The primary objective of LHC is to answer the following questions:
1. Why some particles are heavier than others? If the Higgs mechanism is valid?
2. If the super-symmetry theory is valid? If yes then if super-symmetric particles exist?
3. If the concept of dark matter and dark energy correct?
4. Why our universe is made up of matter only?
5. What was the state of matter in the early universe?
6. What will be the properties of strongly interacting matter at very high energy density?
To give the answer to these questions and to prove certain hypothesis there are seven detectors installed at LHC's four intersection points named ATLAS , CMS, LHCb, ALICE, TOTEM, MoEDAL and LHCf. In which ATLAS and CMS are general Purpose particle detectors, LHCb and ALICE are specific purpose detectors and others are used for very specific research. The overview of these will be given in following sections. To process huge amount of data from the detectors there is a worldwide LHC's computing grid.
The first LHC run started in 2009 producing energy output 1.18 Tev per beam. Energy increased upto 4 Tev per beam till …show more content…
LAr electromagnetic calorimeter: This is designed to measure the energy of particles which interact via elctromagnetic interactions. To achieve good calorimeter performance the central solenoid and LAr emc is placed in a common vacuum vessel. It consists of two parts: barrel and two end caps placed in cryostat. The barrel consists of two identical half-barrels, seperated by a small gap (4 mm) at interation point. End-caps are further divided into two coaxial wheels: inner and outer. This calorimeter is a lead-LAr detctor having accordian shape (full azimuthal symmetry without cracks) electrodes and lead absorber plates over entire coverage. The thickness of the absorber has been optimised as a function of pseudorapidity (η) in order to get higher energy