The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described.

LH C b i s the dedi cated heavy avour experi m ent at the Large H adron C ol l i der at C ER N . T he parti al l y assem bl ed si l i con vertex l ocator (V ELO ) of the LH C b experi m ent has been tested i n a beam test.T he data from thi sbeam testhave been used to determ i ne the perform ance ofthe V ELO al i gnm ent al gori thm .T he rel ati ve al i gnm ent ofthe two si l i con sensors i n a m odul e and the rel ati ve al i gnm ent ofthe m odul es has been extracted.T hi s al i gnm ent i s show n to be accurate at a l evelof approxi m atel y 2 m and 0: 1 m rad for transl ati ons and rotati ons,respecti vel y i n the pl ane of the sensors.A si ngl e hi tpreci si on at norm altrack i nci dence ofabout10 m i s obtai ned forthe sensors. T he al i gnm ent of the system i s show n to be stabl e at better than the 10 m l evel under ai r to vacuum pressure changes and m echani calm ovem ents ofthe assem bl ed system .

No abstract

The LHCb VErtex LOcator (VELO) is a silicon based vertexing sub-detector which has active silicon positioned only 8 mm from the LHC beams and will operate in an extreme (up to 1.3 x 10 14 1 MeV neutron equivalents / cm 2 / year) and non-uniform radiation environment. The complex design of the VELO silicon sensors exploits oxygenated silicon and n + -on-n technology. Research has been carried out into new materials which could significantly extend the lifetime of silicon detectors at the LHC, these would have particular application in a VELO upgrade. Promising new results on the first test beam of a large, high resistivity Czochralski silicon detector with 50 µm pitch and 40 MHz electronics will be presented. The performance was studied before and after irradiation with high energy protons. A signal to noise of over 20 : 1 was obtained from the detector and after a fluence of 4.3 x 10 14 1 MeV neq significant charge collection efficiencies were measured at relatively modest voltages. Studies using the Transient Current Technique probed the electric field within MCz test detectors and proved that MCz silicon does not type invert up until a radiation level of at least 5 x 10 14 24 GeV/c p/cm 2 . This would mean the VELO could replace, in a potential upgrade, n +on-n DOFZ sensors and the complicated processing involved, for standard p + -on-n processing with MCz -if MCz sensors prove to be sufficiently radiation hard.

No abstract