Process of fabricating YBCO SQUIDs for 51-channel HTS MCG system

We have constructed a high throughput HTS SQUID fabrication process to develop a 51-channel HTS MCG system. To increase the process throughput of the YBCO deposition, we designed and developed a new deposition system based on a pulsed laser deposition technique. In this deposition system, nine YBCO thin films could be deposited in one deposition sequence by successively depositing the YBCO thin films one by one. In addition to the improvement of the fabrication throughput, the magnetometer pattern was designed to improve the yield of the SQUID fabrication. In our magnetometer design, four SQUIDs were connected with one pickup coil. The yield of good magnetometer chips could be increased by selecting the best SQUID among the four. Using the developed SQUID fabrication process, about one hundred magnetometers were fabricated in a month. The 51-channel HTS MCG system was successfully developed and used for clinical testing.