Bulletin of the American Physical Society
APS April Meeting 2012
Volume 57, Number 3
Saturday–Tuesday, March 31–April 3 2012; Atlanta, Georgia
Session L9: Instrumentation in High Energy Physics |
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Sponsoring Units: DPF Chair: Marcel Demarteau, Argonne National Laboratory Room: Embassy E |
Sunday, April 1, 2012 3:30PM - 3:42PM |
L9.00001: Radiation Damage Studies of the D0 Silicon Microstrip Tracker SungWoo Youn The Silicon Micro-strip Tracker (SMT) at the D0 experiment at Fermilab (Batavia, IL) has been operated since 2001. An additional silicon layer, referred to as ``Layer 0", was installed within the original innermost SMT layer in 2006 to improve impact parameter resolution and compensate for detector aging due to radiation damage. Various properties of the silicon sensors have been monitored on a regular basis while they were being irradiated through 2011 when the final Tevatron collisions occurred. At the end of 2011, the SMT was warmed from its nominal operating temperature up to 16 C and measurements have been continued for the Layer 0 sensors to monitor annealing effects. We present the results of the radiation damage study and the subsequent annealing study. [Preview Abstract] |
Sunday, April 1, 2012 3:42PM - 3:54PM |
L9.00002: Accurate, low-energy Compton polarimetry for Hall C at Jefferson Lab Donald Jones A new Compton polarimeter has recently been commissioned in Hall C at Jefferson Lab in Newport News, VA, to provide a non-invasive, continuous measurement of electron beam polarization. The new Compton polarimeter is currently measuring electron beam polarization for Qweak, an experiment with a strict error budget allowing a combined statistical and systematic error of only $\pm1\%$ for beam polarization. Using well-established techniques we are able to determine electron beam polarization by measuring the scattering asymmetry of both the backscattered photons and the scattered electrons. Although the photon and electron detectors provide somewhat independent measurements they share the common systematic of the laser polarization. I discuss the optical setup for the photon target used in the Compton polarimeter and recent efforts in reducing systematic error in determination of laser polarization. [Preview Abstract] |
Sunday, April 1, 2012 3:54PM - 4:06PM |
L9.00003: A Fast Hardware Tracker for the ATLAS Trigger System Yangyang Cheng A track reconstruction system being designed for the trigger of the ATLAS detector at the Large Hadron Collider will be described. The Fast Tracker (FTK) is a highly parallel hardware system designed to operate at the full Level-1 trigger output rate. It will provide high-quality tracks reconstructed over the entire inner detector by the start of processing in the Level-2 trigger. The system is based on associative memories for pattern recognition and fast FPGA's for track reconstruction. Recent innovations in system design will be presented as will the expected performance with instantaneous luminosities up to 3x10$^{34}$cm$^{-2}$s$^{-1}$. A FTK vertical slice being installed for the 2012 LHC running will also be described. [Preview Abstract] |
Sunday, April 1, 2012 4:06PM - 4:18PM |
L9.00004: R\&D for the Tracking Detector for the Muon g-2 Experiment at Fermi National Accelerator Laboratory Laura Napierkowski, Mandy Rominsky Fermilab's new muon g-2 experiment is designed to make high-precision measurements of the magnetic moment of the muon in order to test the validity of the Standard Model. It is currently undergoing detector research and development. The tracking detector is made of straw chambers, which consists of a small tube filled with gas and a thin wire running down the center. As the particles we detect move through the gas, they ionize and the current is collected on the wire. We are focusing on testing materials to be used for the straw tube as well as preparing vacuum chambers for testing the prototype. [Preview Abstract] |
Sunday, April 1, 2012 4:18PM - 4:30PM |
L9.00005: A Wavelength-shifting Light Collector for the LBNE Water Cerenkov Far Detector William Johnston, Norm Buchanan The Long-Baseline Neutrino Experiment (LBNE) is a proposed neutrino oscillation experiment designed to look for CP-violation in the neutrino sector, determine the neutrino mass hierarchy, as well as to measure the neutrino mixing angle $\theta_{13}$. In addition, the far detector has the goals of measuring neutrinos from supernovae as well as being able to search for proton decay with sensitivity beyond current limits. A light collection system is being investigated for the proposed 200 kton water Cerenkov far detector. Studies are underway to determine if two different light collector designs will be effective at preserving the physics potential of the detector while enabling large cost savings through a reduction in the number of photomultiplier tubes needed. Measurements and simulations of one light collector design, based on flat wavelength-shifting plates, will be presented. [Preview Abstract] |
Sunday, April 1, 2012 4:30PM - 4:42PM |
L9.00006: Study of pixilated CdZnTe Detectors and Comparison of Data with Simulations Alexander Leder, Thomas Kutter, Jun Miyamoto A search for neutrinoless {\ss}{\ss} decay provides an opportunity to determine whether neutrinos are Majorana particles and promises to determine an effective neutrino mass. Detecting this phenomenon requires very sensitive detectors with good energy resolution and background rejection capabilities. Pixilated CdZnTe detectors offer good energy resolution and allow the reconstruction of charged particle tracks. We studied the performance of a CdZnTe pixelated detector over a wide range of energies using both experimental data and a GEANT4 based simulation of particle interactions inside the detector. By recording signal locations as well as energy deposited per pixel, a linear track reconstruction was used to determine the original particle track. The comparison between simulated and collected data helped to interpret the experimental data. In this presentation we will describe the experimental setup, the simulation and show results of the study. [Preview Abstract] |
Sunday, April 1, 2012 4:42PM - 4:54PM |
L9.00007: Results from the Fermilab Liquid Argon Purity Demonstrator Chad Johnson Liquid Argon Time Projection Chambers (TPCs) show promise for the large detectors needed for future long-baseline neutrino oscillation physics. The TPC detectors require ultra-pure liquid argon with respect to electronegative contaminants such as oxygen and water. This talk describes the 30 ton capacity Liquid Argon Purity Demonstrator (LAPD) constructed at Fermilab. LAPD is designed to show that sufficient purity for electron drift lifetimes of at least 3 ms can be achieved from a non-evacuated environment. Initial purification was achieved by exchanging several vessel volumes of clean, warm argon gas to push out ambient air and to dry out the vessel surfaces. The gas was then recirculated through a filtration system to achieve less than 1 ppm oxygen and water contamination. The vessel was then cooled and filled with LAr. The desired lifetime was achieved after 11 volume exchanges of LAr. [Preview Abstract] |
Sunday, April 1, 2012 4:54PM - 5:06PM |
L9.00008: Multianode Photomultiplier Testing for 2013 CMS Hadronic Forward (HF) Upgrades Garrett Funk, Zhe Jia, Yasar Onel The Hadronic Forward (HF) section of the Compact Muon Solenoid, a detector at the Large Hadron Collider at CERN, will undergo various upgrades in 2013. HF requires photomultiplier tubes (PMTs) to detect the energy signatures of hadronic collisions. The University of Iowa High Energy Physics group is responsible for testing new PMTs for the upgrade. These tests provide seven different operational parameters that will be used for calibration and quality control before installation. The dark current test checks the noise generated by the PMTs at different voltages when there is no light source. The after pulse test measures the degradation of the vacuum chamber of each PMT as it relates to pulse noise. The gain test measures the degree of amplification provided by the PMT. This is the most vital test, as it allows for the reconstruction of the energies observed by the PMT. The surface non-uniformity test checks the active face of the PMTs for signal uniformity and ``hot spot'' sensitivity to light. The timing test observes the PMT's reading and recovery speed. The linearity test measures the tube's output under varying levels of light. The double pulse test checks the linearity of the PMT with two signals occurring 25 nanoseconds apart. [Preview Abstract] |
Sunday, April 1, 2012 5:06PM - 5:18PM |
L9.00009: A Diamond Micro-strip Electron Detector for Compton Polarimetry Amrendra Narayan The Q$_{weak}$ experiment at Jefferson Lab aims to measure the weak charge of the proton with a precision of 4.1\% by measuring the parity violating asymmetry in polarized electron-proton elastic scattering. Beam polarimetry is the largest experimental contribution to the error budget. A new Compton polarimeter was installed in Fall 2010 for a non-invasive and continuous monitoring of the electron beam polarization in Hall C at Jefferson Lab. The Compton-scattered electrons are detected in four planes of diamond micro-strip detectors. This is the first use of diamond micro-strip detectors as a tracking device in a physics experiment. These detectors are read out using custom built electronic modules that include a pre-amplifier, a pulse shaping amplifier and a discriminator for each detector micro-strip. We use Field Programmable Gate Array based general purpose logic modules for event selection and histogramming. This polarimeter is being used for online monitoring of beam polarization in the experiment. We have achieved the design goals of 1\% statistical uncertainity per hour and expect to achieve 1\% systematic uncertainity. We will discuss the details of our polarimetry setup, the analysis approach and the preliminary results. [Preview Abstract] |
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