The persistent current switch (PCS) is essential for magnetic resonance imaging magnet (MRI) magnet which works in closed-loop mode. In this paper, the design of NbTi/CuNi thermally triggered PCS is presented. Furthermore, quench test and switching time test have been given at 4.2-K temperature and 0-3 T magnetic field.
The imaging quality of the Low-field magnetic resonance imaging (MRI) equipment is usually inferior to that of the high-field MRI equipment, however, the low-field MRI equipment has the advantages of lightweight, low cost, flexibility, etc., and is enough to meet most of the medical standards. With the progress of image reconstruction technology, the competitive disadvantage of the low-field...
To study and explore the key technology of Ultra-high field MRI system, the 14 T body-size MRI magnet technology study activities has be launched by the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP). The Nb3Sn Rutherford-type cables is designed for the conductor structure due to the 14 T magnet. The preload must be applied for the coil at room temperature, to counteract the...
In September 2020, a 4-year national project was embarked on to develop a conduction-cooled 6 T 320 mm all-HTS magnet for MRI with support from the Korea Medical Device Development Fund. It is a collaborative R&D effort led by SuperGenics, Co. Ltd., in participation with Changwon National University, Korea Electrotechnology Research Institute, Korea Maritime and Ocean University, Korea...
Abstract: Superconducting joints are essential for persistent-mode operation in a superconducting magnet system, the resistance has to be around 10-14-10-12 Ω thus to produce an ultra-stable magnetic field. Based on the national collaboration program of the MRI for small animals, the development of superconducting joints between bronze-route Nb3Sn multifilamentary wires manufactured by...
Dry magnets using MgB2 wires are one of effective options to eliminate dependence on liquid helium in MRI scanners. In the dry magnets, however, lack of thermal mass of cryogen makes a controlled quench difficult and extends time for restarting the magnets after the quench. In this study, a novel rapid ramp-down procedure, which can be substituted for the controlled quench in emergency...
Nb3Sn strand was used to enable the development of short (1.4 m) segmented coil designs, as opposed to the nearly 2 m long compensated solenoid designs needed for NbTi machines. Using Nb3Sn strand will allow a conduction cooled design, if quench is properly managed. We modeled two designs with magnetic field homogeneity better than 10 ppm (part-per-million) within DSV (Diameter of Spherical...
A no-insulation (NI), cryogen free HTS MRI magnet is currently being developed at the Robinson Research Institute. Consisting of 23 double pancake coils of varying size, width and REBCO material, the magnet is designed to image the human brain (1.5T of moderate uniformity, +/- 150 ppm over a 200 x 150 ellipsoidal imaging volume).
Risk of a quench arises from several sources, such as defects...
Abstract gradients minimized in order to retain thermal and operating margin. We have used 3D finite element method (FEM) simulation in COMSOL Multiphysics software to calculate the temperature distribution both along the winding direction and across the cross-section of an MRI segment coil at its equilibrium operating temperature. We have also modelled the evolution of the thermal...
High-quality magnetic resonance imaging (MRI) techniques can provide precise anatomical details of small extremities such as hands and feet. Conventional MRI systems use cryogenic superconducting magnets cooled by liquid helium, and these occupy a large amount of space. Therefore, we have been developing a compact and high-performance desktop finger MRI system using REBCO wires. The proposed...
In this study, we report on the optimized design results of REBCO high-temperature superconducting magnets for 3T whole body MRI. That is, for the REBCO magnet consisting of the main coil, the compensation coil, and the shield coil, an optimized design using an immunogenetic algorithm is carried out with two objective functions of maximizing the magnetic field uniformity in the uniform sphere...
