Bulletin of the American Physical Society
APS April Meeting 2010
Volume 55, Number 1
Saturday–Tuesday, February 13–16, 2010; Washington, DC
Session B9: Instrumentation for Particle Physics I |
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Sponsoring Units: DPF Chair: Alice Bean, University of Kansas Room: Maryland A |
Saturday, February 13, 2010 10:45AM - 10:57AM |
B9.00001: Improving the Electron Energy Resolution at CMS Richard Ruiz, Samuel Harper, Kaori Maeshima In the CMS electromagnetic barrel calorimeter an electron deposits most of its energy in three adjacent crystals in $\eta$, with the fraction of the energy in the center crystal dependent on the $\eta$ position of the electron within the central crystal. We report on a technique to estimate the fraction of the electron's energy in the central crystal using the position of the electron as measured by the CMS tracker. We then use the energy fraction estimate to improve the CMS detector's electron energy resolution for cases where not all the energy of the electron was reconstructed, such as electrons close to the intermodule $\eta$ boundaries and highly energetic TeV scale electrons, which saturate the electromagnetic calorimeter readout electronics. [Preview Abstract] |
Saturday, February 13, 2010 10:57AM - 11:09AM |
B9.00002: Uniformity Studies of the ATLAS Electromagnetic Calorimeter using Cosmic Ray Muons R. Caputo The completed Atlas detector was used to record cosmic ray data in the fall of 2008. For the first time, the inner detector, calorimeters and muon systems were used together to identify the cosmic rays. Over 200 million events were recorded using specially designed triggers. We present measurements of the most probable value (MPV) of the energy deposited by cosmic ray muons in the calorimeter. The MPV scales linearly with the path and logarithmically with the incident energy. Several different calorimeter cluster sizes were used to determine which one gave the best combination of unbiased energy measurement and limited noise. We present these studies and use the resulting energy to test the uniformity of the calorimeter response. The upper limit on non-uniformity was observed to be less than 1\% over the given acceptance. [Preview Abstract] |
Saturday, February 13, 2010 11:09AM - 11:21AM |
B9.00003: Systematic effects on photon measurement in ATLAS David Joffe The LAr calorimeter in ATLAS is designed to measure the energy and momenta of electromagnetic particles with very high precision. We summarize the systematics that affect the precision of photon measurements: calibration, noise, material effects, photon conversions and primary vertexing. We then discuss strategies for using early data to improve measurement precision. [Preview Abstract] |
Saturday, February 13, 2010 11:21AM - 11:33AM |
B9.00004: Studies of Electron Trigger and Identification Efficiencies using $Z \to e^{+}e^{-}$\ simulation at the ATLAS Ho Li, Monica Dunford, Young-Kee Kim Events with electrons in the final state are important signatures for many physics topics envisaged at the LHC, including studies of $W$\ and $Z$bosons, top quarks, Higgs bosons, Supersymmetry, $Z^{\prime}$\ bosons, and other new physics processes beyond the standard model. It is therefore crucial to understand and measure the electron trigger efficiencies and identification efficiencies. In this presentation, we show studies of electron trigger and identification efficiencies at the ATLAS experiment using $Z \to e^ {+}e^{-}$\ Monte Carlo simulation events. We present the efficiencies of various electron selection criteria and their dependency on electron energy. We also present the acceptance of $Z \to e^{+}e^{-}$\ events, and the acceptance of $Z^{\prime} \to e^{+}e^{-}$\ events. [Preview Abstract] |
Saturday, February 13, 2010 11:33AM - 11:45AM |
B9.00005: Measuring Electron-Photon Misidentification in the ATLAS Detector Using Z$\rightarrow e^+e^-$ Decay R. Daya, D. Joffe, R. Ishmukhametov, R. Stroynowski The rate at which electrons are misidentified as photons in the ATLAS detector is an essential parameter in many physics analyses. This study proposes a method to measure this rate in early data using Z boson decay. The data-driven method involves examination of Z events identified as decaying in one of three ways: to an electron- positron pair, to an electron or positron plus one photon, or to two photons. Through isolating the number of events in the e$\gamma$ and $\gamma\gamma$ final states that come from misidentified electrons, an overall electron-photon misidentification rate can be extracted. [Preview Abstract] |
Saturday, February 13, 2010 11:45AM - 11:57AM |
B9.00006: ABSTRACT WITHDRAWN |
Saturday, February 13, 2010 11:57AM - 12:09PM |
B9.00007: Study of the Pulse Shapes from the 3-in-1 Cards at ATLAS TileCal Y. Cheng, M. Dunford, Y.K. Kim The ATLAS Tile Calorimeter (TileCal) is designed to measure energy depositions in a single cell from $30$ MeV to $2$ TeV, and we expect to calibrate its response to $1$-$2\%$. We present studies of pulse shapes from the front-end electronics of the TileCal and infer their impact on minimum bias pile-up events, especially at high luminosity. High and low gain signals were obtained from both CERN and the University of Chicago test benches, using both the charge injection system and LED. In our studies, we quantify pulse-shapes and undershoot, measure card-to-card variations, and then compare these pulse shapes to the reference shapes used in ATLAS simulation. By running the TileCal pulse shape reconstruction using both the standard shapes in simulation and the shapes from test bench measurements, we are able to investigate the sensitivity of the reconstruction procedure to differences in pulse shape. [Preview Abstract] |
Saturday, February 13, 2010 12:09PM - 12:21PM |
B9.00008: Studies of TPB dissolved in Toluene Ruel Jerry, Lindley Winslow, Janet Conrad Scintillation light in liquid argon calorimeters is produced at 128 nm. This must be shifted to the visible so that the light can be observed by phototubes. A traditional method for accomplishing this is to dissolve Tetraphenyl butadiene and plastic into toluene, and then use this mixture to coat surfaces. After the toluene evaporates, the TPB in the thin plastic skin will shift the light. In both the WARP and MicroBooNE experiments, it has been observed that impure TPB will react with Toluene when exposed to light turning the mixture green. We report on this effect in this talk. [Preview Abstract] |
Saturday, February 13, 2010 12:21PM - 12:33PM |
B9.00009: Electronics for a Liquid Scintillator Neutrino Detector Erica Caden, Charles Lane Double Chooz is a neutrino oscillation experiment with a two detector design located in Chooz, France. We have developed and tested a new electronics system to be used for the experiment. The electronics needed to read our signals must amplify PMT signals and send them to be digitized, handle muons that cause dead time in our detector, provide the trigger with well formed pulses, and monitor the performance of the detector. I will discuss the development and testing of these ``Front End Electronics,'' their integration into the far-detector site, and their performance with the rest of the detector. [Preview Abstract] |
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