Lead tungstate crystalsVacuum Phototriode

Endcap SupercrystalHolds 25 crystals and VPTs

Lead tungstate crystalsDense material that stops electrons and photons. Emits scintillation lightThe endcap calorimeter contains 14648 crystals

Vacuum Phototriode (VPT) Detects scintillation light from the crystals. Converts to electrical signals

Endcap SupercrystalMechanical structure supporting a group of 25 crystals and VPTsa) Carbon Fibre Alveolar – supports

fragile crystals and VPTs.b) VPT Inserts – hold VPTs in placec) Interface plate: provides structural

rigidity to Crystal/VPT/Alveolar unit.

Background image: half of one endcap of the Electromagnetic Calorimeter, consisting of a matrix of 3662 crystals

Elements of the CMS Endcap Electromagnetic CalorimeterA HIGH-RESOLUTION CRYSTAL CALORIMETER DESIGNED TO DISCOVER THE HIGGS BOSON

The Endcap Calorimeter Project:International collaboration with project leadership provided by RAL PPDMechanical design and engineering provided by RAL Technology DepartmentStrong collaboration and partnership with UK Industry

a)

b)

c)

Elements of an endcap supercrystal(a) Carbon Fibre alveolar, (b) VPT inserts, (c) Interface plate

Also shown: d) Crystal + VPT, e) Optical Fibres, f) High Voltage housing

Rear viewShowing alveolar, VPT wires emerging through

25 VPT inserts

d)

e)

f)