Iseult/INUMAC Whole Body 11.7 T MRI Magnet Status

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In the framework of the French-German consortium Iseult/INUMAC, focused on very-high-magnetic-field molecular imaging, the development of an 11.7 T whole body MRI magnet has been launched in 2006. This magnet is mainly composed of one wet and cryostable main coil and two fully impregnated coils that shield the magnetic field in order to meet the security requirements on the fringe field. To protect the magnet in case of quench, the stored magnetic energy (338.5 MJ) is dissipated in an external resistor and inside the two shielding coils windings. It is thus an important issue to master the normal zone propagation kinetics in those coils. This paper presents the 3d finite-element computations carried out to treat that problem and the more significant obtained results.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quench Propagation Kinetics Within ‘Iseult/INUMAC’ Whole Body 11.7 T MRI Magnet Shielding Coils

Juster

Berriaud

Fazilleau

2010

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“…Low field superconducting MRI magnets were extensively investigated [4]- [7] in the past, uniquely using Nb-Ti superconducting material and operated in 4.2 K liquid helium temperature, with the exception of a 11.7 T Iseult-Inumac whole body MRI magnet [8], which operated in superfluid helium temperature to utilize enhanced upper critical field of niobium titanium. The 11.7 T Iseult-Inumac MRI magnet is designed by stacking Nb-Ti/Cu double pancakes which is wound with Rutherford flat cables.…”

Section: Introductionmentioning

confidence: 99%

Structural Design of a 9.4 T Whole-Body MRI Superconducting Magnet

Dai

Wang

et al. 2012

A project to develop a 9.4 T magnetic resonance imaging system is proposed for bioscience research applications. A whole body superconducting magnet system will be manufactured and test in the Institute of Electrical Engineering, Chinese Academy of Sciences (IEE, CAS). This magnet system features a room temperature bore of 800 mm in diameter, helium bath cooing, 9.4 T center magnetic field and passive iron shielding. The magnet is designed with radial layer-winding method. Five coaxial coils will be wound independently and assembled together as the main magnet. Coil length of the magnet is 3000 mm. In the magnet design, current density grading is performed to optimize the magnetic field distribution and stress level in the coil windings. The maximum magnetic field is 9.505 T, corresponding to an operating current of 224.515 A. The total magnetic energy storage is 138 MJ. Detailed magnetic and mechanic structure design as well as structure stress analysis are presented in this paper.

“…I N ORDER TO build Iseult, the first full body 500 MHz MRI system [1]- [3], a dedicated conductor R&D program has been made with Alstom (MSA) to validate the best conductor solution [4]. Iseult is a shielded MRI magnet wound with two NbTi types of conductor: -The main conductor for the pancake solenoid creating the 11.75 T magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Iseult/INUMAC 11.7 T Conductor Production Status

Berriaud¹,

Bermond²,

Dechambre³

et al. 2012

The Iseult/INUMAC 11.7 T MRI magnet uses NbTi conductors larger than those typically used in conventional MRI magnets. The principal conductors are the main coil one, producing the magnetic field of 11.7 T and the conductor of the shielding coil that limits the fringe field. Both conductors are being produced by Luvata Waterbury Inc. The main coil conductor is a Rutherford cable in a copper channel (160 km) and carries 1500 A at 12 T and 2.8 K (2727 A at 9.5 T and 4.2 K). The shielding coil conductor is a wire in channel (60 km) and carries 2100 A at 5 T and 4.2 K. The conductor shape must be very precise with reproducible dimensions (tolerances below 15 microns) to enable good magnetic field homogeneity. They must also simultaneously exhibit a low electrical resistance (20 at 10 K and 12 T) and a high mechanical strength . Conductors of this industrial production are characterized by mechanical, electrical and geometrical measurements.