LHCb Ring Imaging Cherenkov Research Articles

Pixel readout electronics development for the ALICE pixel vertex and LHCb RICH detector

The ALICE1LHCB pixel readout chip emerged from previous experience at CERN. The RD-19 collaboration provided the basis for the installation of a pixel system in the WA97 and NA57 experiments. Operation in these experiments was key in the understanding of the system issues. In parallel the RD-49 collaboration provided the basis to obtain radiation tolerance in commercial submicron CMOS through special circuit layout. The new ALICE1LHB chip was developed to serve two different applications: particle tracking in the ALICE Silicon Pixel Detector and particle identification in the LHCb Ring Imaging Cherenkov detector. To satisfy the different needs for these two experiments, the chip can be operated in two different modes. In tracking mode all the 50 μm×425 μm pixel cells in the 256×32 array are read out individually, whilst in particle identification mode they are combined in groups of 8 to form a 32×32 array of 400 μm×425 μm cells. The circuit is currently being manufactured in a commercial 0.25 μm CMOS technology.

Performance of a hybrid photon detector prototype with electrostatic cross-focussing and integrated silicon pixel readout for Cherenkov ring detection

We report on the first test beam performance of a hybrid photon detector prototype, using binary readout electronics, intended for use in the ring imaging Cherenkov detectors of the LHCb experiment at the CERN Large Hadron Collider. The photon detector is based on a cross-focussed image intensifier tube geometry. The anode consists of a silicon pixel array bump-bonded to a binary readout chip with matching pixel electronics. The detector has been installed in a quarter-scale prototype vessel of the LHCb ring imaging Cherenkov system. Focussed ring images produced by 120 GeV/c negative pions traversing an air radiator have been recorded. The observed light yield and Cherenkov angle resolution are discussed.

Development of large area hybrid photodiodes for the LHCb ring imaging Cherenkov detectors

We report on the development of large area hybrid photodiodes (HPD) which are one of the proposed photodetectors for the RICH counters of the LHCb experiment. The HPD's consist of a cylindrical vacuum envelope of 127 mm diameter capped with a spherical borosilicate UV-glass entrance window. Focusing electrodes demagnify the image on a silicon detector of 50 mm diameter comprising 2048 pads with a surface of 1 mm/sup 2/ each. The analogue readout electronics is integrated in the vacuum tube. As an intermediate step a HPD with a UV sensitive CsI photocathode has been produced which allowed to verify the electron optics of the HPD. A large UHV evaporation plant for the production of HPD's with visible light transmissive bialkali photocathodes (K/sub 2/CsSb) has been built and successfully operated. The evaporation process is optimized for maximum quantum efficiency and life time of the photocathodes. A cold indium sealing technique developed for a minimum thermal load of the photocathode and the silicon sensor has proven to provide excellent vacuum tightness.

LHC-B ring imaging Cherenkov detector

The progress towards the realisation of the LHC-B Ring Imaging Cherenkov detector is reported.