CMS ECAL Prompt Feedback Group

1. CMS ECAL Prompt Feedback Group Introduction to the ECAL Prompt Feedback Group ECAL Performance with Cosmics Data • The ECAL PFG was formed in early 2008 with the aim of providing a close link between the commissioning, data acquisition, and data quality monitoring teams and the ECAL analysis community Muon Showering in EB & EE TCTH • Throughout 2008, we have commissioned the detector with cosmic ray muon events. We have used the large cosmics dataset to understand problematic channels, debug the DAQ and trigger systems, synchronize ECAL with the rest of CMS, and have even sparked analyses studying photons from muon bremsstrahlung events. TCTV TCLP DT HCAL TAN • The PFG members are in charge of: • Performing fast analyses to check properties of the data and assist with specific goals of technical or physics runs • Diagnosing and characterizing problems when they arise and answering requests from the experts at P5 • Deploying tools to achieve all of the above, in a coherent and documented fashion • Compiling a list of known problems and solutions CMS 146 m EB EE CRUZET4 CRAFT ECAL Occupancy and Timing • The PFG works ~every day: not just during global runs but also during day-to-day ECAL operations Timing (1 Unit =25 ns) ECAL PFG People • We started in March 2008, as a loose collection of ~5 people with a wide range of skills and experiences • Grew by summer 2008 to reach > 20 people, many expert by that time • Now we are ~15 active members with: 40% students, 20% postdocs, 40% more senior members • Many students have started their ECAL work with our group • Have at least one member “on duty” every day that data taking is planned, with increased support during global runs • Each normal working day, we typically had one shifter on duty, with more (~2 to 5) during global running periods BOTTOM TOP BOTTOM TOP • Occupancy (left): higher occupancy in the top/bottom regions and also in EB- region where P5 shaft exists • Timing (right): measured in clock units (25 ns) wrt the settings for collisions; Clusters in the bottom are seen later wrt the top as a result of the time of flightl of the cosmic rays. CRAFT ECAL Energy Spectrum • High Energy Events from  Bremsstrahlung CRUZET event with 290 GeV cluster ECAL Performance with First LHC Beam • In Sep 2008, CMS recorded first LHC beam events. The most interesting events for ECAL were the beam splash events, in which the beam was sent to closed collimators ~150m upstream of CMS. A Brief History: From GRUMM to First Beam Beam Splash Event: ECAL Energy Beam Splash ECAL Energy and Timing • More than 99% of ECAL active • ~200 TeV energy in EB+EE • Data is being used for understanding problematic channels, validation of intercalibration constants, and timing synchronization Timing (1 Unit =25 ns) The Future of the ECAL PFG • Offline Analyses: PFG has sparked several offline studies, as a natural and necessary continuation of prompt observations • ECAL DPG Offline Analyses:Cosmics Analysis, Trigger, Noise/Problematic Channels, Timing, Stability • Data Quality Monitoring: We have worked with the ECAL DQM team to incorporate our studies into the official CMS DQM GUI. • Physics Validation Team: We will work with the new PVT to guarantee good data quality of data and Monte Carlo for physics analysis. • Commissioning Activities: The most important activities of this year are the commissioning of the ECAL endcap trigger and preshower detector, in addition to preparation for first collisions later this year. • Readiness for First Collisions: We have already started developing diagnostic tools for beam data and will continue our preparation to understand the detector with first collisions. Beam Splash Correlations • Correlation between ECAL energy and measurements from beam loss monitors near CMS Toyoko J. Orimoto, California Institute of Technology