Bulletin of the American Physical Society
APS April Meeting 2013
Volume 58, Number 4
Saturday–Tuesday, April 13–16, 2013; Denver, Colorado
Session Y11: Instrumentation I |
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Sponsoring Units: DPF Chair: Ron Lipton, Fermi National Accelerator Laboratory Room: Governor's Square 17 |
Tuesday, April 16, 2013 1:30PM - 1:42PM |
Y11.00001: Track-based alignment of the CMS Muon System Austin Schneider, Vadim Khotilovich, Yuriy Pakhotin, Alexei Safonov, Aysen Tatarinov The Muon system of the Compact Muon Solenoid (CMS) Detector at the Large Hadron Collider (LHC) is comprised of 250 Drift Tube (DT) and 468 Cathode Strip (CSC) Chambers. These detectors identify muons, provide a fast muon trigger, and are used to measure muon trajectories. The latter allows improvement of the momentum resolution for highly energetic muons compared to resolutions obtained with the central CMS silicon tracker alone. Performance of the Muon system depends on precise knowledge of the positions of each of the muon tracking elements within the CMS detector. We describe the techniques used to align the Muon system elements with high precision and quantify the accuracy of the alignment procedure. The current baseline algorithm provides an in-situ alignment of the system using tracks from the pp collision data. We particularly emphasize the software environment design and tools built to measure and validate positions of the muon detectors. [Preview Abstract] |
Tuesday, April 16, 2013 1:42PM - 1:54PM |
Y11.00002: Testbeam and laboratory characterization of 3D CMS pixel sensors Mayur Bubna, Alex Krzwyda, Enver Alagoz, Daniela Bortoletto Future generations of colliders, like High Luminosity Large Hadron Collider (HL-LHC) at CERN will deliver much higher radiation doses to the particle detectors, specifically those closer to the beam line. Inner tracker detectors will be the most affected part, causing increased occupancy and radiation damage to Silicon detectors. Planar Silicon sensors have not shown enough radiation hardness for the innermost layers where the radiation doses can reach values around 10$^{16}$ neq/cm$^2$. As a possible replacement of planar pixel sensors, 3D Silicon technology is under consideration as they show higher radiation hardness, and efficiencies comparable to planar sensors. Several 3D CMS pixel designs were fabricated at FBK, CNM, and SINTEF. They were bump bonded to the CMS pixel readout chip and characterized in the laboratory using radioactive source (Sr90), and at Fermilab MTEST beam test facility. Sensors were also irradiated with 800 MeV protons at Los Alamos National Lab to study post-irradiation behavior. In addition, several diodes and test structures from FBK were studied before and after irradiation. We report the laboratory and testbeam measurement results for the irradiated 3D devices. [Preview Abstract] |
Tuesday, April 16, 2013 1:54PM - 2:06PM |
Y11.00003: Performance of the ATLAS Tile Calorimeter Stephe Cole The Tile Calorimeter is the central section ($0 < |\eta| < 1.7$) of the ATLAS hadronic calorimeter. It is a key detector for the measurement of hadrons, jets, tau leptons decaying hadronically, and missing transverse energy. Because of its very good signal to noise ratio it is also useful for the identification and reconstruction of muons. The calorimeter consists of thin steel plates and 460,000 scintillating tiles configured into 4900 cells, each viewed by two photomultipliers. The calorimeter response is monitored to better than 1\% using radioactive source, laser, and electronic charge injection systems. The calibration and performance of the calorimeter have been established through test beam measurements, cosmic ray muons and the large sample of pp collisions acquired during 2011 and 2012. Results on the calorimeter performance will be presented, including the absolute energy scale, time resolution, and associated stabilities. These results demonstrate that the Tile Calorimeter is performing well within the design requirements and is giving essential input to the physics results. [Preview Abstract] |
Tuesday, April 16, 2013 2:06PM - 2:18PM |
Y11.00004: CMS HCAL Endcap Simulations for the High Luminosity LHC Kevin Pedro The long-term high luminosity upgrade to the LHC will increase the levels of radiation affecting the CMS calorimeters. By the end of Phase 2, parts of the electromagnetic and hadronic endcap calorimeters could receive up to 10 MRad of radiation. A model of the radiation damage to HCAL, which has been implemented in the CMS fast simulation, will be described. The effects of radiation on physics capabilities with jets will be presented, with the most important effect coming from scaling of photodetector noise due to recalibration. In addition, a standalone Geant4 simulation with a simplified geometry can be used to test configurations with new radiation-hard ECALs. Results for pion response and resolution with new configurations will be shown. [Preview Abstract] |
Tuesday, April 16, 2013 2:18PM - 2:30PM |
Y11.00005: A Hardware Track Finder for the ATLAS Trigger System Jeremy Love The existing ATLAS three tier trigger system reduces the event rate from 40~MHz to $\sim$400~Hz, at the LHC design luminosity of 10$^{34}$~cm$^{-2}$~s$^{-1}$. After the upgrades of Long Shutdown 2, the LHC will deliver luminosities beyond the design specification. The increasing luminosity will lead to larger event sizes and will require more sophisticated trigger algorithms to reduce backgrounds and maintain bandwidth limitations. These issues are most difficult to handle for the Level-2 trigger system. The ATLAS Fast TracKer~(FTK) is a hardware trigger designed to operate at the full Level-1 accept rate of 100~KHz and provide high quality tracks to the Level-2 trigger system. FTK performs track reconstruction in custom electronics with massive parallelism of associative memories and FPGAs. An overview of the FTK system design will be presented along with the latest R\&D prototype progress of the individual components. Recent results on the performance impact for important physics areas including b-tagging, lepton isolation, tau-tagging, and primary vertex finding will be shown from ATLAS MC simulation studies for different LHC luminosities. [Preview Abstract] |
Tuesday, April 16, 2013 2:30PM - 2:42PM |
Y11.00006: Optimization of Energy Resolution in the Digital Hadron Calorimeter using Longitudinal Weights J.R. Smith, B. Bilki, K. Francis, J. Repond, J. Schlereth, L. Xia Physics at a future lepton collider requires unprecedented jet energy and dijet mass resolutions. Particle Flow Algorithms (PFAs) have been proposed to achieve these. PFAs measure particles in a jet individually with the detector subsystem providing the best resolution. For this to work a calorimeter system with very high granularity is required. A prototype Digital Hadron Calorimeter (the DHCAL) based on the Resistive Plate Chamber (RPC) technology with a record count of readout channels has been developed, constructed, and exposed to particle beams. In this context, we report on a technique to improve the single hadron energy resolution by applying a set of calibration weights to the individual layers of the calorimeter. This weighting procedure was applied to approximately 1 million events in the energy range up to 60 GeV and shows an improvement in the pion energy resolution. Simulated data is used to verify particle identification techniques and to compare with the data. [Preview Abstract] |
Tuesday, April 16, 2013 2:42PM - 2:54PM |
Y11.00007: A Wireless Power and Data Acquisition System for Large Detectors Himansu Sahoo, Patrick De Lurgio, Zelimir Djurcic, Gary Drake, Andrew Kreps, Reza Hashemian, Michael Oberling, Timothy Pearson A new prototype wireless data acquisition system has been developed with the intended application to read-out instrumentation systems having thousands of channels. The data acquisition and control is based on a compliant implementation of 802.11 based hardware and protocols. Our case study is for a large detector containing photomultiplier tubes. The front-end circuitry, including a high-voltage power supply is powered wirelessly thus creating an all-wireless detector readout. The goal of this project is to build a single detector module that operates from wireless power and then sends data wirelessly. The benchmarked performance of the prototype system and how a large scale implementation of the system might be realized will be presented. [Preview Abstract] |
Tuesday, April 16, 2013 2:54PM - 3:06PM |
Y11.00008: Device Engineering of Large Area, High Performance Bi-Alkali Photocathodes for Fast-Timing Applications Junqi Xie, Marcel Demarteau, Henry Frisch, Edward May, Alexander Paramonov, Robert Wagner, Dean Walters The photo-cathodes are devices that convert a photon into free electrons, used in vacuum tubes for detecting photons. With its extremely low dark current and ultra-fast time response, alkali photo-cathodes have been widely used in high energy physics and astrophysics. However, until recently, fundamental understanding of the physics behind the variation of the photo-cathode performance was still limited, which prevents reliable and reproducible production of high performance photo-cathodes. This talk will discuss the development of large area bi-alkali photo-cathode for pico-second detector project. With thorough and careful investigation of several mature growth recipes, critical parameters which may affect the cathode performance were identified and subsequently studied. Optical and electrical measurements clearly reveal the affection of Sb thickness to the overall photo-cathode performance. Based on these studies, large area photo-cathode with high uniformity was achieved. The study also makes it possible for high performance photo-detector development. [Preview Abstract] |
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