6 Calorimetry
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Fig. 6.46 Photograph taken during the assembly of the ATLAS electromagnetic barrel calorimeter. The pre-sampler sectors (in gray) are visible in front of the 16 calorimeter modules
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Fig. 6.47 Inclusive diphoton mass spectrum in ATLAS, from the Higgs discovery paper
the barrel and up to 3% in some pseudorapidity ranges of the end-caps covers the
unavoidable dispersion in materials and in calibration, and the effects of material
in front of the calorimeter not fully described in the simulation. Like for CMS, the
electromagnetic calorimeter of ATLAS fulfilled successfully its task. Among the
most important results, based in particular on the calorimeter data, is the already
mentioned discovery of the Higgs boson in 2012. The corresponding inclusive diphoton spectrum is shown in Fig. 6.47. Also worth mentioning is the contribution of