Ramp-rate sensitivity of SSC dipole magnet prototypes

Devred, A.; Ogitsu, T.

doi:10.2172/71687

Cited by 16 publications

(11 citation statements)

References 10 publications

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“…This interaction is observed in dedicated experiments as well as in operating magnets. Examples of coupling are the helium induced flow that affects stability and quench propagation in force-flow cooled cables [1], [2] and the limitation found on the quench current during ramps in multi-strand cables that is thought to be caused by premature current sharing due to large current imbalances among strands [3], [4]. Not only magnet quench, but also field quality in accelerator magnets is influenced by the current distribution in the superconducting cables through interaction with the filament magnetization [5], [6].…”

Section: Introductionmentioning

confidence: 99%

A general model for thermal, hydraulic and electric analysis of superconducting cables

Rosso²,

2000

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In this paper we describe a generic, multi-component and multi-channel model for the analysis of superconducting cables. The aim of the model is to treat in a general and consistent manner simultaneous thermal, electric and hydraulic transients in cables. The model is devised for most general situations, but reduces in limiting cases to most common approximations without loss of efficiency. We discuss here the governing equations, and we write them in a matrix form that is well adapted to numerical treatment. We finally demonstrate the model capability by comparison with published experimental data on current distribution in a two-strand cable.

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Section: Introductionmentioning

confidence: 99%

A general model for thermal, hydraulic and electric analysis of superconducting cables

Rosso²,

2000

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“…Thus a low interstrand resistance seems to bring greater stability against random disturbances (eg wire movement) in the magnet. Secondly there is the phenomenon of ramp rate induced quenching, found in some fusion magnets and investigated in detail during the development of magnets for the SSC High Energy Booster [7]. As shown in Fig 2, these magnets went to their full critical current at slow ramp rates, but quenched early when the current was ramped up quickly.…”

Section: Current Sharing and Lossesmentioning

confidence: 97%

Cored rutherford cables for the GSI fast ramping synchrotron

Wilson¹,

Ghosh

Haken

et al. 2003

IEEE Trans. Appl. Supercond.

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Abstract-The new heavy ion synchrotron facility proposed by GSI will have two superconducting magnet rings in the same tunnel, with rigidities of 200T-m and 100T.m. Fast ramp times are needed, which can cause significant problems for the magnets, particularly in the areas of s c loss and field distortion. This paper discusses the 200T.m ring, which will use Cos0 magnets based on the RHIC dipole design. We discuss the reasons for choosing Rutherford cable with a resistive core and report loss measurements carried out on cable samples. These measurements are compared with theoretical calculations using measured values of inter-strand resistance. Reasonably good agreement is found, but there are indications of non-uniformity in the adjacent resistance R,. Using these measured parameters, losses and temperature rise are calculated for a RHIC dipole in the operating cycle of the accelerator. A novel insulation scheme designed to promote efficient cooling is described.Index Terms--ac loss, dipole magnet, field error, superconducting synchrotron, Rutherford cable.

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“…The current ramps up and down are executed with constant ramp rates and correspondingly. The total loss was obtained by recording the current and the total voltage applied to the magnet as (1) In addition to the total voltage we measured voltage drops in portions of the magnet. In this case (1) provides an apparent loss in the portion of the magnet measured.…”

Section: Measurements Techniquesmentioning

confidence: 99%

“…The results are used for the evaluation of the contact electrical resistance between the crossing strands of the two layers of the cable. The last value governs the current distribution in the flat cable subjected to a time-dependent magnetic field [1], [2]. Due to the wide variety of the magnets and a gradual development of experimental techniques, we do not intend here to characterize every dipole mea- sured.…”

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confidence: 99%

Loss and dynamic magnetic field measurements in LHC dipoles

Akhmetov

Amet

Balaazi

et al. 2002

IEEE Trans. Appl. Supercond.

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Abstract-Knowledge of AC loss and dynamic magnetic field distortion in the main LHC dipoles is both important for the assessment of the accelerator performance and providing insight into the properties of assembled magnets. We measured the loss due to the current cycling in a few 1-meter long model dipoles, 15-meter long dipole prototypes and pre-series magnets. As expected the loss depends linearly on the rate of the current change. From the slope of this dependence, the contact resistance between the strands of the opposite layers of the cable, , was evaluated for the inner winding of the dipole. We discuss the method to estimate the value in the outer winding. The value has been also derived independently from measurements of the magnetic field. For this, the ramp rate dependent component of the main field as well as of the harmonics has been measured. The main magnetic field measurements were performed using both stationary coils and Hall probes. Rotating coils were used to perform the harmonic measurements.

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Ramp-rate sensitivity of SSC dipole magnet prototypes

Cited by 16 publications

References 10 publications

A general model for thermal, hydraulic and electric analysis of superconducting cables

A general model for thermal, hydraulic and electric analysis of superconducting cables

Cored rutherford cables for the GSI fast ramping synchrotron

Loss and dynamic magnetic field measurements in LHC dipoles

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