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
An analytical approach to the design of electrodes in high-power, fast-transverse-flow CO2 lasers
Abstract Usually, the design of the electrodes of fast-transverse-flow CO 2 lasers relies more on experimental data than on theoretical analysis. Traditional systems sustain a stable, high-power discharge but the current distribution generates a peaked, non-uniform small-signal-gain pattern. We present a theoretical model suitable for the design of electrodes that achieves a quasi uniform gain distribution. The analysis, based on a two-temperature model and the gas-transport equations, computes the electron density that supports a flat gain pattern. Combining the desired electron density with the electron-balance equations, the model determines the required electric field. The results were used to design a new set of electrodes for a home-made fast transverse flow CO 2 laser. A stable, large volume discharge ( 4 × 8 × 90 cm 3 ) with very good uniformity was obtained. The resulting gain distribution was registered in a bi-dimensional map. The peak gain rose from 1.2 m - 1 , attained with the old electrode set, to 1.6 m - 1 with the new one and the gain showed a homogeneous profile.