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.

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Abstract. The influence of Cu 7 PS 6 nanoparticles with the average size 117 nm on the dielectric properties of planar oriented nematic liquid crystal 6CB has been investigated within the frequency range 10 1 …106 Hz and at the temperature 293 K. It has been shown that when changing the concentration of nanoparticles within the range 0 to 1 wt.%, the conductivity of the liquid crystal changes stronger than its dielectric permittivity. It has been shown that the electrical conductivity increases monotonously with increasing the concentration of nanoparticles. However, for this dependence a saturation effect is observed. The mechanism of this effect was proposed.

The frequency of dipole relaxation of liquid crystal (LC) layer at LC-solid interface, f r , is shown to be in full correlation with the polar anchoring energy W p ; the increase of W p is accompanied with the decrease of f r . This correlation is established by the use of the aligning polyimide layers treated with different methods. The anchoring energy increases and the relaxation frequency decreases in the following sequence of processes: rubbing-photoalignment-plasma beam alignment. The correlation between W p and f r is an evidence of strong contribution of dipole-to-dipole interaction at the LC-substrate interface to polar anchoring of LC. Based on this correlation new method of polar anchoring measurement can be developed.

The ion adsorption=desorption processes initiated by LC filling in liquid crystal (LC) cells are studied. The LC we used was 5CB and the aligning substrates were UV irradiated polyvinylcinnamate (PVCN) films providing planar alignment of LC. It is shown that intensity of adsorption=desorption processes is strongly determined by purity of LC and irradiation associated parameters, such as exposure dose t exp and time period between irradiation and LC filling t fÀi . To fill the cells we used both 5CB kept in air and 5CB vacuumed at 10 À2 Torr over 1 h. The ion concentration in first portion of LC was estimated to be higher by factor 2 compared with the second one. The cell filling with LC kept in atmosphere is associated with intensive ion adsorption from LC bulk to aligning substrates (when exposure time is zero or when t fÀI > 1h) or with both adsorption and desorption of ions (in case when t fÀi ( 1h). In contrast, cell filling with vacuumed LC mainly initiates ions desorption from the polymer substrates. The latter effect is observed for non-irradiated cells too. This shows that even non-irradiated substrate charges, more likely by adsorption of air ions. The following UV irradiation just increases charging of aligning substrates.

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We examine here photorefractive and dielectric properties of a novel system: nematic liquid crystal mixture doped with 1-(5-methylfuran-2-yl)-3-(4-dimethylaminophenyl)-propenon dye. Kinetics of formation of refractive index gratings induced by light in a two-wave mixing experiment in this dye-doped nematic liquid crystal together with dielectric relaxation and ionic conductivity are investigated. We perform a degenerate four-wave mixing experiment, enabling us to observe the generation of an optical phase conjugation signal by the studied system, and report on some optical microscope observations of hydrodynamic instabilities related to charge injection from the electrodes and ionic current¯ow through liquid crystal layer. We discuss the results in reference to other similar liquid crystalline materials.