ATLAS Detector Performance in 2012 : Calorimeters

1. ATLAS Detector Performance in 2012 :Calorimeters ATLAS operatedwith an excellent efficiencyduring 2012 data takingperiod, recording an integratedluminosity of 21.6 fb-1 at √s = 8 TeV. The Liquid Argon and TileCalorimetercontributed to this effort by operating with a good data qualityefficiency of 99.1% and 99.6% respectively, as shown by the table on the left. This poster presents the overallstatus, operations, performance and shutdown plans for the calorimeters. Liquid Argon Calorimeter Operations, Performance and Plans • Only 0.06% unusable channels (42 dead/disconnected channels: 23 channels with dead electronics readout, 55 high noise) • Factor of 3 reduction in high voltage trips from 2011 • New HV modules (with independent HV generators) installed in inner radius of electromagnetic endcaps • High voltage modules with improved current reading installed in forward calorimeters for luminosity monitoring • Cooling leak in part of endcap C front-end cooling developed during November 2012: 4 front end boards were turned off, affecting 4.5% of the hadronicendcapC channels and 1.2% of the electromagnetic endcap C channels, fixed end of November • Front end board timing is stable • Online software and monitoring is very stable • Improvements were made in trigger monitoring Overall Status and Performance • Keep LAr in operation with the high voltage off and do regular calibrations with high voltage at 50V to check for shorts • Extract, repair and re‐install 10‐20 front end boards • Improve calibration speed • Update software for online, HV, DCS • Study LAr performance in 4 sample mode • Installation of demonstratorfor the Phase-I upgrade of the L1 calo trigger for higher granularity readout in LAr • On the front end crates, install 46 new low voltage power supplies (12 already installed) • LAris ready for 100KHz as shown by September 2012 tests. LArran in 4 sample mode with 0% busy Data Quality and Physics 2013-2014 Shutdown Plans • 0.46% Loss from HV trips (data is recoverable when HV is ramping, but data during trip is lost) • Time evolution of data rejection due to high voltage trips is shown below • Proportion of channels above 3σ(electronic noise) improves after vetos • LAr operated with good data quality efficiency of 99.1% in 2012 data taking • 0.3% Loss from noise bursts (flagged at the trigger level) • Example of typical noise burst in electromagnetic endcap shown below • LAr has demonstrated good energy response stability with increasing pileup in the 2012 data as show below Tile Calorimeter Operations, Performance and Plans 12 Detector Status in 2012-2013 Data Stability of the Calibration Systems 2013-2014 Shutdown Plans • The observed drifts in Cesium decay is attributed mostly to a variation of the photomultiplier response and not to the scintillator degradation from irradiation, except for the gap & crack cells. • Down-drift is observed when beam is on, up-drift when beam is off and during heavy ion run. • Cells re-calibration is done periodically to keep electromagnetic scale to a level of <1% precision. • Tile operated with good data quality efficiency of 99.6% in 2012 data taking. • At the end of 2013 run, 2.9% of the cells were flagged as bad in Tile. The improvement of detector stability with respect to 2011 data-taking was largely attributed to the installation of the new LVPS in 45 of the 256 phi-wedges during the end of 2011 maintenance. • Install new LVPS • Drawer consolidation (connectors, flex foils,...) • Standard maintenance (repair a few % of channels) • Install 16 missing crack scintillators (after disconnecting MBTS) • Consolidate cesium calibration (new hydraulic system) • Install new laser calibration system • Improve DAQ, DCS, monitoring, DQ, calibration, & software tools • Install first demonstrator in spring 2014, full replacement of electronics planned ~ 2022. • The response of TileCal cells is monitored periodically with a 137-Cesium radioactive source and a Laser calibration systems that monitors respectively the scintillator and photomultiplier chain. • The similar response behavior in both systems indicates that the scintillators irradiation was negligible in 2012. Performance of New Low Voltage Power Supplies (LVPS) • The new production also benefits from a lower electronic noise. The average cell noise is decreased by 13% and the noise distribution is more Gaussian. • Full production of the new LVPS will be installed during 2013-2014 long shutdown (LS1). • During the winter 2011-2012 maintenance, 40 new LVPS were installed in the detector. These LVPS were mostly in the long barrels where most of the LVPS trips occur. • Only one of the 40 new LVPS tripped in 2012. Nikolina Ilic and Ki Lie, for the ATLAS Collaboration