Bulletin of the American Physical Society
APS April Meeting 2014
Volume 59, Number 5
Saturday–Tuesday, April 5–8, 2014; Savannah, Georgia
Session X12: Instrumentation & Methods II |
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Sponsoring Units: DPF Chair: Nikos Varelas, University of Illinois at Chicago Room: 100 |
Tuesday, April 8, 2014 10:45AM - 10:57AM |
X12.00001: Beam test of a large-area GEM detector prototype for the upgrade of the CMS muon endcap system Vallary Bhopatkar Gas Electron Multiplier (GEM) technology is being considered for the forward muon upgrade of the CMS experiment in Phase 2 of the CERN LHC. The first such implementation is planned for the GE1/1 system in the 1.5\textless $\left| \eta \right|$\textless 2.2 region of the muon endcap. With precise tracking and fast trigger information, this system can significantly improve the CMS muon trigger as shown previously in simulations. We assembled a 1m full-size prototype of a GE1/1 triple-GEM detector with 3,072 radial readout strips at Florida Tech and tested it in hadron beams at Fermilab in October 2013. Construction of this largest GEM detector type built to-date is briefly described. Strip cluster parameters, detection efficiency, and spatial resolution for charged particles are studied with position and high voltage scans and at different inclination angles. Strip cluster sizes increase with high voltage. We find a plateau detection efficiency of (97.7 $\pm $ 0.2){\%}. All eight eta sectors of the prototype detector show similar high efficiencies. Results of response uniformity and spatial resolution studies using four GEM-based reference tracking detectors will be presented. [Preview Abstract] |
Tuesday, April 8, 2014 10:57AM - 11:09AM |
X12.00002: The ATLAS Hadronic Tau Trigger Elizabeth Caitlin Brost As proton-proton collisions at the LHC reach luminosities close to 10$^{34}$ cm$^{-2}$ s$^{-1}$, the strategies for triggering have become more important than ever for physics analyses. Simplistic single tau lepton triggers suffer from severe rate limitation, despite the sophisticated algorithms used in the tau identification. The development of further fast algorithms and the design of topological selections are the main challenges to allow a large program of physics analysis. The tau triggers provide many opportunities to study new physics beyond the Standard Model, and to get precise measurements of the properties of the Higgs boson decaying to tau-leptons. We present the performance of the hadronic tau trigger taken in Run 1 data with the ATLAS detector at sqrt(s)$=$8TeV p-p collision. One of the major challenges is to sustain high efficiencies in events with multiple interactions. To do this we introduced faster tracking methods, multivariate selection techniques, and new topological criteria in the software trigger. We present measurements of the trigger efficiency using Z to tau tau events as the application to searches for tau tau resonances, such as the Higgs boson searches. We also outline the upgrade plan expected for Run 2 for the 14(13) TeV LHC pp collisions. [Preview Abstract] |
Tuesday, April 8, 2014 11:09AM - 11:21AM |
X12.00003: The Design of an Upgrade to the Level-1 Trigger for the Endcap Muon System of the CMS Experiment Matthew Carver We present a description of a novel track finding algorithm and associated hardware to be implemented as an upgrade to the L1-Trigger of the endcap muon system of the CMS experiment at the LHC in Geneva, Switzerland. To handle the increased luminosity and pile-up expected from the LHC after the current shutdown, the algorithm uses predefined patterns to identify tracks left by muons in the detector at a rate of 40 MHz. If multiple tracks are found they are sorted on the quality of the muon, defined by the number of hit detectors and straightness of the pattern. The track finding logic is pipelined such that the trigger will operate with no deadtime and has an available latency on the order of 1 $\mu s$ to make a decision. The electronics board housing this logic makes use of state-of-the-art field-programmable gate arrays and large memory lookup tables to accomplish its track finding purpose. Preliminary studies on simulated data show roughly 99.5\% efficiency for both single and multiple muon tracks. [Preview Abstract] |
Tuesday, April 8, 2014 11:21AM - 11:33AM |
X12.00004: The Trigger and Data Acquisition System of the ATLAS experiment in preparation for Run 2 Lukas Heinrich After its first shutdown, LHC will provide $pp$ collisions with increased luminosity and energy. In the ATLAS experiment, aimed at recording these collisions, the Trigger and Data Acquisition (TDAQ) system is upgrading to deal with increased event rates. A new trigger strategy is deployed, exploiting new methods and technologies that will further increase robustness and flexibility. The first stage of the trigger, hardware based, will increase the number and complexity of the input signals, while accommodating new hardware for improved performance. The high-level trigger, software based, will become more flexible in operating over both limited regions of the detector, the so-called Regions-of-Interest (RoI), or complete events. Higher rejection power is achieved by incorporating more elements of the offline reconstruction in the trigger. The data-acquisition architecture is simplified, with a single network for automatically balanced distribution of the computing resources and a single node execution of the software selections, to enable further evolution. In this paper, we report on both the design and the status of the development of the new TDAQ system, pointing up performance and possible limitations of the new elements, shown as results of ongoing tests. [Preview Abstract] |
Tuesday, April 8, 2014 11:33AM - 11:45AM |
X12.00005: Phase 1 Upgrade of the CMS Pixel Detector: Module Assembly and Testing Ashish Kumar The CMS pixel detector is the innermost component of the all-silicon tracking system located closest to the interaction point and thus operates in a high-occupancy/high-radiation environment created by particle collisions. The performance of the current pixel detector has been excellent during Run 1 of the LHC. However, the foreseen increases of the instantaneous and integrated luminosities at the LHC necessitate an upgrade of the pixel detector in order to maintain the excellent tracking and physics performance of the CMS detector. The new pixel detector is expected to be installed during the extended end-of-year shutdown in 2016/17. The main new features of the upgraded pixel detector would be ultra-light mechanical design with four barrel layers and three end-caps on either side of the interaction point, digital readout chip with higher rate capability and new cooling system. These and other design improvements, along with the current status on module assembly and testing, will be discussed. [Preview Abstract] |
Tuesday, April 8, 2014 11:45AM - 11:57AM |
X12.00006: CMS Forward Hadron Calorimeters Phase II Upgrade Burak Bilki Phase II Upgrade of the CMS forward hadron calorimeters necessitates from the fact that these calorimeters will not be able to survive the HL-LHC (High Luminosity LHC) conditions. The upgrade path is tentatively divided into two scenarios: The replacement of the active media in the endcap hadron calorimeter section keeping the existing mechanical and electronics structure in place; the construction of a new forward hadron calorimeter system. This talk will discuss various upgrade options based on these two scenarios. Brief explanation of the detector concepts and future test plans will be presented. [Preview Abstract] |
Tuesday, April 8, 2014 11:57AM - 12:09PM |
X12.00007: Novel Cerenkov Detector for Particle Identification Kamuran Dilsiz, Hasan Ogul, Emrah Tiras Particle identification based on Cerenkov radiation has been utilized in many detector systems mostly with ring imaging Cerenkov detectors. Gas Cerenkov detectors have also been instrumented in the Fermilab and CERN test beam lines for beam users. Here we describe a novel, tracking Cerenkov detector constructed with a quartz-based crystal read out with multiple, directly coupled photomultiplier tubes. Upon optimization, the idea can be generalized to particle identification systems in the future collider detector experiments as well as Compton polarimeters. [Preview Abstract] |
Tuesday, April 8, 2014 12:09PM - 12:21PM |
X12.00008: Secondary Emission Ionization Calorimetry R{\&}D Emrah Tiras Secondary Emission (SE) Calorimetry is a new promising technique to measure the electromagnetic showers in extreme radiation environment and very high rate. In this detector type, SE dynode planes are used as the active medium where the SE electrons are generated from these SE surfaces when charged particles penetrate an SE sampling module. Here we report on the response of a dedicated SE sampling module in electromagnetic showers. Projections for a full-scale calorimeter will also be discussed. [Preview Abstract] |
Tuesday, April 8, 2014 12:21PM - 12:33PM |
X12.00009: Beam test results for a large-area GEM detector read out with radial zigzag strips Aiwu Zhang, Vallary Bhopatkar, Marcus Hohlmann, Eric Hansen, Nicholas Lowing, Mike Phipps, Elizabeth Starling, Jessie Twigger, Kimberly Walton The FLYSUB consortium conducted a beam test at the Fermilab Test Beam Facility in October 2013 to study performances of several Gas Electron Multiplier (GEM) prototype detectors that are being considered for forward tracking and particle identification in an experiment at a future Electron Ion Collider (EIC) in the US. Our group operated five GEM tracking detectors with different areas including one of the two largest GEM detectors built and operated in the US to-date. This detector, a trapezoidal 1m-long Triple-GEM with 22-45 cm width, was designed with a readout using radial zigzag strips. This allows a substantial reduction of the total number of strips and electronics channel - and consequently system cost - while preserving good spatial resolution for tracking purposes. The design and manufacturing of the readout board with 1,024 zigzag strips is briefly described. We find that this detector performed well in the beam. The charged-particle detection efficiency is $\sim$ 98{\%}, strip cluster charge distributions closely follow a Landau shape, and measured spatial resolution is $\sim$ 0.5 mm using charge sharing among adjacent zigzag strips with 2.5 mm pitch. We discuss how the details of the interleaving of adjacent zigzag strips could be further improved in a re-designed readout board to get even better spatial resolution. [Preview Abstract] |
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