580 research outputs found

    Recent Progress of RF Cavity Study at Mucool Test Area

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    In order to develop an RF cavity that is applicable for a muon beam cooling channel, a new facility, called Mucool Test Area (MTA) has been built at Fermilab. MTA is a unique facility whose purpose is to test RF cavities in various conditions. There are 201 and 805 MHz high power sources, a 4-Tesla solenoid magnet, a cryogenic system including a Helium liquifier, an explosion proof apparatus to operate gaseous/liquid Hydrogen, and a beam transport line to send an intense H- beam from the Fermilab Linac accelerator to the MTA hall. Recent activities at MTA will be discussed in this document.Comment: 4 pp. 13th International Workshop on Neutrino Factories, Superbeams and Beta beams (NuFact11) 1-6 Aug 2011: Geneva, Switzerlan

    Accelerator performance analysis of the Fermilab Muon Campus

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    Fermilab is dedicated to hosting world-class experiments in search of new physics that will operate in the coming years. The Muon g-2 Experiment is one such experiment that will determine with unprecedented precision the muon anomalous magnetic moment, which offers an important test of the Standard Model. We describe in this study the accelerator facility that will deliver a muon beam to this experiment. We first present the lattice design that allows for efficient capture, transport, and delivery of polarized muon beams. We then numerically examine its performance by simulating pion production in the target, muon collection by the downstream beam line optics, as well as transport of muon polarization. We finally establish the conditions required for the safe removal of unwanted secondary particles that minimizes contamination of the final beam.Comment: 10 p

    THE CO.TR.I.S SYSTEM: TOWARDS A SMARTER COASTAL TRANSPORT NETWORK FOR SMART ISLANDS

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    The Coastal Transport Information System (Co.Tr.I.S) is a multifunction information system that is developed for the effective design of coastal transportation lines. The system incorporates several subsystems which include the models, tools, and techniques that support the design of improved coastal networks. Co.Tr.I.S main aim is to support any decision making process of the involved players (Ministry, Maritime companies, Local Authorities, Travel Agencies, Passengers, etc) regarding the improvement & the optimal use of a coastal transport network. Co.Tr.I.S data retrieval, analysis, visualization, network design & decision support can accelerate the very slow (currently annual in Aegean) rate of coastal transport network update/upgrade procedures, and, create smarter network implementations that may adapt online on the various demand or requirement changes or updates. Connections, transportation, mobility, as well as port automation are some of the key factors for the “smartification” of entire islands especially in an archipelago like the Aegean Sea. In this work, we present the network design optimization functionality of Co.Tr.I.S, the various optimization stages, the Genetic Algorithm (GA) implementations and its potential to propose a better network design based on each user preferences. A sample case study is given to show its smartness & adaptability to each user needs and, finally, a discussion follows on how it could be complemented by emerging smart technologies for smarter islands

    Dynamics of ripple formation on silicon surfaces by ultrashort laser pulses in sub-ablation conditions

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    An investigation of ultrashort pulsed laser induced surface modification due to conditions that result in a superheated melted liquid layer and material evaporation are considered. To describe the surface modification occurring after cooling and resolidification of the melted layer and understand the underlying physical fundamental mechanisms, a unified model is presented to account for crater and subwavelength ripple formation based on a synergy of electron excitation and capillary waves solidification. The proposed theoretical framework aims to address the laser-material interaction in sub-ablation conditions and thus minimal mass removal in combination with a hydrodynamics-based scenario of the crater creation and ripple formation following surface irradiation with single and multiple pulses, respectively. The development of the periodic structures is attributed to the interference of the incident wave with a surface plasmon wave. Details of the surface morphology attained are elaborated as a function of the imposed conditions and results are tested against experimental data

    Making silicon hydrophobic: wettability control by two-lengthscale simultaneous patterning with femtosecond laser irradiation

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    We report on the wettability properties of silicon surfaces, simultaneously structured on the micrometre-scale and the nanometre-scale by femtosecond (fs) laser irradiation to render silicon hydrophobic. By varying the laser fluence, it was possible to control the wetting properties of a silicon surface through a systematic and reproducible variation of the surface roughness. In particular, the silicon–water contact angle could be increased from 66° to more than 130°. Such behaviour is described by incomplete liquid penetration within the silicon features, still leaving partially trapped air inside. We also show how controllable design and tailoring of the surface microstructures by wettability gradients can drive the motion of the drop's centre of mass towards a desired direction (even upwards)

    Investigation of femtosecond laser induced ripple formation on copper for varying incident angle

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    The hydrodynamic mechanisms associated with the formation of femtosecond laser induced ripples on copper for two angles of incidence are reported. Laser pulse length used for this work is 35 fs. A revised two-temperature model is presented that comprises transient changes of optical characteristics during the irradiation with femtosecond pulses to model relaxation processes and thermal response in bulk copper. The theoretical model takes into account the fluid flow dynamics that result in ripple periods shorter than the wavelength of the surface plasmon polaritons. Theoretical and experimental results are reported for incident angles of 0°and 45° relative to the surface normal. There is agreement between the experimentally measured and the theoretically predicted ripple periodicity for 50 pulses at 0° incidence. By contrast, for 100 pulses at 0° incidence, and 50 and 100 pulses at 45° incidence, the experimentally measured ripples have a larger period than the one predicted by the model while the trends in period with increased incident angle, and increased fluence are in agreement between the experimental and the theoretical results
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