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Overview

The LHCb electromagnetic calorimeter (ECAL) uses the ``shashlik'' technology. It is built from individual modules that are made from lead absorber plates inter spaced with scintillator tiles as active material. Wavelength-shifting (WLS) fibers penetrate the lead/scintillator stack through holes, and are readout at the back of the sampling structure by photomultipliers.

Figure 5.9: The electromagnetic calorimeter $3d$-view from behind the detector towards the interaction point. Shown are the three sections of the calorimeter, the ECAL main platform, and the electronics platform with the racks on the top of the calorimeter wall. Around the beam pipe is drawn the inner supporting frame. One of two ECAL platforms is partially moved out.
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The ECAL structure is segmented into three sections with one type of module per section. The lateral dimensions of the three sections are $\pm$970 mm, $\pm$1939 mm and $\pm$3878 mm in x and $\pm$727 mm, $\pm$1212 mm and $\pm$3151 mm in y for the inner, middle and outer section, respectively. All three types of module have an identical square size of 121.2 mm, but differ by the number of readout cells. The ECAL section closest to the beam pipe consists of 167 modules containing 9 cells each, the middle section has 448 modules containing 4 cells each, and the 2688 outer-section modules are made from a single cell. The detector is built in two separate halves from individual modules that are positioned in layers on two movable platforms and fixed to a surrounding frame. A global view of the ECAL structure is shown in Figure 5.9. The ECAL starts at z=12.49 m from the interaction point with a total depth along z of 835 mm. The overall dimension of the active area is x=7.8 m and y=6.3 m. In the following the construction of the ECAL is discussed [4], describing the engineering design of modules, their construction and assembly, and the installation of the ECAL detector in the experimental zone.
next up previous contents
Next: Design of modules Up: The electromagnetic calorimeter Previous: The electromagnetic calorimeter   Contents
Andreas Schopper
2000-09-11