The Experts below are selected from a list of 113526 Experts worldwide ranked by ideXlab platform
J N Hewitt - One of the best experts on this subject based on the ideXlab platform.
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a multipole taylor expansion for the potential of the gravitational lens mg j0414 0534
The Astrophysical Journal, 2000Co-Authors: Catherine S Trotter, Joshua N Winn, J N HewittAbstract:We employ a multipole-Taylor expansion to investigate how tightly the gravitational potential of the quadruple-image lens MG J0414+0534 is constrained by recent VLBI observations. These observations revealed that each of the four images of the background radio source contains four distinct components, thereby providing more numerous and more precise constraints on the lens potential than were previously available. We expand the two-dimensional lens potential using multipoles for the angular coordinate and a modified Taylor series for the radial coordinate. After discussing the physical significance of each term, we compute models of MG J0414+0534 using only VLBI positions as constraints. The best-fit model has both interior and exterior Quadrupole moments, as well as exterior m = 3 and m = 4 multipole moments. The deflector centroid in the models matches the optical galaxy position, and the Quadrupoles are aligned with the optical isophotes. The radial distribution of mass could not be well constrained. We discuss the implications of these models for the deflector mass distribution and for the predicted time delays between lensed components.
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a multipole taylor expansion for the potential of gravitational lens mg j0414 0534
arXiv: Astrophysics, 2000Co-Authors: Catherine S Trotter, Joshua N Winn, J N HewittAbstract:We employ a multipole-Taylor expansion to investigate how tightly the gravitational potential of the quadruple-image lens MG J0414+0534 is constrained by recent VLBI observations. These observations revealed that each of the four images of the background radio source contains four distinct components, thereby providing more numerous and more precise constraints on the lens potential than were previously available. We expand the two-dimensional lens potential using multipoles for the angular coordinate and a modified Taylor series for the radial coordinate. After discussing the physical significance of each term, we compute models of MG J0414+0534 using only VLBI positions as constraints. The best-fit model has both interior and exterior Quadrupole moments as well as exterior m=3 and m=4 multipole moments. The deflector centroid in the models matches the optical galaxy position, and the Quadrupoles are aligned with the optical isophotes. The radial distribution of mass could not be well constrained. We discuss the implications of these models for the deflector mass distribution and for the predicted time delays between lensed components.
Catherine S Trotter - One of the best experts on this subject based on the ideXlab platform.
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a multipole taylor expansion for the potential of the gravitational lens mg j0414 0534
The Astrophysical Journal, 2000Co-Authors: Catherine S Trotter, Joshua N Winn, J N HewittAbstract:We employ a multipole-Taylor expansion to investigate how tightly the gravitational potential of the quadruple-image lens MG J0414+0534 is constrained by recent VLBI observations. These observations revealed that each of the four images of the background radio source contains four distinct components, thereby providing more numerous and more precise constraints on the lens potential than were previously available. We expand the two-dimensional lens potential using multipoles for the angular coordinate and a modified Taylor series for the radial coordinate. After discussing the physical significance of each term, we compute models of MG J0414+0534 using only VLBI positions as constraints. The best-fit model has both interior and exterior Quadrupole moments, as well as exterior m = 3 and m = 4 multipole moments. The deflector centroid in the models matches the optical galaxy position, and the Quadrupoles are aligned with the optical isophotes. The radial distribution of mass could not be well constrained. We discuss the implications of these models for the deflector mass distribution and for the predicted time delays between lensed components.
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a multipole taylor expansion for the potential of gravitational lens mg j0414 0534
arXiv: Astrophysics, 2000Co-Authors: Catherine S Trotter, Joshua N Winn, J N HewittAbstract:We employ a multipole-Taylor expansion to investigate how tightly the gravitational potential of the quadruple-image lens MG J0414+0534 is constrained by recent VLBI observations. These observations revealed that each of the four images of the background radio source contains four distinct components, thereby providing more numerous and more precise constraints on the lens potential than were previously available. We expand the two-dimensional lens potential using multipoles for the angular coordinate and a modified Taylor series for the radial coordinate. After discussing the physical significance of each term, we compute models of MG J0414+0534 using only VLBI positions as constraints. The best-fit model has both interior and exterior Quadrupole moments as well as exterior m=3 and m=4 multipole moments. The deflector centroid in the models matches the optical galaxy position, and the Quadrupoles are aligned with the optical isophotes. The radial distribution of mass could not be well constrained. We discuss the implications of these models for the deflector mass distribution and for the predicted time delays between lensed components.
Joshua N Winn - One of the best experts on this subject based on the ideXlab platform.
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a multipole taylor expansion for the potential of the gravitational lens mg j0414 0534
The Astrophysical Journal, 2000Co-Authors: Catherine S Trotter, Joshua N Winn, J N HewittAbstract:We employ a multipole-Taylor expansion to investigate how tightly the gravitational potential of the quadruple-image lens MG J0414+0534 is constrained by recent VLBI observations. These observations revealed that each of the four images of the background radio source contains four distinct components, thereby providing more numerous and more precise constraints on the lens potential than were previously available. We expand the two-dimensional lens potential using multipoles for the angular coordinate and a modified Taylor series for the radial coordinate. After discussing the physical significance of each term, we compute models of MG J0414+0534 using only VLBI positions as constraints. The best-fit model has both interior and exterior Quadrupole moments, as well as exterior m = 3 and m = 4 multipole moments. The deflector centroid in the models matches the optical galaxy position, and the Quadrupoles are aligned with the optical isophotes. The radial distribution of mass could not be well constrained. We discuss the implications of these models for the deflector mass distribution and for the predicted time delays between lensed components.
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a multipole taylor expansion for the potential of gravitational lens mg j0414 0534
arXiv: Astrophysics, 2000Co-Authors: Catherine S Trotter, Joshua N Winn, J N HewittAbstract:We employ a multipole-Taylor expansion to investigate how tightly the gravitational potential of the quadruple-image lens MG J0414+0534 is constrained by recent VLBI observations. These observations revealed that each of the four images of the background radio source contains four distinct components, thereby providing more numerous and more precise constraints on the lens potential than were previously available. We expand the two-dimensional lens potential using multipoles for the angular coordinate and a modified Taylor series for the radial coordinate. After discussing the physical significance of each term, we compute models of MG J0414+0534 using only VLBI positions as constraints. The best-fit model has both interior and exterior Quadrupole moments as well as exterior m=3 and m=4 multipole moments. The deflector centroid in the models matches the optical galaxy position, and the Quadrupoles are aligned with the optical isophotes. The radial distribution of mass could not be well constrained. We discuss the implications of these models for the deflector mass distribution and for the predicted time delays between lensed components.
Paolo Ferracin - One of the best experts on this subject based on the ideXlab platform.
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summary of test results of mqxfs1 the first short model 150 mm aperture nb3sn Quadrupole for the high luminosity lhc upgrade
IEEE Transactions on Applied Superconductivity, 2018Co-Authors: S Stoynev, R Bossert, J Dimarco, G Ambrosio, D R Dietderich, H Felice, M Anerella, E Cavanna, Daniel Cheng, Paolo FerracinAbstract:The development of Nb3Sn Quadrupole magnets for the High-Luminosity LHC upgrade is a joint venture between the US LHC Accelerator Research Program (LARP)* and CERN with the goal of fabricating large aperture Quadrupoles for the LHC interaction regions (IR). The inner triplet (low-β) NbTi Quadrupoles in the IR will be replaced by the stronger Nb3Sn magnets boosting the LHC program of having 10-fold increase in integrated luminosity after the foreseen upgrades. Previously, LARP conducted successful tests of short and long models with up to 120 mm aperture. The first short 150 mm aperture Quadrupole model MQXFS1 was assembled with coils fabricated by both CERN and LARP. The magnet demonstrated a strong performance at Fermilab's vertical magnet test facility reaching the LHC operating limits. This paper reports the latest results from MQXFS1 tests with changed prestress levels. The overall magnet performance, including quench training and memory, ramp rate, and temperature dependence, is also summarized.
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fabrication of the 7 3 m long coils for the prototype of mqxfb the nb3sn low b Quadrupole magnet for the hilumi lhc
IEEE Transactions on Applied Superconductivity, 2018Co-Authors: Friedrich Lackner, Paolo Ferracin, E Todesco, G Ambrosio, Max Duret, S Triquet, Marc Pozzobon, Sebastien Luzieux, Juan Carlos Perez, C ScheuerleinAbstract:The high-luminosity LHC upgrade target is to increase the integrated luminosity by a factor of 10, resulting in an integrated luminosity of 3000 fb−1. One major improvement foreseen is the reduction of the beam size at the collision points. This requires the development of 150-mm single aperture Quadrupoles for the interaction regions. These Quadrupoles are under development in a joint collaboration between CERN and the US-LHC Accelerator Research Program. The chosen approach for achieving a nominal Quadrupole field gradient of 132.6 T/m is based on the Nb3Sn technology. The coils with a length of 7281 mm will be the longest Nb3Sn coils fabricated so far for accelerator magnets. The production of the long coils was launched in 2016 based on practice coils made from copper. This paper provides a status of the production of the first low grade and full performance coils and describes the production process and applied quality control. Furthermore, an outlook for the prototype assembly is provided.
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performance of the first short model 150 mm aperture nb3sn Quadrupole mqxfs for the high luminosity lhc upgrade
IEEE Transactions on Applied Superconductivity, 2017Co-Authors: G Chlachidze, R Bossert, J Dimarco, G Ambrosio, D R Dietderich, H Felice, M Anerella, E Cavanna, D W Cheng, Paolo FerracinAbstract:The U.S. LHC Accelerator Research Program (LARP) and CERN combined their efforts in developing Nb3Sn magnets for the high-luminosity LHC upgrade. The ultimate goal of this collaboration is to fabricate large aperture Nb 3Sn Quadrupoles for the LHC interaction regions. These magnets will replace the present 70-mm-aperture NbTi Quadrupole triplets for expected increase of the LHC peak luminosity up to 5 × 1034 cm –2s–1 or more. Over the past decade, LARP successfully fabricated and tested short and long models of 90 and 120-mm-aperture Nb3Sn Quadrupoles. Recently, the first short model of 150-mm-diameter Quadrupole MQXFS was built with coils fabricated both by LARP and CERN. The magnet performance was tested at Fermilab's vertical magnet test facility. This paper reports the test results, including the quench training at 1.9 K, ramp rate and temperature dependence, as well as protection heater studies.
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magnet design of the 150 mm aperture low beta Quadrupoles for the high luminosity lhc
IEEE Transactions on Applied Superconductivity, 2014Co-Authors: Paolo Ferracin, R Bossert, F Borgnolutti, G Ambrosio, D R Dietderich, H Felice, M Anerella, D W Cheng, A Ghosh, A GodekeAbstract:The high luminosity LHC (HL-LHC) project is aimed at studying and implementing the necessary changes in the LHC to increase its luminosity by a factor of five. Among the magnets that will be upgraded are the 16 superconducting low-β Quadrupoles placed around the two high luminosity interaction regions (ATLAS and CMS experiments). In the current baseline scenario, these Quadrupole magnets will have to generate a gradient of 140 T/m in a coil aperture of 150 mm. The resulting conductor peak field of more than 12 T will require the use of Nb3Sn superconducting coils. We present in this paper the HL-LHC low-β Quadrupole design, based on the experience gathered by the US LARP program, and, in particular, we describe the support structure components to pre-load the coils, withstand the electro-magnetic forces, provide alignment and LHe containment, and integrate the cold mass in the LHC IRs.
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design studies for the low beta Quadrupoles for the lhc luminosity upgrade
IEEE Transactions on Applied Superconductivity, 2013Co-Authors: E Todesco, Paolo Ferracin, F Borgnolutti, Herve Allain, G Ambrosio, F Cerutti, D R Dietderich, L S Esposito, H Felice, G SabbiAbstract:In this paper, we outline the present status of the design studies for the high-luminosity Large Hadron Collider, focusing on the choice of the aperture of the inner triplet Quadrupoles. After reviewing some critical aspects of the design such as energy deposition, shielding, heat load, and protection, we present the main tentative parameters for building a 150-mm-aperture Nb3Sn Quadrupole, based on the experience gathered by the LARP program in the past several years.
R Bossert - One of the best experts on this subject based on the ideXlab platform.
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summary of test results of mqxfs1 the first short model 150 mm aperture nb3sn Quadrupole for the high luminosity lhc upgrade
IEEE Transactions on Applied Superconductivity, 2018Co-Authors: S Stoynev, R Bossert, J Dimarco, G Ambrosio, D R Dietderich, H Felice, M Anerella, E Cavanna, Daniel Cheng, Paolo FerracinAbstract:The development of Nb3Sn Quadrupole magnets for the High-Luminosity LHC upgrade is a joint venture between the US LHC Accelerator Research Program (LARP)* and CERN with the goal of fabricating large aperture Quadrupoles for the LHC interaction regions (IR). The inner triplet (low-β) NbTi Quadrupoles in the IR will be replaced by the stronger Nb3Sn magnets boosting the LHC program of having 10-fold increase in integrated luminosity after the foreseen upgrades. Previously, LARP conducted successful tests of short and long models with up to 120 mm aperture. The first short 150 mm aperture Quadrupole model MQXFS1 was assembled with coils fabricated by both CERN and LARP. The magnet demonstrated a strong performance at Fermilab's vertical magnet test facility reaching the LHC operating limits. This paper reports the latest results from MQXFS1 tests with changed prestress levels. The overall magnet performance, including quench training and memory, ramp rate, and temperature dependence, is also summarized.
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performance of the first short model 150 mm aperture nb3sn Quadrupole mqxfs for the high luminosity lhc upgrade
IEEE Transactions on Applied Superconductivity, 2017Co-Authors: G Chlachidze, R Bossert, J Dimarco, G Ambrosio, D R Dietderich, H Felice, M Anerella, E Cavanna, D W Cheng, Paolo FerracinAbstract:The U.S. LHC Accelerator Research Program (LARP) and CERN combined their efforts in developing Nb3Sn magnets for the high-luminosity LHC upgrade. The ultimate goal of this collaboration is to fabricate large aperture Nb 3Sn Quadrupoles for the LHC interaction regions. These magnets will replace the present 70-mm-aperture NbTi Quadrupole triplets for expected increase of the LHC peak luminosity up to 5 × 1034 cm –2s–1 or more. Over the past decade, LARP successfully fabricated and tested short and long models of 90 and 120-mm-aperture Nb3Sn Quadrupoles. Recently, the first short model of 150-mm-diameter Quadrupole MQXFS was built with coils fabricated both by LARP and CERN. The magnet performance was tested at Fermilab's vertical magnet test facility. This paper reports the test results, including the quench training at 1.9 K, ramp rate and temperature dependence, as well as protection heater studies.
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magnet design of the 150 mm aperture low beta Quadrupoles for the high luminosity lhc
IEEE Transactions on Applied Superconductivity, 2014Co-Authors: Paolo Ferracin, R Bossert, F Borgnolutti, G Ambrosio, D R Dietderich, H Felice, M Anerella, D W Cheng, A Ghosh, A GodekeAbstract:The high luminosity LHC (HL-LHC) project is aimed at studying and implementing the necessary changes in the LHC to increase its luminosity by a factor of five. Among the magnets that will be upgraded are the 16 superconducting low-β Quadrupoles placed around the two high luminosity interaction regions (ATLAS and CMS experiments). In the current baseline scenario, these Quadrupole magnets will have to generate a gradient of 140 T/m in a coil aperture of 150 mm. The resulting conductor peak field of more than 12 T will require the use of Nb3Sn superconducting coils. We present in this paper the HL-LHC low-β Quadrupole design, based on the experience gathered by the US LARP program, and, in particular, we describe the support structure components to pre-load the coils, withstand the electro-magnetic forces, provide alignment and LHe containment, and integrate the cold mass in the LHC IRs.
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optimization and test of 120 mm larp nb _ 3 sn Quadrupole coils using magnetic mirror structure
IEEE Transactions on Applied Superconductivity, 2012Co-Authors: R Bossert, N Andreev, G Ambrosio, D R Dietderich, M Anerella, E Barzi, S Caspi, G Chlachidze, D W Cheng, H FeliceAbstract:The US-LARP collaboration is developing a new generation of large-aperture high-field Quadrupoles based on Nb Sn superconductor for the LHC upgrades. The development and implementation of this new technology involves the fabrication and testing of series of model magnets, coils and other components with various design and processing features. New 120-mm HQ coils made of Rutherford cable, one with an interlayer resistive core, and both with optimized reaction processes, were fabricated and tested using a Quadrupole mirror structure under operating conditions similar to those in a real magnet. The coils were instrumented with voltage taps and strain gauges to study the mechanical and quench performance. Quench antenna and temperature gauges were installed in the mirror structure to measure the coil temperature and locate quench origins. This paper presents details of the coil design and fabrication procedures, coil assembly and pre-stress in the Quadrupole mirror structure, and coil test results.
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test results of the first 3 7 m long nb3sn Quadrupole by larp and future plans
IEEE Transactions on Applied Superconductivity, 2011Co-Authors: G Ambrosio, R Bossert, N Andreev, M Anerella, E Barzi, B Bingham, D Bocian, S Caspi, G Chlachidize, D R DietderichAbstract:In December 2009 during its first cold test, LQS01, the first Long Nb3Sn Quadrupole made by LARP (LHC Accelerator Research Program, a collaboration of BNL, FNAL, LBNL and SLAC), reached its target field gradient of 200 T/m. This target was set in 2005 by the US Department of Energy, CERN and LARP, as a significant milestone toward the development of Nb3Sn Quadrupoles for possible use in LHC luminosity upgrades. LQS01 is a 90 mm aperture, 3.7 m long Quadrupole using Nb3Sn coils. The coil layout is equal to the layout used in the LARP Technological Quadrupoles (TQC and TQS models). Pre-stress and support are provided by a segmented aluminum shell pre-loaded using bladders and keys, similarly to the TQS models. After the first test the magnet was disassembled, reassembled with an optimized pre-stress, and reached 222 T/m at 4.5 K. In this paper we present the results of both tests and the next steps of the Long Quadrupole R&D.
