Showing papers by "Evangelos Trifon Laskaris published in 2015"

Development of a 3 T–250 mm Bore $\hbox{MgB}_{2}$ Magnet System

Abstract: The authors had reported components' development of 3 T-250 mm bore MgB 2 magnet system. Pre-reacted MgB 2 tape wire with copper lamination had n-value related problem due to raw Boron particle size inequality, but it had been corrected. Long MgB 2 wires over 3 km had been supplied. All six component coils were made with a wet winding procedure. They were tested individually with the same cooling scheme of conduction cooling as the actual magnet assembly. Though all coils could be ramped to some extent, some coils showed fairly large remnant voltage. Since the voltage distribution over the coil was not even, the uniformity along the wire length may not be good enough. The stability of the coil was verified by its no training performance even with fast ramping. The magnet assembly and its test with conduction cooling were planned. I c of the superconducting joint with this pre-reacted wire was doubled during past one year's development.

Superconducting magnet system and quench protection method of high temperature superconductor lead thereof

Abstract: The invention relates to a superconducting magnet system and a quench protection method of a high temperature superconductor lead thereof. The superconducting magnet system comprises a superconducting coil, the high temperature superconductor lead, a heater, a heater trigger and a high temperature superconductor lead sensing unit. The high temperature superconductor lead sensing unit is used for detecting a working state of the high temperature superconductor lead, and outputting a control signal to the heater trigger when a detection signal from the high temperature superconductor lead is greater than a preset value so as to trigger the heater to quench the superconducting coil. The preset value corresponds to a quench point or a quench critical point of the high temperature superconductor lead.

Current lead for cryogenic apparatus

Abstract: In embodiments of the invention, a superconductor lead is configured to have less ohmic heating by its own current and less heat conduction from room temperature to cryogenic temperature, where a cryogenic apparatus is located. The superconducting lead with no ohmic resistance and low thermal conductivity disclosed herein maximizes current capacity by placing superconductors in parallel, each having equal current. Thus, the resistances are controlled to provide uniform current distribution through each superconductor of the high temperature superconducting (HTS) lead.

Quench protection apparatus for superconducting magnet system

Abstract: A quench protection apparatus includes a number N of superconducting coils and a heater matrix. The number N of superconducting coils are electrically coupled in series. The heater matrix module includes the number N of heater units. The number N of heater units is electrically coupled in parallel with the number N of superconducting coils respectively. A number M of the heater units each includes at least the number N of heaters. Each superconducting coil is thermally coupled with at least one heater of each of the number M of the heater units. The number of N-M of the heater units each includes at least one heater. Each of the number M of superconducting coils correspondingly coupled with the number M of the heater units is thermally coupled with at least one heater of each of the number N-M of the heater units. A superconducting magnet system protected by above quench protection apparatus is also provided.

System and method for cooling a magnetic resonance imaging device

Abstract: A cooling system for a low-cryogen superconducting magnet includes a primary cooling loop having a liquid reservoir containing a supply of liquid cryogen and a plurality of cooling tubes fluidly coupled to the liquid reservoir and in thermal communication with the superconducting magnet. The liquid cryogen is configured for circulation through the cooling tubes for providing primary cooling for the magnet for cooling the magnet to a target temperature. The cooling system also includes a thermal battery coupled to a component that is cooled to the target temperature by the primary cooling loop and is configured to be cooled by the primary cooling and to absorb heat from the at least one component during an interruption in the primary cooling to maintain the magnet at approximately the target temperature.