAS site
Re-writing science

Are students involved?

ATLAS is involving students at many levels - from high school through graduate school. Education is a major component of our work. This research is having a big impact in inspiring young people to study and appreciate science, and then go into many fields using their skills including science, education, industry, finance, and public policy.

ATLAS students