7 research outputs found
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CLIQ-Based Quench Protection of a Chain of High-Field Superconducting Magnets
Conventional quench protection systems for high-magnetic-field superconducting magnets are based on external heaters composed of resistive strips in close contact with the coil and rely on thermal diffusion across insulation layers on the order of tens of micrometers. The large contact areas between the coil and the heater strips, and the thin insulation between them required for an effective protection constitute a significant risk of electrical breakdown and one of the most common causes of magnet damage. Coupling-loss-induced quench (CLIQ) technology offers a valid option for a time-and cost-effective repair of magnets with failing heater-based protection systems. In fact, its effective heating mechanism utilizing coupling loss, its robust electrical design, and its fast implementation, as compared to alternative repair options, constitute definite advantages over the conventional technology. In the past years, CLIQ was successfully implemented on various coils in a single-magnet configuration. Now the design of a CLIQ-based protection system integrated in a chain of series-connected magnets is presented. The protection of a chain of superconducting magnets usually is considerably more challenging than the protection of stand-alone magnets due to the increased energy stored in the circuit and the presence of transitory effects. The effectiveness of this new method is demonstrated by means of electrothermal simulations modeling the transition to the normal state and the temperature evolution in one quenched magnet, and the electrodynamics of the entire magnet chain
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Quench Protection of a 16-T Block-Coil Dipole Magnet for a 100-TeV Hadron Collider Using CLIQ
Protection against the effects of a quench is a crucial challenge for 16-T-class superconducting dipole magnets for a future 100-TeV Hadron collider. To avoid damage due to overheating of the coil's hot spot, heat generated during the quench has to be homogeneously distributed in the winding pack by quickly and uniformly transferring to the normal-state voluminous coil sections. Conventional protection systems rely on quench heaters placed on the outer surfaces of the coils. However, this technique has to confront significant challenges in order to achieve the fast transitions required by high magnetic field magnets. The recently developed coupling-loss-induced quench (CLIQ) utilizes interfilament coupling loss as an effective intrawire heat deposition mechanism, which, in principle, is faster than thermal diffusion. Furthermore, the CLIQ technology is based on simple and robust electrical components in contact with the coil only in a limited number of easily accessible and well-insulated points. Hence, expected occurrence of failure and electrical breakdown is significantly reduced. As a case study, the design of a CLIQ-based protection system for a 14-m-long 16-T Nb 3Sn block-coil dipole magnet is demonstrated here. Various magnet design features can be adjusted to improve CLIQ performance and optimize its integration in the magnet system. CLIQ provides future magnet designers with a solution for a very effective, yet electrically robust, quench protection system, resulting in better magnet performance and lower cost than would be possible with a traditional approach to magnet protection
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First Implementation of the CLIQ Quench Protection System on a Full-Scale Accelerator Quadrupole Magnet
The coupling-loss induced quench system (CLIQ) is an innovative method for the protection of high-field superconducting magnets. With respect to the conventional method based on quench heaters, it offers significant advantages in terms of electrical robustness and energy-deposition velocity. Its effective intrawire heating mechanism targets a fast and homogeneous transition to the normal state of the winding pack, hence assuring a quick magnet discharge and avoiding overheating of the coil's hot spot. Furthermore, it is possible to implement CLIQ as a time- and cost-effective repair solution for the protection of existing magnets with broken quench heaters. After being successfully tested on model magnets of different geometries and made of different types of superconductor, CLIQ is now applied for the first time for the protection of a full-scale quadrupole magnet at the CERN magnet test facility. One aperture of a 3.4-m-long LHC matching quadrupole magnet is equipped with dedicated terminals to allow the connection of a CLIQ system. Experimental results convincingly show that CLIQ can protect this coil over the entire range of operating conditions. The complex electrothermal transients during a CLIQ discharge are successfully reproduced by means of a 2-D model. The test is part of the RD program of CLIQ quench protection systems, which has convincingly demonstrated the maturity of this technology and its effectiveness also for large-scale magnet systems. The proposed CLIQ-based solution for the quench protection of the LHC matching quadrupole magnet is now ready to be implemented in the LHC machine if needed
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Advanced Quench Protection for the Nb 3Sn Quadrupoles for the High Luminosity LHC
The goal of the High Luminosity LHC project is upgrading the LHC in order to increase its luminosity by a factor of five. To achieve this, 24 150-mm-aperture 12-T Nb 3Sn quadrupole magnets are to be installed close to the two interaction regions at ATLAS and CMS. This new generation of high-field magnets poses a significant challenge concerning the protection of the coils in the case of a quench. The very high stored energy per unit volume requires a fast and effective quench heating system in order to limit the hot-spot temperature and hence avoid damage due to overheating. Conventional protection systems based on quench heaters have a limited response time due to the thermal insulation between the heater and the coil. An advanced solution for the protection of high-field magnets is the coupling-loss induced quench (CLIQ) system, recently developed at CERN. Due to its fast intrawire energy-deposition mechanism, CLIQ is a very effective, yet electrically robust, quench protection system. Various protection scenarios, including quench heaters, CLIQ, or combinations of the two methods, are analyzed and discussed, with the aim of minimizing the coil's hot-spot temperature and thermal gradients during the discharge. The proposed design assures a fully redundant system
Recommended from our members
Advanced Quench Protection for the Nb 3Sn Quadrupoles for the High Luminosity LHC
The goal of the High Luminosity LHC project is upgrading the LHC in order to increase its luminosity by a factor of five. To achieve this, 24 150-mm-aperture 12-T Nb 3Sn quadrupole magnets are to be installed close to the two interaction regions at ATLAS and CMS. This new generation of high-field magnets poses a significant challenge concerning the protection of the coils in the case of a quench. The very high stored energy per unit volume requires a fast and effective quench heating system in order to limit the hot-spot temperature and hence avoid damage due to overheating. Conventional protection systems based on quench heaters have a limited response time due to the thermal insulation between the heater and the coil. An advanced solution for the protection of high-field magnets is the coupling-loss induced quench (CLIQ) system, recently developed at CERN. Due to its fast intrawire energy-deposition mechanism, CLIQ is a very effective, yet electrically robust, quench protection system. Various protection scenarios, including quench heaters, CLIQ, or combinations of the two methods, are analyzed and discussed, with the aim of minimizing the coil's hot-spot temperature and thermal gradients during the discharge. The proposed design assures a fully redundant system