725 research outputs found

    A 3-D Track-Finding Processor for the CMS Level-1 Muon Trigger

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    We report on the design and test results of a prototype processor for the CMS Level-1 trigger that performs 3-D track reconstruction and measurement from data recorded by the cathode strip chambers of the endcap muon system. The tracking algorithms are written in C++ using a class library we developed that facilitates automatic conversion to Verilog. The code is synthesized into firmware for field-programmable gate-arrays from the Xilinx Virtex-II series. A second-generation prototype has been developed and is currently under test. It performs regional track-finding in a 60 degree azimuthal sector and accepts 3 GB/s of input data synchronously with the 40 MHz beam crossing frequency. The latency of the track-finding algorithms is expected to be 250 ns, including geometrical alignment correction of incoming track segments and a final momentum assignment based on the muon trajectory in the non-uniform magnetic field in the CMS endcaps.Comment: 7 pages, 5 figures, proceedings for the conference on Computing in High Energy and Nuclear Physics, March 24-28 2003, La Jolla, Californi

    New materials for Organic Light-Emitting Diodes

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    We have investigated the performance of a class of heterocycles, 5, 10-dihetera-5,10-dihydroindeno[3,2b]indenes, as hole transport agents in simple double heterostructure organic light-emitting diodes with tris(8-hydroxyquinoline)aluminum (Alq). The best of these materials, 5,10-dihydroindolo[3,2b]indole, yields devices with luminance and lifetimes comparable to those obtained using N,N{prime}-di-(3-methylphenyl)-N,N{prime}diphenyl-4,4{prime}-diaminobiphenyl (TPD) as a hole transporting material

    SUSY Survey with Inclusive Muon and Same-Sign Dimuon Accompanied by Jets and MET with CMS

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    Generic signatures of supersymmetry with R-parity conservation include those of single isolated muons or like-sign isolated dimuon pairs, accompanied with energetic jets and missing transverse energy. The ability of CMS to discover supersymmetry with these signals is estimated for 10 fb^{-1} of data collected with the inclusive single-muon and dimuon High-Level-Trigger paths. The selection criteria are optimized and the systematic effects are studied for a single low-mass benchmark point of the constrained MSSM with m_0 = 60,GeV/c^2, m_{1/2} = 250,GeVc^2, tan beta=10, A_0=0 and mu> 0. Discovery contours in the m_0, m_{1/2}) plane are presented for integrated luminosities ranging from 1 to 100, fb^{-1}

    Probable causes of increasing brucellosis in free-ranging elk of the Greater Yellowstone Ecosystem

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    While many wildlife species are threatened, some populations have recovered from previous Overexploitation, and data linking these population increases with disease dynamics are limited. We present data suggesting that free-ranging elk (Cervus elaphus) are a maintenance host for Brucella abortus in new areas of the Greater Yellowstone Ecosystem (GYE). Brucellosis seroprevalence in free-ranging elk increased from 0-7% in 1991-1992 to 8 20% in 2006-2007 in four of six herd units around the GYE. These levels of brucellosis are comparable to some herd units where elk are artificially aggregated on supplemental feeding grounds. There are several possible mechanisms for this increase that we evaluated using statistical and population modeling approaches. Simulations of an age-structured population model suggest that the observed levels of seroprevalence are unlikely to be sustained by dispersal from supplemental feeding areas with relatively high seroprevalence or an older age structure. Increases in brucellosis seroprevalence and the total elk population size in areas with feeding grounds have not been statistically detectable. Meanwhile, the rate of seroprevalence increase outside the feeding grounds was related to the population size and density of each herd unit. Therefore, the data suggest that enhanced elk-to-elk transmission in free-ranging populations may be occurring due to larger winter elk aggregations. Elk populations inside and outside of the GYE that traditionally did not maintain brucellosis may now be at risk due to recent population increases. In particular, some neighboring populations of Montana elk were 5-9 times larger in 2007 than in the 1970s, with some aggregations comparable to the Wyoming feeding-ground populations. Addressing the unintended consequences of these increasing populations is complicated by limited hunter access to private lands, which places many ungulate populations out of administrative control. Agency-landowner hunting access partnerships and the protection of large predators are two management strategies that may be used to target high ungulate densities in private refuges and reduce the current and future burden of disease

    The CMS Modular Track Finder boards, MTF6 and MTF7

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    To accommodate the increase in energy and luminosity of the upgraded LHC, the CMS Endcap Muon Level 1 Trigger system has to be significantly modified. To provide the best track reconstruction, the Trigger system must now import all available trigger primitives generated by Cathode Strip Chambers and by other regional subsystems, such as Resistive Plate Chambers. In addition to massive input bandwidth, this also requires a significant increase in logic and memory resources. To satisfy these requirements, a new Sector Processor unit for muon track finding is being designed. This unit follows the micro-TCA standard recently adopted by CMS. It consists of three modules. The Core Logic module houses the large FPGA that contains the processing logic and multi-gigabit serial links for data exchange. The Optical module contains optical receivers and transmitters; it communicates with the Core Logic module via a custom backplane section. The Look-Up Table module contains a large amount of low-latency memory that is used to assign the final transverse momentum of the muon candidate tracks. The name of the unit — Modular Track Finder — reflects the modular approach used in the design. Presented here are the details of the hardware design of the prototype unit based on Xilinx's Virtex-6 FPGA family, MTF6, as well as results of the conducted tests. Also presented are plans for the pre-production prototype based on the Virtex-7 FPGA family, MTF7
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