1,191 research outputs found

    Commissioning of CMS Forward Hadron Calorimeters with Upgraded Multi-anode PMTs and {\mu}TCA Readout

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    The high flux of charged particles interacting with the CMS Forward Hadron Calorimeter PMT windows introduced a significant background for the trigger and offline data analysis. During Long Shutdown 1, all of the original PMTs were replaced with multi-anode, thin window photomultiplier tubes. At the same time, the back-end electronic readout system was upgraded to {\mu}TCA readout. The experience with commissioning and calibration of the Forward Hadron Calorimeter is described as well as the {\mu}TCA system. The upgrade was successful and provided quality data for Run 2 data-analysis at 13 TeV

    SNOWMASS WHITE PAPER - SLHC Endcap 1.4<y<4 Hadron Optical Calorimetry Upgrades in CMS with Applications to NLC/T-LEP, Intensity Frontier, and Beyond

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    Radiation damage in the plastic scintillator and/or readout WLS fibers in the HE endcap calorimeter 1.4<y<4 in the CMS experiment at LHC and SLHC will require remediation after 2018. We describe one alternative using the existing brass absorber in the Endcap calorimeter, to replace the plastic scintillator tiles with BaF2 tiles, or quartz tiles coated with thin(1-5 micron) films of radiation-hard pTerphenyl(pTP) or the fast phosphor ZnO:Ga. These tiles would be read-out by easily replaceable arrays of straight, parallel WLS fibers coupled to clear plastic-cladded quartz fibers of proven radiation resistance. We describe a second alternative with a new absorber matrix extending to 1.4<y<4 in a novel Analog Particle Flow Cerenkov Compensated Calorimeter, using a dual readout of quartz tiles and scintillating (plastic, BaF2, or pTP/ ZnO:Ga thin film coated quartz, or liquid scintillator) tiles, also using easily replaceable arrays of parallel WLS fibers coupled to clear quartz transmitting fibers for readout. An Analog Particle Flow Scintillator-Cerenkov Compensated Calorimeter has application in NLC/T-LEP detectors and Intensity Frontier detectors

    Snowmass White Paper CMS Upgrade: Forward Lepton-Photon System

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    This White Paper outlines a proposal for an upgraded forward region to extend CMS lepton (e, mu) and photon physics reach out to 2.2<eta<5 for LHC and SLHC, which also provides better performance for the existing or new forward hadron calorimetry for jet energy and (eta, phi) measurements, especially under pileup/overlaps at high lumi, as LHC luminosity, energy and radiation damage increases

    Development of Hybrid Resistive Plate Chambers

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    Resistive Plate Chambers (RPCs) are essential active media of large-scale experiments as part of the muon systems and (semi-)digital hadron calorimeters. Among the several outstanding issues associated with the RPCs, the loss of efficiency for the detection of particles when subjected to high particle fluxes, and the limitations associated with the common RPC gases can be listed. In order to address the latter issue, we developed novel RPC designs with special anode plates coated with high secondary electron emission yield materials such as Al2_2O3_3 and TiO2_2. The proof of principle was obtained for various designs and is in progress for the rest. The idea was initiated following the achievements on the development of the novel 1-glass RPCs. Here we report on the construction of various different RPC designs, and their performance measurements in laboratory tests and with particle beams; and discuss the future test plans

    Tests of a Digital Hadron Calorimeter

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    In the context of developing a hadron calorimeter with extremely fine granularity for the application of Particle Flow Algorithms to the measurement of jet energies at a future lepton collider, we report on extensive tests of a small scale prototype calorimeter. The calorimeter contained up to 10 layers of Resistive Plate Chambers (RPCs) with 2560 1 \times 1 cm2 readout pads, interleaved with steel absorber plates. The tests included both long-term Cosmic Ray data taking and measurements in particle beams, where the response to broadband muons and to pions and positrons with energies in the range of 1 - 16 GeV was established. Detailed measurements of the chambers efficiency as function of beam intensity have also been performed using 120 GeV protons at varying intensity. The data are compared to simulations based on GEANT4 and to analytical calculations of the rate limitations

    Total Absorption Dual Readout Calorimetry R&D

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    Abstract This calorimetry R&D focuses on establishing a proof of concept for totally active hadron calorimetry. The research program involves evaluating the performance of the different crystal and glass samples in combination with different light collection and readout alternatives to optimize simultaneous collection of Cerenkov and scintillation light components for application of the Dual Readout technique to total absorption calorimetry. We performed initial studies in two short test beam phases in April and November 2010 at Fermilab. Here we present first measurements from these two beam tests
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