1000A 級永久電流スイッチの研究

Superconducting magnets of superconducting magnetic resonance imaging systems for medical use (MRI) and the test vehicles of a superconducting magnetically levitated train system (MAGLEV) have persistent current switches (PSIs), of which current passing capacities are rated from some hundreds amperes to a thousand amperes. So far the small sized laboratory superconducting magnets in some cases have used persistent current switches of a hundred ampere-class. We can say a hundred-class persistent current switch is a finished goods as far as it is used in a laboratory. However, an MRI and a MAGLEV require well developed persistent current switches as industrial goods from the standpoints of safety and reliability, and also demand compactness in order to be equipped to a host superconducting coil and not to disturb magnetic field homogeneity from a host magnet. Today\u27s MRI and MGLEV are using superconducting magnets with near thousand ampere-class persistent current switches which consist of from five to eight hundred ampere-class persistent current switches. It takes a large space in a cryostat and shows a complicated on-off behavior. This report summarizes the results of research how we develop such a compact, large current persistent current switch for an MRI and a MAGLEV.Superconducting magnets of superconducting magnetic resonance imaging systems for medical use (MRI) and the test vehicles of a superconducting magnetically levitated train system (MAGLEV) have persistent current switches (PSIs), of which current passing capacities are rated from some hundreds amperes to a thousand amperes. So far the small sized laboratory superconducting magnets in some cases have used persistent current switches of a hundred ampere-class. We can say a hundred-class persistent current switch is a finished goods as far as it is used in a laboratory. However, an MRI and a MAGLEV require well developed persistent current switches as industrial goods from the standpoints of safety and reliability, and also demand compactness in order to be equipped to a host superconducting coil and not to disturb magnetic field homogeneity from a host magnet. Today\u27s MRI and MGLEV are using superconducting magnets with near thousand ampere-class persistent current switches which consist of from five to eight hundred ampere-class persistent current switches. It takes a large space in a cryostat and shows a complicated on-off behavior. This report summarizes the results of research how we develop such a compact, large current persistent current switch for an MRI and a MAGLEV