Focusing Strength Measurements of the Main Quadrupoles for the LHC

Smirnov, N.; Bottura, L.; Calvi, M.; Deferne, G.; DiMarco, J.; Sammut, Nicholas; Sanfilippo, S.

doi:10.1109/tasc.2006.871218

Cited by 10 publications

(7 citation statements)

References 7 publications

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“…In practice, the best solution providing the lowest uncertainty on the focusing strength (FStrength) is the single stretched wire (SSW), 18 where FStrength is defined as the gradient integrated over the quadrupole axis,…”

Section: In Situ Coil Calibrationmentioning

confidence: 99%

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In situ calibration of rotating sensor coils for magnet testing

Arpaïa

Buzio

Golluccio

et al. 2012

Review of Scientific Instruments

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An in situ procedure for calibrating equivalent magnetic area and rotation radius of rotating coils is proposed for testing accelerator magnets shorter than the measuring coil. The procedure exploits measurements of magnetic field and mechanical displacement inside a reference quadrupole magnet. In a quadrupole field, an offset between the magnet and coil rotation axes gives rise to a dipole component in the field series expansion. The measurements of the focusing strength, the displacement, and the resulting dipole term allow the equivalent area and radius of the coil to be determined analytically. The procedure improves the accuracy of coils with large geometrical irregularities in the winding. This is essential for short magnets where the coil dimensions constrain the measurement accuracy.Experimental results on different coils measuring small-aperture permanent magnets are shown. (2012) Geneva, Switzerland Published in Review of Scientific Instruments CERN-ATS-2012-018 February 2012Abstract REVIEW OF SCIENTIFIC INSTRUMENTS 83, 013306 (2012) In situ calibration of rotating sensor coils for magnet testing An in situ procedure for calibrating equivalent magnetic area and rotation radius of rotating coils is proposed for testing accelerator magnets shorter than the measuring coil. The procedure exploits measurements of magnetic field and mechanical displacement inside a reference quadrupole magnet. In a quadrupole field, an offset between the magnet and coil rotation axes gives rise to a dipole component in the field series expansion. The measurements of the focusing strength, the displacement, and the resulting dipole term allow the equivalent area and radius of the coil to be determined analytically. The procedure improves the accuracy of coils with large geometrical irregularities in the winding. This is essential for short magnets where the coil dimensions constrain the measurement accuracy. Experimental results on different coils measuring small-aperture permanent magnets are shown.

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Section: In Situ Coil Calibrationmentioning

confidence: 99%

“…Therefore, the SSW is the most accurate method, 4 although limited by the highorder multipoles. 18,20 The multipole influence increases according to the distance from the magnet axis. In particular, by expressing the estimation of Smirnov, 18 …”

Section: A Calibration Issuesmentioning

confidence: 99%

In situ calibration of rotating sensor coils for magnet testing

Arpaïa

Buzio

Golluccio

et al. 2012

Review of Scientific Instruments

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“…Permanent Magnet The system was tested on a prototype of permanent magnet 45 mm long, with 20 mm aperture and integrated gradient of 2.435 Tm/m, measured by a stretched wire system [14], with an accuracy of ±0.002 Tm/m. The magnetic measurement was carried out by moving the magnet along the longitudinal axis to evaluate the coil uniformity.…”

Section: B Preliminary Tests On Drift Tube Linac Prototypementioning

confidence: 99%

A measurement system for fast-pulsed magnets: a case study on Linac4 at CERN

Arpaïa

Buzio

Dunkel

et al. 2010

2010 IEEE Instrumentation &Amp; Measurement Technology Conference Proceedings

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A new magnetic measurement system for validating and characterizing permanent and fast-pulsed iron-dominated magnets is presented. This system is going to be used on the magnet series tests of the new linear particle accelerator Linac 4 of the Large Handron Collider at the European Organization for Nuclear Research (CERN) to perform a complete field analysis of the entire acceleration line. Measurement results will be useful to tune better the beam brightness during the first acceleration step. In this paper, the requirements, the architecture, and the most critical parts of the design are highlighted. Then, the preliminary experimental results obtained over the first Linac 4 magnet prototypes are discussed. Abstract-A new magnetic measurement system for validating and characterizing permanent and fast-pulsed iron-dominated magnets is presented. This system is going to be used on the magnet series tests of the new linear particle accelerator Linac 4 of the Large Handron Collider at the European Organization for Nuclear Research (CERN) to perform a complete field analysis of the entire acceleration line. Measurement results will be useful to tune better the beam brightness during the first acceleration step. In this paper, the requirements, the architecture, and the most critical parts of the design are highlighted. Then, the preliminary experimental results obtained over the first Linac 4 magnet prototypes are discussed.

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“…Field quality measurements at cold were performed using rotating coil based systems [15] and cross-checked with Single Stretched Wire measurements [16] for the transfer function. This combination guarantees for the main field an uncertainty of 5 units and 1 unit for the reproducibility.…”

Section: Test Procedures and Measurementsmentioning

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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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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Focusing Strength Measurements of the Main Quadrupoles for the LHC

Cited by 10 publications

References 7 publications

In situ calibration of rotating sensor coils for magnet testing

In situ calibration of rotating sensor coils for magnet testing

A measurement system for fast-pulsed magnets: a case study on Linac4 at CERN

Magnetic Performance of the Main Superconducting Magnets for the LHC

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