Lead tungstate crystal s

1. Elements of the CMS Endcap Electromagnetic Calorimeter A high-resolution crystal calorimeter designed to discover the Higgs Boson Lead tungstate crystals Dense material that stops electrons and photons. Emits scintillation light The endcap calorimeter contains 14648 crystals Vacuum Phototriode (VPT) Detects scintillation light from the crystals. Converts to electrical signals EndcapSupercrystal Mechanical structure supporting a group of 25 crystals and VPTs Carbon Fibre Alveolar – supports fragile crystals and VPTs. VPT Inserts – hold VPTs in place Interface plate: provides structural rigidity to Crystal/VPT/Alveolar unit. Lead tungstate crystals Vacuum Phototriode EndcapSupercrystal Holds 25 crystals and VPTs c) a) f) d) e) b) Elements of an endcapsupercrystal (a) Carbon Fibre alveolar, (b) VPT inserts, (c) Interface plate Also shown: d) Crystal + VPT, e) Optical Fibres, f) High Voltage housing Rear view Showing alveolar, VPT wires emerging through 25 VPT inserts Background image: half of one endcap of the Electromagnetic Calorimeter, consisting of a matrix of 3662 crystals The Endcap Calorimeter Project: International collaboration with project leadership provided by RAL PPD Mechanical design and engineering provided by RAL Technology Department Strong collaboration and partnership with UK Industry