As part of the JST project, we have been developing advanced high-temperature superconducting quantum interference devices (HTS SQUIDs) for biomedical diagnosis and nondestructive testing. In this paper, we show the recent progress of our research. First, we show a highly sensitive and reliable HTS SQUID sensor. Using HTS SQUIDs, we have developed advanced magnetic-sensing systems. We show the results of biosensing systems, such as magnetocardiogram measurement of small animals, magnetic immunoassay and low field MRI. We also show the results of nondestructive testing systems, such as evaluation of solar-cell panels, rapid and quantitative detection of water, and detection of small magnetic contamination. We demonstrate the promising results of these magnetic-sensing techniques.
This project aims to establish key hard technologies for large-scale high-temperature superconducting (HTS) rotating machines for a ship propulsion system. Using HTS technology, compact, right weighted and highly efficient ship propulsion motors can be realized. The objectives of the project are R&D of robust and reliable HTS field coils with low loss,and compact cooling systems integrated to a rotor and design technology for a 20 MW-class ship propulsion motor. This project is now in the first year of the stage III; stage II was completed in the last Japanese fiscal year. This report reviews the R&D results in stage II and the plans in stage III.
Application of high Tc superconductors to accelerator magnets provides the following benefits. It reduces power consumption compared to copper magnets, it allows simple operation and less governmental regulation compared to low Tc superconductors because of the applicability of cryocoolers, and it is potentially more stable thermally, when operated at high temperatures where the specific heats of materials are large. An R&D project focusing on fundamental technologies for accelerator magnets using coated conductors is in progress, funded by the Japan Science and Technology Agency from January, 2010. Stage I of the project was completed successfully in March, 2012, and the project moved to the four-year Stage II in April, 2012. We aim to realize application of high Tc superconductors to magnets of strong-focusing accelerators for carbon cancer therapy or accelerator-driven subcritical reactors (ADSR). In Stage I, we conceptually designed a couple of fixed-field alternating gradient (FFAG) accelerators for carbon cancer therapy and for ADSR as well as a beam transport line for a carbon cancer therapy facility. Based on the conceptual designs of accelerators, coil-dominated magnets and iron-dominated magnets wound with coated conductors were designed. The required winding technologies were clarified through designing these magnets, and the R&D of winding technologies for coils with three-dimensional shape and those with negative bend have been carried out. The influence of the magnetization of coated conductors on the field quality of magnets was studied experimentally. The influence of the neutron radiation on the conductivity of aluminum and that of copper was also studied.
Conventionally, LTS magnets have been used in NMR systems. However, through use of HTS materials for the superconducting magnets, it will be possible to reduce the size of the magnet significantly. Reducing the size of the magnet will allow, high magnetic field NMR systems to be installed in a much wider range of environments, and thus widen their range of application. The objective of this research is to design and manufacture a 1H 600 MHz-class magnet capable of NMR usage using HTS technology. In addition, we will use HTS material in place of the metal coil of the NMR probe in order to yield high sensitivity beyond any conventionally available technology and thus allow extremely high throughput NMR measurements.
DC electric railway systems are widely used in Japan, including in the metropolitan areas. However, they have some problems, such as limited use of regenerative brakes and energy loss. In order to solve those problems, and to attain energy savings for next-generation electric railway systems, we have been studying the feasibility of applying superconducting power cables to DC electric feeder systems. In this study, investigations regarding issues such as effective use of regenerative brakes and loss reduction have been carried out on the assumption that the substations concerned are connected with each other via superconducting power cables placed in parallel with the feeder line. This research was supported by the Japan Science and Technology Agency, JST, as part of the Strategic Promotion of Innovative Research and Development Problem.