7,611 research outputs found
Testrun results from prototype fiber detectors for high rate particle tracking
A fiber detector concept has been realized allowing to registrate particles
within less than 100 nsec with a space point precision of about 0.1 mm at low
occupancy. Three full size prototypes have been build by different producers
and tested at a 3 GeV electron beam at DESY. After 3 m of light guides 8-10
photoelectrons were registrated by multichannel photomultipliers providing an
efficiency of more than 99%. Using all available data a resolution of 0.086 mm
was measured.Comment: 18 pages, 17 figure
DELPHES 3, A modular framework for fast simulation of a generic collider experiment
The version 3.0 of the DELPHES fast-simulation is presented. The goal of
DELPHES is to allow the simulation of a multipurpose detector for
phenomenological studies. The simulation includes a track propagation system
embedded in a magnetic field, electromagnetic and hadron calorimeters, and a
muon identification system. Physics objects that can be used for data analysis
are then reconstructed from the simulated detector response. These include
tracks and calorimeter deposits and high level objects such as isolated
electrons, jets, taus, and missing energy. The new modular approach allows for
greater flexibility in the design of the simulation and reconstruction
sequence. New features such as the particle-flow reconstruction approach,
crucial in the first years of the LHC, and pile-up simulation and mitigation,
which is needed for the simulation of the LHC detectors in the near future,
have also been implemented. The DELPHES framework is not meant to be used for
advanced detector studies, for which more accurate tools are needed. Although
some aspects of DELPHES are hadron collider specific, it is flexible enough to
be adapted to the needs of electron-positron collider experiments.Comment: JHEP 1402 (2014
Genetic Characterization of the Tick-Borne Orbiviruses
The International Committee for Taxonomy of Viruses (ICTV) recognizes four species of tick-borne orbiviruses (TBOs): Chenuda virus, Chobar Gorge virus, Wad Medani virus and Great Island virus (genus Orbivirus, family Reoviridae). Nucleotide (nt) and amino acid (aa) sequence comparisons provide a basis for orbivirus detection and classification, however full genome sequence data were only available for the Great Island virus species. We report representative genome-sequences for the three other TBO species (virus isolates: Chenuda virus (CNUV); Chobar Gorge virus (CGV) and Wad Medani virus (WMV)). Phylogenetic comparisons show that TBOs cluster separately from insect-borne orbiviruses (IBOs). CNUV, CGV, WMV and GIV share low level aa/nt identities with other orbiviruses, in 'conserved' Pol, T2 and T13 proteins/genes, identifying them as four distinct virus-species. The TBO genome segment encoding cell attachment, outer capsid protein 1 (OC1), is approximately half the size of the equivalent segment from insect-borne orbiviruses, helping to explain why tick-borne orbiviruses have a ~1 kb smaller genome
Outsourcing of the New Wave Form Acquisition, Surveillance and Diagnostic System for the LEP Injection Kickers
In 1996, a project has been launched to improve the acquisition, surveillance and diagnostic system of the LEP injection kickers. The technical solution is formed by a VXI acquisition hardware and a Windows NT / LabVIEW software environment. The realisation has been entirely outsourced to industry. This paper discusses the different phases of the project, from market survey over technical specification to acceptance tests, explains the technical choices and evaluates the results, presents the point of view of both parties on the collaboration and concludes with the experiences learned from this project
Generation of unpredictable time series by a Neural Network
A perceptron that learns the opposite of its own output is used to generate a
time series. We analyse properties of the weight vector and the generated
sequence, like the cycle length and the probability distribution of generated
sequences. A remarkable suppression of the autocorrelation function is
explained, and connections to the Bernasconi model are discussed. If a
continuous transfer function is used, the system displays chaotic and
intermittent behaviour, with the product of the learning rate and amplification
as a control parameter.Comment: 11 pages, 14 figures; slightly expanded and clarified, mistakes
corrected; accepted for publication in PR
Radiation Shielding Optimization on Mars
Future space missions to Mars will require radiation shielding to be optimized for deep space transit and an extended stay on the surface. In deep space, increased shielding levels and material optimization will reduce the exposure from most solar particle events (SPE) but are less effective at shielding against galactic cosmic rays (GCR). On the surface, the shielding provided by the Martian atmosphere greatly reduces the exposure from most SPE, and long-term GCR exposure is a primary concern. Previous work has shown that in deep space, additional shielding of common materials such as aluminum or polyethylene does not significantly reduce the GCR exposure. In this work, it is shown that on the Martian surface, almost any amount of aluminum shielding increases exposure levels for humans. The increased exposure levels are attributed to neutron production in the shield and Martian regolith as well as the electromagnetic cascade induced in the Martian atmosphere. This result is significant for optimization of vehicle and shield designs intended for the surface of Mars
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