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
Resonant Auger decay study of C1s -> pi* core-excited OCS
The present work aims at characterizing short-lived C1s((-1)) pi*((1)) core-excited states of the OCS molecule based on the analysis of the vibrational fine structure and lineshape profiles of the high-resolution resonant Auger decay spectra recorded at the excitation energies along the C1s -> pi* resonance in the binding energy region 15-19eV. Very different behavior in terms of lineshape and resonant enhancement is observed for the (A) over tilde, (B) over tilde and (C) over tilde final states. This is explained by (1) the variation in the C-O bond lengths for the states involved in the electronic relaxation and (2) different contributions in terms of Mulliken population to the molecular orbitals determining the electronic character of the corresponding states. Since the final-state geometries are known from a number of previous experiments and ab initio calculations, the geometry of the C1s((-1)) pi*((1)) intermediate states can be predicted in analogy with e.g. the N-2, CO2 and N2O molecules. (C) 2009 Elsevier B.V. All rights reserved. (Less)