THE ATLAS EXPERIMENT

1
THE ATLAS EXPERIMENT FCAL3

• at CERNs Large Hadron Collider

2
Why build ATLAS?

• LHC will be completed in 2007
• Two colliding proton beams of 7TeV each for a
  total of 14TeV energy
• Billions upon billions of have been invested
  in this accelerator
• Without ATLAS, this investment would be worthless

3
What is an ATLAS?

• A Toroidal LHC ApparatuS
• One of the five particle detectors to be built at
  CERN for use with the LHC

Nov 17 2005
October 2004
4
What can it do?

• The ATLAS detector was designed as a general
  purpose particle detector
• Wide array of particle energies/types can be
  measured
• FCAL3 is a crucial part of the ATLAS detector

5
Main Duties

• Will also more closely measure the properties of
  the recently (1995) observed top quark. For
  instance it will measure its mass more
  accurately right now it is known to be 174.3 /-
  3.4 GeV/c2

6
Main Duties

• Will be used to probe CP symmetry violations,
  which may help explain the lack of observable
  antimatter in the universe

7
Main Duties

• One of the most eagerly awaited results from
  ATLAS is confirmation of the existence of the
  Higgs Boson
• The Higgs boson occurs in a mechanism in the
  Standard Model (Higgs Mechanism) its discovery
  would help to answer the question, what is mass?

8
Structure

• The detector can be thought to consist of 4
  distinct parts
• The inner detector
• The calorimeters
• The muon spectrometer
• The outer magnet
• FCAL3, is one of the ATLASs many calorimeters,
  whose purpose is to measure particle energy.

Atlas
9
FCAL3

• Stands for Forward CALorimeter 3
• Built by the physics department at Carleton U, in
  collaboration with U of T and University of
  Arizona.
• It will measure the energy of particles produced
  and deflected in the proton-proton collisions
  that will occur at LHC

10
FCAL 3

• Consists of a large hexagonal matrix of copper
  tubes and tungsten rods
• Gaps of 0.375mm are maintained between the rod
  and tube by non-conductive fibre
• The entire assembly is then placed in a chamber
  filled with liquid Argon

11
FCAL3

• Specifically the FCAL3 will detect hadronic
  particles, (i.e.particles which experience the
  strong nuclear force)

12
FCAL3 particle detection

• A large voltage difference is maintained between
  the rod and the tube
• Hadronic particles collide with the large nuclei
  in the copper and tungsten
• Result Hadronic Shower

13
FCAL3 particle detection

• Ions which cross the gap produce a detectable
  current which is measured at the end of the
  tungsten rod.
• The FCAL3 will have thousands of the these copper
  tubes.

14
FCAL3

• Clearly, we get large amounts of data from all
  the collision events(1 million GB/yr).
• Once the data from all parts of the ATLAS device
  is collected it can then be analyzed
• Decay particles are observed and from their
  motion and energy the larger particles that were
  produced can be inferred.

15
FCAL3

• The decay products which are theorized to be
  results of Higgs boson interaction contain mesons
  (quark-antiquark) which are hadrons.
• Thus, FCAL3 will be an crucial tool in the search
  for the elusive god particle

16
References

• Generations of matter
• http//quanta.khu.ac.krgt
• "Combination of CDF and D0 Results on the
  Top-Quark Mass
• http//arxiv.org/abs/hep-ex/0507006
• Various Articles
• http//wikipedia.org
• "Carleton ATLAS Home
• http//www.physics.carleton.ca/research/experiment
  al/atlas/index.html
• "Atlas Collaboration
• http//atlas.web.cern.ch/Atlas/index.html
• "Measurement shows asymmetry in matter and
  antimatter behavior
• www.research.vt.edu
• Atlas
• http//atlas.ch/