LHCb Calorimeter modules arrive at CERN

The first two of the 56 Hadron Calorimeter (HCAL) modules and 1200 of the 3300 modules of the Electromagnetic Calorimeter (ECAL) have reached CERN from Russia. The third part of the system, the Preshower detector, is still being prepared in Russia. The calorimeter system identifies and triggers on high-energy particles, namely electrons, hadrons and photons by measuring their positions and energies.
The HCAL is going to be a pure trigger device. The ECAL will also be used in the triggering, but in addition it will reconstruct neutral pions and photons from B meson decays. One of the major aims of the LHCb experiment is to study CP violation through B meson decays including Bs mesons with high statistics in different decay modes. CP violation (violation of charge and parity) is necessary to explain why the Universe is mainly made of matter. To spot B meson decays, the trigger system will look for tracks with high transverse energy, originating a few millimetres away from where the proton-proton collision takes place. Every second there will be 40 million bunches of protons crossing each other, so the triggering system and the detectors that provide the information to the trigger have to be really fast.
The ECAL uses the 'shashlik' technology. It is built from individual 12 by 12 square cm large modules, 30 kg each, that are made from lead absorber plates interspaced with scintillator tiles as active material. Wavelength-shifting fibres penetrate the lead/scintillator stack through holes, and are readout at the back of the sampling structure by photomultipliers. There are three types of modules with different number of readout cells. The total number of readout channels amounts to around 6000. ECAL modules are being produced by Russia's Institute for Theoretical and Experimental Physics in collaboration with CERN.
The Hadron Calorimeter with its 1500 readout channels is a sampling device made out of steel and scintillating tiles, as absorber and active material respectively. There are two types of modules with readout cells of different size. Each module is 4.2 metres long, 1.7 metres wide and 26 cm high, with a weight of 10 tonnes. The HCAL tile calorimeter is the responsibility of the Institute of High Energy Physics in Protvino (Russia Federation) with contributions from the Horia Hulubei National Institute for Physics and Nuclear Engineering in Bucharest (Romania), the Institute of Physics and Technologies in Kharkiv (Ukraine) and CERN.
Although many modules still haven't arrived, their production is going really fast: ten ECAL modules are produced every day, and one HCAL module every two weeks. Meanwhile, series production of the Preshower detector is under preparation at the Institute for Nuclear Research Moscow.