471 research outputs found

    INITIAL HIGH ELECTRIC FIELD – VACUUM ARC BREAKDOWN TEST RESULTS FOR ADDITIVELY MANUFACTURED PURE COPPER ELECTRODES

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    Additive Manufacturing (AM) is already wellestablished for various manufacturing pplications, providing many benefits such as design freedom, novel and complex cooling designs for the parts and different performance improvements, as well as significantly reducing the production time. With the mentioned characteristics, AM is also being considered as a technology for manufacturing a Radio Frequency Quadrupole (RFQ) prototype. For this application, an important parameter is the voltage holding capability of the surfaces. Furthermore, the voltage holding capability of pure copper surfaces manufactured by AM is of interest for the accelerator community at large for prospective future developments. To characterize these properties, a series of high electric field tests were performed on pure copper electrodes produced by AM, using the CERN pulsed highvoltage DC system. The tests were carried out with AM produced electrodes with large surface roughness. During the testing process, a high vacuum was maintained. The electric breakdown rate was also monitored to ensure not to exceed the breakdown limit of 10ିହ breakdowns per pulse. The achieved results provide the first, initial reference values for the performance of AM built pure copper electrodes for vacuum arc breakdown testing. Initial results prove the capability of AM electrodes to hold a high electric field, while having low breakdown rates. These are crucial results for further AM technology usage for different AM pure-copper accelerator components

    Two-layer laser clad coating as a replacement for chrome electroplating on forged steel

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    Chrome plating is one of many surface engineering techniques used for corrosion resistance, as well as a protective coating against surface damage in load bearing applications, with surface hardness in the region of 1000Hv. Laser cladding is an alternative hardfacing technique often chosen for corrosion resistance and for increasing the surface hardness of components, through thick clad coatings. The application of chrome plating and other similar surface engineering techniques for thick coatings can be inefficient and costly with practical process limitations. The objective of this case study was to investigate the feasibility of replacing the chrome plated layer of a rod mill pinion, made of forged steel, with a Nickel-based Tungsten-Carbide (Ni-WC) composite layer and an intermediate layer of Inconel 625. Mechanical properties were obtained using microhardness and nanoindentation techniques. Three-point bend tests were performed on test specimens from a pinion sample, in order to observe crack propagation resistance, a challenging task due to the curved geometry of the pinion sample and the difference in thickness between the existing and proposed coating layers. Crack development was captured, and plastic deformation was quantified with the use of Digital Image Correlation (DIC). In bending it was found that the bond between the composite coating, Inconel 625 and the steel substrate provided improved resistance to axial crack propagation, where the composite coating could withstand more than twice the bending tool displacement than the chrome electroplating

    EVALUATION OF GREEN LASER SOURCE ADDITIVE MANUFACTURING TECHNOLOGY FOR ACCELERATOR APPLICATIONS WITH ULTRA-HIGH VACUUM REQUIREMENTS

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    Additive Manufacturing (AM) offers different benefits such as efficient material usage, reduced production time and design freedom. Moreover, with continuous technological developments, AM expands in versatility and different material usage capabilities. Recently new energy sources have been developed for AM – green wavelength lasers, which provide better energy absorption for pure copper. Due to high thermal and electrical conductivity of copper, this novel AM technology is highly promising for various industries, particularly, there is a huge interest to use it for accelerator applications. In particular, these AM produced accelerator components should reach the associated Ultra High Vacuum (UHV) requirements. In this study, vacuum membranes of pure copper were produced by AM using a green laser source, in different thicknesses and built angles. Furthermore, a vacuum membrane helium leak tightness test was performed at room temperature by using a high-sensitivity mass spectrometer. Comparison of these test results was performed with previously established results. Through this study, novel knowledge and initial results are provided for green laser source AM technology usage for applications for UHV accelerator components

    A Massive Open Online Course on Particle Accelerators

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    International audienceThe TIARA (Test Infrastructure and Accelerator Research Area) project funded by the European Union 7th framework programme made a survey of provision of education and training in accelerator science in Europe. This survey highlighted the need for more training opportunities targeting undergraduate-level students. This need is now being addressed by the European Union H2020 project ARIES (Accelerator Research and Innovation for European Science and Society) via the preparation of a Massive Online Open Course (MOOC) on particle accelerator science and engineering. We present here the current status of this project, the main elements of the syllabus, how it will be delivered, and the schedule for providing the course

    HE-LHC: The High-Energy Large Hadron Collider – Future Circular Collider Conceptual Design Report Volume 4

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    In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries

    FCC-ee: The Lepton Collider – Future Circular Collider Conceptual Design Report Volume 2

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    FCC-ee: The Lepton Collider: Future Circular Collider Conceptual Design Report Volume 2

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    In response to the 2013 Update of the European Strategy for Particle Physics, the Future Circular Collider (FCC) study was launched, as an international collaboration hosted by CERN. This study covers a highest-luminosity high-energy lepton collider (FCC-ee) and an energy-frontier hadron collider (FCC-hh), which could, successively, be installed in the same 100 km tunnel. The scientific capabilities of the integrated FCC programme would serve the worldwide community throughout the 21st century. The FCC study also investigates an LHC energy upgrade, using FCC-hh technology. This document constitutes the second volume of the FCC Conceptual Design Report, devoted to the electron-positron collider FCC-ee. After summarizing the physics discovery opportunities, it presents the accelerator design, performance reach, a staged operation scenario, the underlying technologies, civil engineering, technical infrastructure, and an implementation plan. FCC-ee can be built with today’s technology. Most of the FCC-ee infrastructure could be reused for FCC-hh. Combining concepts from past and present lepton colliders and adding a few novel elements, the FCC-ee design promises outstandingly high luminosity. This will make the FCC-ee a unique precision instrument to study the heaviest known particles (Z, W and H bosons and the top quark), offering great direct and indirect sensitivity to new physics

    FCC Physics Opportunities: Future Circular Collider Conceptual Design Report Volume 1

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    We review the physics opportunities of the Future Circular Collider, covering its e+e-, pp, ep and heavy ion programmes. We describe the measurement capabilities of each FCC component, addressing the study of electroweak, Higgs and strong interactions, the top quark and flavour, as well as phenomena beyond the Standard Model. We highlight the synergy and complementarity of the different colliders, which will contribute to a uniquely coherent and ambitious research programme, providing an unmatchable combination of precision and sensitivity to new physics

    Study of dijet events with large rapidity separation in proton-proton collisions at s \sqrt{s} = 2.76 TeV

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    The cross sections for inclusive and Mueller-Navelet dijet production are measured as a function of the rapidity separation between the jets in proton-proton collisions at s√ = 2.76 TeV for jets with transverse momentum pT > 35 GeV and rapidity |y| 20 GeV is introduced to improve the sensitivity to the effects of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) evolution. The measurement is compared with the predictions of various Monte Carlo models based on leading-order and next-to-leading-order calculations including the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi leading-logarithm (LL) parton shower as well as the LL BFKL resummation

    HE-LHC: The High-Energy Large Hadron Collider: Future Circular Collider Conceptual Design Report Volume 4

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    In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries
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