Conveners
Tue-Mo-Po2.07 - MRI Magnets III
- Lionel Quettier (CEA Paris-Saclay)
- Shoichi Yokoyama (Mitsubishi Electric Corporation)
We have finalized the design of a full-scale tabletop 1.5-T/90-mm MgB2 “finger” MRI magnet system for osteoporosis screening based on our preliminary test results of small coils and superconducting joints. The magnet will operate in persistent mode at 10 K with an additional 5 K temperature margin. The magnet design satisfies the required specification of a field homogeneity of <5...
This paper presents the design, manufacturing and testing of a 2 + 3 T high field MgB2 ø178 bore solenoid magnet demonstrator (around 55 kgs). The magnet was designed to produce 2 T standalone at 10K and to be operated in a homogenous background field of 3 T. The magnet is helium free and is cooled down by a cryocooler. Three lengths of Columbus MgB2 conductors (1.6 kms) were used to wind the...
Recently, we developed a 0.5-T/300 mm MgB2 magnet using the partial insulation (PI) winding technique that only employs layer-to-layer insulations without the turn-to-turn insulations; the magnet was self-protective but has a significant charge–discharge delay. In this study, the use of Cr-coated MgB2 wires was proposed as an alternative solution to enhance the characteristic resistance of the...
The temporal stability of the magnetic field generated by an MRI magnet is of critical importance for higher resolution medical imaging. However, large screening currents are induced in High Temperature Superconducting (HTS) tapes such as REBCO tapes during the excitation, and attenuated after the excitation due to the flux creep of the HTS tapes. The temporal variation of the magnetic field...
A magnet consisting of five no-insulation (NI) double pancakes (DPs) has been constructed and tested. In this paper, operating currents in each excitation mode were optimized to achieve the highest magnetic field and three excitation modes of the magnet have been conducted in 77 K to compare. Test results showed the central magnetic field increased by multiple sources. Charging performance and...
Generally, MgB2 wires possess a niobium diffusion barrier to prevent an unacceptable reaction between magnesium powder and copper stabilizer. However, given that niobium is costly, extensive studies were conducted to replace the niobium diffusion barrier with iron. Nevertheless, the MgB2 wire with iron diffusion barrier is not yet practically applied to magnetic resonance imaging magnets...
Since UHF MRI offer the possibility to study in a deeper way the brain functionality, these kind of magnets are becoming essential in neuroscience research. ASG is involved in this sector with an active shielded, zero boil-off 7T/700 bore magnet. The magnet with stringent dimensional parameters has been designed and developed by ASG superconductors team for Magnex MS Inc., in order to fulfil...
