Effects of Collar Permeability on the Field Quality of the Large Aperture Quadrupoles for the LHC

Lasheras, Nuria Catalán; Auchmann, Bernhard; Kirby, G.; Mess, Karl-Hubert; Ostojić, R.; Russenschuck, Stephan

doi:10.1109/tasc.2008.922245

Cited by 2 publications

(2 citation statements)

References 2 publications

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“…The superconducting coils are clamped in austenitic steel collars inside an iron yoke, the whole structure being contained in a shrinking cylinder. During MQ and MQY series production significant anomalies in the strength and in the allowed multipoles were observed from room temperature magnetic measurements [5], [12]. This was traced back to values of the relative magnetic permeability in the collars which was in some cases out of tolerance.…”

Section: Coil Assembly and Magnet Parametersmentioning

confidence: 99%

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Magnetic Performance of the Main Superconducting Magnets for the LHC

Sanfilippo

Sammut

Bottura

et al. 2008

IEEE Trans. Appl. Supercond.

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Abstract-The field strength and homogeneity of all the LHC superconducting magnets were measured as a part of the production control and qualification process that has taken place during the past four years. In addition to field measurements at room temperature performed on the integral of the production, a significant part of the magnets has been subjected to extensive magnetic measurements at cold. The measurements at cryogenic temperatures, generally performed up to excitation currents of 12 kA corresponding to the ultimate LHC energy of 7.6 TeV, were mainly based on static and dynamic field integral and harmonic measurements. This allowed us to study in detail the DC effects from persistent current magnetization and long-term decay during constant current excitation. These effects are all expected to be of relevance for the field setting and error compensation in the LHC. This paper reports the main results obtained during these tests executed at operating conditions. The integrated field quality is discussed in terms of distribution (average and spread) of the field strength and low-order harmonics as obtained for all the main ring magnet families (dipoles, main and matching quadrupoles). The dependence of field quality on coil geometry, magnet and cable manufacturer is analyzed. A projection of the field quality expected for the critical components in the machine is presented.

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Section: Coil Assembly and Magnet Parametersmentioning

confidence: 99%

“…Some of them were measured at cold and a correction was therefore applied on room temperature data for the extrapolation of , and at cold. The room temperature to cold conditions correlations are summarized in [5] for the MQ and in [12] for the MQY.…”

Section: Coil Assembly and Magnet Parametersmentioning

confidence: 99%

Magnetic Performance of the Main Superconducting Magnets for the LHC

Sanfilippo

Sammut

Bottura

et al. 2008

IEEE Trans. Appl. Supercond.

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Comparison between Electromagnetic Models and Magnetic Measurements in the LHC Magnets

Hagen

Auchmann

Todesco

2012

IEEE Trans. Appl. Supercond.

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We present a comparison between the electromagnetic model of the main LHC magnets and the magnetic measurements carried out during production. The goal of this study is to test the validity range of the model and to uncover discrepancies between models and reality. We de-compose the field computation into several parts: geometry (coils, collars, and yoke), persistent currents in the superconducting cables, and saturation of the iron yoke. For each component we give the agreement between model and measurements. This gives an indication about the precision one can expect to obtain from a simulation code -this information is particularly relevant for future upgrades of the LHC. CERN-ATS-2012-026February 2012 Abstract 2IP1-1 EDMS 1138818 1 Abstract-We present a comparison between the electromagnetic model of the main LHC magnets and the magnetic measurements carried out during production. The goal of this study is to test the validity range of the model and to uncover discrepancies between models and reality. We decompose the field computation into several parts: geometry (coils, collars, and yoke), persistent currents in the superconducting cables, and saturation of the iron yoke. For each component we give the agreement between model and measurements. This gives an indication about the precision one can expect to obtain from a simulation code -this information is particularly relevant for future upgrades of the LHC.

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Effects of Collar Permeability on the Field Quality of the Large Aperture Quadrupoles for the LHC

Cited by 2 publications

References 2 publications

Magnetic Performance of the Main Superconducting Magnets for the LHC

Magnetic Performance of the Main Superconducting Magnets for the LHC

Comparison between Electromagnetic Models and Magnetic Measurements in the LHC Magnets

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