Production and commissioning performance tests of the read-out driver boards for the hadronic tile calorimeter of the ATLAS detector at the LHC
The ATLAS hadronic tile calorimeter detector (TileCal) is an iron-scintillating tiles sampling calorimeter designed to operate at the Large Hadron Collider (LHC) accelerator at CERN. The central element of the back-end system of the TileCal detector is a 9U VME read-out driver (ROD) board. The operation of the TileCal calorimeter requires a total of 32 ROD boards. We report here on the overall electrical performance of the ROD boards during their production phase and during their first operation at the ATLAS commissioning setup at CERN. We report also on the real time operation and performance of the ROD digital signal processors (DSPs) on the first cosmic data runs taken at the commissioning setup. The DSP operation is based on the use of optimal filtering algorithms for the signal amplitude, pedestal and time online reconstruction and which, in addition, monitor the quality of the reconstructions
Data acquisition in TileCal/ATLAS experiment. Design of the optical multiplexer board prototype
The optical multiplexer board is one of the elements present in the read out chain of the tile calorimeter in ATLAS experiment. Due to radiation effects, two optical fibers with the same data come out from the front end boards to this board, which has to decide in real time which one carries good data and pass them to the read out driver motherboard for processing. This paper describes the design and tests of the first prototype, implemented as a 6U VME64x slave module, including both hardware and firmware aspects. In this last, algorithms for cyclic redundancy code checking are used to make the decision. Besides, the board may be used as a data injector for testing purposes of the read out driver motherboard
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.