| Project/Area Number |
12558056
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Nuclear engineering
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
MAEHATA Keisuke Kyushu University, Faculty of Engineering, Associate Professor, 大学院・工学研究院, 助教授 (30190317)
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| Co-Investigator(Kenkyū-buntansha) |
KAMIOKA Yasuharu Taiyo Toyo Sanso Co. Ltd., Cryogenics Equipment Dept, Scientist, 超低温事業部, 研究主幹(研究職)
NAKAGAWA Hiroshi National Institute of Advanced Industrial Science and Technology, Researcher, エレクトロニクス研究部門, 主任研究員(研究職)
AKOH Hiroshi National Institute of Advanced Industrial Science and Technology, Researcher, エレクトロニクス研究部門, 主任研究員(研究職)
ARIMA Hidehijo Kyushu University, Faculty of Engineering, Research Associate, 大学院・工学研究院, 助手 (20253495)
ISHIBASHI Kenji Kyushu University, Faculty of Engineering, Professor, 大学院・工学研究院, 教授 (00159766)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥12,000,000 (Direct Cost: ¥12,000,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2001: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2000: ¥8,600,000 (Direct Cost: ¥8,600,000)
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| Keywords | X-ray detector / Superconducting tunnel junction / Microstrip coil integration / Dilution refrigerator / マイクロストリップコイル集積型素子 / 極低温放射線検出器 |
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| Research Abstract |
An on-chip coil integrated superconducting tunnel junction (OC^2-STJ) was developed for high performance X-ray detector. The OC^2-STJ consists of a Nb-based junction and a superconducting microstrip coil deposited on the insulating layer deposited on the top electrode of the STJ. The microstrip coil generates the magnetic field in the insulating layer of the junction for suppression of Josephson current. The fabricated OC^2-STJ chip was mounted in a cooling capsule with the ^<55>Fe X-ray source. The cooling capsule was attached to the mixing chamber of a compact ^3He-^4He dilution refrigerator. The OC^2-STJ chip was held at a constant temperature in the capsule against the Joule heat generation in the current feed line of the strip coil during the detector operation. Electric charges produced by tunneling of excited quasiparticles by incident X-rays were collected by a charge sensitive preamplifier. To reduce noise components in the output signals, a field effect transistor (FET) of the signal input was placed on the 1 K pot of the refrigerator through a weak thermal link. The temperature of the input FET was regulated at 100 K by a heater to generate the output voltage pulses with the minimum noise equivalent charge. The temperature of the OC^2-STJ chip was kept around 600 mK with regulating the FET temperature at 1 K. In the operation of the OC^2-STJ for X-ray detection, the current from 10 to 30 mA was supplied to the microstrip coil. Response characteristics were obtained for a diamond-shaped Nb-based tunnel junction with a sensitive area of 100 × 100 μm^2 in the OC^2-STJ chip. A stable operation of the OC^2-STJ was demonstrated without using usual external electromagnets.
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