(Premium) Gist of Science Reporter Magazine: December 2012

Premium - Gist of Science Reporter: December 2012

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Large Hadron Collider

The large Hadron Collider (LHC) was constructed for the purpose of searching for the Higgs Boson. It is the most complex machine that human beings have built until now, and involved thousands of physicists from dozens of countries working for a decade to build and operate. LHC is also the largest apparatus build by man. It is located in a 26-kilometer tunnel, to accelerate two streams of protons in apposite directions and smash them. Two detectors spanning the size of office buildings measure the particles and more than three thousand computers analyze these events in real time.

The cost of constructing the large Hadron Collider was about 4.5 billion USD. Computing power and electricity to run this massive apparatus are not trivial, and their yearly expenditure runs into about 286 million USD and 23.5 million USD respectively. Research expenses costs CERN about 5.5 million USD each year, which is 20% of the full cost of these experiments. Considering that the LHC has been running in the Higgs Boson search since August 2008, the cost of finding the Higgs Boson is pegged at above ten billion USD.

Q. What is a five-sigma result?

Much of science is conducted under the framework of Gaussian or normal distribution. A measurement of a large number of events of any phenomenon yields a bell shaped curve, with the expected value () at the highest point of the curve. The sigma system of classification is simply a categorization based on standard deviations from the expected value. A three-sigma result, which is accepted as “strong evidence” in particle physics, constitutes 99.73% of the normal distribution curve. A five-sigma result, which is standard for new particle discovery, constitutes 99.99994% of the normal distribution curve.

Salient Contributions from India in CMS Experiment

  • Detector R & D in 1990s
  • Study of scintillator material for the electromagnetic detector and design of its granularity
  • Optimization study of tracker detector material and geometry
  • Fabrication of subdetector systems, installation and testing
  • Physics studies for optimization of detector in preparatory stage
  • Software development for detector simulation
  • Studies with test beam and cosmic ray muons
  • Data collection, data quality monitor
  • Understanding of detector performance and possible improvements
  • Calibration of detector
  • Physics analyses and review of collision data leading to publications
  • Several collaboration-wide responsibilities within CMS
  • Representing collaboration in international conferences
  • CMS grid computing via Tier2 centre
  • Detector upgrade for future operational phases of LHC, including R & D

India at CERN

CERN was founded in 1954, is headquartered in the outskirts of Geneva, Switzerland, and extends over the border into France. CERN or Conseil European pour Ia Recherche Nucleaire is the European laboratory for particle physics, its mandate is to carry out front-ranking research in particle physics, a field that delves into the nature of the fundamental constituents of matter and the forces between them. Over its lifetime, CERN has developed and hosted a succession of state-of-the-art accelerators and has been the birthplace and development cradle for related advanced technologies, like particle detectors and computing and information technology.
Indian collaboration with CERN began with scientist-to-scientist and institutional collaborations in the 1960s, evolving into institutional agreements between CERN and Departments of Atomic Energy (DAE) and Science and Technology (DST) of India in the 1960s. Following these agreements, CERN was accorded “Observer” status at CERN. We are standing on the brink of an associate membership status at CERN, signaling even more significant ties particularly in the area of Quark Gluon Plasma research. The Indian investment in LHC activities from 1996 to now is estimated at Rs. 400 crore.

Construction of many components of the LHC was done in Indian industries, and these were tested by our scientists to met stringent specifications. These components include superconducting corrector magnets, precision magnetic positioning system (PMPS) jacks, accelerator protection system, quench detection electronics, vacuum system design for log beam transport lines and cryogenic systems.

Apart from the scientists manpower on the Quick Gluon Plasma experiments conducted on the ALICE detector, we have hardware contributions to the ALICE detector as well. Particularly noteworthy are the MANS chip and Photon Multiplicity Detector (PMD) in the Forward Muon Spectrometer, and more recently the Forward Calorimeter.

Indian scientists have also contributed substantially to the building and operation of the Large Hadron Collider Grid (LCG). A typical heavy operation at CERN generates about 2000 particles, which are observed through 180000 channels and yielding about 10 petabytes (1000000 gigabytes) of data each year. Grids are indispensable to share this data among scientists spread around the world, as well as other computing resources. LCG has a hierarchical structure of data dissemination, of which India hosts two Tier 2 centres at TIFR and Variable Energy Cyclotron Centre (VECC) respectively, in addition to several Tier 3 centres. Scientists of BARC have also developed two software tools for LCG: GRIDVIEW (to visualize functional metrics of the grid) and SHIVA (problem tracking system for software projects.

July 4, 2012 marks an important epoch in the history of science as well as of mankind in unraveling nature’s deep sectors. The major experiments of the Large Hadron Collider (LHC) machine at CERN, ATLAS (A Toroidal Lhc ApparatuS) and CMS (Compact Muon Solenoid) announced the discovery of a particle of mass about 125 GeV (Giga election Volt, roughly the mass of the proton) which is likely to be the hitherto sought after Higgs boson. The discovery marks the beginning of an exciting era in the story of the LHC.


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