COMPARISON OF TODAY'S SQUID ACTIVITIES IN JAPAN AND THE UNITED STATES

Japan ( Post SSL)

While it might be difficult to determine exactly which companies, and to what extent, were influenced directly by the technology created at SSL, it was not difficult to compare the SQUID activities in Japan at the time of the WTEC visit, roughly one year after the completion of SSL, with those before SSL, say in the mid-1980s.

In the mid-1980s, there was no SQUID technology of note in Japan, and no SQUID products were made by Japanese companies. Today, Daikin has prototypes of 32-channel MCG and 61-channel MEG systems integrated with closed cycle refrigerators, as described in its site visit report (Appendix B) and shown in Figure 7.3 (p. 49). One of the 61-channel prototypes has been shipped to a potential customer. Panelists were told that Seiko has shipped prototypes of NDE systems, while Shimadzu has developed a 129-channel MEG system and has received government approval for its use. Hitachi is continuing development of LTS MCG systems. At Sumitomo Electric, as described in its site visit report (Appendix B), another 64-channel HTS MCG system has been developed in the past year or so. Perhaps more importantly, Sumitomo Electric is using an HTSQUID NDE prototype system to monitor copper wire manufacture in a factory and has introduced Japan's first HTSQUID product. Fig. 6.5 shows Sumitomo's magnetometer and the high Tc SQUIDs it uses. This is a single-channel system for nondestructive evaluation and educational purposes that is similar to the "Mr. SQUID" educational kit that has been sold by Conductus since 1992. The panel finds it remarkable that a large company like Sumitomo would introduce this type of product for what is at present a small market.


Fig. 6.5. Sumitomo Electric Industries' magnetometer, which includes a high Tc SQUID and its driving electronics.

A most interesting development, considering that small high-tech companies are not formed in Japan as readily as in the United States, is the path followed by Prof. Kado after completion of the SSL project. Rather than return to his position at ETL, he joined Mattolab, part of the Kanazawa Institute of Technology (KIT), with a building in an industrial research park to the west of the city. There, as a professor with some of his ex-SSL colleagues, he has continued his R&D into LTSQUID systems for both earthquake monitoring and for MEG. They have developed a number of MEG systems of different types. One such system that is of particular interest, in that the Dewar and a number of other aspects are of a novel design, is shown in Fig. 6.6. This system is a result of technology transfer from KIT through a small company named Eagle Technology (ET) to the much larger company, Yokogawa. Manufacturing and sales of the systems resulting from this KIT/ET/Yokogawa collaboration will be carried out by Yokogawa.

The 208-channel system of Figure 6.6 resembles a magnetic resonance imaging (MRI) machine, but the patient reclines on the couch and slides the head into a hemispherical depression in the side of the Dewar. This depression is surrounded by SQUID sensors in the helium space to give coverage of the whole head. The sensors for this system, which are conventional Nb trilayer devices with Nb wire gradiometer coils, are supplied by Conductus. Similar systems are in operation at the medical school of Keio University in Tokyo, and the medical school of Osaka City University.

The activity at KIT and ET is the only creation of a "small company" in SCE that the panel observed in Japan, whereas in the United States there are at least 12 such companies, not including those "infrastructure companies" supplying materials, sputter targets, refrigerators, deposition systems, etc. The U.S. companies are BTi, Conductus, Hypres, Illinois Superconductor, Magnesensors, Neocera, Quantum Design, Quantum Magnetics, SCT, STI, 2G, and Tristan. Of these 12, only Quantum Design and 2G have a large fraction of their revenues from the sale of commercial products.

The KIT research activity is also unusual in that it represents one of the few cases in SCE where cooperation between the communities in Japan and the United States has been strong. A number of U.S. scientists have been frequent visitors to KIT; the sensors of the KIT/ET/Yokogawa systems are made at Conductus; and an early system is in operation at the Cognitive Science Laboratory of MIT as part of a KIT/MIT collaborative activity.


Fig. 6.6. A SQUID multichannel MEG system under development by KIT and Yokogawa. (A similar system was in operation early in 1998 at MIT's Cognitive Science Lab.)
Published: July 1998; WTEC Hyper-Librarian