The Experts below are selected from a list of 60138 Experts worldwide ranked by ideXlab platform
Junichi Hasegawa - One of the best experts on this subject based on the ideXlab platform.
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compact and low Loss zro 2 sio 2 plc based 8 8 multicast switch for cdc roadm application
2016Co-Authors: Masanori Takahashi, Shintaro Yamasaki, Yasuyoshi Uchida, Junichi HasegawaAbstract:In this paper, we report design and characteristics of a compact and low-Loss multicast switch (MCS) based on a high Δ planar lightwave circuit (PLC) which consists of ZrO2 doped silica glass. Chip size of an 8 × 8 MCS consists of an eight-arrayed 1 × 8 splitter and an eight-arrayed 8 × 1 switch is reduced to 30 mm × 9 mm by using the ZrO2-SiO2 PLC with 5.5%-Δ. Eight-input and eight-output ports of the MCS are arrayed at the one side of the chip, and coupled to optical fibers with a 16-fiber V-groove array. A high Δ fiber is used to reduce Coupling Loss to the ZrO2-SiO2 PLC, and the high Δ fiber is spliced to a single-mode fiber (SMF) by using low-Loss splicing technique. Coupling Loss between the ZrO2-SiO2 PLC and the SMF is reduced to 0.4 dB/facet. Average insertion Loss of the fabricated MCS is 12.8 dB including Coupling Loss to the SMF. Extinction ratio and polarization dependent Loss of the MCS are over 50 dB and less than 0.5 dB in L-band, respectively.
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compact and low Loss zro 2 sio 2 plc based 8 8 multicast switch for cdc roadm application
2015Co-Authors: Masanori Takahashi, Shintaro Yamasaki, Yasuyoshi Uchida, Junichi HasegawaAbstract:We report a compact 30×9mm2 8×8 multicast switch based on a ZrO 2 -SiO 2 PLC. Low insertion Loss of 12.8dB including Coupling Loss to SMF, low crosstalk less than −50dB, and low polarization dependent Loss of 0.5dB are achieved.
E Ravaioli - One of the best experts on this subject based on the ideXlab platform.
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protecting a full scale nb3sn magnet with cliq the new Coupling Loss induced quench system
2015Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, Vincent Desbiolles, J Feuvrier, Michal Maciejewski, H Bajas, G Sabbi, Arjan VerweijAbstract:A new protection system for superconducting magnets called Coupling-Loss induced quench system (CLIQ) has been recently developed at CERN. Recent tests on Nb-Ti coils have shown that CLIQ is a valid, efficient, and promising method for the protection of high-magnetic-field superconducting magnets. However, the protection of new-generation Nb3Sn accelerator magnets is even more challenging due to the much higher stored energy per unit volume and to the significantly larger enthalpy needed to initiate and propagate a normal zone in such coils. Now, the CLIQ system is tested for the first time on a Nb3Sn magnet in the CERN magnet test facility in order to investigate its performance in practice, thereby validating the method for this type of superconducting magnets as well. Furthermore, we successfully reproduced the electrothermal transients during a CLIQ discharge. Finally, the implementation of various CLIQ-based protection schemes for the full-scale Nb3Sn quadrupole magnet for the LHC high luminosity upgrade is discussed. The impact of key system parameters on CLIQ performance and the advantages and drawbacks of using multiple CLIQ units on a single magnet are discussed.
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towards an optimized Coupling Loss induced quench protection system cliq for quadrupole magnets
2015Co-Authors: E Ravaioli, V Datskov, G Kirby, K A Sperin, Vincent Desbiolles, J Feuvrier, Michal MaciejewskiAbstract:The recently developed Coupling-Loss-Induced Quench (CLIQ) protection system is a new method for initiating a fast and voluminous transition to the normal state for protecting high energy density superconducting magnets. Its simple and robust electrical design, its lower failure rate, and its more efficient energy deposition mechanism make CLIQ often preferable to other conventional quench protection methods. The system is now implemented for the protection of a two meter long superconducting quadrupole model magnet and as such fully characterized in the CERN magnet test facility. Test results convincingly show that CLIQ allows for a more global quench initiation and thus a faster discharge of the magnet energy than conventional quench heaters. Nevertheless, the CLIQ performance is strongly affected by the length of the magnet to protect, hence an optimization is required for effective application to full-size magnets. A series of measures for the optimization of a quench protection system for a quadrupole magnet based on CLIQ is outlined here. The impact of various key parameters on CLIQ’s performance, the most efficient CLIQ configuration, and the advantage of installing multiple CLIQ units are assessed.
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new Coupling Loss induced quench protection system for superconducting accelerator magnets
2014Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, C Giloux, A P VerweijAbstract:A new and promising method for the protection of superconducting high-field magnets is developed and tested on the so-called MQXC quadrupole magnet at the CERN magnet test facility. The method relies on a capacitive discharge system inducing, during a few periods, an oscillation of the transport current in the superconducting cable of the coil. The corresponding fast change of the local magnetic field introduces a high Coupling-current Loss, which, in turn, causes a fast quench of a large fraction of the coil due to enhanced temperature. Results of measured discharges at various levels of transport current are presented and compared to discharges by quenching the coils using conventional quench heaters and an energy extraction system. The hot-spot temperature in the quenching coil is deduced from the coil voltage and current. The results are compared to simulations carried out using a lumped-element dynamic electro-thermal model of the so-called MQXC magnet developed with Cadence PSpice. The calculated voltages and currents are in good agreement with the measured data. Simulation and test results show that this new protection system, called Coupling-Loss induced quench, is a feasible method to reduce the hot-spot temperature in high-field superconducting magnets, even more when used in combination with conventional quench heaters.
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a new hybrid protection system for high field superconducting magnets
2014Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, A P VerweijAbstract:The new generation of high-field superconducting accelerator magnets poses a challenge concerning the protection of the magnet coil in the case of a quench. The very high stored energy per unit volume requires a fast and efficient quench heating system in order to avoid damage due to overheating. A new protection system for superconducting magnets is presented, comprising a combination of a novel Coupling-Loss induced quench (CLIQ) system and conventional quench heaters. CLIQ can provoke a very fast transition to the normal state in coil windings by introducing Coupling Loss and thus heat in the coil's conductor. The advantage of the hybrid protection system is a global transition, resulting in a much faster current decay, a significantly lower hot-spot temperature, and a more homogeneous temperature distribution in the magnet's coil.
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first experience with the new Coupling Loss induced quench system
2014Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, A Dudarev, K A Sperin, A P VerweijAbstract:New-generation high-field superconducting magnets pose a challenge relating to the protection of the coil winding pack in the case of a quench. The high stored energy per unit volume calls for a very efficient quench detection and fast quench propagation in order to avoid damage due to overheating. A new protection system called Coupling-Loss Induced Quench (CLIQ) was recently developed and tested at CERN. This method provokes a fast change in the magnet transport current by means of a capac- itive discharge. The resulting change in the local magnetic field induces inter-filament and inter-strand Coupling Losses which heat up the superconductor and eventually initiate a quench in a large fraction of the coil winding pack. The method is extensively tested on a Nb–Ti single-wire test solenoid magnet in the CERN Cryogenic Lab- oratory in order to assess its performance, optimize its operating parameters, and study new electrical con- figurations. Each parameter is thoroughly analyzed and its impact on the quench efficiency highlighted. Furthermore, an alternative method is also considered, based on a CLIQ discharge through a resistive coil magnetically coupled with the solenoid but external to it. Due to the strong Coupling between the external coil and the magnet, the oscillating current in the external coil changes the magnetic field in the solenoid strands and thus generates Coupling Losses in the strands. Although for a given charging voltage this con- figuration usually yields poorer quench performance than a standard CLIQ discharge, it has the advantage of being electrically insulated from the solenoid coil, and thus it can work with much higher voltage.
Masanori Takahashi - One of the best experts on this subject based on the ideXlab platform.
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compact and low Loss zro 2 sio 2 plc based 8 8 multicast switch for cdc roadm application
2016Co-Authors: Masanori Takahashi, Shintaro Yamasaki, Yasuyoshi Uchida, Junichi HasegawaAbstract:In this paper, we report design and characteristics of a compact and low-Loss multicast switch (MCS) based on a high Δ planar lightwave circuit (PLC) which consists of ZrO2 doped silica glass. Chip size of an 8 × 8 MCS consists of an eight-arrayed 1 × 8 splitter and an eight-arrayed 8 × 1 switch is reduced to 30 mm × 9 mm by using the ZrO2-SiO2 PLC with 5.5%-Δ. Eight-input and eight-output ports of the MCS are arrayed at the one side of the chip, and coupled to optical fibers with a 16-fiber V-groove array. A high Δ fiber is used to reduce Coupling Loss to the ZrO2-SiO2 PLC, and the high Δ fiber is spliced to a single-mode fiber (SMF) by using low-Loss splicing technique. Coupling Loss between the ZrO2-SiO2 PLC and the SMF is reduced to 0.4 dB/facet. Average insertion Loss of the fabricated MCS is 12.8 dB including Coupling Loss to the SMF. Extinction ratio and polarization dependent Loss of the MCS are over 50 dB and less than 0.5 dB in L-band, respectively.
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compact and low Loss zro 2 sio 2 plc based 8 8 multicast switch for cdc roadm application
2015Co-Authors: Masanori Takahashi, Shintaro Yamasaki, Yasuyoshi Uchida, Junichi HasegawaAbstract:We report a compact 30×9mm2 8×8 multicast switch based on a ZrO 2 -SiO 2 PLC. Low insertion Loss of 12.8dB including Coupling Loss to SMF, low crosstalk less than −50dB, and low polarization dependent Loss of 0.5dB are achieved.
H Ten H J Kate - One of the best experts on this subject based on the ideXlab platform.
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measurement and numerical evaluation of ac Losses in a rebco roebel cable at 4 5 k
2016Co-Authors: J Van Nugteren, G Kirby, H Ten H J Kate, B Van Nugteren, P Gao, L Bottura, M Dhalle, W Goldacker, A Kario, E KrooshoopAbstract:EuCARD-2 aims to research ReBCO superconducting magnets for future accelerator applications. The properties of ReBCO conductors are very different from low-temperature superconductors. To investigate dynamic field quality, stability, and normal zone propagation, an electrical network model for coated conductor cables was developed. To validate the model, two identical samples were prepared at CERN, after which measurements were taken at the University of Twente and Southampton University. The model predicts that for a Roebel cable, in a changing magnetic field applied in the perpendicular direction, hysteresis Loss is much larger than Coupling Loss. In the case of a changing magnetic field applied parallel to the cable, Coupling Loss is dominant. In the first case, the experiment is in good agreement with the model. In the second case, the data can only be compared qualitatively because the calibration for the inductive measurement is not available.
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protecting a full scale nb3sn magnet with cliq the new Coupling Loss induced quench system
2015Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, Vincent Desbiolles, J Feuvrier, Michal Maciejewski, H Bajas, G Sabbi, Arjan VerweijAbstract:A new protection system for superconducting magnets called Coupling-Loss induced quench system (CLIQ) has been recently developed at CERN. Recent tests on Nb-Ti coils have shown that CLIQ is a valid, efficient, and promising method for the protection of high-magnetic-field superconducting magnets. However, the protection of new-generation Nb3Sn accelerator magnets is even more challenging due to the much higher stored energy per unit volume and to the significantly larger enthalpy needed to initiate and propagate a normal zone in such coils. Now, the CLIQ system is tested for the first time on a Nb3Sn magnet in the CERN magnet test facility in order to investigate its performance in practice, thereby validating the method for this type of superconducting magnets as well. Furthermore, we successfully reproduced the electrothermal transients during a CLIQ discharge. Finally, the implementation of various CLIQ-based protection schemes for the full-scale Nb3Sn quadrupole magnet for the LHC high luminosity upgrade is discussed. The impact of key system parameters on CLIQ performance and the advantages and drawbacks of using multiple CLIQ units on a single magnet are discussed.
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new Coupling Loss induced quench protection system for superconducting accelerator magnets
2014Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, C Giloux, A P VerweijAbstract:A new and promising method for the protection of superconducting high-field magnets is developed and tested on the so-called MQXC quadrupole magnet at the CERN magnet test facility. The method relies on a capacitive discharge system inducing, during a few periods, an oscillation of the transport current in the superconducting cable of the coil. The corresponding fast change of the local magnetic field introduces a high Coupling-current Loss, which, in turn, causes a fast quench of a large fraction of the coil due to enhanced temperature. Results of measured discharges at various levels of transport current are presented and compared to discharges by quenching the coils using conventional quench heaters and an energy extraction system. The hot-spot temperature in the quenching coil is deduced from the coil voltage and current. The results are compared to simulations carried out using a lumped-element dynamic electro-thermal model of the so-called MQXC magnet developed with Cadence PSpice. The calculated voltages and currents are in good agreement with the measured data. Simulation and test results show that this new protection system, called Coupling-Loss induced quench, is a feasible method to reduce the hot-spot temperature in high-field superconducting magnets, even more when used in combination with conventional quench heaters.
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a new hybrid protection system for high field superconducting magnets
2014Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, A P VerweijAbstract:The new generation of high-field superconducting accelerator magnets poses a challenge concerning the protection of the magnet coil in the case of a quench. The very high stored energy per unit volume requires a fast and efficient quench heating system in order to avoid damage due to overheating. A new protection system for superconducting magnets is presented, comprising a combination of a novel Coupling-Loss induced quench (CLIQ) system and conventional quench heaters. CLIQ can provoke a very fast transition to the normal state in coil windings by introducing Coupling Loss and thus heat in the coil's conductor. The advantage of the hybrid protection system is a global transition, resulting in a much faster current decay, a significantly lower hot-spot temperature, and a more homogeneous temperature distribution in the magnet's coil.
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first experience with the new Coupling Loss induced quench system
2014Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, A Dudarev, K A Sperin, A P VerweijAbstract:New-generation high-field superconducting magnets pose a challenge relating to the protection of the coil winding pack in the case of a quench. The high stored energy per unit volume calls for a very efficient quench detection and fast quench propagation in order to avoid damage due to overheating. A new protection system called Coupling-Loss Induced Quench (CLIQ) was recently developed and tested at CERN. This method provokes a fast change in the magnet transport current by means of a capac- itive discharge. The resulting change in the local magnetic field induces inter-filament and inter-strand Coupling Losses which heat up the superconductor and eventually initiate a quench in a large fraction of the coil winding pack. The method is extensively tested on a Nb–Ti single-wire test solenoid magnet in the CERN Cryogenic Lab- oratory in order to assess its performance, optimize its operating parameters, and study new electrical con- figurations. Each parameter is thoroughly analyzed and its impact on the quench efficiency highlighted. Furthermore, an alternative method is also considered, based on a CLIQ discharge through a resistive coil magnetically coupled with the solenoid but external to it. Due to the strong Coupling between the external coil and the magnet, the oscillating current in the external coil changes the magnetic field in the solenoid strands and thus generates Coupling Losses in the strands. Although for a given charging voltage this con- figuration usually yields poorer quench performance than a standard CLIQ discharge, it has the advantage of being electrically insulated from the solenoid coil, and thus it can work with much higher voltage.
A P Verweij - One of the best experts on this subject based on the ideXlab platform.
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new Coupling Loss induced quench protection system for superconducting accelerator magnets
2014Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, C Giloux, A P VerweijAbstract:A new and promising method for the protection of superconducting high-field magnets is developed and tested on the so-called MQXC quadrupole magnet at the CERN magnet test facility. The method relies on a capacitive discharge system inducing, during a few periods, an oscillation of the transport current in the superconducting cable of the coil. The corresponding fast change of the local magnetic field introduces a high Coupling-current Loss, which, in turn, causes a fast quench of a large fraction of the coil due to enhanced temperature. Results of measured discharges at various levels of transport current are presented and compared to discharges by quenching the coils using conventional quench heaters and an energy extraction system. The hot-spot temperature in the quenching coil is deduced from the coil voltage and current. The results are compared to simulations carried out using a lumped-element dynamic electro-thermal model of the so-called MQXC magnet developed with Cadence PSpice. The calculated voltages and currents are in good agreement with the measured data. Simulation and test results show that this new protection system, called Coupling-Loss induced quench, is a feasible method to reduce the hot-spot temperature in high-field superconducting magnets, even more when used in combination with conventional quench heaters.
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a new hybrid protection system for high field superconducting magnets
2014Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, A P VerweijAbstract:The new generation of high-field superconducting accelerator magnets poses a challenge concerning the protection of the magnet coil in the case of a quench. The very high stored energy per unit volume requires a fast and efficient quench heating system in order to avoid damage due to overheating. A new protection system for superconducting magnets is presented, comprising a combination of a novel Coupling-Loss induced quench (CLIQ) system and conventional quench heaters. CLIQ can provoke a very fast transition to the normal state in coil windings by introducing Coupling Loss and thus heat in the coil's conductor. The advantage of the hybrid protection system is a global transition, resulting in a much faster current decay, a significantly lower hot-spot temperature, and a more homogeneous temperature distribution in the magnet's coil.
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first experience with the new Coupling Loss induced quench system
2014Co-Authors: E Ravaioli, V Datskov, G Kirby, H Ten H J Kate, A Dudarev, K A Sperin, A P VerweijAbstract:New-generation high-field superconducting magnets pose a challenge relating to the protection of the coil winding pack in the case of a quench. The high stored energy per unit volume calls for a very efficient quench detection and fast quench propagation in order to avoid damage due to overheating. A new protection system called Coupling-Loss Induced Quench (CLIQ) was recently developed and tested at CERN. This method provokes a fast change in the magnet transport current by means of a capac- itive discharge. The resulting change in the local magnetic field induces inter-filament and inter-strand Coupling Losses which heat up the superconductor and eventually initiate a quench in a large fraction of the coil winding pack. The method is extensively tested on a Nb–Ti single-wire test solenoid magnet in the CERN Cryogenic Lab- oratory in order to assess its performance, optimize its operating parameters, and study new electrical con- figurations. Each parameter is thoroughly analyzed and its impact on the quench efficiency highlighted. Furthermore, an alternative method is also considered, based on a CLIQ discharge through a resistive coil magnetically coupled with the solenoid but external to it. Due to the strong Coupling between the external coil and the magnet, the oscillating current in the external coil changes the magnetic field in the solenoid strands and thus generates Coupling Losses in the strands. Although for a given charging voltage this con- figuration usually yields poorer quench performance than a standard CLIQ discharge, it has the advantage of being electrically insulated from the solenoid coil, and thus it can work with much higher voltage.
