LHCb VE rtex LO cator For precision measurements of CP-violation at CERN (GENEVE)

1. Si strip detector Read-out electronics Technical Proposal Start Prototyping work Technical Design Report Design Review Start production Installation in the LHCb experimental area 1998 1999 2000 2001 2002 2003 2004 2005 LHCb VErtex LOcator For precision measurements of CP-violation at CERN (GENEVE) HALF of DETECTOR Secondary vacuum container Vacuum vessel Exit foil Vacuum pump Prototype foil of the Secondary vacuum container SILICON MODULE PROJECT DESCRIPTION: Design and production of the Silicon VErtex LOcator for the LHCb experiment at CERN. During collisions of the two proton beams in the 'Large Hadron Collider' (LHC) B-mesons will be produced. The decay of these B-mesons is not invariant under Charge and Parity reversal: they show CP-violation. The B-mesons travel about 7 mm before decaying into other particles. The micro vertex has been designed to do an accurate measurement of the decay position (vertex) of these B-mesons. The VErtex LOcator consists of a row of silicon detectors, each 0.3 mm thick. Charged particles that traverse the silicons generate an electrical charge which can be measured. The silicons are positioned perpendicular to the proton beam at a radial distance of 8 mm from the beam. To be close to the proton proton interaction and with a minimum amount of material in front, the sensors have to be placed in a secondary vacuum box During the filling and ramping of the LHC ring the detectors have to moved out by 30 mm in order to prevent radiation damage. For the actual measurements they have to be moved in again with a position accuracy of 0.05 mm. The whole VErtex LOcator is placed inside the vacuum system. The detectors and the read-out electronics are constructed from radiation hard components. The heat produced by the electronics is taken care of by a cooling system that uses CO2 as refrigerant. The signals from the detector are transported outside the vacuum system for further analysis through 22,000 signal cables. PROJECT GROUPS : NIKHEF, VU (The Netherlands), Liverpool University (UK), CERN, Lausanne University (Switzerland), ASIC lab. University Heidelberg (Germany) LHC-b detector VErtex LOcator VErtex LOcator www.nikhef.nl/pub/experiments/bfys/lhcb/vertex/