| 1. |
- Galvin, Tom, et al.
(författare)
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Characterisation of SiC Varistor Quench Protection Operating at 4 Kelvin for Use With Superconducting Magnets
- 2023
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Ingår i: IEEE transactions on applied superconductivity (Print). - : IEEE. - 1051-8223 .- 1558-2515. ; 33:5
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Tidskriftsartikel (refereegranskat)abstract
- Silicon carbide (SiC) composite high-energy varistors have been demonstrated as a viable alternative to linear resistors as energy extraction devices during an abrupt loss of superconductivity in a magnet, called a quench. These have typically been installed external to the cryostat at ambient temperatures, but for some superconducting magnets it may be beneficial to mount the varistors within the cryostat in vacuum, a gaseous environment, or submerged in liquid cryogens. Varistors are semiconductors and therefore exhibit a temperature-dependent voltage-current relationship, so characterising their behaviour at low temperatures is important to predict their energy extraction behaviour. In this paper we present characterisation data of SiC varistor devices from 4-300 K: voltage-current characteristics, thermal conductivity, specific heat capacity, thermal expansion, and flexural strength. These varistors are a candidate for protection at 1.9 K of the MCBY magnets, currently being built at Uppsala University for CERN.
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| 2. |
- Mangiarotti, Franco J., et al.
(författare)
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Test of Short Model and Prototype of the HL-LHC D2 Orbit Corrector Based on CCT Technology
- 2019
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Ingår i: IEEE transactions on applied superconductivity (Print). - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1051-8223 .- 1558-2515. ; 29:5
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Tidskriftsartikel (refereegranskat)abstract
- In the frame of the high-luminosity upgrade project for the large hadron collider, new twin aperture beam orbit corrector magnets will be installed near the recombination dipole (D2). These magnets are 2.2 m long canted cosine theta NbTi dipoles, with two independently powered apertures oriented such that their field vectors are perpendicular to each other and to the direction of the beams. A 0.5 m model magnet in single and double aperture configuration and a full-length double aperture prototype were built and tested at CERN. In this paper, the performance of these magnets at 1.9 K in terms of training behavior, quench detection and protection, and other tests is discussed. In addition, the thermal response of the magnet to a hypothetical beam discharge is simulated and analyzed.
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| 3. |
- Mangiarotti, Franco J., et al.
(författare)
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Test of the First Full-Length Prototype of the HL-LHC D2 Orbit Corrector Based on Canted Cosine Theta Technology
- 2020
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Ingår i: IEEE transactions on applied superconductivity (Print). - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1051-8223 .- 1558-2515. ; 30:4
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Tidskriftsartikel (refereegranskat)abstract
- In the context of CERN's high-luminosity upgrade project (HL-LHC) for the Large Hadron Collider (LHC), a new double aperture beam orbit corrector magnets will be installed near the recombination dipole (D2). These 2.2 m long NbTi dipoles are built with the canted cosine theta (CCT) technique. The two independently powered apertures are oriented such that their field vectors are perpendicular to each other and to the direction of the beams. A full-length double aperture prototype was built and tested at CERN in the SM18 test facility. Here we present the results of powering tests at 1.9 and 4.5 K: training of each aperture, magnetic field quality and cross-talk effects, quench detection system effectiveness, quench protection performance and quench-back with several energy extraction systems.
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